t-

. ~ . i~'

~, ~ ,f ~ ,

l' ,,~ , '

l ••

l . ;.'

ASPHAL T INSTITUTE~' .. ":. Manual Series No~ .. 19· )) ... Second Edition, / .'. ;~,~~1:,

.~ , \l., ,,:,;.:,!

This manual is based upon the publication of the same title Issued by the Federal Highway Administration of the U.S. Department of Transportation as FHWA· IP·79-1 In January 1979. the contents of which were prepared by The Asphalt Institute under contract to the Asphalt Emulsion Manufacturers Association acting for the Federal Highway Administration.

LIBRARY OF CONGRESS CATALOG CARD NUMBER:

86-72240

The Asphalt Institute does not endorse products or manufacturers. Trade or manufacturers' names appear herein solely because they are considered essential to the object of this publication.

PRINTED IN USA

FOREWORD

The primary purpose of this manual is to impart a basic understanding of asphalt emulsions to those who work with the product. Further, it is intended to be useful in choosing the emulsion that best fits a project's specific conditions. And it should be most helpful in evaluating pavement systems for construction and maintenance.

The manual is not written in such detail that one can use it to produce asphalt emulsions. Neither is it directed toward the specific features of one manufacturer's products. Rather, it explains the general characteristics of asphalt emulsions and their uses. In times past, lack of information of this type may to some extent have prevented realization of the full potential of emulsions.

This new second edition is thoroughly updated and special attention should be paid to Parts II and III for new and revised tests and procedures.

A thorough study of the manual, then, should enable one to recommend where, when, and how emulsions should be used. It also should aid in the solving of problems that may arise on projects in which emulsions are used.

The Asphalt Institute can accept no responsibility for inappropriate use of this manual. Engineering judgment and experience must be used to properly utilize the principles and guidelines contained in this Manual taking into account available equipment, local materials and conditions.

iii

CONTENTS

Page

Foreword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii

List of Illustrations ..................:.................................. vii

List of Tables ......................................................... ix

PART ONE:

UNDERSTANDING ASPHALT EMULSIONS

Chapter Page

I. Introduction ..................................................... 1

II. The Chemistry of Asphalt Emulsions ...................................... 5

A. General ...................................................... 5

B. Emulsion Ingredients .............................................. 7

C. Producing the Emulsion ........................................... 12

D. Breaking and Curing ............................................. 15

III. Storing, Handling, and Sampling Asphalt Emulsions ........................... 17 IV. Emulsified Asphalt Tests ............................................ 25

PART TWO:

USING ASPHALT EMULSIONS

V. Selecting the Right Type and Grade of Asphalt Emulsion . . . . . . . . . . . . . . . . . . . . . . .. 37

VI. Asphalt Emulsion Surface Treatments ........ . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 41

A. Materials .................................................... 45

B. Types of Treatments and Seals. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 48

C. Surface Treatment Design .......................................... 54

D. Equipment ................................................... 58

E. Construction Procedure ........................................... 64

VII. Asphalt Emulsion-Aggregate Mixes ..................................... 67

A. Mixed-in-Place ................................................ 71

B. Asphalt Emulsion Plant Mix (Cold) .................................... 79

C. Asphalt Emulsion Plant Mix (Hot) .................................... 87

v

CONTENTS (Cont'd)

Chapter

VIII. Miscellaneous Asphalt Emulsion Applications

IX. Maintenance Mixes .............................................. .

X. Recycling .................................................... .

PART THREE:

EMULSIFIED ASPHALT-AGGREGATE

MIX-DESIGN METHODS

Page

89 97

JOI

Introduction ................................................... 109

XI. Modified Hveem Mix Design. . .. . .. . . . . .. . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . .. . . . . . . . .. III

XII. Procedural Outline and Design Criteria for The Asphalt Institute

Design Method for Open-Graded Mixes ........................................... 147

XIII. Procedural Outline and Design Criteria for the McConnaughay

Design Method for Cold Mixtures ................................................ 151 XIV. Marshall Method for Emulsified Asphalt-Aggregate Cold Mixture Design ............. 155

APPENDICES

Appendix A Glossary .................................................. 171

Appendix B Testing Emulsified Asphalt (ASTM D 244) ............................ 175

Appendix C Miscellaneous Tables .......................................... 197

Appendix D Standard Method of Test for Unit Weight of Aggregate

(AASHTO T19; ASTM D 29) .................................. 209

Appendix E Bibliography ............................................... 213

Index 221

vi

Figure

II-I

Il-2

IV-I

IV-2

IV-3

LIST OF ILLUSTRATIONS

Diagram of an asphalt emulsion manufacturing plant ....... .

Relative sizes and distribution of asphalt particles in an emulsion

Distillation test for emulsified asphalts

Particle charge lest

Saybolt Furol viscosity test

IV -4 Float test ...... .

VI-I Longitudinal streaking

VI-2 Bleeding asphalt ...

VI-3 Loss of cover aggregate ........ .

VI-4 Flat particles are covered when enough asphalt is used to hold cubical particles

VI-5 Slurry seal machine ............. .

VI-6 Flow diagram of a typical slurry seal mixer

VI-7 Asphalt emulsion distributor ........ .

VI-8 Proper nozzle angle setting ........ .

VI-9 Spray bar height must be set exactly for proper coverage

VI-IO Tailgate vane spreader ....... .

VI-II Hopper type tailgate spreader

VI-12 Truck-attached mechanical spreader

VI-13

VI-14

VI-15

VI-16

VII-I

VII-2

VII-3

VII-4

VII-5

VII-6

VII-7

VIII-I

Self-propelled mechanical spreader

Pneumatic-tired roller .. .

Power broom ............ .

Surface treatment operation

Major uses of emulsified asphalt mixes

Volume of windrows

Travel plant. windrow type

Travel plant. hopper type

Rotary mixer. pulvimixer type

Blade mixing ....... .

Cold-mix continuous plant ..

Applying tack coat ..... .

VIII-2 Using emulsified asphalt to tie down mulch

VIII-3 Completed section of Interstate with emulsified asphalt mulch on median and close-up

Page

13

14

28

28

29

32

43

44

45

47

50

50

58

59

59

60 60 62

62

63

64

65

68

72 75

76

77 78

80

90

92

93

95 VIII-4 Filling crack with emulsified asphalt .. .

X-I A candidate for recycling ........ .

X-2 Loss of curb depth and draining capacity

X-3 Cold mix recycling operation

X-4 Hammermill pulverizing old pavement

X-5 Heater-overlay methods ........ .

XI-l Testing schedule for dense-graded emulsified asphalt mixes

XI-2 Chart for determining sUlface constant for fine material, Kf

XI-3 Chart for determining surface constant for coarse material, Kc

vii

102

103

104 104 106

112

119

120

(Continued next page)

LIST OF ILLUSTRATIONS (Cont'd)

Figure Page

XI-4 Chart for combining Kf and Kc to determine surface constant for combined aggregate ..... 121

XI-5 Chart for computing oil ratio for dense-graded asphalt mixtures . . . . . . . . . . . . . .. 122

XI-6 Apparatus for Hveem C.K.E. tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123

XI-7 Transfer of mix to mold .......................................... 127

XI-S Rodding mix in mold ............................................. 127 XI-9 Mechanical kneading compactor

XI-lO Resilient modulus device

XI-II Transducers and Mr yoke ......... .

XI-I2 Mr yoke on holder ............. .

XI-I3 Tightening Mr clamping screws

XI-I4 Seating Mr specimen on loading block

XI-I5 Adjusting Mr recording meter .....

XI-I6 Adjusting Mr pressure regulator

127

131

131

132

132

132

133

133 XI -17 Vacuum manometer and desiccator ...................... . . . . . . . . . 135

XI-IS Hveem stabilometer ............................................. 136

XI-I9 Chart for determining R-value from stabilometer data ..................... 139

XI-20 Chart for correcting R-values to height of 63.5mm (2.50 in.) ................ 140

XI-2I Chart for correcting stabilometer values to effective specimen height of 64mm (2.5 in.) 142

XI-22 Diagrammatic sketch showing principal features of the Hveem cohesiometer. . . . 144 XII-I

XIV-I

Wire screen funnel ...................... .

Typical emulsified asphalt-aggregate mixture design plots

viii

14S

169

LIST OF TABLES

Table

II-I Requirements and typical applications for emulsified asphalt ........... .

11-2 Requirements and typical applications for cationic emulsified asphalt ....... .

Page

.. 8

10

III-I Storage temperatures for emulsified asphalts ................................ 18

III-2 Guide for condition of emptied tanks before loading emulsified asphalts ........... 20

III-3 Possible causes of contamination of asphalt material or samples and suggested precautions 20

IV-l Summary of emulsion tests

V -I General uses of emulsified asphalt ............................... .

V-2 Emulsified asphalt seal coats and surface treatments .................. .

26

...... 39

. ..... 40

VI-I Suggested distributor spraying temperatures for various grades of emulsified asphalt 46

VI-2 Slurry mixture gradings ....................................... 52

VI-3 Quantities of asphalt and aggregate for single surface treatments and seal coats .......... 55

VI-4 Quantities of asphalt and aggregate per square metre (square yard) for double

surface treatment .............................................. 56

VI-5 Quantities of asphalt and aggregate per square metre (square yard) for triple

surface treatment (armorcoat) ............................ .

VI-6 Quantities of asphalt and aggregate per square metre (square yard) for cape seal

VII-l

VII-2

VII-3

VII-4

VII-5

VII-6

IX-I

XI-I

XI-2

XI-3

Coarse aggregates for asphalt paving mixtures ............ .

Fine aggregates for asphalt paving mixtures ... .

Aggregate evaluation procedures .................... .

Aggregates for open-graded emulsion mixes ........ .

Aggregates for emulsified dense-graded asphalt mixtures .

Sand-emulsion mixes .......... .

Mineral aggregate gradations ..... .

Selection of emulsified asphalt amount

Surface area factors ............. .

Variables affecting asphalt dispersion

XI-4 Multiplying factors for cohesiometer values ...... . ....... .

XI-5 Design criteria for emulsified asphalt-aggregate mixes ........... .

XII-I Selection of emulsified asphalt amount

XIV -I Emulsified asphalt mixture data sheet .............. .

57 57

69 70

71

81

83

85

99

114

116 124

143

145

147

164 XIV-2 Stability correlation ratios ......................................... 167

XIV-3 Emulsified asphalt-aggregate mixture design criteria .......................... 168

C-l Temperature-volume corrections for emulsified asphalts..... .......................... 198

C-2 Mass per cubic metre of dry mineral aggregates of different specific gravity and various void contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199

C-2a Weight per cubic foot and per cubic yard of dry mineral aggregates of different specific gravity and various void contents ......................................... 200

C-3 Linear measurement covered by tank of any capacity for various widths and rates of application. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201

C-4 Linear metres covered by 4000 litre tank of asphalt for various widths and litres per square metre. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202

C-4a Linear feet covered by looO-gallon tank of emulsified asphalt for various widths and rates. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202

ix

LIST OF TABLES (Cont'd)

Table Page

C-5 Litres of asphalt required for 50 linear metres; various widths and lit res per square metre. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 203

C-5a Gallons of emulsified asphalt required per 100 linear feet; various widths and rates. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 203

C-6 Megagrams of material required per kilometre for various widths and kilograms per square metre ................................................. 204

C-6a Tons of aggregate required per mile for various widths and rates ........................ 204

C-7 Quantities at depths in cylindrical tanks in a horizontal position .. . . . . . . . . . . . . . . . . . . . . .. 205

C-8 Area in square metres of road surface for various road widths. . . . . . . . . . . . . . . . . . . . . . . . .. 206

C-8a Area in square yards of road surface for various road widths. . . . . . . . . . . . . . . . . . . . . . . . . .. 206

C-9 Temperature conversion chart. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 207

C-IO Conversion factors: U.S. customary to metric units ................................... 208

D-l Dimensions of measures, metric ................................................... 210

D-2 Dimensions of measures, U.S. customary system ..................................... 210

D-3 Unit weight of water. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 211

x

PART ONE:

UNDERSTANDING ASPHALT EMULSIONS

CHAPTER I

INTRODUCTION

1.01 BASIC TYPES OF PAVING ASPHALTS Virtually all asphalts used in the United States are products of the distillation of crude

petroleum. Asphalt is produced in a variety of types and grades ranging from hard and brittle solids to almost water-thin liquids. Asphalt cement is the basis of all of these products. It can be made fluid for construction uses by heating, by adding a solvent, or by emulsifying it. When a petroleum solvent, such as naphtha or kerosene, is added to the base asphalt to make it fluid, the product is called a cutback. When asphalt is broken into minute particles and dispersed in water with an emulsifier it becomes an asphalt emulsion. The tiny droplets of asphalt remain uniformly suspended until the emulsion is used for its intended purpose.

When combined with an~.£riate hydrocarbon solvent the asphalt ceJ.D~.nLin..a cutback is in solution. In an emulsion, the chemical emulsifier is orientated in and around droplets of asphalt cement which influences their dispersion and stable suspension in water. When either type is used in the field, evaporation of the asphalt carrier, i.e., the cutback hydrocarbon solvent or the emulsion water, usually takes place to cause the cutback or emulsion to revert to asphalt cement. In the case of the emulsion, the chemical emulsifier is retained with the deposited asphalt.

1.02 ASPHALT EMULSION IN THE PAST The use of asphalt emulsions for road construction and maintenance is not new. Emulsions

were first developed in the early 1900s. It was not until the 1920s, however, that emulsions, as we know them today, came into being. Their early use was confined largely to spray applications and use as a dust palliative. The growth in the use of asphalt emulsions was relatively slow. It was limited by the types available and a lack of knowledge as to how they should be used. Continuing development of new types and grades, coupled with improved construction equipment and practices, now gives a broad range of choices, with which virtually any roadway requirement can be met. Judicious selection and use can yield significant economic benefits.

Use records reveal a slow but steady increase iii the amount of emulsions used between 1930 and the mid 1950s. Following World War II, traffic loads and volumes increased so much that roadway designers began to curtail the use of these materials. Instead, they specified high-type hot plant mixes requiring the use of asphalt cement. While the volume of asphalt cement used has shown a rapid increase since 1953, the combined use of other asphalt products has remained almost constant. But one interesting trend is worthy of note-there has been a steady rise in the volume of asphalt emulsions used.

The major uses of asphalt emulsion in the United States are:

- Surface treatments

- Patching and thin overlays

- Stabilization

- Slurry sealing

1

Asphalt emulsions also are used in base, surface course mixes and in recycling. In the past several factors contributed to a nationwide interest in the use of asphalt emulsions,

namely:

- The energy crisis of the early 1970s that prompted conservation measures by the Federal Energy Administration. Asphalt emulsion does not require a petroleum solvent to make it liquid. (However, some medium-setting grades contain limited amounts of solvent to enhance mixing qualities.) Also, asphalt emulsion can be used (in most cases) without additional heat. Both of these contribute to energy savings.

- Reduced atmospheric pollution. There are little or no hydrocarbon emissions from asphalt emulsions.

- The ability of certain types of asphalt emulsion to coat damp aggregate surfaces, which is another energy saving feature.

- Availability of a variety of emulsion types, coupled with improved laboratory procedures, to satisfy design and construction requirements.

- Potential cost savings by the use of less fuel.

( Two_maj<?!.~!1yi~~~~~I1.~aUa.ctor:.s-energy conservation and atmospheric pollution--caused I grave concern and a realization that some type of Federal action was needed. Our nation

suddenly became aware that energy needs soon could exceed supply unless conservation laws were enactly promptly. In one of the early actions, the Federal Highway Administration (FHW A) issued notices that directed attention to fuel savings that could be realized by using asphalt emulsions instead of cutback asphalts. It estimated that a huge amount of petroleum solvents could be saved annually by such substitution. While the substitution was not

\ mandatory, it was strongly suggested that it be considered. Since that time, all states are \ substituting, or allowing the substitution of, asphalt emulsions for cutback asphalts.

1.03 LOOKING AHEAD The demand for a well maintained, efficient highway network continues and consequently

asphalt is essential to meet these requirements. The Federal Highway Administration annual survey shows that the United States has

about 6.3 million kilometres (3.9 million miles) in the roadway network. The survey also shows that of the 3.2 million kilometres (2.0 million miles) of paved highways, about 93 percent have asphalt paved surfaces. A 1983 FHW A survey of the nation's major road system, about 1.9 million kilometres (1.2 million miles), estimated that over 161,000 kilometres (100,000 miles) were in poor condition and needed immediate repair while another 97,000 kilometres (60,000 miles) were only in fair condition.

Other significant findings contained in the report include:

- The cost of maintaining these roads, even at the current level of performance, will exceed $300 billion over the next 15 years and this does not include money that will be required on the 4.3 million kilometres (2.7 million miles) of local roads.

2

- Between 1983 and the year 2000, approximately 66,000 kilometres (41,000 miles) of Interstate, 538,000 kilometres (334,000 miles) of arterials and 1,024,000 kilometres (636,000 miles) of collector roads will require capital improvements to maintain serviceability.

- Total travel between 1984 and the year 2000 is expected to grow at an annual rate of 2.0 to 2.7 percent. Thus, by the end of the century, America's highways must accommodate 40 to 60 percent more travel than in 1984.

Thus, the demands for a well maintained roadway will be high, and the demand for asphalt will continue. Because of these tremendous needs, every attempt should be made to utilize road materials in an efficient, conservative manner.

A clear understanding of the "Why and How" of using asphalt emulsions offers a promise of such an efficient use. The proper use of asphalt emulsion can result in high performance pavements and thrifty but versatile maintenance systems. This manual is directed toward those ends.

As an aid in understanding technical terms that may not be familiar, a glossary is provided as Appendix A.

3

CHAPTER II

THE CHEMISTRY OF ASPHALT EMULSIONS A.GENERAL

2.01 EMllkS1QNS There are many types of emul1iion produ~t.~that we use in our daily lives. Some of the more

common are mayonnaise, paints, hair dyes, and ice cream. In each case, certain mechanical and chemical processes are involved that permit the combining of two or more materials that, under normal conditions, will not mix. An entire scientific field is devoted to the study of emulsifica­tion. You don't have to understand how an internal combustion engine works to operate an automobile. Neither do you have to understand complex emulsion chemistry to obtain high quality results with asphalt emulsion. The key is to select the right emulsion for the aggregate and construction system involved. Throughout this text when the term "emulsionj' is used it is

_.'-...,

intended to mean "asphalt emulsion.i" \ -.. --.' .. ~.' -',. . -'"

2.02 COMPOSITION OF ASPHALT EMULSIONS An asphalt~mJllsjQn consists of th~e basic ingredieQ!s: ,~sP~"ill,(~~~1, and an (emulsifying

agefi~. On some occasions the emulsifying agent may cont~in a stabilizer. ---Ii' is well known tbat water and asphalt will not mix, except under carefully controlled conditions using highly specialized equipment and chemical additives. The blending of asphalt cement and water is somewhat akin to an .@.t<L.l))~f.h~llic trying to wash grease from his hands with water only. It is not until a detergent or soapy agent of some type is used that grease can be successfully removed. The soap particles surround the globules of grease, break the surface tension that holds them, and allow them to be washed away. Some of the same physical and chemical principles apply in the formulation, production, and use of asphalt emulsion.

The object is to make a dispersion of the asphalt cement in water, stable enough for pumping, prolonged storage, and mixing. Furthermore, the emulsion should break down quickly after contact with aggregate in a mixer, or after spraying on the roadbed. Upon curing, the residual asphalt retains all ofthe adhesion, durability, and water-resistance ofthe asphalt cement from which it was produced.

2.03 CLASSIFICATION Asphalt emulsions are divided into three categories: anionic, cationic, and nonionic. In

practice, the _~!,-st.tw9~S are ~r~i~<:trily_useg jn .. roadW<lYG.QnstructioD-and.maintenanc.e. Nonionics, however, may be more widely used as emulsion technology advances. The anionic and cationic classes refer to the electrical charges surrounding the asphalt particles. This identification system stems from one of the basic laws of electricity -like charges repel one another and unlike charges attract. When two poles (an anode and a cathode) are immersed in a liquid and an electric current is passed through, the anode becomes positively charged and the cathode becomes negatively charged. If a current is passed through an emulsion containing negatively charged particles of asphalt they will migrate to the anode. Hence, the emulsion is referred to as anionic. Conversely, positively charged asphalt particles will move to the cathode and the emulsion is known as cationic. With non ionic emulsions, the asphalt particles are neutral and therefore do not migrate to either pole.

5

Emulsions are further classified on the basis of how quickly the asphalt will coalesce; i.e., revert to asphalt cement. The terms if{,s, ~S', and(~ have been adopted to simplify and standardize this classification. They are relative terms only and mean raQi~~ettiI!.g, ITlediu}11~sJ~1.­ting, and !g9F_-:-_~~tting. The tendency to coalesce is closely related to the mixing of an emulsion. An @emulsion has !!!!!~ .. QLnO ab!l!ty to mix wJth an aggt:cgate, an M~~~u!siQn is expected to mix with coarse but ,not fi_n~ aggrega.te, and an SS emulsion is designed to mix withfi!le ~~. --

The emulsions are further subdivided by a series of numhers related to viscosity of the emulsions and hardness of the base asphalt cements. The letter "C" in front of the emulsion type denotes cationic. The absence of the "C" denotes a,nionic or nonionic. For example, RS-l is anionic or non ionic and CRS-I is cationic.

Four grades of high-float medium-setting anionic emulsions, designated HFMS, have been added to standard American Society for Testing and Materials (ASTM) specifications. These grades are used primarily in cold and hot plant mixes, coarse aggregate seal coats, and road mixes. High float emulsions have a specific quality that permits a thicker film coating without danger of runoff.

A quick-set type of emulsion (QS) has been developed for slurry .3eals. Its use is rapidly increasing as the unique quick-setting property solves one of the major problems associated with the use of slurry seals.

Standard specifications for quick-set emulsions are under development. Additionally, some emulsions are made with the water dispersed in asphalt, usually a cutback. As these so-called "inverted emulsions" are seldom used, they are not discussed in this manual.

2.04 SPECIFICATIONS ASTM and the American Association of State Highway and Transportation Officials

(AASHTO) have developed standard specifications for the following grades of emulsions:

EMULSIFIED ASPHALT

(RS-1 " 'R.S;2'

/MS-1 ( MS-2

~~~1h/ tHffMS-2 13fMS-2h ,HfMS-2s

'8S-1 SS~J)'

CATIONIC EMULSIFIED ASPHALT

CRS-1 CRS-2

CMS-2 CMS-2h

CSS-1 CSS-1h

The "h" that follows certain grades simply means that a harder base asphalt is used. The "HF" preceding some of the MS grades indicates high-float, as measured by the Float Test (ASTM D 139 or AASHTO T 50). High-float emulsions have a quality, imparted by the addition of certain chemicals, that permits a thicker asphalt film on the aggregate particles with minimum probability of drainage. Some user agencies specify an additional cationic sand-mixing grade designated CMS-2s, which contains more solvent than other cationic grades. All grades in this lengthy list of emulsions may not be stocked by most producers. Communication and planning between user and producer helps facilitate service and supply of a given grade.

6

The specifications for emulsified asphalts (ASTM D 977 and AASHTO M 140) make no mention of a solvent in the emulsion. CRS- and CMS- cationic emulsion specifications (ASTM D 2397, AASHTO M 208), on the other hand, permit solvent but restrict the amount.

General Uses of Emulsified Asphalts are given in Table V-I, Chapter V. Standard specifi­cations for emulsified asphalts carry ASTM Designations D 977 and D 2397 and AASHTO Designations M 140 and M 208. For convenience, the basic requirements of these specifications are given in Tables 11-1 and 11-2.

2.05 VARIABLES AFFECTING ASPHALT EMULSION There are many factors that affect the production, storage, use, and performance of an asphalt

emulsion. It would be hard to single out anyone as being the most significant. But, among the variables having a significant effect are:

- Chemical properties of the base asphalL£~..!!1ent - Hardness and quantity of the base asphalt cement - Asphalt particle size in the emulsion - Type and concentration of the emulsifying agent - Manufacturing conditions such as temperatures, pressures, and shear - The ionic charge on the emulsion particles - The order of addition of the ingredients - The type of equipment used in manufacturing the emulsion - The property of the emulsifying agent - The addition of chemical modifiers.

The above factors can be varied to suit the available aggregates or to suit construction conditions. It is always advisable to consult the emulsion supplier with respect to a particular asphalt-aggregate combination as there are few absolute rules that will work the same under all conditions.

An examination of the three main constituents-asphalt, water, and emulsifier-is essential to an understanding of why asphalt emulsions work as they do.

B. EMULSION INGREDIENTS

2.06 ASPHALT Asphalt cement is the basic ingredient of asphalt emulsion and, in most cases, it makes up from

55 to 70 percent of the emulsion. Tables II-I and 11-2 show the asphalt content specified for various types of emulsions. ----'

Because asphalt cement is such a complex material, only those properties that significantly affect emulsions are discussed. There is not an exact correlation, however, between the properties and the ease with which the asphalt can be emulsified. Although hardness of base asphalt cements may be varied as desired, most emulsions are made with asphalts in the 100-250 penetration range. On occasion, climatic conditions may dictate that a harder or softer base asphalt be used. In any case, compatibility of the emulsifying agent ~itii."-ih~ asphalt cement IS essential for production of a stable emulsion.

Asphalt is a colloid composed of several fractions, the major ones being asphaltenes and maltenes. The colloidal make-up ofthe asphalt depends on thechemical nature and percentage of these fractions and their relationship to each other.

7

~nr~ 0977

Type

Grade.

Tests on emulsions: Viscosity. Saybolt Furol at 77°F

(25°C), s Viscosity. Saybolt Furol at 122°F

(SO°C). s Storage stabili~ test. 24-h. % ~u~ibility. _35 mt, O.~ N ~aCI.. % >. --- >-

Coating ability and water resistance: Coating. dry aggregate

00 Coating. after spraying Coating. wet aggregate Coating. after spraying

Cement mixing test. % Sieve test. % Residue by distillation. % Oil distillate by volume of emulsion.

% T~sts.on> r.esidue from distillation test: .

Penetration. 77°F (25°C). lOOg. 5 s Ductility. 7i~F. (25"(:). 5 em/min.

em Solubility in trichloroethylene. % Float test, 140°F J600 C). 5

TABLE 11-1 REQUIREMENTS AND TYPICAL APPUCATIONS FOR EMULSIRED ASPHALT

Rapid-Setting Medium-Setting

RS-I RS-2 MS-I MS-2

min max min max min max min max

20 100 20 100 100

75 400

60 60

good- good fair fair fair fair fair fair

0.\0 0.10 0.\0 0.\0 55 63 55 65

100 200 100 200 100 200 100 200 40 1 40 40 40

.j

97.5 97.5 97.5 97.5

MS-2h

min max

100

good fair fair fair

0.10 65

40 90 40

97.5

4~f~ D9n

Type . . . . . . . . . . . . . . . . .

Grade ..................

TalS on emulsions: Viscosity. Saybolt Furol at 7rF

(2S"C). s Viscosity. Saybolt Furol at 122"F

(SO"C). s Storaae stability test, 24-h. % Demulsibility. 3S mI. 0.02 N

caO)' % Coating ability and water resist-

ance: Coatina. dry aggresate Coating, after spraying Coating, wet aggresate Coating, after spraying

Cement mixing test. % Sieve test. % Residue by distillation. % Oil distillate by volume of emul-

sion. " Tall 011 residue/rom distil/ation lesl: Pe~tion. TTF (2S°C). 100 g, 5

s Ductility, 77°F, (25°C), 5 em/min,

em Solubility in trichloroethylene. % Roat test, 14O"F (6O"C). s

TABLE 11-1 REQUIREMENTS AND TYPICAL APPUCATIONS FOR EMULSIRED ASPHALT (Continued)

Mcdium-Setting

HFMS-I HFMS-2 HFMS-2h HFMS-2s

min max min max min max min max min

20 100 100 100 50 20

good good good good fair fair fair fair fair fair fair fair fair fair fair fair

0.10 0.10 0.10 0.10 55 65 65 65 57

I 7

100 200 100 200 40 90 200 100

40 40 40 40 40

97.S 97.5 97.5 97.5 97.5 1200 1200 1200 1200

The American Society for Testing and Materials takes no position respecting the validity of any potent rights assened in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights. is entirely their own responsibility.

Slow-Setting

SS-I SS-Ih

max min max

100 20 100

2.0 2.0 0.10 0.10

57

200 40 90

40

97.5

0

TABLE 11-2 REQUIREMENTS AND TYPICAL APPUCATIONS FOR CATIONIC EMULSIFIED ASPHALT

~~l~ 02397

Type .................. .... ' ....... Rapid-Setting Medium-Setting

CRS-I CRS-2 CMS-2 CMS-2h Grade .....................

min max min max min max min max

Test on emulsions: Viscosity, Saybolt Fuml at 77"F (25"C), s Viscosity, Saybolt Fuml at 122"F (50"C), s 20 100 100 400 50 450 50 450 Storage stability test, 24-h, % I 1 Oassification test passes passes Coating ability and water resistance:

Coating, dry aggregate good good Coating, after spraying fair fair Coating, wet aggregate fair fair Coating, after spraying fair fair

Particle charge test positive positive positive positive Sieve test, % 0.10 0.10 0.10 0.10 Cement mixing test, % I>sillation:

Oil distillate, by volume of em uIsion, % 3 3 12 12 Residue, % 60 65 65 65

Tests on residue from distillation test: Penetration, TTF (25"C), 100 II. 5 s 100 250 100 250 100 250 40 90 Ductility, 7TF (25"C), 5 em/min, em 40 40 40 40 Solubility in trichloroethylene, % 97.5 9i.5 97.5 97.5

Slow-Setting

CSS-I CSS-Ih

min max min max

20 100 20 100

positive positive 0.10 0.10 2.0 2.0

57 57

100 250 40 90 40 40 97.5 97.5

The asphaltenes are the dispersed phase in the asphalt whereas the maltenes are the continuous phase. The asphaltenes are thought to furnish hardness while the maltenes are believed to provide the adhesive and ductile properties of the asphalt. The maltenes present have an influence on the viscosity, or flow properties, of the asphalt. The complex interaction of the different fractions makes it almost impossible to predict accurately the behavior of an asphalt to be emulsified. For this rcason, constant quality control is maintained on emulsion production.

Several analytical methods of asphalt analysis are in use today to separate and evaluate the asphalt fractions. There is no agreement among technologists as to how each fraction affects field performance.

Each emulsion manufacturer has his own formulations and production techniques. They have been developed to achieve optimum results with the asphalt cement and emulsifying chemicals that are used.

2.07 WATER The second largest ingredient in an asphalt emulsion is water. Its contribution to the desired

properties of the finished product cannot be minimized. Water wets and dissolves; it adheres to other substances; and, it moderates chemical reactions. These are all important factors to the production of a satisfactory emulsion. On the other hand, water may contain minerals or other matter that affect the production of stable asphalt emulsions.

Water found in nature may be unfit because of impurities, either in solution or colloidal suspension. Of particular concern is the presence of positive and negative ions, which can affect the properties of the emulsion.

Water containing impurities should not be used in emulsion production. It may result in an imbalance of the emulsion components that can adversely affect performance or cause premature hrcaking.

2.08 EMULSIFYING AGENTS Properties of an asphalt emulsion depend greatly upon the chemical used as the emulsifier.

That chemical is a surface-active agent, commonly called a surfactant, that determines whether the emulsion will be classified as anionic, cationic, or nonionic. The emulsifier keeps the asphalt droplets in stable suspension and controls the breaking time. The surfactant changes the surface tension at the interface, i.e., the area of contact between the asphalt droplets and the water. A great many chemical emulsifiers are available. Each must be appraised for compatibility with the asphalt cement being used.

In the early days of asphalt emulsion production, such materials as ox-blood, clays, and soaps were used as emulsifying agents. As the demand for emulsions increased, new and more efficient emulsifying agents were found. Several chemical emulsifiers now are commercially available.

The most often used anionic emulsifiers are fatty acids, which are wood-product derivatives such as tall oils, rosins, and lignins. Anionic emulsifiers are saponified (turned into soap) by reacting with sodium hydroxide or potassium hydroxide.

Most cationic emulsifiers are fatty amines (diamines, imidazolines, amidoamines, to name three). The amines are converted into soap by reacting with acid, usually hydrochloric. Another type of emulsifying agent, fatty quarternary ammonium salts, is used to produce cationic

11

emulsions. They are water-soluble salts as produced and do not require the addition of acid to make them water-soluble. They are stable, effective cationic (positively charged) emulsifiers.

Each manufacturer has his own procedure for using his agent in asphalt emulsion production. In most cases, the agent is combined with the water before introduction into the colloid mill. In other cases, however, it may be combined with the asphalt cement just before it goes into the colloid mill.

C. PRODUCING THE EMULSION

2.09 EMULSIFYING EQUIPMENT Basic equipment to prepare an emulsion includes a high-speed, high-shear mechanical device

(usually a colloid mill) to divide the asphalt into tiny droplets. Also needed are an emulsifier solution tank, heated asphalt tank, pumps, and flow-metering gauges. The colloid mill has a high-speed rotor that revolves at 17-100 Hz (l ,000-6,000 rpm) with mill-clearance settings in the range of about 0.25 to 0.50 mm (0.01 to 0.02 in.). Such settings yield emulsions with asphalt droplet sizes smaller than the diameter of a human hair [about O.OOt to 0.010 mm (0.00004 to 0.0004 in.)]. There is a slight variation in mill clearance settings and, thus, asphalt droplet sizes depend upon the equipment used. Some emulsion mills have fixed clearances with no latitude for variation.

Separate pumps are used to meter asphalt and the emulsifier solution into the colloid mill. Because the emulsifier solution can be highly corrosive, it may be necessary to use a pump made of corrosion resistant materials.

A schematic diagram of a typical asphalt emulsion manufacturing plant is shown in Figure II-I.

2.10 THE EMULSIFYING PROCESS In the general method of emulsifying asphalts, concurrent streams of molten asphalt cement

and treated water are directed by pumps into the intake of the colloid mill. The asphalt and emulsifying water are subjected to intensive shear stresses as they pass through the cg.!l0id mill. The newly-formed emulsion may then be pumped through aheat exchanger. The excess h6aiis used to raise the temperature of the incoming emulsifying water just before it reaches the colloid mill. From the heat exchanger the emulsion may be pumped into bulk storage tanks. These tanks sometimes are equipped with some type of stirring device to keep the product uniformly blended.

Heated asphalt cement, the base of the asphalt emulsion, is fed into the colloid mill where it is divided into tiny droplets. At the same time, water containing the emulsifying agent is fed into the colloid mill. The asphalt, as it enters the colloid mill, is heated to ensure a low viscosity, and the water temperature is adjusted accordingly. These temperatures vary; they depend upon the emulsification traits of the asphalt cement and the compatibility between the asphalt and the emulsifying agent. Extremely high asphalt temperatures are not used because the temperature of the emulsion leaving the mill must be below the boiling point of water.

12

Figure 11-1. Diagram of an asphalt emulsion manufacturing plant. Courtesy Chemicolloid Laboratories. Inc.

The method of adding the emulsifier to the water varies according to the maker's procedure. Some emulsifiers, such as amines, must be mixed and reacted with an acid, such as hydrochloric, to attain water solubility. Others, such as fatty acids, must be mixed and reacted with an alkali, such as sodium hydroxide, to attain water solubility. Mixing is most typically done in a batch mixer. The emulsifier is introduced into warm water containing acid or alkali and agitated until completely dissolved.

Asphalt and emulsifier solution must be proportioned accurately. It is done by monitoring the temperature of each phase and the mill discharge, or with meters. If the temperature regulation method of proportioning is used, the outlet temperature of the finished emulsion is calculated from the temperatures of the various emulsion ingredients.

13

Asphalt particle size is a vital factor in making a stable emulsion. A mi~roscopic photograph of a typical emulsion reveals the following average particle sizes:

Smaller than 0.001 mm (Ip,m) ................................. 28 percent 0.001-0.005 mm (l-5p,m) .................................... 57 percent 0.005-0.010 mm (5-IOp,m) ................................... IS percent

These microscopic-sized asphalt droplets are dispersed in water in the presence of the chemical surface-active emulsifier (surfactant). The surfactant causes a change in the surface tension at the contact area between the asphalt droplets and the surrounding water, and this permits the asphalt to remain in a suspended state. The particles, all having a similar electrical charge, repel each other, which also aids in their remaining in a suspended state. Figure 11-2 is a photomicrograph showing the sizes and distribution of the asphalt particles.

Figure 11-2. Relative sizes and distribution of asphalt particles in an emulsion.

Courtesy Chevron U.S.A. Inc.

14

D. BREAKING AND CURING

2.11 BREAKING If the asphalt emulsion is to perform its ultimate function of cementing and waterproofing, the

asphalt must separate from the water phase. For surface treatments and seals, er:n""Jsig!l..L1!re f~rmulated to break upon contact with a Jor~ign su~stance. such a~_ilggr~gate __ Qr..Jl_pav~ment surface. The asphalt droplets coalesce and produce a continuous film of asphalt on the aggregate or pavement. For dense mixtures, more time is needed to _ ~lIow for mixing and '!~O~\ Therefore, emulsionsus~qJorOl.i:,,:tu:':.es are formulated for delayed breaking. Asphalt coales­cence is commonly referred to as breaking, or setting. The rate at which the asphalt globules separate from the water phase is referred to as breaking or setting time. For example, a rapid-set RS e~n will break within ~(~Jive _!]lint~ .. tes after Qeil!L~E.Rlied, whereas a medium- or slow-set material may take ~0l"1~l(ten!Q!Y JQl]gCL .

The rate of breaking is controlled primarily by the specific type and concentration of the emulsifying agent llsed, as well as atmospheric conditions. . .....

The fact that different aggregate types have differ~!1!rates of absorption (sucking up a liquid) me~.ns that breaking is also related to the relative absorption characteristics of the aggregate used. Those with higher absorption rates tend to accelerate the breaking of the emulsion due to the more rapid removal of the emulsifying water. rTo asphalt emulsion-aggregate rni.xWres, gradation and surface area of the aggregate also are

significant factors in the rate of breaking. As the surface area changes, the breaking characteristic of the emulsion also changes because of the altered adsorption (gathering on the surface) of the emulsifying agent by the aggregate. In order to achieve optimum results, it is necessary to control the sizing of the aggregate or to adjust the emulsion formulation to meet the specific requirements of the aggregate.

2.12 CURING For paving uses, both anionic and cationic asphalt emulsions depend on the evaporation of

water for development of their curing and adhesion characteristics. ~r displacement can be fairly rapid under favorable weather conditions but high humidity, low temperatures, or rainfall soon after application can deter proper curing. Although surface and atmospheric conditions are less critical for cationic emulsions than for anionic, they still depend somewhat on weather con­ditions for optimum results. Perhaps the principal advantage of the cationics is their willingness .. togive Ul? their water a little faster. af1!a.itio-narjh~orYillOlds that anionic emulsions (with a negative charge on the asphalt cirOR.@)

perform best with aggregates having mo~tl)' positive surface charges-limestone and dolomite are examples. The theory also holds that cationic emulsions (with a positive charge on the asphalt droplets) perform best with aggregates having mostly negative surface charges-some examples are siliceous or granitic aggregates. Presently, there is not complete agreement on the subjec.Lof electrical charges on aggregatesurface.s. Recent studies have challenged the traditional theories. The theories presented in this manual follow the line of traditional usage, which may change in the future.

When using either the anionic or cationic rapid-set emulsion the initial deposition of aspbJll1 develops through an electrochemical phenomenon. But the main bond of strength between the asphalt film and the aggregates comes after the loss of emulsifying water. This water fi!l!l can be

15

displaced by evaporation, pressure (rolling), or by absorption. In actual use, breaking is usually a function of the combination of these three factors.

Medium- and slow-set emulsions, being more heavily stabilized, depend less on the aggregate type although the same basic principles of electrical charges with respect to selection of emulsion type still apply. When the MS and SS grades are used for paving mixes, the use of ~ightly damp a~s facilitates the mixing and coating process. The development of strength in the SS types depends mainly on dehydration and absorption \\lith remov~LQL water by ~ither oLthese mechanisms breaking the emulsion. Solvent-free CMS and CSS emulsions require that the moisture on'the aggregate be at or near optimum for proper mixing and coating.

Some types of emulsions contain slight amounts of petroleum solvent to aid in the mixing and coating process. While the solvent does not enter directly into the breaking mechanism, p~must be made for the evaporation of the solvent in order for the mixture to be properly cured. Where multiple courses are to be placed, a sllccessive c,)urse should not be applied until the water (and solvent, if applicable) has been removed from the preceding course.

2.13 FACTORS AFFECTING SETTING RATE In general, some of the factors that affect setting rate of an asphalt emulsion are as follows:

1. The rate that water is absorbed by the aggregate. A rough-textured, porous aggregate speeds the setting time by absorbing water from the emulsion.

2. Moisture content of the aggregate prior to mixing. 3. Weather conditions-temperature, humidity, and wind velocity all have l '! b~aring on

rate of set. 4. Mechanical forces brought to bear by roll ing and by traffic. Roller pressure, to a

limited extent, fQ[C~.s. the water fr..Q!D the materials. 5. Size distribution and mineral composition of aggregate. Fine aggregate mixes tend to

break faster because they possess greater surface area than an equal mass (weight) of coarse aggregate. The miI1eral composition also affects the speed at which the asphalt emulsion breaks. There may be some type of <:;hemical reaction between the ~fI)ulsifier_ (ind the aggregate surface. Also, dirty aggregate or excess!~~line£. may accelerate breaking.

6. The type and amounfof emulsifying agent used. 7. Intensity of charge on aggregate versus intensity of emulsifier charge, in combination

with surfaq;~ area, is a major setting-rate determinant. 8. ~hemical coagulation) The emulsion becomes unstable because of a decreased water

. content. " \The above factors must be considered in determining working time after the emulsion has been

sprayed or mixed with the aggregate in the field.

16

CHAPTER III

STORING, HANDLING, AND SAMPLING ASPHALT EI\IIULSIONS

3.01 GENERAL The storage and handling of asphalt emulsions require precaution beyond that used for other

types of asphalt materials. Improper handling or storage of the emulsion, or both, may cause premature breaking, thereby making it useless. The Asphalt Institute, in recognition of these necessary precautions, has outlined some of the safeguards that must be followed. Failure to follow even a single one of them may cause the material to be unsatisfactory at the time of use. Careful study of each item is therefore suggested. StickingJQ.these simple rules will save time and money by having the material ready for use when needed. The safeguards listed by the Asphalt Institute are repeated below to help those who have little or no experience with asphalt emulsions. However, it is not intended to give the impression that asphalt emulsions are so delicate as to limit their field use. The use of almost any other material would have a long list of admonitions for the uninitiated.

3.02 STORING ASPHALT EMULSIONS Emulsified asphalt, being a dispersion of fine droplets of asphalt cement in water, has both

the advantages and disadvantages of t~e_~arrier meqiuIll, wat.~r. When storing emulsified asphalts:

DO store as you would fluid water-between 10°C (50°F) and 85°C (185°F), depending \

on the use.

DO use hot water as the heating medium for storage tanks with heating coils. Low pressure or waste steam also may be used, with temperature controlled on the coil surface to not more than 85°C (185°F).

DO store at the temperature sp~fied for the particular grade. ffi_s.p~ayappIic~~ the emulsions are stored at higher temperatures than for mixing with aggregate. For example, the higher viscosity rapid-set spray grades are stored at 50°C to 85°C (l25°F to 185°F) since they are usually applied il] this temperature range. The lower viscosity grades are stored at lower temperatures. Table 111-1 shows the normal storage temperature ranges. Store the mixing gradeshat -the\f~wer end of the temperature ranges as shown in Table III-I. ,-_ ... _ .... ,) {2.R..L fP [ 13.

DO NOT permit the emulsified asphalt to be heated above '~~C (1 85°F). Elevated temperatures evaporate the water, resulting in an increase in viscosity and an asphalt layer in the tank. The materials can no longer be used as intended and it will be difficult to empty the tank.

DO NOT let the emulsion fr(!e~~. This breaks the emulsion, separating the asphalt from the water. The result will be two layers in'the tank, neither suited for the intended use, and the tank will be difficult to clean.

DO NOT allow the temperature of the heating surface to exceed 100°C (212°F). This will cause premature breakdown of the emulsion on the heating surface.

DO NOT use forced air to agitate the emulsion. It may cause the emulsion to break.

17

TABLE 111-1 STORAGE TEMPERATURES FOR EMULSIFIED ASPHALTS

Grade Temperature, °C (OF)

Minimum Maximum

RS-1 20° (70°) 60° (140°)

RS-2, CRS-1, CRS-2 50° (125°) 85° (185°)

SS-1, SS-1h, CSS-1, CSS-1h, MS-1, HFMS-1 10° (50°) 60° (140°)

CMS-2, CMS-2h, MS-2, MS-2h, HFMS-2, HFMS-2h, HFMS-2s 50° (125°) 85° (185°)

3.03 STORAGE FACILITIES For protection from freezing and best utilization of heat, storage tanks should be insulated.

A skin of asphalt can form on the surface of emulsions when exposed to air. It is best, therefore, to use tall, vertical tanks as they expose the least amount of surface area to the air. Most fixed storage tanks are vertical but horizontal tanks are often used for short-term field storage. Skinning can be reduced by keeping horizontal tanks full to minimize the area exposed to air.

Side-entering propellers located about one metre (three feet) up from the tank bottom may be used to prevent surface skin formation. Large diameter, slow-turning propellers are best and should be used to roll the material over. Avoid overmixing. Secondly, tanks may be circulated top to bottom with a pump. A void over-pumping. In tanks not equipped with propellers, or a circulating system, a very light film of kerosene or oil on the surface can reduce skin formation. Emulsions that are rolled or circulated generally do not require a layer of kerosene or oil on the surface. Cathodic protection should be provided to avoid possible corrosion of tank walls and heating coils.

3.04 HANDLING EMULSIFIED ASPHALTS DO when heating emulsified asphalt agitate it gently to eliminate or reduce skin forma­

tion.

DO protect pumps, valves, and lines from freezing in winter. Drain pumps or fill them with anti-freeze according to the manufacturer's recommendations.

DO blowout lines and leave drain plugs open when they are not in service.

DO use pumps with proper clearances for handling emulsified asphalt. Tightly fitting pumps can cause binding and seizing.

DO use a mild heating method to apply heat to the pump packing or casing to free a seized pump. Discourage the use of propane torches.

DO warm the pump to about 65°C (150°F) to facilitate start-up.

DO when a pump is to be out of service for even a short period of time, fill it with No. fuel oil to ensure a free start-up.

18

DO when diluting grades ofclllulsified asphalt. check the compatibility of the water with the emulsion, by testing a small quantity.

DO if possible, use warm water for diluting and always add the water slowly to the cmulsion (not the emulsion to the water).

DO avoid repeated pUlllPing and /\:cycl ing, if possible, as thc viscosity may drop and air may bccomc cntrained, causing the cmulsion to be unstablc.

DO guard against mixing diffcrcnt c1asscs, types, and grades of cmulsified asphalt in storage tanks, transports, and distributors. For example, if cationic and anionic emulsified asphalts are mixed, the blend will break and scparate into water and coagulated asphalt that will be difficult to remove. Because it is hard to determine visually the difference between various emulsified asphalts, always make a trial blend of the newly-delivered emulsion and the stored emulsion before pumping off. Check the trial blend for compatibility.

DO place inlet pipes and return lines at the bottom of tanks to prevent foaming.

DO pump from the bottom of the tank to minimize contamination from skinning that may have formed.

DO remember that emulsions with the same grade designation can be very different chemically and in performance.

DO haul emulsion in truck transports with baffle plates to prevent sloshing.

no Illix by circulation, or otherwise, ellluisions that have bcen in prolonged storagc.

DO NOT use tight-fitting pumps for pumping emulsified asphalt; they may "freeze."

DO NOT apply severe heat to pump packing glands or pump casings. The pump may be damaged and the asphalt may become even harder.

DO NOT dilute rapid-setting grades of emulsified asphalt with water. Medium and slow setting grades may be diluted, but always add water slowly to the asphalt emulsion. Never add the asphalt emulsion to a tank of water when diluting.

DO NOT recirculate emulsified asphalts for too many cycles. They tend to lose viscosity when subjected to pumping. Also, air bubbles may become entrained which would render the emulsion unstable.

DO NOT load emulsified asphalt into storage tanks, tank cars, tank transports, or distributors containing remains of incompatible materials. See Tables 111-2 and 111-3.

19

TABLE 111-2 GUIDE FOR CONDITION OF EMPTIED TANKS BEFORE LOADING EMULSIFIED ASPHALTS

LAST PRODUCT IN TANK

PRODUCT Asphalt Cutback Cationic Anionic Crude Any product TO BE Cement Asphalt Emulsion Emulsion petroleum not listed

LOADED (includes In- and residual above dustrial fuel oils Asphalt)

Empty to no Empty to no Empty to no Empty to no Tank Cationic Measurable Measurable OK to load Measurable Measurable must be Emulsion Quantity Quantity Quantity Quantity cleaned

-Empty to no Empty to no Empty to no Empty to no Tank

Anionic Measurable Measurable Measurable OK to load Measurable must be Emulsion Quantity Quantity Quantity Quantity cleaned

NOTE: All tanks to be emptied to 0.5 percent or less of capacity. Pump section. unloading line. and all piping must be drained.

TABLE 111-3 POSSIBLE CAUSES OF CONTAMINATION OF ASPHALT MATERIAL OR SAMPLES AND SUGGESTED PRECAUTIONS

HAULERS AND HAULING VEHICLES Field observations and studies of test results have indicated that contamination of materials during

transportation often occurs.

Possible Causes

(a) Previous load not compatible with material being loaded.

(b) Remains of diesel oil or sol­vents used for cleaning and flushing of tanks. lines, and pump.

(c) Flushing of solvents into re­ceiving storage tank or equip­ment tanks.

Precautions

Examine the log of loads hauled or check with the supplier to determine if pre\lious material hauled is detri mental. If it is. make sure vehicle tanks. unloading lines. and pump are properly cleaned and drained before being presented for loading. Provide a ramp at the unloading point at the plant that will ensure complete drainage of vehicle tank while material is still fluid.

When this is necessary. make sure all solvents are completely drained.

Do not allow even small amounts to flush into stor­age tank as entire contents may be contaminated

(Continued on next page)

20

TABLE 111-3 (con't.)

MIX PLANT STORAGE TANK AND EQUIPMENT Many investigations and test results point to mix plant storage tanks and associated equipment as the

source of contamination.

Possible Causes (a) Previous material left over in tank

when changing to another material.

(b) Solvents used to flush hauling ve­hicle tank discharged into storage tank.

(c) Flushing of lines and pump between storage tank and hot-plant witll sol­vents and then allowing this material to return to tank.

(d) Cleaning of distributor tank, pump, spray bar, and nozzles with solvents.

(e) Dilutions from hot oil heating systems.

Precautions Any material allowed to remain must be compatible with new material; and the amount remaining in the tank must be insuffi­cient to cause new material to become out-of-specification. If in doubt, check with your supplier. To be on the safe side, tank should be drained or cleaned prior to using tank for each different type or grade of asphalt. Be sure discharge line connects at low point of storage tank to ensure complete emptying when changing type or grades of asphalt or cleaning tank.

Observe unloading operations, caution driver about flushing cleaning materials into storage tank. If possible, provide place for hauler to discharge cleaning materials.

If necessary to flush lines and pump, suggest providing by­pass valves and lines to prevent solvents from returning to tank. A better solution is to provide insulated, heated lines and pump, thereby eliminating the necessity of flushing.

Be sure all possible cleaning material is drained off or re­moved prior to loading. Do not take sample from nozzle until sufficient material has been discharged to guard against taking a contaminated sample.

Check reservoir on hot oil heating system. If oil level is low, or oil has been added, check system for leakage into the asphalt supply.

NON-REPRESENTATIVE OR CONTAMINATED SAMPLE Test results are greatly dependent upon proper sampling techniques. Extra care, on the part of the

sampler, to obtain samples that are truly representative of the material being sampled will do much to eliminate the possibility of erroneous test results by reason of improper sampling. Make sure samples are taken only by those authorized persons who are trained in sampling procedures.

Possible Causes (a) Contaminated sampling device

(commonly called a "sample thief").

(b) Samples taken with sampling de­vice from top of tank where, under certain conditions, contaminants can collect on the surface.

Precautions

If sampling device (of type described in ASTM 0 140 or AASHTO T 40 is cleaned with diesel oil or solvent, make sure that it is thoroughly drained and then rinsed out several times with material being sampled prior to taking sample.

In taking a sample from the top of a tank lower sampling de­vice below the extreme top before opening. Note: This sample may come from the top one-third of the tank.

(Continued on next page)

21

TABLE 111-3 (Con't.)

Possible Causes

(c) Contaminated sample container.

(d) Sample contaminated after taking.

(e) Samples taken from spigot in lines between storage tank and hot-plant.

(f) Samples taken from unloading line of hauling vehicle.

Precautions

Use only new clean containers. Never wash or rinse a sample container with solvent. Glass or polyethylene containers should be used.

DO NOT submerge container in solvent or even wipe outside of container with solvent-saturated rag. If necessary to clean spilled material from outside of container, use a clean dry rag. Make sure container lid is tightly sealed prior to stor­age or shipment. Ship to testing laboratory promptly.

If sampling spigot is in suction line between tank and pump, this necessitates stopping pump prior to taking sample. Samples thus taken are by gravity and only representative of material localized in the r.>ipe area of the spigot. Rather, the spigot should be in lines between pump and return line discharge, thereby allowing slow withdrawal of material during circulation. DO NOT take sample while hauling vehicle is pump­ing into storage tank. DO NOT take sample without allowing sufficient time for circulation and thorough mixing of material.

DO drain off sufficient material through spigot prior to taking sample to ensure removal of any contaminant lodged in spigot. DO take sample slowly during circulation to be more rerre­sentative of material being used.

Drain off sufficient material through spigot prior to taking sample to ensure removal of any contaminant lodged there. Sample should be taken after one-third and not more than two-thirds of the load has been removed. Take sample slowly to be sure it is representative of the material being used.

3.05 SAMPLING ASPHALT EMULSIONS The purpose of any sampling method is to obtain samples that will show the true nature and

condition of the material. The general procedure is described in the following articles. The standard procedure is detailed in "Standard Methods of Sampling Bituminous Materials," ASTM D 140 or AASHTO T 40.

3.06 SAMPLE CONTAINERS Containers for emulsified asphalt materials shall be wide-mouth jars or bottles made of

plastic, or wide-mouth plastic-lined cans with lined screw caps, or plastic-lined triple-seal friction-top cans.

22

3.07 SIZE OF SAMPLES The size of samples shall correspond to the required sample containers.

3.08 SAMPLES Whenever practicable, the emulsified asphalt shall be sampled at the point of manufacture or

storage. If that is not practicable, samples shall be taken from the shipment immediately upon delivery. Three samples of the emulsified asphalt shall be taken. The samples shall be sent to the laboratory for testing as soon as possible.

3.09 SAMPLING PRECAUTIONS (I) Sample containers shall be new. They shall not be washed or rinsed. I f they contain

evidence of solder flux or if they are not clean and dry they shall be discarded. Top and container shall fit together tightly.

(2) Care shall be taken to prevent the samples from becoming contaminated. The sample container shall not be submerged in solvent, nor shall it be wiped with a solvent saturated cloth. Any residual material on the outside of the container shall be wiped with a clean, dry cloth immediately after the container is sealed and removed from the sampling device.

(3) The sample shall not be transferred into another container. (4) The filled sample container shall be tightly and positively sealed immediately after the

sample is taken.

3.10 SAFETY PRECAUTIONS (I) Safety precautions are mandatory at all times when handling asphalt materials. These

safety precautions include, but are not limited to, the ones that follow. (2) Gloves shall be worn and sleeves shall be rolled down and fastened over the gloves at the

wrist while sampling and while sealing containers. (3) Face shields should be worn while sampling. (4) There shall be no smoking while sampling asphalts. (5) The sampler shall stand on the windward side when taking the sample. (6) During sealing and wiping the container shall be placed on a firm level surface to prevent

splashing, dropping or spilling the material.

3.11 PROTECTION AND PRESERVATION OF SAMPLES (I) Immediately after filling, sealing, and cleaning the sample containers shall be properly

marked for identification with a wick marking pencil on the container itself, not on the lid. Linen tags also may be used for identification if they can be securely fastened to the container in such a manner as to ensure that they will not be lost in transit.

Linen tags shall not be attached to containers by using the lids to secure them. (2) Samples of emulsions shall be packaged, labeled, and shipped in such a manner as to

protect them from freezing. (3) All samples should be packaged and shipped to the laboratory the same day they are taken.

The containers, tightly sealed, should be packed in absorbent material, such as sawdust, excelsior, or vermiculite, to reduce the probability of damage during shipment.

(4) Each sample shall be identified with at least the following information: (a) Shipper's name and bill of lading or loading slip number. (b) Date sampled. (c) Sampler'S name. (d) Product grade.

CHAPTER IV

EMULSIFIED ASPHALT TESTS

4.01 REASONS FOR TESTING ASPHALT EMULSIONS Proper interpretation of laboratory test results can greatly aid in determining the traits of an

asphalt emulsion. As advances in asphalt emulsion technology have been made through the years, corresponding advances in emulsion testing have evolved. Some of these tests are designed to measure performance qualities. Others deal mainly with the manufacturing process.

Laboratory tests are normally performed for one of four purposes:

I. To measure properties related to handling, storage, and field use.

2. To control the quality and uniformity of the product during manufacturing and use.

3. To provide reference procedures for specifications.

4. To pred ict or control field performance.

Table I V-I is a useful summary of most of the tests. J\. review of emulsion specifications used across the United States reveals a wide variety of

requirements. Many are directly related to the emulsions produced by specific manufacturers. Because it is impraticable to discuss the multitude of requirements and test methods, this chapter is confined to the methods in ASTM Method D 244 and AASHTO Test Method T 59.

4.02 ASPHALT EMULSION TESTS Asphalt emulsions are made by taking asphalt cement, and by special formulation, converting

it to a liquid form. That makes the asphalt easy to apply, mix, or handle before it reverts to its original state. Test methods for evaluating properties of asphalt cement are well known. Among them are penetration, ductility, and solubility in trichloroethylene, tests that apply also to the residual asphalt in the emulsion after the water has evaporated. The primary purpose of this chapter is to consider the tests that apply to asphalt emulsion, rather than the base asphalt cement. The major emulsion tests are briefly discussed, with details of each test method presented in Appendix B. Most of the tests are standard procedures and are outlined in "Testing Emulsified Asphalts," ASTM Method of Test D 244 and AASHTO Method T 59.

4.03 RESIDUE BY DISTILLATION The relative proportions of asphalt cement and water in the emulsion can be determined by a

distillation test. Additional tests may be made on the asphalt cement residue when the emulsifed asphalt contains an oil distillate. A micro-distillation test or residue-by-evaporation test also can be performed to determine the amount of this material in the emulsion.

The distillation test procedure for asphalt emulsion is closely akin to that fiJr cutback asphalt. The main difference is that an aluminum alloy still and ring burners are used instead of the glass flask and Bunsen Burner (note Figure IV-I). The equipment is designed to prevent trouble from

25

TABLE IV-1 SUMMARY OF EMULSION TESTS Test Property Factor Requirement

-~--'---------------~----------------------------CONSTANCY A) Uniformity Product must have the same 'Residue: Proportions of asphalt & water.

(Indication of uniformity of manufacture.) Residue is measured by dehydrating the emulsion by evaporation or distillation.

B) Storage Stability

handling, mixing and setting characteristics from shipment to shipment.

Product must be capable of storage without excessive damage or change.

CLASSIFICATION A) Differentiate mixing grade product from rapid set types. (Select proper grade)

B) Differentiate cationic from anionic emulsions. (Prevent mixing of grades which could result in breakdown)

'Sieve:

'Settlement: 'Storage Stability:

Freeze-Thaw:

'Demulsibility:

'Particle Charge Test:

pH:

Amount of oversize particles, shot and slugs retained on #20 mesh sieve.

Amount of settlement of asphalt particles in 5 days -- one day for storage stability test. The difference in residue between top and bottom is measured.

Most emulsions are damaged by freezing.

Amount of coagulation on addition of a salt-calcium chloride with anionic emulsion; Aerosol OT with cationic emulsion.

Deposition of asphalt on an electrode.

Cationics are generally acidic with a pH of less than 7. Anionics are generally alkaline with a pH greater than 7. Water has a pH=7.

------------------------CONSTRUCTION A) Handling CHARACTERISTICS

DURABILITY

ASPHALT PURITY

B) Rate of Set

C) Mixing Stability

A) Traffic Densification

B) Resistance to Stripping

C) Long-Term Service Life

A) Ensure Presence of Asphalt

Product must be s.ale to handle and capable of being pumped and sprayed without breakdown or run-off.

The product must break rapidly and hold aggregate under the action of traffic.

The product must mix with water and aggregate without balling or breakdown. Once mixed, the mix must cure rapidly to an asphalt film.

Properly designed pavements must not bleed under repeated' load application by heavy traffic.

Mixes must not strip when in prolonged contact with water.

Asphalt must remain flexible at cold temperatures and not deteriorate on long-term weathering in a pavP'T1ent.

Keep to a minimum the additives, emulsifiers and fillers used to emulsify the asphalt.

"Included in ASTM D 244 and AASHTO T 59

26

'Consistency:

Pumping Stability:

Dehydration:

'Cement Mixing:

'Stone Coating­Water Resistance:

Miscibility With Water:

'Penetration: 'Float Test: 'Residue:

Adhesion Test:

'Penetration & Ductility After Laboratory Distillation: Specification Tests On Original Asphalt:

'Solubility 01 The Asphalt After Laboratory Distillation:

Emulsion viscosity.

No test in current specifications.

Amount of water lost in 96 hours at 100°F.

(Note: Improved test method for Rate of Set is needed.)

Emulsion mixed with cement.

Job (or reference) aggregate is mixed with the emulsion to determine coating and early rain resistance.

Ability to mix with water without coagulation.

Consistency of base asphalt after laboratory distillation.

Made on job aggregate or a reference aggregate.

Courtesy Chevron U.S.A., Inc.

foaming of the emulsified asphalt as it is being heated to a maximum of 260°C (500°F). The usual test method, however, is not necessarily preferred for recovery of the asphalt

residue and for defining the properties of the asphalt base stock used in the emulsion. Properties of the asphalt base can be altered substantially by:

- Concentration of inorganic salts from the aqueous phase in the asphalt residue.

- Concentration of emulsifying agents and stabilizers (if present) in the asphalt residue. These materials remain in the distillation residue and may alter the asphalt properties.

Thennally-induced changes do not occur in actual usage because the applied emulsion is allowed to break either electrochemically or by evaporation of the water. In field use, the temperature of the system never approaches that observed in the distillation test. Therefore, the real purpose of the test-to detennine accurately the amount of asphalt cement in the emulsion-is not always realized. Evaporation of the water at subatmospheric pressure and at lower temperatures (ASTM D 244 or AASHTO T 59) provides a more realistic means for defining the properties of the asphalt after it is cured on the pavement surface. Similar procedures are now recognized and used by many agencies and emulsified asphalt producers.

4.04 OIL DISTILLATE The oil distillate, percent by volume of the original emulsion sample, is obtained from the

amount of oil in the cylinder at the end of the test for residue by distillation.

4.05 RESIDUE BY EVAPORATION This test is designed to measure the percentage of asphalt cement in the emulsion by

evaporating the water. The residue derived from this procedure usually yields lower penetration and lower ductility than that from distillation. However, residue from evaporation can be used for other tests.

4.06 PARTICLE CHARGE TEST The particle charge test is made to identify cationic emulsions. It is perfonned by immersing

a positive electrode (anode) and a negative electrode (cathode) into a sample emulsion and connecting them to a controlled direct-current electrical source, Figure IV -2. At the end of a specified period, the electrodes are observed to detennine if the cathode has an appreciable layer of asphalt deposited on it. Cationic emulsions will migrate toward the cathode.

4.07 VISCOSITY Viscosity is defined as a flu id' s resistance to flow. In the case of emulsified asphalts the

Saybolt Furol visl:::osity test (Figure IV -3) is used as a measure of consistency. Results are reported in Saybolt Furol seconds. For convenience and for testing accuracy, two testing temperatures, which cover the normal working range, are used. These temperatures are 25°C (77°F) and 50°C (122°F).

27

Figure IV-1. Distillation test for emulsified asphalts.

Figure IV-2. Particle charge test.

28

Figure IV-3. SayboH Furol viscosity test.

4.08 DEMULSIBILITY The demulsibility test indicates the relative rate at which the colloidal asphalt globules in

the rapid-setting type of emulsified asphalts will break when spread in thin films on soil or aggregate. Calcium chloride causes the minute asphalt globules present in these emulsified asphalts to coalesce. In the test, a solution of calcium chloride and water is thoroughly mixed with emulsified asphalt; then it is poured over a sieve to determine how much the asphalt globules coalesce.

In testing rapid-setting (RS) emulsions, a very weak solution of calcium chloride and water is employed. Specifications prescribe the concentration of the solution and the minimum amount of asphalt to be retained on the sieve. A high degree of "demulsibility" indicates a rapid-setting (RS) emulsion. It is expected to break almost immediately upon contact with the aggregate on which it is applied.

29

4.09 SETTLEMENT The settlement test indicates the emulsion's stability in storage. It detects the tendency of

asphalt globules to settle during storage. This test also serves as an indicator of quality even if the emulsion is not to be stored for a period of time. Failure of the settlement test indicates that something is wrong or out of balance in the emulsification process.

A prescribed volume of emulsion is allowed to stand in a graduated cylinder for a specified number of days (usually five). Small samples are then taken from the top and bottom parts. Each sample is placed in a beaker and weighed. The sample is then heated until all water evaporates; then the residue is weighed. The weights obtained are used to find the difference, if any, between the asphalt cement content in the upper and lower portions of the cylinder. This provides a measure of settlement.

When the asphalt emulsion is to be used promptly, most agencies will accept the storage stability test (one-day settlement), Article 4.14, in lieu of the settlement test.

4.10 CEMENT MIXING The cement mixing test does the same for slow-setting (SS) emulsified asphalts as the

demulsibility test does for rapid-setting grades. The SS grades are used with fine materials and dusty aggregates. They are normally unaffected by calcium chloride solution as used in the demulsibility test.

In the cement mixing test, a sample of emulsified asphalt is mixed with finely-ground portland cement and the mixture washed over a 1.40 mm (No. 14) sieve. Specifications usually limit the amount of material that may be retained on the sieve.

The cement mixing reaction for cationic and noncationic emulsions is quite different. The cationic emulsion reacts to portland cement because of surface area; the noncationic, particularly the anionic type, reacts chemically with portland cement constituents, forming a water-insoluble salt.

4.11 SIEVE TEST The sieve test complements the settlement test and has a somewhat similar purpose. It is used

to find the amount of asphalt in the form of rather large globules that may not have been detected in the settlement test and could clog the spraying equipment. Such globules will not provide thin and uniform coatings of asphalt on the aggregate particles.

In the sieve test, a representative sample of emulsified asphalt is poured through a 850 /Lm (No. 20) sieve. For anionic emulsions, the sieve and retained asphalt are then rinsed with a mild sodium oleate solution and finally with distilled water. For cationic emulsions, distilled water only is used for rinsing. After rinsing, the sieve and asphalt are dried in an oven and the amount of retained asphalt determined by weighing.

4.12 MISCIBILITY WITH WATER This test finds if medium-setting or slow-setting emulsions can be mixed with water. It is not

applicable to rapid-setting asphalt emulsions. After adding and stirring distilled water, the emulsion sample is allowed to stand for two hours. It is then examined for any appreciable coagulation of the asphalt droplets in the emulsion.

The test is a quality measure in addition to indicating whether the emulsion is capable of mixing with, or being diluted with, water. Quite often there will be a deposit of heavy emulsion

30

in the bottom of the beaker. If the deposit in the beaker is minimal, it signifies that the emulsion is properly formulated and that the dispersed particles are in the desired size range.

4.13 COATING ABILITY AND WATER RESISTANCE This test has a threefold purpose. It determines the ability of an asphalt emulsion to: (I) coat the

aggregate thoroughly. (2) withstand mixing action while remaining as a film on the aggregates and (3) resist the washing action of water after completion of mixing. The test is primarily intended to identify medium-setting asphalt emulsions suitable for mixing with coarse-graded calcareous aggregates. Other aggregates may be used in the test if calcium carbonate is omitted throughout the method. This test is not adaptable to rapid-setting or slow-setting asphalt emulsions.

The reference aggregate is coated with calcium carbonate dust and then mixed with the emulsified asphalt. About one-half of the mixture is then placed on absorbent paper for a visual inspection of the surface area of aggregate coated by the emulsified asphalt. The remainder of the mixture is sprayed with water and rinsed until the rinse water runs clear. This material is then placed on absorbent paper and inspected for coating.

A sample of job aggregate is similarly coated with calcium carbonate dust. A given quantity of water is then mixed with the dust-coated aggregate. Emulsified asphalt is added and thoroughly mixed. Inspections are made as described above for the dry-coated aggregates.

4.14 STORAGE STABILITY The storage stability test is used to determine the ability of an emulsified asphalt to remain

as a uniform dispersion during storage. It is a measure of the permanence of the dispersion as related to time.

A measured representative sample is placed in each of two glass cylinders. They are stoppered and allowed to stand at laboratory temperature for 24 hours. A 50g sample from each cylinder is siphoned from the top. The samples are placed for a set time in an oven heated to a prescribed temperature. Then they are removed, allowed to cool, and weighed. After the top sample is removed, all but a small portion of the asphalt emulsion remaining in each cylinder is siphoned off. A 50g sample of the portion that is left is put through the same procedure as for the top samples.

The storage stability is expressed as the numerical difference between the average percentage of residue in the top samples and the bottom samples.

4.15 EXAMINATION OF RESIDUE The same desirable characteristics in the base asphalt cement should show up in the residual

asphalt after emulsification and coalescence. The most common tests run on the residue include penetration, solubility, ductility, float test, and specific gravity. These tests are described in detail in ASTM Methods D 5, D 2042, D 113, D 139 and D 70 (AASHTO Methods T 49, T 44, T 51, T 50, and T 228) respectively.

The penetration test is an empirical test of consistency. It has been carried over in some viscosity-based asphalt specifications to ensure that materials of an undesirably low penetration are precluded from use. This test measures the depth of penetration in units of 0.1 mm of a standard needle under a load of 100g for exactly five (5) seconds when the asphalt sample is at a temperature of 25°C (77°F). Lower test temperatures are sometimes checked when the asphalt is to be used in an area where very low temperatures are prevalent.

The solubility test is a measure of the "purity" of the asphalt cement. The portion of the asphalt cement that is soluble in specified solvents represents the active cementing constituents.

31

Only such inert matter as saIts, free carbon, or nonorganic contaminants, such as clay or finely divided mineral matter, are insoluble. Solubility is determined by dissolving the asphalt cement in the solvent and separating the soluble and insoluble portions by filtering.

The ductility of an asphalt cement is its ability to be extended or pulled into a narrow thread. In many applications, it is an important characteristic of asphalt cements. The presence or absence of ductility, however, is usually of more significance than the actual degree of ductility. This test is made by molding a briquette of asphalt cement under standard conditions and dimensions. The asphalt briquette is then brought to a standard test temperature in a water bath. It is pulled at a specified rate of speed until the thread connecting the two ends breaks. The elongation, in centimeters, at which the thread of material breaks is designated as ductility.

The float test is performed on the residue from distillation of HFMS emulsified asphalts. The test is a measure of consistency of the material being examined.

In the test, illustrated in Figure IV -4, a plug of asphalt residue is solidified in a brass collar by cooling to 5°C (41°F). The collar is then screwed into the bottom of an aluminum float which is placed into a testing bath of water heated to 60°C (140°F). The time required for the water to break through the plug is determined. Values are limited by specifications for the HFMS emulsified asphalts (see Table II-I, Chapter II). The test is prescribed in ASTM Method of Test D 139 (AASHTO Method of Test T 50).

4.16 CLASSIFICATION TEST FOR RAPID-SETTING CATIONIC ASPHALT EMULSIONS

Figure IV-4. Float test.

This test identifies rapid-setting cationic asphalt emulsions by their failure to coat a specific Ottawa sand-portland cement (Type III) mixture. Following a 2Vz minute mixing period, an estimate is made of the amount of uncoated and coated areas in the mixture. An excess of uncoated area over a coated area is considered as a passing rating for rapid-setting cationic emulsions.

4.17 FIELD COATING TEST This test is used at the project site to determine:

- The ability of an asphalt emulsion to coat the job aggregate. - The ability of the emulsion to withstand mixing. - The water resistance of the emulsion-coated aggregate.

Measured amounts of the job aggregate and job emulsion are hand mixed. The ability of the emulsion to remain as a coating during a five-minute cycle is observed. The resistance of the coating to wash-off is determined by filling with water and emptying a container of the

32

coated aggregate five times. The coating of the aggregate is visually rated as good, fair, or poor. A rating of good means that the aggregate is fully coated (except for pinholes and sharp edges). A rating of fair indicates an excess of coated over uncoated aggregate area. A rating of poor indicates an excess of uncoated aggregate over coated area.

4.18 MASS PER LITRE (WEIGHT PER GALLON) This test is used to determine the mass per litre (weight per gallon) of asphalt emulsion.

This unit mass (weight) is computed by finding the mass (weight) of an asphalt emulsion in a standard measure of known volume. Results are reported in kilograms per litre (pounds per gallon) to the nearest 0.005 kg (0.01 lb.) at 25°C (77°F).

4.19 SPECIFIC GRAVITY Finding the specific gravity of asphalt cement is not normally a specification item. It can

be helpful, however, in making volume corrections at elevated temperatures and determining necessary quantities. Asphalt cements fall within a specific gravity range of about 1.0 to 1.05. This means that they weigh 1.0 to 1.05 times as much as the same volume of water under the same test conditions. The specific gravity is usually determined with a pycnometer.

4.20 SPECIAL TEST-ZETA POTENTIAL The measurement of zeta potential is not a standard ASTM or AASHTO test. The zeta

potential is a measurement of the intensity of positive or negative charge of emulsified asphalt and/or aggregate particles. A device called a Zeta Meter measures the speed of movement (electrophoretic mobility) of individual emulsified asphalt droplets or aggregate particles when placed in an aqueous medium. The intensity of charge each droplet or particle inherently possesses, either positive or negative, can be expressed in millivolts (111000 volt) as the zeta potential.

33

PART TWO:

USING ASPHALT EMULSIONS

CHAPTER V

SELECTING THE RIGHT TYPE AND GRADE OF ASPHALT EMULSION

5.01 GENERAL Asphalt emulsions can be used for almost any purpose for which cutback asphalts are used.

Furthermore, they have a broader range of uses that include many not suited to cutbacks. That does not mean that they can be used indiscriminately. Successful performance of asphalt emulsions requires selecting the proper type and grade for the intended use. Guidelines presented in this chapter should help select the specific grade and type of emulsion to be used.

5.02 CONSIDERATIONS FOR SELECTION The first consideration in picking the right type and grade of emulsion is the kind of

construction in which it will be used. Is it a seal coat or a plant mix (central or mixed-in-place)? Is it some type of surface application only? Is it for maintenance? Once this decision is made other project variables must then be considered. Some other factors that affect the selection are:

- <;:1!..!!Iatic con.QHjo~~ anti~ipated duringC.onst[uc.tian.: The selection of emulsion grade, design of mix or treatment, and construction equipment depend upon this factor.

- Aggregate type and availability.

- Construction equipment availabil ity.

- Geographical location: hauling distance, and in some cases, water availability.

'(- Traffic control: can traffic be detoured?

1/-' Environmental considerations. l

While general guidelines can be given for selecting emulsions, laborat~y .t~sting.l.~~rongly. recommended. There is no good substitute for a laboratory evaluation of the emulsion and the aWegate-To be used, Different types and quantities of emulsion should be tried with the aggregate to find the best combination for the intended use. An experienced technician can determine the type and amount of emulsion to be used. He can also determine if additional water must be added, and the amount of time for breaking to occur.

5.03 GENERAL USES Each grade of asphalt emulsion is designed for specific uses. They are described in general

terms in the following paragraphs,

- Rapid-Setting EmuLsions: The rapid-setting grades are designed'to react quickly with aggregate and revert from the emulsion state to asphalt.

37

They are used primarily for spray applications, such as aggregate (chip) seals, sand seals, surface treatments, and asphalt penetration macadam. The RS-2 and CRS-2 grades have high viscosities to prevent runoff.

- Medium-Setting Emulsions: The medium-setting grades are designed for mixing with coarse aggregate. Because these grades do not break immediately upon contact with aggregate, mixes using them remain workable for a few minutes. They are used extensively in t!:~y'e!Jiliints~ The CMS grades have high viscosities to prevent runoff.

A newly standardized medium-setting asphalt emulsion, identified as high float, is anionic in nature. The major difference between this emulsion and the conventional medium-setting is the high float characteristic, measured on the asphalt residue by the Float Test, ASTM D 139 (AASHTO T 50). It reportedly gives better aggregate coating and asphalt retention under extreme temperature conditions. While regular asphalts have a tendency to flow, or migrate- at about 60°C (140°F), the high float residues are designed to stay in place up to about 71 °C (l60°F). Therefore, high float residues are less susceptible to changes in temperature. They soften less in summer and do not harden as much in winter.

The American Society for Testing and Materials has standardized four grades of high-float emulsions-HFMS-I, HFMS-2, HFMS-2h and HFMS-2s. Their specifi­cations are contained in ASTM D 977 (see Table II-I).

- Slow-Setting Emulsions:

The slow-setting grades are designed for maximum mixing stability. They are used with high fines content, dense-graded aggregates. The SS grades have long work­ability times to ensure good mixing with dense-graded aggregates. All slow-setting grades have low viscosities that can be further reduced by adding water. These grades, when diluted, can also be used for tack coa~s, f()g §.~~ls, and <i!:!§l.p-!;llU1ltiYe.s. The SS grade of emulsioll.depends entirely upon ev~poratioll 9L!.he yater...f9f c@1escen~of the.aspbJ!lLparticies'. If a faster setting rate is needed in mixtures, as is t~9!~.e for slurry seals, p()r,tland cement or hydrated lime can be added. ~~e SS emulsions are generally used for dense-graded aggregate-emulsion ba,ses, so!!:-as­p~~IL~tabilization, asphalt surface mixes, and slurry seal:;.

,Table V-I shows the general uses of standard emulsion types and grades .

. 04 ADHESIVE PROPERTIES Success with any aggregate-emulsion combination depends greatly on t~lectrici!Lsurface

c_harges.,Qf the asphalt droplets and the aggregate. The probability of good adhesion is diminished if tl!~ charges are similar. Conversely, the probability of good adhesion is greatly improved if the charges are different. The predominating charge on the aggregate surface determines whether anionic or cationic emulsion will produce the best results. The only way to be sure

,js to test in the laboratory.

5.05 GUIDELINES FOR SUCCESSFUL PERFORMANCE In summary, success with any type and grade of asphalt emulsion system is best ensured

by adherence to each of the following steps:

38

I. Laboratory testing using the actual aggregate and emulsion that is to be used on the project.

2. Selection of grades in conformance with TabIeV -l~nd Article 5.02_ .. Table V -2 may he helpful also.

J. Strict adherence to the specifications and guides for usage. 4. Careful handling of the emulsion to prevent con~ITl}!!ation, settlem~l1tofJhe_asphalt

droplets, or premature coatt!~<:~!lce. 5. Consultation with the emulsion manufacturer's representative when special or un­

usual problems occur. Asphalt emulsions as an alternative for use in paving and maintenance operations are now a

reality. Following proper procedures will produce a system that should provide a high level of service.

TABLE V-1 GENERAL USES OF EMULSIFIED ASPHALT NOTE-Only those grades of emulsified asphalt in general use have been indicated herein. It is possible that under certain variations of aggregates, or climatic conditions, or both, additional selections might be appropriate. Where the use of emulsified asphalt for applications other than those listed in the table are contemplated, the emulsion supplier should be consulted.

ASTMD977 ASTMD2397 AASHTOM208 AASHTOM 140

Type of ;h .c '" t"1

~ Construction r.h .r.h r.h '" .c

-7~ ;t~ ~~ .c ;;; ~ r.h ;;; ;;; '" ~ ;;; '" '" r.h r.h "'::c ~::c r.h 00: 00: ::l! ~ '" ~ 00: 00: ~, ~ ::c '" '" U U U U

Asphalt-aggregate mixtures: For pavement bases and surfaces:

Plant mix (hot) X' Plant mix (cold)

Open-graded aggregate X X X X Dense-graded aggregate X X X X X Sand X X X X X

Mixed-in-place: Open-graded aggregate X X X X Dense-graded aggregate X X X X X Sand X X X X X Sandy soil X X X X X Slurry seal X X X X X

Asphalt-aggregate applications:

Treatments and seals: Single surface treatment (Chip Sea\) X X X X Multiple surface treatment X X X X Sand seal X X X X X

A.,phalt applications: X"' XC XC XC ( Fog seal XC

L~i.f11e~()at:penetrable suri~c~ X" XO XO XD XD /!!!.CKCOar] - .' - XB) XC XC XC XC

Dust binder XC XC XC XC

Mulch treatment XC XC XC XC Crack filler X X X X

Maintenance mix: Immediate use X X X X X

A Grades of emulsion other than FH MS-2h may be used where experience has shown that they give satisfactory performance.

II Diluted with water by the manufacturer. {' Diluted with water. " Mixed-in prime only.

39

TABLE V-2 EMULSIFIED ASPHALT SEAL COATS AND SURFACE TREATMENTS

Type of Construction

SAND SEAL

CHIPSEAL

DOUBLE SEAL

TRIPLE SEAL

SLURRY SEAL

CAPE SEAL

Description and Uses

Restores uniform cover. In city street work, improves street sweeping, traffic line visibility. Enriches dry, weathered pave­ments; reduces raveling.

Single most important low cost maintenance method. Produces an all-weather surface, renews weathered pavements, improves skid resist­ance, lane demarcation, seals pavement.

Two applications of binder and aggregate. The second chip application uses a smaller sized stone, than the first. Durable, provides some leveling, available in a number of textures.

Typical Emulsified Asphalts

CRS-1 , CRS-2, RS-1, RS-2, MS-1, HFMS-1

CRS-2 or RS-2

CRS-2 or RS-2

Three applications of binder CRS-2 or RS-2 and 3 sizes of chips are applied. Provides up to a 20mm (3A in.) thick, flexible pavement. Levels as well as providing a seal, tough wearing surface.

Used in airport and city street maintenance where loose aggregate cannot be tolerated. Seals, fills minor depressions, provides an easy-to-sweep surface. The liquid slurry is machine-applied with a sled-type box containing a rubber-edged strike-off blade.

Combines a single chip seal with a slurry seal. Provides the rough, knobby surface of a chip seal to reduce hydroplaning yet has a tough sand matrix for durability.

Test track data indicate better studded tire damage resistance than a chip seal.

CSS-1, CSS-1 h, SS-1, SS-1 h, or OS" Grades

CS-1, CSS-1 h, SS-1, SS-1 h, RS-2 CRS-2and OS" Grades

Modified table from Chevron, U.S.A.

Construction Hints

Spray-applied with sand cover. Roll With pneumatic roller. Avoid excess bin1er.

Spray-applied. Many types of textures availabie. Key to success: Coordinate construc­tion, use hard, bulky grained, clean aggregate, and have properly calibrated spray equipment.

See Chip Seal.

Spray-applied in three lifts.

Pretest the aggregate and emulsion mix to achieve desired workability, setting rate, and durability. Calibrate equipment prior to starting the project.

Apply an aggregate single chip seal. Broom and apply slurry seal. Have the strike-off ride on the rock surface to form the matrix.

Avoid excess slurry as this destroys the knobby stone texture desired.

• The quick-set grades of emulsion (OS) have been developed for slurry seals. While not yet standardized, their use is rapidly increasing, as the unique quick-setting property solves one of the major problems associated with the use of slurry seals.

40

CHAPTER VI

ASPHALT EMULSION SURFACE TREATMENTS

6.01 SURFACE TREATMENTS Asphalt surface treatment is a broad term embracing several types of asphalt and asphalt­

aggregate applications, usually less than 25 millimetres (I in.) thick, to any kind of road surface. The road surface may be a primed granular base, or similar, or it may be an existing pavement. Surface treatments applied to an existing pavement surface often are called seal coats.

V~Qhal!~!:f1E.!sion.-Mm.!ications without aggr~ate cover are also cal~s .. They are included in Chapter VIII. This chapter covers surface treatments consisting of asphalt emulsion-aggregate applications only. And, as surface treatments and seal coats differ in name only for this type of construction, they are treated as a single subject.

A single surface treatment involves spraying asphalt emulsion followed at once by a thin aggregate cover, which is rolled as soon as possible. For multiple surface treatments the process is repeated a second, or even a third time with the aggregate size becoming smaller with each application. The maximum size aggregate for each successive application is about one-half that of the previous one. The total thickness of the treatment is about the same as the maximum size aggregate particles of the first course.

Properly constructed, asphalt surface treatments are economical, easy to place, and long lasting. They seal and add life to road surfaces but each type has one or more special purposes. A surface treatment is not a pavement in itself. Rather, it resists traffic abrasion and provides a waterproof cover over the underlying structure. It adds little load-carrying strength and therefore is not normally taken into account in computing the load limit of a pavement. While a surface treatment can provide an excellent surface if used for the correct purpose, it is not a cure-all to solve all paving problems. A clear understanding of the advantages and limitations of asphalt emulsion surface treatments is essential for best results. It is vital that a careful study of traffic requirements, along with an evaluation of the condition of existing materials and pavement layers, be made.

6.02 USES OF SURFACE TREATMENTS Surface treatments are primarily used for the following purposes:

I. To provide a low-cost, all-weather surface for light to medium traffic.

2. To provide a waterproof layer to prevent the intrusion of moisture into the underlying course.

3. To provide a skid-resistant surface. Pavements that have become slippery because of bleeding or wear and polishing of surface aggregates may be treated with sharp, hard aggregate to restore skid resistance.

4. To give new life to a dry, weathered surface. A pavement that has become weathered

41

to the point where raveling might occur can be restored to useful service by application of a single or multiple surface treatment.

5. To provide a temporary cover for a new base course. The surface treatment is an appropriate cover for a new base course that is to be carried through a winter, or for planned stage construction. The surface treatment makes an excellent temporary surface until the final asphalt courses are placed.

6. To salvage old pavements that have deteriorated because of aging, shrinkage crack­ing, or stress cracking. Although the surface treatment has little or no structural strength, it can serve as an adequate stop-gap measure until a more permanent upgrading can be completed.

7. To define shoulders so they won't be mistaken as traffic lanes.

8. To provide rumble strips for safety.

The need for a strong base or sound pavement under asphalt surface treatments cannot be overemphasized. If the base or pavement is weak, the surface treatment stands little chance of doing its job. Common defects may include unstable materials, faulty compaction, poor aggregate grading, lack of drainage, and insufficient strength for the expected traffic.

6.03 SAFEGUARDS A few simple safeguards will greatly increase the chance of success when a surface treatment

is used. These are • 'common-sense" items that apply much the same in other types of construc­tion.

- Make sure that all materials to be used meet the job specifications.

- Check to be certain the existing pavement structure can support expected traffic loads before the surface treatment is appl ied.

- Inspect all construction equipment to be assured of proper operation. Calibration of gauges and meters, aggregate spreader, and inspection of spray nozzles is essential.

- Be sure that the asphalt emulsion and aggregate are compatible. Will cationic or anionic emulsion work best? Is the aggregate free from dust?

- Determine the optimum application rate of emulsion and correct amount of aggregate cover.

- Select the proper type and weight of rollers.

- Adhere to good construction techniques.

- Use proper traffic controls.

- Do the work only in proper weather conditions; i.e., warm and dry. (Emulsions are significantly less tolerant than cutbacks to cool temperature surface treating.)

6.04 COMMON PROBLEMS Adherence to the simple safeguards will prevent problems that could start during the job. Three

of the most common problems and their causes are discussed in the following paragraphs.

42

Streaking. This is the non-uniform application of the asphalt emulsion on the road surface, Figure VI-I. It can be either longitudinal or transverse. Longitudinal streaking shows up as alternating lean and heavy narrow bands of asphalt running parallel to the centerline of the road. Transverse streaking, on the other hand. runs across the road. Streaking not only leaves an unsightly appearance, it can greatly reduce service life through loss of cover aggregate.

Some causes of longitudinal streaking are: - Spray bar on the asphalt emulsion distributor not set at the correct height for the spray

fans to overlap properly.

- Spray bar rising as load in distributor lightens.

- Nozzle on spray bar not set at correct angle, not all set at same angle, are the wrong size, differ in size, some plugged with cold asphalt, or have imperfections.

- Wrong asphalt emulsion pump speed.

- Asphalt emulsion too cold.

- Pump pressure too low. A single centerline streak may be caused by too little or too much emulsified asphalt at the

joint between two applications. Transverse streaking is caused by spurts in the asphalt spray from the distributor spray bar.

These spurts may be produced by pulsation of the asphalt pump due to worn or loose parts, by improper pump speed, or by poor governor control of the pump motor.

Figure VI-1. Longitudinal streaking.

43

Bleeding (Flushing). This is the upward movement of asphalt in an asphalt pavement that results in a film of asphalt on the surface, see Figure VI-2. Bleeding can cause a slick, hazardous condition during wet weather.

The most common cause of bleeding of a surface treatment is spraying too much asphalt. Other causes are not enough or too small aggregate, or water vapor pressure from the base or subgrade causing flow of asphalt upward.

Figure VI-2. Bleeding asphalt.

Loss of Cover Aggregate. This is the whipping-off of aggregate under traffic from a surface­treated pavement. leaving the asphalt, see Figure VI-3. This condition can be dangerous because loose chips thrown by the tires of a moving vehicle can fly into the windshield of another vehicle. Also, the chip-free asphalt, resembling the bleeding condition, can become a skid hazard.

Several things can cause loss of cover aggregate. If it is not spread immediately after the asphalt emulsion is applied to the surface, the aggregate may not hold. Dry, dusty aggregate may cause premature breaking of the asphalt emulsion and may not leave enough asphalt to hold the

44

aggregate under traffic. If it is not rolled immediately after placing, the aggregate may not become seated firmly enough to hold under traffic. Other causes include: not enough asphalt emulsion; too little aggregate embedment; weather too cool when the treatment is applied; surface being treated is too wet or too dusty when asphalt emulsion is applied; fast traffic too soon on new surface treatment; a surface that absorbs part of the asphalt, leaving too little to hold the aggregate; and a rainstorm that washes away the emulsion.

Figure VI-3. Loss of cover aggregate.

A. MATERIALS

6.05 GENERAL To produce high quality, durable, surface treatments both the asphalt emulsion and the

aggregate must meet established quality standards. Although other types of asphalt materials may be used, this manual is concerned only with the use of emulsified asphalt and the guidelines given will apply only to them.

6.06 ASPHALT EMULSION The successful use of asphalt emulsion for surface treatments is well established. The

emulsions offer several advantages over other types of available materials:

45

-They can be used with cold or hot aggregate.

-They can be used with aggregate that is damp.

-They need not be at highly elevated temperatures for proper application.

-They eliminate the fire hazard that is associated with the use of cutback asphalt.

-They set up more quickly than cutback asphalt.

One of the keys to good performance lies in the selection of the correct type, grade, and application rate of emulsion. Using the correct grade, the asphalt emulsion for surface treatment will:

-When applied, be fluid enough to spray properly and cover the surface uniformly.

-After application, retain the proper consistency to wet the surface being treated and the applied aggregate.

-Cure and develop adhesion quickly.

-After rolling and curing, hold the aggregate tightly to the road surface to prevent dislodgement by traffic.

-When applied in the right amount, not bleed or strip with changing weather conditions.

Table V-I in Chapter V shows the types of emulsified asphalt recommended for surface treatments and seals. Table VI-I gives typical application temperature ranges for the various types and grades. The use of these materials with relatively low temperatures is a significant energy-saving feature.

TABLE VI-1 SUGGESTED DISTRIBUTOR SPRAYING TEMPERATURES FOR VARIOUS GRADES OF EMULSIFIED ASPHALT -DEGREES CELSIUS (CO)

OR FAHRENHEIT (FO)

Spraying Temperatures

Type and Grade Road Mixes Surface Treatments of Asphalt (0C) (OF) (0C) (OF)

Emulsified Asphalts RS-1 - - 20-60 70-140 RS-2 - - 50-85 125-185 MS-1 20-70 70-160 20-70 70-160 MS-2 20-70 70-160 - -MS-2h 20-70 70-160 - -HFMS-1 20-70 70-160 20-70 70-160 HFMS-2 20-70 70-160 - -HFMS-2h 20-70 70-160 - -HFMS-2s 20-70 70-160 - -SS-1 20-70 70-160 - -SS-1h 20-70 70-160 - -CRS-1 - - 50-85 125-185 CRS-2 - - 50-85 125-185 CMS-2 20-70 70-160 - -CMS-2h 20-70 70-160 - -CSS-1 20-70 70-160 - -CSS-1h 20-70 70-160 - -

46

Asphalt emulsion binders used for surface treatment operations are normally the rapid-setting type. Rapid-setting emulsions should be used when heavy traffic makes a rapid rate of cure essential, or when uncertainty about wet weather makes rapid-setting imperative.

6.07 AGGREGATE Any aggregate used in a surface course is subjected to the abrasive action of traffic. If it

is not hard enough to resist rapid wear, the pavement may become a skid hazard when wet. Most hard aggregates can be used with success for surface treatments. But all that are considered for use should be tested for abrasion wear, the standard test being the Los Angeles Abrasion Test, ASTM C 131 (AASHTO T 96). For surface treatment use, the abrasion wear should be not more than 45 percent. Angular particles with rough surface texture and relatively low absorption will produce the best results. The aggregate selected, however, also must meet job requirements for size, shape, and cleanliness.

Size. The aggregate should be as close to one size as is economically practical, preferably in the range of 12.5 to 6 mm (1J2 to 1J4 in.) for single surface treatments. Larger sizes may be used in multiple treatments. If it is much larger than 12.5 mm (1J2 in.), it can cause objectionable tire noise. If much finer than 6 mm (1J4 in.), it is hard to spread evenly. Also, the finer the aggregate the smaller the allowable range for asphalt application rate becomes. Generally, the largest particle should be no more than twice the diameter of the smallest one. An allowance should be made for a slight amount of oversized and undersized particles. For single treatments, the top size is limited by the amount of emulsified asphalt that can be applied in one pass of the distributor without flowing off the surface.

Shape. The ideal shape for surface treatment aggregate is cubical. Flat or elongated particles are undesirable. They tend to become aligned on their flat sides and may be completely covered with asphalt when enough is used to hold the cubical particles in place. Figure VI-4 is an example of this condition. If all particles are flat, it takes so little asphalt to hold them that control becomes difficult .

Clealliiness. Clean aggregate is very important. If the particles are dusty or coated with clay or silt, the emulsified asphalt may not stick. The dust produces a fil m that prevents the asphalt from adhering to the aggregate.

VOIDS AGGREGATE PARTICLES

Figure VI-4. Flat particles are covered when enough asphalt is used to hold cubical particles.

47

B. TYPES OF TREATMENTS AND SEALS

6.08 SINGLE SURFACE TREATMENT A single surface treatment, often called "chip seal," may be used for one of several reasons:

- As an interim measure pending application of a higher pavement type.

- To correct surface raveling and oxidation of old pavements.

- To provide a waterproof cover over an existing pavement structure.

- To correct excessive traffic wear beyond that presumed in the original design.

The single treatment approach is expecially suited for light duty traffic and as an interim maintenance procedure. It also may be used following crack sealing operations. The surface treatment is applied to resist the abrasive forces of the traffic.

Problems that can be associated with a treatment of this type include:

- Construction during cool weather. It usually requires about one month of warm weather following construction for the aggregate particles to become reoriented and properly embedded in the asphalt membrane.

- Possible damage to windshields by loose aggregate not embedded in the asphalt membrane.

Possible loss of cover aggregate because of the relatively thin layer and the time required for embedding and bonding to develop. In a single treatment the larger aggregate particles are more prone to be lost.

6.09 MULTIPLE SURFACE TREATMENT A multiple surface treatment can produce a pavement thickness in the order of 13 to 19

mm (Y2 to % in.). Some extra reinforcement may be added with this type of treatment. If properly designed and constructed, double surface treatments give about three times the service life of a single surface treatment for about I Y2 times the construction cost. Because the cover stone for the second layer is smaller, loss of particles from a graded cover aggregate is greatly minimized.

In a double surface treatment the largest size of stone in the first course determines the surface layer thickness. The second course serves to fill the voids in the mat of the first course aggregate. The extent to which these voids are filled determines the texture and riding quality of the surface treatment.

One type of surface treatment known as "cape seal," involves application of a slurry seal to a newly-constructed surface treatment. Because this system does not have widespread usage, it is not presented in detail~ but refer to Table VI-6, Chapter VI, and Par 6.13.

A good, long-lasting pavement can be produced by increasing the thickness with more surface treatments, either single or multiple, as traffic conditions demand.

48

6.10 SAND SEAL Sand seal is defined as a spray application of asphalt emulsion followed with a light covering

of fine aggregate, such as clean sand or screenings. Although this is a rather simple operation, it can be useful in correcting a number of pavement flaws. The procedure involves an emulsion spray application. Usually, emulsion grades RS-I, CRS-I, MS-I or HFMS-I are used at a rate of about 0.68 to 0.90 litre/m2 (0.15 to 0.20 galjyd2). This is followed by about 5.5 to 8 kgjm2 (10 to 15lbjyd2) of sand, or screenings cover.

The sand seal is used primarily for the following purposes:

a. To enrich a dry, weathered or oxidized surface. The sand seal will help prevent loss of material from the old surface by traffic abrasion.

b. To prevent the intrusion of moisture and air. When an existing pavement surface begins to crack, moisture and air may pass into the underlying pavement structure thereby reducing its load carrying ability. A sand seal can provide a barrier to prevent this intrusion.

c. To develop a skid-resistant surface texture. By selecting a sharp, angular fine aggregate, a highly skid-resistant surface can be provided. The sand may also be used to "soak up" spots of asphalt that have appeared on the surface because of an overly rich condition.

6.11 SLURRY SEAL A slurry seal is a mixture of well-graded fine aggregate, mineral filler (if needed), emulsified

asphalt, and water applied to a pavement as a surface treatment. It is used in both the preventive and corrective maintenance of asphalt pavement surfaces. It does not, nor is it intended to, increase the structural strength of a pavement section. Any pavement that is structurally weak in localized areas should be repaired before applying the slurry seal. All ruts, humps, low pavement edges, crown deficiencies, waves, or other surface irregularities that diminish the riding quality should be corrected before placing the slurry seal.

Slurry seal, when applied to the surface of an older pavement, can be used quite effectively. It will seal the surface cracks, stop raveling and loss of matrix, make open surfaces impermeable to air and water, and improve skid resistance. Its timely appl ication will help reduce surface distress caused by oxidation of the asphalt and embrittlement of the paving mixture.

Slurry seal has a number of advantages: some are listed below: -Rapid application.

-No loose cover aggregate.

-Excellent surface texture for paint striping.

--Ability to correct minor surface irregularities.

-Minimum loss of curb height.

-No need for manhole and other structure adjustments.

- In many cases, the relatively low cost of the treatment makes it practical to import aggregates for special effects, such as high skid resistance, color contrast and noise reduction.

49

Figure VI-S. Slurry seal machine. Courtesy Slurry Seal Incorporated.

CD 1\j!llrellate Bin

0) Filler Bin

CD AIlllrellate Flow Gate

0 AIlllregate Conveyor Belt

CD Emulsion Injector

<1) Water Injector

(i) Pugmill

CD Spreader Box

CD Slurry

Figure VI-6. Flow diagram of a typical slurry seal mixer. Courtesy Scan Road , Inc.

50

The slurry is usually applied in a thickness of 3 to 6 mm (Vs to V4 in.). It comes directly from a traveling mixing plant into an attached spreader box that spreads the slurry by a squeegee-type action, Figure VI-5. The machine used for production of the slurry seal is a self-contained, continuous-flow mixing unit. It is capable of delivering accurately to the mixing chamber predetermined amounts of aggregate, mineral filler (if required), water, and asphalt emulsion. It also discharges the thoroughly mixed materials on to the prepared surface. Certain basic features are common to all batch type slurry machines. They are truck-mounted units with separate storage tanks, bins, and metering systems for emulsified asphalt, water, aggregate and mineral filler. The slurry machine has a continuous-flow mixing unit, either single or double pugmill, from which the slurry is discharged into a spreader box. The box is equipped with flexible squeegees and a device for adjustable width. Spreader boxes may be equipped with hydraulically-powered augers to keep the slurry in motion and help keep the mixture uniformly spread across the spreader box width. These are helpful when quick-set (QS) emulsion is used (refer to Article 2.03). One type of slurry mixer unit is depicted in the schematic drawing, Figure VI-6.

Continuously self-loading machines capable of mixing 15 lane miles per day of coarse slurry are in use in many regions of the United States.

The aggregate used in slurry seal must be clean, angular, durable, well graded, and uniform. An individual aggregate or a blend of aggregates to be used in a slurry mix should meet these limits:

- Sand equivalent value, ASTM D 2419 (AASHTO T 176) = 45 minimum.

- Los Angeles abrasion loss, ASTM C 131 (AASHTO T 96) Grading C or D = 35 maximum.

Also, the amount of smooth-textured sand of less than 1.25 percent water absorption is limited to not more than 50 percent of the total combined aggregate.

The three generally accepted gradings used for slurry mixtures are shown in Table VI-2. Type I is used for maximum crack penetration. Also, it makes an excellent pretreatment

for hot-mix overlay or chip seal. It is usually used in low density traffic areas such as light aircraft airfields, parking areas, or shoulders where the primary objective is sealing.

Type II is the most widely used gradation. It is used to seal; to correct severe raveling, oxidation, and loss of matrix; and to improve skid resistance. It is used for moderate to heavy traffic, depending upon the quality of aggregates available and the design.

Type III is used to correct surface conditions, as the first course in multicourse applications for heavy traffic, and to impart skid resistance.

Emulsified asphalt used in the slurry mix may be SS-I, SS-lh, CSS-l, or CSS-lh. The recently developed quick-setting (QS) asphalt emulsion is being used when early opening to traffic is necessary. Sometimes, a small amount of liquid or powdered additive is added to the asphalt emulsion to control the setting time of the slurry mixture. This additive starts the set in anionic quick-set emulsions. It retards the set in cationic quick-set emulsions.

It is almost always necessary to add a small amount of mineral filler-hydrated lime, limestone dust, portland cement, or fly ash-to aid in stabilizing and setting the slurry.

Water used in the slurry should be potable and compatible with the mix. Blending the slurry seal materials in varying proportions in the laboratory is a great aid in

selecting the proper mixture. Correct blending should produce a slurry with a creamy texture that will flow smoothly in a rolling wave ahead of the strike-off squeegee. This slurry should be a semifluid, homogenous mass with no emulsion runoff.

51

TABLE VI-2 SLURRY MIXTURE GRADINGS*

Type of Slurry I II III

1 st and or 2nd Crack General seal, application,

General filling medium two-course Usage & fine textured slurry, highly

seal surfaces textured surfaces

Sieve Size Percent Passing

9.5mm Wain.) 100 100 100 4.75mm (No.4) 100 90-100 70-90 2.36mm (No.8) 90-100 65-90 45-70 1.18mm (No. 16) 65-90 45-70 28-50 600 flm (No. 30) 40-65 30-50 19-34 300 flm (No. 50) 25-42 18-30 12-25 150 flm (No. 100) 15-30 10-21 7-18 75 flm (No. 200) 10-20 5-15 5-15

Residual Asphalt Content, % Weight 10-16 7.5-13.5 6.5-12 of dry aggregate

Application Rate, kg/m2 (lb/yd2

),

based on mass 3-5.5(6-10) 5.5-8(10-15) 8(15) or more (weight) of dry aggregate

* Recommended by International Slurry Seal Association.

If lumping, balling, or unmixed aggregate is observed, the slurry should be removed from the pavement. It should also be removed if coarser aggregate particles settle to the bottom of the mix. Streaks, such as those caused by oversized aggregate, should be repaired at once with a hand squeegee.

After mix proportions have been determined in the laboratory it is always advisable to place one or more trial mixes. This should be done either at the job site or in a location where small spreads of the slurry seal would not be objectionable. The trial sections serve a two-fold purpose. First, to calibrate the feeding and metering devices on the slurry machine. Aggregate flow should be determined for different gate openings and the amount of emulsion pumped per revolution of the aggregate feed belt. Second, to see if the slurry mix proportions are right. It is often necessary to make several trial runs to find the best blend of materials - even when starting with a laboratory-determined mixture.

Just before applying the slurry, the pavement surface should be cleaned of all dirt, dust, mud spots, vegetation, and other foreign matter. A tack coat of diluted emulsified asphalt of the same type and grade specified for the slurry may be rC4uircd directly ahead of the slurry application. With relatively new asphalt pavements, the tack coat may be omitted. In this case, the surfuce should be pre-wetted by water fogging. The surface should be damp but with no free water in front of the slurry machine.

Special care must be taken with longitudinal and transverse joints to prevent excessive buildup of slurry (ridging) or to prevent streaking. It is best to make the joint after the: first placed lane is

52

either completely cured or is stilI in a semi-fluid condition. For good appearance and durability, a joint should not be made when the lane to be joined is only partially set, as tearing and scarring may result.

Quite often a drag is pulled behind the spreader box to improve the joint and overall surface appearance. Drags should be changed regularly. Hand squeegees and hand drags are used to improve joints and place the slurry in areas inaccessible to the machine.

It is especially important to get a good homogenous mix; one that will produce a slurry with a creamy texture that will flow smoothly in a rollaway wave inside the spreader box. A non-homogenous mixture will cause an asphalt rich surface and many ensuing problems.

On flat grades, slurry in the spreader box must be kept at a uniform thickness. On high crowned pavements or superelevated curves, slurry should be diverted to the high side of the spreader box. Gravity will keep the low side filled. Spreading slurry in hilly areas is easier if the slurry machine travels in an uphill direction. If circumstances require placing in a downhill direction, the slurry must be thickened to contain it from flowing ahead of the machine.

Rolling a slurry seal is only needed in those areas where pneumatic-tired rolling will improve durability. Such areas include taxiways, runways, truck terminal yards, and intersections of heavily traveled roads. All of these are subject to power steering turns, braking, or acceleration forces. For rolling, a 4.5 tonne (5 ton) pneumatic roller with 345 kPa (50 psi) tire pressure will be most effective. Rolling can start as soon as clear water can be pressed out of the slurry mixture with a piece of paper, without discoloring the paper. In most cases, however, traffic will iron out the slurry and close any hairline cracks of dehydration. Rolling usually is not needed unless the thickness is more than 6 mm (V4 in.) or unless late season work is involved.

Slurry should be placed only when the temperature is at least 10°C (50°F) and rising and when no rain is expected. A newly placed slurry should not be opened to traffic until it has completely cured. As with rolling, traffic generally can be allowed on the slurry as soon as a clear water can be pressed out of the slurry mixture with a piece of paper without discoloring the paper. The traffic, of course, must be controlled somewhat as quick stops or accelerations and the turning of wheels while parked will cause damage to the slurry.

For slurry seal design the following sources are recommended:

ASTM D 3910 "Standard Practices for Design, Testing and Construction of Slurry Seal" American Society for Testing and Materials 1916 Race Street Philadelphia, PA 19103

"Recommended Performance Guidelines for Emulsified Asphalt Slurry Seal Surfaces" Al 05

International Slurry Seal Association 1101 Connecticut Avenue Washington, D. C. 20036

"Recommended Guideline for Slurry Seal" Asphalt Emulsion Manufacturers Association 1133 Fifteenth Street, N. W. Washington, D.C. 20005

53

C. SURFACE TREATMENT DESIGN

6.12 SINGLE SURFACE TREATMENTS When a decision has been made that a surface treatment is to be used, the next step is to

find the proper rates of application for asphalt emulsion and aggregate. The objective is to produce a pavement surface one stone thick with enough asphalt to hold the aggregate in place, but not so much that it will bleed.

When a one-sized cover aggregate is dropped by a spreader on an asphalt film the particles will lie in an unarranged position. After compaction and considerable traffic, the particles will become oriented into their densest position with about 20 percent voids between the particles. It is desirable to fill these voids about two-thirds to three-fourths full with asphalt. A typical design will call for 70 percent of the voids filled. Because of the meniscus effect of the residual asphalt left on the aggregate upon the evaporation of the water when emulsified asphalt is used, the residual asphalt can be reduced to 55 to 60 percent of the voids between the aggregates under average conditions.

There are several theoretical procedures for determining the quantity of cover aggregate. These usually involve determining the average least dimension, the voids in the cover aggregate and the bulk specific gravity.

Mathematical calculations, coupled with laboratory testing, are usually employed in deter­mining the required quantities of asphalt and aggregate. Rather than herein presenting a complex means of making these determinations, Table VI-3 is presented. This table gives a range of asphalt and aggregate applications with respect to the specific size of aggregate being used. The suggested quantities of asphalt cover the average range of conditions that include primed granular bases and old pavement surfaces. The quantities and types of materials may be varied according to local conditions and experience.

However, a rather simple way of determining the quantity of aggregate is simply to spread the aggregate to be used over an area of I square metre (I yd2). A pan I x I metre x 25 mm (3 x 3 ft. x 1 in.) deep is suggested, as this will also allow determination of the asphalt quantity. Place aggregate in the pan carefully by hand, arranging the aggregate so that it fills the pan in the densest condition anticipated to exist in the field after the surface treatment has been subjected to traffic. In order to do this it is necessary to have a good visual image ofthe finished product. Determine the mass (weight) of the aggregate required, and that mass (weight) will be the spread rate of the aggregate, in kilograms per square metre (pounds per square yard.)

With the aggregate carefully arranged as described, fill the pan with water until the surface of the water comes just to the top of the aggregate. Measure this volume of water and use approximately two-thirds of that volume as the asphalt quantity required (adjusted, of course, by Note 3 of Table VI-3).

54

TABLE VI-3 QUANTITIES OF ASPHALT AND AGGREGATE FOR SINGLE SURFACE TREATMENTS AND SEAL COATS,* 123

Quantity of Quantity of Line Nominal Size Size Aggregate Asphalt Type and Grade

of Aggregate No. kg/m2 (lb/yd2) 11m2 (gal/yd2) of Asphalt

1 19.0t09.5mm 6 22-27 1.8-2.3 RS-2, (% to 3/a in.) (40-50) (0.40-0.50) CRS-2

2 12.5t04.75mm 7 14-16 1.4-2.0 RS-1, RS-2, (112 in. to No.4) (25-30) (0.30-0.45) CRS-1 , CRS-2

3 9.5t02.36mm 8 11-14 0.9-1.6 RS-1,RS-2, (3fa in. to No.8) (20-25) (0.20-0.35) CRS-1 , CRS-2

4 4.75 to 1. 18mm 9 8-11 0.7-0.9 RS-1, MS-1 (No.4 to No. 16) (15-20) (0.15-0.20) CRS-1, HFMS-1

5 Sanel AASHTO 5-8 0.5-0.7 RS-1, MS-1 M-6 (10-15) (0.10-0.15) CRS-1, HFMS-1

*These quantities of asphalt cover the average range of conditons that Include primed granular bases and old pavement surfaces. The quantities and types of materials may be varied according to local conditions and experience.

lThe lower application rates of asphalt shown in the above table should be used for aggregate having gradations on the fine side of the specified limits. The higher application rates should be used for aggregate having gradations on the coarse side of the specified limits.

2The mass (weight) of aggregate shown in the table is based on aggregate with a specific gravity of 2.65. In case the specific gravity of the aggregate used is lower than 2.55 or higher than 2.75, the amount shown in the table above should be multiplied by the ratio that the bulk specific gravity of the aggregate used bears to 2.65.

3ft is important to E'djust the asphalt content for the condition of the road, increasing it if the road is absorbent, badly cracked, or coarSI~, and decreasing it if the road is "fat" with flushed asphalt.

Texture

Black, flushed asphalt .................................. . Smooth. non-porous ................................... . Absorbent -slightly porous, oxidized ................. .

-slightly pocked, porous, oxidized ....... . -badly pocked, porous, oxidized ........ .

Correction**

Iitre/m2

-0.04 to -0.27 0.00 0.14 0.27 DAD

(gal/yd2)

(-0.01 to -0.06) (0.00) (0.03) (0.06) (0.09)

**This correction must be made from observations at the jobsite.

55

6.13 MULTIPLE SURFACE TREATMENTS There are several arbitrary design methods for multiple surface treatments. In the method

described here, each course is designed as though it is a single surface treatment. For each succeeding course the nominal top size of cover stone should be not more than one-half the size of that for the previously placed course. No allowance is made for wastage. Also, after the first course, no correction is made for underlying surface texture.

Asphalt quantities for each course are added together and 40 percent of the total should be applied for the first application and 60 percent for the second application in a double surface treatment. In a triple surface treatment, 30 percent of the total should be applied for the first application, 40 percent for the second application and 30 percent for the third application.

In multiple surface treatments, the first course of cover aggregate generally determines the thickness. Subsequent courses partially fill the upper voids in the previously placed courses. [See Tables VI-4 and VI-5.]

The term "Cape Seal" is attributed to the Cape Provincial Administration of South Africa. A Cape Seal can be defined as a single layer surface treatment (chipseal) followed by an emulsion mix slurry seal.

In order to have a successful Cape Seal project beyond following standard surface treatment and slurry seal specifications and methods, it is important that the surface treatment be placed as a single course only. The most critical element to avoid in a Cape Seal is an excess of slurry, as this can destroy the desired knobby surface texture. A cure time of four to ten days between placement of the surface treatment and subsequent slurry seal application should also be provided for, during which time regular brooming should occur to remove loose cover material or other foreign material that would prevent the adherence of the slurry. [See Table VI-6.]

TABLE VI-4 QUANTITIES OF ASPHALT AND AGGREGATE PER SQUARE METRE (SQUARE YARD) FOR DOUBLE SURFACE TREATMENT

Quantity of Quantity of Nominal Size Size Aggregate Asphalt of Aggregate No. kg/m2 (lb/yd2

) 11m2 (gal/yd2)

12.Smm (%") Thick 1 st Application* 9.5 to 2.36mm 8 14-19 0.9-1.4

(3fs in to No.8) (25-35) (0.20-0.30) 2nd Application 4.75to 1.18mm 9 5-8 1.4-1.8

(No.4 to No. 16) (10-15) (0.30-0.40)

1S.9mm (%") Thick 1 st Application* 12.5t04.75mm 7 16-22 1.4-1.8

(% in. to No.4) (30-40) (0.30-0040)

2nd Application 4.75to 1.18mm 9 8-11 1.8-2.3 (No.4 to No. 16) (15-20) (0.40-0.50)

19.0mm (3f4") Thick 1 st Application * 19.0t09.5mm 6 22-27 1.6-2.3

(3f4 to 3fs in.) (40-45) (0.35-0.50) 2nd Application 9.5t02.36mm 8 11-14 2.3-2.7

We in. to No.8) (20-25) (0.50-0.60)

* If applied on untreated granular (stone) base use penetrating prime in lieu of emulsions (See Par. 8.06)

56

TABLE VI-5 QUANTITIES OF ASPHALT AND AGGREGATE PER SQUARE METRE (SQUARE YARD) FOR TRIPLE SURFACE TREATMENT

(ARMORCOAT)

Quantity of Quantity of Nominal Size Size Aggregate Asphalt of Aggregate No. kg/m2 (lb/yd2

) 11m2 (gal/yd2)

12.5mm (%") Thick 1 st Application· 9.5 to 2.36mm 8 14-19 0.9-1.4

(% in to No.8) (25:35) (0.20-0.30) 2nd Application 4.75 to 1.18mm 9 5-8 1.1-1.6

(No.4 to No. 16) (10-15) (0.25-0.35) 3rd Application 4. 75mm to 150,.,.m 10 5-8 0.9-1.4

(No.4 to No.1 00) (10-15) (0.20-0.30)

15.9mm (5fs") Thick 1 st Application· 12.5t04.75mm 7 16-22 0.9-1.4

(% in. to No.4) (30-40) (0.20-0.30) 2nd Application 9.5 to 2.36mm 8 8-11 1.4-1.8

(% in. to No.8) (15-20) (0.30-0.40) 3rd Application 4.75to 1.18mm 9 5-8 0.9-1.4

(No.4 to No. 16) (10-15) (0.20-0.30)

19.0mm (3f4") Thick 1 st Application· 19.0t09.5mm 6 19-25 1.1-1.6

(%to%in.) (35-45) (0.25-0.35) 2nd Application 9.5 to 2.36mm 8 11-14 1.4-1.8

(% in. to No.8) (20-30) (0.30-0.40) 3rd Application 4.75 to 1 .18mm 9 5-8 1.1-1.6

(No.4 to No. 16) (10-15) (0.25-0.35)

• If applied on untreated granular (stone) base use penetrating prime in lieu of emulsions (See Par. 8.06)

TABLE VI-6 QUANTITIES OF ASPHALT AND AGGREGATE PER SQUARE METRE (SQUARE YARD) FOR CAPE SEAL

Llm2-Asphalt Kg/m2-Aggregate Kg/m2-Slurry Mixture 12.5mm (% .. ) Thick (gal/yd2) (lbs./yd2) (lbs./yd2)

Emulsion (RS-2. CRS-2) 1.4 - 2.0 (0.30-0.45)

Cover Aggregate ASTM or AASHTO Size No. 7 12.5 to 4. 75mm 14-16 (W'toNo.4) (25-30)

Slurry Seal Type I 3-5.5 (See Par. 6.11) (6-10)

57

Figure VI-7. Asphalt emulsion distributor. Courtesy E. D. Etnyre Co.

D. EQUIPMENT

6.14 GENERAL The equipment used for surface treatment construction is a major contributor to the quality

of the finished product. It should be kept in proper adjustment and good operating condition by routine maintenance and frequent inspection for excessive wear, breakdown, and calibration. A brief description of the major equipment items is contained in the following articles.

6.15 THE ASPHALT DISTRIBUTOR The most important piece of equipment used in surface treatment construction is the asphalt

distributor, Figure VI -7. Its function is to apply uniformly the asphalt emulsion over a surface at the specified rate.

The distributor consists of either a truck-mounted or trailer-mounted insulated tank with controls for setting the rate at which the asphalt is applied. At the back end of the tank is a system of spray bars and nozzles. Through this system the asphalt is forced under pressure on to the surface of the road. The spray bars cover widths of 3 to 9 m (10 to 30 ft.) in a single pass, depending on the pump capacity. A hand spray is included to apply the emulsion to areas that cannot be reached with the spray bar. The distributor tank normally has a capacity of 3,000 to 20,800 litres (800 to 5,500 gal.). Attached to the tank is a circulating system that includes the spray bar unit. Pressure generated when a noncirculating or un-bypassed spray bar is shut off can cause the emulsion to break and plug the unit with asphalt. The tank is also equipped with one or more heaters that can be used to bring the emulsified asphalt to spray application temperature. Extreme care should be taken in the use of these heaters. Premature breaking of the emulsion may occur if heater temperatures are too high. If the heaters are to be used, the emulsion should be circulating in the tank while heat is applied and excessive temperatures in the heaters should not be allowed.

Two extremely important adjustments are the spray nozzle angle setting and spray bar height. The angle of the long axis of the nozzle openings must be adjusted so that the spray fans will not interfere with each other. The recommended angle, measured from the spray bar axis, is from 0.26 to 0.52 radians (15 to 30 deg.) see Figure VI-8. To ~nsure uniformity of spread, the spray bar must be set and maintained at the proper height above the pavement surface. If it is set too high, wind distortion of the spray fans may occur. The best results usually are achieved with an exact double coverage, but triple coverage can sometimes be used with spray bars with

58

100 mm (4 in.) nozzle spacing. Figure VI-9 illustrates the heights of the spray bar necessary to achieve these coverages.

~- NOZZLE ANGLE SETTING, 0.26 TO 0.52 RADIANS (15 TO 30 DEQ.)

s --SPRAY BAR AXIS

Figure VI-S. Proper nozzle angle setting.

SINGLE COVERAGE

DOUBLE COVERAGE

TRIPLE COVERAGE

Figure VI-g. Spray bar height must be set exactly for proper coverage.

Three controls are standard equipment on most distributors. One is a valve system that governs the flow of material. Another is a pump tachometer or pressure gauge that registers pump output. And the third is a bitumeter with an odometer that indicates the number of metres (feet) per minute and the total distance traveled.

Despite the rather precise controls on the distributor it is always advisable to check the rate of application in the field. This can be done with a shallow metal tray exactly one square metre (1 sq. yd.) in area. If a tray is not available, a sheet of heavy paper or cardboard can be used. The tray is weighed and placed on the surface to be sprayed. Immediately after the distributor has passed, the tray is lifted and weighed again. The difference between the two is the mass (weight) of the emulsified asphalt. The application rate can then be found by the equation below.

where

S.l. Metric R = wM

R = application rate, litre/m2 (gallyd2)

U.S. Customary (R = 0.12wM)

w = weight of emulsified asphalt on tray, kg/m2 (lb/yd2)

M = temperature-volume correction factor, see Table C-l, Appendix C.

59

~16AGGREGATESPREADERS The aggregate spreader is second only to the asphalt distributor in the order of importance

of surface treatment equipment. Its function is to apply a uniform aggregate cover at a specified rate. Spreaders range from the simple vane type attached to a truck tail gate to the highly efficient self-propelled type.

Tail gate spreaders are usually one of two types. One is a steel plate to which is attached a series of vanes to provide coverage across the lane, Figure VI-IO. Another is a truck-mounted hopper with a feed roller activated by small wheels driven by the the truck wheels, Figure VI-II. In

Figure VI-10. Tailgate vane spreader.

Figure VI-11. Hopper type tailgate spreader. Courtesy Chevron U.S.A. Inc.

60

each case, the truck backs to spread the stone. This prevents the freshly applied asphalt from: being picked up by the truck's tires.

Mechanical aggregate spreaders contain hoppers mounted on pneumatic tires. Each has a built-in distribution system to ensure a uniform spread of the aggregate across the entire lane width. Mechanical spreaders are either truck-attached (Figure VI-12) or self-propelled (Figure VI-l3). In both types, the aggregate is dumped from a truck into a receiving hopper for spreading. The truck-attached spreader contains an auger and a roughened spread roll in the hopper that ensures a positive, uniform feed of material. The self-propelled unit has a similar feed mechanism. One difference is that the self-propelled spreader contains a scalping screen over the aggregate receiving hopper; another is a sloped screen, over which the cover aggregate passes that drops the larger particles into the asphalt film first, followed by the finer particles which fall through the screen. This system ensures that the larger particles are embedded in the asphalt enough to hold them in place while the fines fall onto the larger particles. The self-propelled unit has the advantage of being able to follow closely behind the asphalt dis­tributor, with minimum stopping to change aggregate trucks.

Mechanical self-propelled aggregate spreaders should be calibrated to apply the quantity of cover stone indicated by the design requirements for any given project. The required equipment can be very simple, and may consist only of several sheets of canvas each being exactly one square metre (square yard), and a bathroom scale. By making several runs at different speeds and gate openings over the sheets of canvas, and carefully weighing the aggregate on each canvas sheet, the gate opening and aggregate spreader speed required to apply the cover stone at the specified rate per square metre (square yard) can be quickly determined.

61

Figure VI-12. Truck-attached mechanical spreader. Courtesy Chevron U.S.A. Inc.

Figure VI-13. Self-propelled mechanical spreader. Courtesy Chevron U.S.A Inc.

62

6.17 ROLLERS Unless the cover stone is properly embedded in the asphalt film there is a danger that some

may be lost through traffic abrasion. Rolling presses the cover material into the asphalt binder, thereby promoting better adhesion. For single surface treatments, pneumatic-tired rollers, Figure VI-14, produce best results. They force the aggregate firmly into the asphalt binder without crushing the particles. The tires are able to press into small depressions to seat the particles. Steel-tired rollers tend to bridge over such depressions.

With multiple surface treatments, one or two steel-tired roller passes, after pneumatic-tired rolling, will help produce a smoother surface.

Figure VI-14. Pneumatic-tired roller.

63

6.18 POWER BROOM Unless the surface to be covered is completely clean, the asphalt may not adhere to the

pavement. It is therefore necessary to clean the whole surface before spraying the asphalt emulsion. A power street sweeper, Figure VI-IS, is recommended to pick up both dust and loose particles; but if one is not available a rotary power broom should be used. Flushing with water may be necessary when brooms are used, to meet clean air standards.

Power sweepers or brooms are also used to remove loose particles after the treatment is completed.

Figure VI-1S. Power sweeper.

6.19 TRUCKS Enough trucks must be available to ensure that the operation can proceed without interruption.

Frequent stops and starts may cause variations in asphalt spray distribution, rate of aggregate cover, or both, and result in a non-uniform surface.

E. CONSTRUCTION PROCEDURE

6.20 SEQUENCE OF OPERATIONS The sequence of operations is basically the same for all types of surface treatment construc­

tion. The usual order is as follows:

64

I. Patch potholes and r~pair damaged areas in existing pavement.

2. Clean surface to be covered with rotary broom or other approved means.

3. Spray asphalt emulsion binder at specified rate and proper temperature (Table VI-I).

4. Spread cover aggregate at specified rate immediately behind the asphalt spray appli­cation (emulsion still brown in color) to achieve maximum possible chip wetting.

5. Roll aggregate cover to seat particles in asphalt membrane.

Figure VI-16 shows a proper surface treatment operation. If a double or triple surface treatment is required, steps 3 through 5 should be repeated once or twice.

Figure VI-16. Surface treatment operation. Courtesy E. D. Etnyre Co.

6.21 PREPARATION The project engineer should be certain that all equipment has been inspected and is in proper

working order before construction begins. An adequate supply of aggregate should be available on the job site, or scheduled for delivery at proper intervals, to permit continuous spreading operations. The required quantity of asphalt emulsion should also be stored at the job site. If not, delivery arrangements should be scheduled at proper intervals to prevent delays in construc­tion. Also, an adequate traffic control plan should be developed.

65

6.22 PRECAUTIONS Most problems with surface treatments are caused by failure to adhere to common-sense

construction practices. Even when the highest quality aggregates and asphalt emulsions are used, inferior pavements may result unless fixed guidelines are strictly followed. An attempt at short cuts, or construction during bad weather, will probably result in increased maintenance.

Surface treatment operations should not be carried out during periods of cold, wet weather. Best results will be obtained if the air temperature is at least lOoC (50°F) in the shade and rising. Some specifications require that the temperature of the road surface be above 27°C (80°F) before an asphalt spray application can be applied. The reason being the emulsified asphalt may not break properly in cold temperatures and the asphalt will not satisfactorily retain the cover aggregate. Surface treatments should not be constructed in the rain, or when rain is threatening. The water may cause a loss of the partly cured emulsion from the cover aggregate.

A simple rule of thumb can be cited when rapid-setting emulsions are used for surface treatments. The emulsion selected should break just after the first roller pass has been made. This assumes that the roller is following as closely as possible behind the aggregate spreader. And that the spreader, in tum, is maintained immediately behind the asphalt distributor. This sequence should result in good wetting of the cover aggregate by the asphalt emulsion and the development of satisfactory adhesion between the emulsion and cover aggregate-also, good cover aggregate retention when the surface treatment is opened to traffic.

6.23 CHECKING APPLICATION RATE Checks on the rate of application of emulsified asphalt should be made after each run with

the distributor. This can be done quite simply by using the formula shown below. The use of this formula requires that the number of litres (gallons) of asphalt sprayed be known along with the length and width of the spread.

where

S1. Metric

TM R =-

WL

R = Rate of application, litre/m2 (gal/yd2)

U.S. Customary

9TM R = --.-WL

T = Total litres (gallons) spread from the distributor at spraying temperature; i.e., (gauge stick reading before spread)--(gauge stick reading after spread)

W = Width of spread, m (ft)

L = Length of spread, m (ft)

M = Multiplier for correcting asphalt volume to basis of 15.6°C (60°F) (from Table C-l in Appendix C).

66

CHAPTER VII

ASPHALT EMULSION - AGGREGATE MIXES

7.01 GENERAL CONSIDERATIONS Until recent years, engineers considered emulsion-aggregate mixes to be of inferior quality

compared to hot-plant mixes made with asphalt cement. There was a common misconception that emulsion mixes can be used only on low volume, secondary roads with low traffic loads; such is not the case. Advances in technology make it possible for emulsion mixes to perform as well as other types of asphalt mixes. They can be used in the whole range of pavement systems from light duty to heavy duty. Figure VII-J lists some major uses of emulsified asphalt mixes along with some suggested design requirements. Emulsified asphalt and aggregate mix design methods are descrihed in Part Three of this manual.

7.02 STRENGTH TE~TS Several strength tests are availahlc as tools to evaluatc the structural contribution of the mix

to a pavcment section. One that is gaining widespread usage is the resilient modulus, MR test. Another one, in general use, is a stability or hearing capacity test (except for open-graded mixes) that measures resistance, R-Value. This test is performed with the Hveem Stahilometer using 1103 kPa (160 psi) maximum vertical pressure. After determining the R- Value, the same test specimen is evaluated for cohesion. Still another test used for evaulation of stability or bearing capacity is the measurement of a stabilometer S-Value. Again, the Hveem Stabilometer is used in this test. In this case the test results are related to the displacement of the specimen under various conditions of loading and pressure.

Development work has been done on asphalt emulsion-aggregate mix design using several other procedure~, including Marshall Stability and split tension tests.

7.03 AGGREGATE REQUIREMENTS Discussion in previous chapters on testing is largely directed toward the base asphalt

cement and properties of the finished emulsion. Characteristics of the aggregate in any emulsion-aggregate mixture are equally important to good results. Responsibility for proper materials evaluation, good design procedures, adherence to established construc­tion practices, and evaluation of the completed pavement structure are in no way diminished when using an asphalt emulsion. For acceptable results, all involved must follow good engineering practice in every detail, as in any other type of construction operation.

Aggregate constitutes about 90 to 95 percent by weight of an emulsion mixture. A wide variety of types and gradations can be used successfully for both hot and cold mixes. But

67

As a construction aid Must meet user agency base requ irements. 2-3% emulsified asphalt generally used.

Must meet Resistance Rt Value of 70 minimum Upgrading marginal (Initial Cure) and 78 minimum (Final Cure) after

aggregate to quality of vacuum saturation. Field Density should be 95%

untreated granular base of laboratory density. Usual emulsified asphalt range 4.5 to 8%.

Must meet Resistance Rt Value of 78 minimum As a temporary Wearing plus minimum 50 cohesiometer value at room Surface temperature (Initial Cure) and 100 (Final Cure).

Usual emulsified asphalt range 5.5 to 10%.

Mix Type

Must meet minimum requirements as above. To reduce pavement Resilient Modulus and mix void data used to thickness determine lift thickness. Typical emulsified

asphalt range 5.0 to 10%.

'v The mix must not have emulsion run off or be

Open-Graded Base and washed off by water. Drainage 0.5% asphalt maximum. Washoff 0.5% maximum (where

Surface Mixes applicable). Typical emulsified asphalt range 4.5 to 8%.

Use highest emulsion content consistent with Stabilometer S-value of 30 minimum - Cohesiome-

Dense-Graded Wearing ter C-value 100 minimum, both measured at 60°C Surface (140°F). Typical emulsified asphalt contents 6.0 to

15% depending on aggregate gradation.

Subbase Must meet Resistance Rt Value of 60 minimum. Usual emulsified asphalt range 4.5 to 8%.

Figure VII-1. Major uses of emulsified asphalt mixes. Courtesy Chevron U.S.A. Inc.

68

TABLE VII-1 COARSE AGGREGATES FOR ASPHALT PAVING MIXTURES (ASTM 0692)

Amounts Finer Than Each Laboratory Sieve (Square Openings),

Size Nominal Size (Sieves with Weight Percent

No. Square Openings)

63mm 50mm 37.5mm 25.0mm 19.0mm 12.5mm 9.5mm 4.75mm 2.36mm 1.18mm (2-1/2 in.) (2 in.) (1-112 in.) (1 in.) (314 in.) (1/2 in.) (3/8 in.) (No.4) (No.8) (No. 16)

3 50 to 25.0 mm (2 to 1 in.) 100 90 to 100 35 to 70 o to 15 - o to 5 - - - -

357 50 to 4.75mm (2 in. to No.4) 100 95 to 100 - 35 to 70 - 10 to 30 - o to 5 - -

4 .37.5 to 19.0mm (1-1/2 to 3/4 in.) - 100 90 to 100 20 to 55 o to 15 - o to 5 - - -- -

-. --467 37.5 to 4.75mm (1-112 in. to No.4) - 100 95 to 100 - 35 to 70 - 10 to 30 o to 5 - ---- .--~

; -- ., - -

5 25.0 to 12.5 mm (1 to 112 in.) - - 100 90 to 100 20 to 55 o to 10 Oto 5 - - -

57 25.0 to 4.75mm (1 in. to No.4) - - 100 95 to 100 - 25 to 60 - o to 10 o to 5 -

6 19.0 to 9.5mm (3/4 to 318 in.) - - - 100 90 to 100 20 to 55 o to 15 Oto 5 - -

67 19.0 to 4.75mm (3/4 in. to No.4) - - - 190 90 to 100 - 20 to 55 o to 10 o to 5 --- --

68 19.0 to 2.36mm (3/4 in. to No.8) - - - 100 90 to 100 - 30 to 65 5to 25 o to 10 o to 5 -

7 12.5 to 4.75mm (1/2 in. to No.4) - - - - 100 90 to 100 40 to 70 o to 15 Oto 5 -

78 12.5 to 2.36mm (1/2 in. to No.8) - - - - 100 90 to 100 40 to 75 5to 25 o to 10 o to 5

8 9.5 to 2.36mm (3/8 in. to No.8) - - - - - 100 85 to 100 10 to 30 o to 10 o to 5

TABLE VII-2 FINE AGGREGATES FOR ASPHALT PAVING MIXTURES (ASTM 0 1073)

Amounts Finer Than Each Laboratory Sieve (Square Openings), Percent by Weight

Sieve Size Grading Grading Grading

No.1 NO.3 N04

9.5mm (3/8 in.) 100 - 100

4.75mm (No.4) 95 to 100 100 80t0100

2.36mm (No.8) 70 to 100 95 to 100 65 to 100

1.18mm (No. 16) 40 to 80 85 to 100 40 to 80

600f,Lm (No. 30) 20 to 65 65 to 90 20t065

300f,Lm (No. 50) 7t040 30 to 60 7t040

150f,Lm (No.1 00) 2t020 5t025 2t020

75f,Lm (No. 200) Oto 10 Ot05 Oto 10

Note - It is recognized for certain purposes satisfactory results may be obtained with materials not conforming to this specification. In such cases the use of fine aggregate not conforming to the grading requirements of this specification may be authorized only under special provisions based on field experience or laboratory studies of the possibility of designing a mixture of materials to be used on the job that will yield asphalt paving mixtures equivalent in quality to the job mix requirements.

certain standards must be maintained if the mixtures are to meet stability, workability, flexibility, skid resistance, and durability requirements.

In several of the following sections, gradation ranges are suggested for specific mixtures. Many of the gradings are intended for local aggregates alone, or with a minimum of imported materials. Others are intended to produce carefully controlled, well-graded mixtures. Tables VII-l and VII-2 contain ranges for standard mixture designations.

7.04 AGGREGATE TESTS Standard test procedures are used to evaluate aggregate properties. The mineral

aggregates should be tested by the m~thods in Table VII-3. Compatibility of the aggregate with the asphalt emulsion is more critical than in a

standard plant mix using asphalt cement. The mineral composition of the aggregate can have a significant bearing on field performance. For this reason, it is necessary that trial mixes be prepared in the laboratory.

7.05 TRIAL MIXES It is essential that trial mixes be made in the laboratory with the actual aggregates

to determine the type and grade of asphalt emulsion that will be used on the project. An optimum asphalt emulsion content should be found to allow for the water that will evaporate from the emulsion. Moisture in the stockpiled aggregates should also be considered in the design of cold mixes because it may have some effect on the coatability, workability, and compaction. Alternatively, partial drying of the aggregate may be required to attain the optimum moisture content for mixing.

70

TABLE VII-3 AGGREGATE EVALUATION PROCEDURES

Characteristics

Amou01t of material finer than 7511m (No. 200) Sieve in aggregate

Unit weight of aggregate

Sieve analysis, fine and coarse aggregates

Sieve analysis of mineral filler

Abrasion of coarse aggregates Los Angeles Machine

Plastic fines in graded aggregates and soils by use of the Sand Equivalent Test

7.06 ASPHALT SELECTION

Method of Test

ASTM

C 117

C 29

C 136

0546

C 131

02419

AASHTO

T 11

T 19

T 27

T 37

T96

T 176

Although general guidelines for emulsified asphalt selection are presented in Chapter ,V,) some personal judgment must be used, The decision must take into account 'Characteristics of the asphalt residue and curing rate of the emulsion. Also, the type of pavement and the specific construction conditions have a bearing on asphalt selection.

A. MIXED-IN-PLACE

7.07 STABILIZA nON The Transportation Research Board defines stabilization as "the modification of soils

or aggregates by incorporating materials that will increase load bearing capacity, firm­ness, and resistance to weathering or displacement." Soil stabilization with asphalt emul­sion is particularly adaptable to stage construction where additional courses may be needed to meet increased traffic demands. The emulsion serves as an excellent cementing and waterproofing agent.

71

7.08 FACTORS TO CONSIDER The stabilization operation can be a simple process where the asphalt elllulsion and aggregate

are mixed-in-place by a traveling mixer. It may also involve the more sophisticated batch or continuous central mix plant as described in Par. 7.16. With some types of emulsion, proper mixing and coating for stabilization depends on the proper amount of pre-wetting water on the aggregate. Some of the factors that must be considered in determining which method to use include:

- Project location (urban, rural, mountainous, coastal, remote ... ).

- Traffic conditions (from both the design and construction viewpoint).

- Whether imported or in-place aggregate is to be used. Aggregate type and gradation, availability, source, and cost.

- Type of pavement, total mix mass (tonnage), structural section of the pavement, and size of the project.

- Climatic conditions.

- Whether the work will be done by contract or force account.

- Type of available construction equipment.

The best balance between these various considerations must be worked out.

7.09 BLENDING IMPORTED AGGREGATE A laboratory evaluation should be made to determine if blending of an imported ag­

gregate will be necessary. If a central mix plant is to be used, the aggregates can be ac­curately blended with the plant'S hopper system. If a travel plant or mixed-in-place operation is to be used and it is necessary to combine an imported aggregate, separate windrows of the two materials should be constructed. To obtain the specified final grada­tion, the volume of each windrow must be carefully calculated and maintained (Figure VII-2). The windrows are then mixed together thoroughly and windrowed again before the emulsified asphalt is added.

104-------B ------...... -.j r-A --1--+--r-c

Figure VII-2. Volume of win~Q~.

72

7.10 APPLICATION RATES FOR MIXED-IN-PLACE It is probable that some mixing water must be sprayed on the aggregate in the windrow.

The amount of water to produce best results, with regard to coating, must be determined in the laboratory. Most important, the optimum application rate of the emulsified asphalt must be determined. The following formulas can be used to find the emulsified asphalt application rate and forward speed of the mixer or distributor:

First, determine the volume of aggregate in the windrow:

(A + B)C Va = 2 x metres (feet)

where: volume of aggregate in windrow, m

3

(ft3

) m ft

A,B,C, = dimension of windrow, m Cft), (Figure VII-2). Then, find the application rate:

where: Ab = application rate of emulsified asphalt

litre (gal) m ft

Va = volume of aggregate in windrow (see Eq. 1)

Wa = loose unit weight of dry aggregate,

~~ G~) ,(refer to ASTM Test Method C 29, Appendix E

or AASHTO Test Method T 19)

Pb = design percent of emulsified asphalt by dry weight of aggregate in the mixture expressed as decimal

W b ~ weight of emulsified asphalt, ~ (Ib ) ~ I ()() kg

(1)

(2)

(or U. S. Customary 8.3 I~;~ fal

. litre

Refer to Appendix C for weight and volume relations and temperature-volume corrections.

*NOTE: As the specific gravity of asphalt materials varies, even for the same type and grade, the mass (weight) relationships shown above are approximate and should be used only for general estimating purposes. Where more precise data are required, they must be computed on the basis oftaboratory tests on the specific product. The approximate data shown above are for materials at lS.6°C (60°F).

73

To determine forward speed:

where: S = forward speed of mixture or distributor,

Dp = pump discharge rate, lit~e (g~l) mm mm

Ab = emulsified asphalt application rate,

m (ft) min min

m ft

EXAMPLE-

litre (gal)

A windrow of dry aggregate .30m (1.0 ft) high, 2.0m (6.5 ft) wide at the top, and 2.5m (8.2 ft) wide at the base is to be mixed with 7.5 percent by weight of MS-2 emulsified asphalt, Pb' The loose unit weight of the aggregate, Wa, is 1 440kg/m3 (90 Ib/ft3). One-half of the emulsified asphalt is to be applied in each of two passes of a rotary mixer equipped with a spraying system. Needed is the total emulsified asphalt application rate and the forward speed of the mixer.

v = a

v = a

(A + B)C 2 x metres (feet)

(2.0 - 2.5) 0.3 xl = 0.68 m3/m (7.35 ft3/ft) 2

Ab = 0.68x 1~gxO.075 = 73.4 litre/m (5.98 gal/ft)

Asphalt application rate per pass = 731,4 = 36. 7litre/m (2.99 gal/ft). Then, the forward speed

of the mixer, assuming a constant asphalt pump discharge, Dp ' of 100 litre/min (26.4 gal/min), is

EL Ab

S=

S = i:'; = 2.7 rnImin (8.8 ftlmin).

74

7. 11 TRAVEL PLANTS Travel plants are self-propelled pugmill plants that proportion and mix aggregates and

emulsified asphalt in-place as they move along the road. There are two general types of travel plants:

1. One that moves through a prepared aggregate windrow on the roadbed, picks up the material, adds and mixes the emulsified asphalt as it moves forward and discharges at the rear of the machine a mixed windrow ready for aeration and spreading. See Figure VII-3.

2. One that receives aggregate into its hopper from a haul truck, adds and mixes emulsified asphalt, and spreads the mix to the rear as it moves forward on the roadbed, Figure VII-4.

Irrespective of the type of equipment used, the purpose of the travel plant is to leave a uniform, properly coated, emulsified asphalt-aggregate mixture on the roadbed. On some types the proportioning devices are interlocked to ensure a constant emulsified asphalt-aggregate blend. On others the proportioning system is keyed to the travel speed of the mixer.

Figure VII-3. Travel plant, windrow type.

75

Figure VII-4. Travel plant, hopper type. Courtesy Midland Machinery Co., Inc.

7.12 ROTARY MIXERS A rotary type mixer consists of a mobile mixing chamber mounted on a self-propelled

machine. The chamber is open at the bottom and has a width of about 2.1 metres (7 feet). Inside are one or more transverse rotating shafts on which are mounted tines or cutting blades, Figure VII-5. These blades serve a two-fold purpose, cutting the in-place material

76

Figure VII-5. Rotary mixer, pulvimixer type.

to a specified depth and mixing it with the emulsified asphalt. As the machine moves forward it strikes off the freshly-mixed material to a predetermined level. The emulsified asphalt can be introduced either of two ways. In some mixers it comes through a spray bar that extends across the mixer chamber, the amount sprayed being governed by the forward speed of the unit. With the second method an asphalt distributor sprays the emulsion on the aggregates ahead of the mobile mixer. The materials are drawn into the mixing chamber as the machine moves forward.

Rotary mixers may be used to cut and scarify the roadbed materials (either old pavement or new aggregate) without the introduction of asphalt emulsion. They also may be used for aeration.

7.13 BLADE MIXING Blade mixing, while not as efficient as the previously described systems, is perhaps

the least complicated of all mixing methods. Even so, it requires experienced operators. The emulsified asphalt is applied by a distributor on a flattened windrow of imported or scarified in-place material immediately ahead of the motor grader. The blade on the motor grader mixes the materials through a series of turning and tumbling actions, Figure VII-6. Scarifiers or plow attachments on the motor grader aid in breaking up the material in the

77

Figure VII-6. Blade mixing.

roadbed. When a motor grader is used for final leveling of the finished surface, it should be equipped with smooth, rather than treaded, pneumatic tires.

In the usual procedure, the material in the windrow is placed either through a spreader box or by running it through a windrow sizer before adding the asphalt emulsion. The emulsion demand of the aggregate in the windrow must be determined and the amount needed per lineal metre (foot) of windrow calculated.

If pre-wetting water is required, slightly more water than is called for by the design is applied to the windrow and thoroughly mixed with the aggregate. Then, the asphalt emulsion is applied on the flattened windrow in successive passes of the distributor truck and folded into the windrow immediately after each pass.

There is a possibility of variation of the grading of the aggregate in the windrow and a resulting fluctuation in asphalt demand. Therefore, as mixing progresses, close attention should be paid to the appearance of the mix. It is important that uniformity of gradation and moisture content be achieved. Mixing should consist of as many manipulations with the motor grader blade as necessary to thoroughly disperse the asphalt and coat the aggregate particles. Too many passes, though, may result in stripping of the asphalt coating from the aggregate, with certain types of aggregates or emulsions.

When mixing, the mold board of the motor grader should be adjusted to give a rolling action to the material as the blade moves through the windrow. Also, care must be used so that extra material is not taken from the mixing table and incorporated into the windrow. At the same time, none of the windrow should be lost over the edge of the mixing table.

After mixing has been completed, the windrow should be moved to one side of the roadbed in preparation for spreading.

7.14 SPREADING AND COMPACTING The mixture should always be spread to a uniform thickness, whether in a single pass

78

or in several thinner layers, so that no thin spots exist in the final mat. Mixtures that do not require aeration may be spread to the required thickness immediately after mixing, and then compacted with pneumatic-tired, vibratory, or steel-tired rollers.

Blade spreading should be accomplished in successive layers, with no layer thinner than about 2 times the diameter of the maximum particle size. As each layer is spread, compaction should follow almost immediately with a pneumatic-tired roller.

Experience has shown that breakdown rolling of emulsified asphalt mixes should begin immediately before, or at the same time as, the emulsion starts to break (this is indicated by a marked color change from brown to black). About this time, the moisture content of the mixture is sufficient to act as a lubricant between the aggregate particles, but is reduced to the point where it does not fill the void spaces, thus allowing their reduction under compactive forces. Also, by this time, the mixture should be able to support the roller without undue displacement.

Because the tires of the motor grader compact the freshly-spread mix, their tracks will appear as ridges in the finished mat unless there is adequate rolling between the spreading of each successive layer. The roller should follow directly behind the motor grader in order to eliminate these ridge marks.

If, at any time during compaction, the asphalt mixture exhibits undue rutting or shov­ing, rolling should be stopped. Compaction should not be attempted until there is a reduction in diluent content, occurring either naturally or by mechanical aeration.

After one course is thoroughly compacted and cured, other courses may be placed on it. This operation should be repeated as many times as necessary to bring the road to proper grade and crown. For a smooth riding surface the motor grader should be used to trim and level as the rollers complete compaction of the upper layer.

After the mat has been shaped to its final required cross-section, it must then be finish rolled, preferably with a steel-tired roller, until all roller marks are eliminated.

B. ASPHALT EMULSION PLANT MIX (COLD)

7.15 GENERAL As mentioned previously, emulsion mixes can be produced for a wide range of service

conditions ranging from light duty, low traffic volume roads to heavy duty pavement structures designed for off-highway vehicles and equipment. They may be used for base, surface, leveling, widening and overlay courses and are especially adaptable to the upgrading and strengthening of thin pavements. In selecting the type of mix to be used for a project the weight and volume of traffic, the availability of aggregates, and the location and size of the project should be considered. Then the kind of mix that will most economically satisfy all requirements can be designated.

" Asphalt cold mix is a mixture of unheated mineral (iggregate and emulsified. asphalt. The variety of types and grades of emulsified asphalt that are available is a distinct ad­vantage when designing cold mixes using pit or bank run aggregates or aggregates of marginal quality.

This advantage is diminished somewhat when designing high-strength, high-quality mixes where quality controls similar to those for hot-mix asphalt concrete are r';!quired. But even in these situations, cold emulsion mixes offer some advantages over hot mixes such as:

79

Economy-High production rates combined with mobility and low investment cost in equipment. Ideally suited for projects in remote areas.

Non-Polluting-With the exception of stockpile dust there are virtually no emis­sions from cold-mix production, hauling and laydown.

Safety-In high hazard fire areas, e.g., National Forests and Bureau of Land Man­agement Grasslands, fire hazard is reduced because there is no dryer and no high-temperature mix or asphalt cement used in construction.

7.16 MIXING PLANTS Cold-mix plant setups may vary depending on the quality and type of mix being produced.

At the very least it should consist of a mixer, emulsified asphalt storage tank, emulsion metering pump, piping and spray bar equipment and spray bar for feeding water and additives, controls for adjusting and monitoring the various components, a conveyor for feeding the aggregate and, of course, a power source. It may also include one or more aggregate bins, proportioning aggregate feeders, scalping screen, aggregate load-sensing device, and surge bin or storage silo. Batch type pugmills can be used. However, this mix production is ideally suited for continuous mixers and these are used almost exclusively.

The production of high-quality cold mixes for heavy-duty pavements requires a well-control­led plant setup to ensure success. In addition to carefully monitored and controlled blending of aggregate, emulsified asphalts and, in some cases, water, the mixer should be of a type that permits variation in mixing times of 5 to 30 seconds. This can be controlled by shifting the emulsion spray bar, or adjusting the depth of material, or both in a continuous mixer. Surge hoppers or storage silos are highly desirable since they minimize plant shutdowns and improve mix uniformity. A typical cold mix continuous plant is shown in Figure VU-7.

Figure VII-7. Cold-mix continuous plant.

7.17 OPEN-GRADED MIXES Open-graded mixtures with asphalt emulsion have been used for bases and surfaces for

many years. Because of the relatively simple plant equipment required, economy of con­struction strongly favors this type of operation. Durability and field performance of the open-graded mixes have been comparable to other types of asphalt paving. Their flex­ibility and high void contents make them highly resistant to fatigue and reflection crack­ing. Open-graded mixes function somewhat differently when used for surface courses as

80

compared to base courses. Further, mix gradations are different. As surface courses, they permit the rapid removal of surface water because of their high permeability, thereby reducing the problem of hydroplaning. This automatically means that a good drainage field must be provided to facilitate rapid removal of water. When an open­graded mix is used as a base course, and when water-susceptible subgrade materials are present, a positive moisture seal must be provided within or under the open-graded layer to prevent water from entering and weakening the subgrade materials.

7.18 MATERIALS FOR OPEN-GRADED MIXES Samples of all materials for use in the mixture should be submitted to the laboratory

for testing in accordance with the procedures previously outlined. A great variety of ag­gregate gradations have been used for open-graded cold mixes, and with varying degrees of success. Most of the research and development work in recent years has centered in the northwestern states where they have been successfully used as bases and surface courses on many miles of Federal, state and county highways and heavy-duty logging roads. Ag­gregate gradation and quality requirements vary somewhat but most of them closely ap­proximate those listed in Table VII-4. Some attempts have been made to use aggregates with up to 20 percent passing the 2.36mm (No.8) sieve and 5 percent passing the 75J.1m (No. 200) sieve and using CMS-2s* emulsified asphalt. Their performance as high-quality base and surface courses has been variable.

TABLE VII·4 AGGREGATES FOR OPEN-GRADED EMULSION MIXES

Sieve Size

38.1 mm (1-1/2 in.)

25.0mm (1 in.)

19.0mm (3/4 in.)

12.5mm (1/2 in.)

9.5mm (3/8 in.)

4.75mm (No.4)

2.36mm (No.8)

1.18mm (No. 16)

75pm (No. 200)

Los Angeles Abrasion loss @ 500 Rev. (ASTM C 131 ) Percent Crushed Faces

Emulsified Asphalt Grades

Coarse

100

95 - 100

25 - 60

0-10

0-5

0-2

40 max 65 min

Base

Medium

100

90 - 100

20 - 55

0-10

0-5

0-2

40 max 65 min

Surface

Fine

100

85 - 100

0-5

0-2

40 max 65 min

MS-2, MS-2h, HFMS-2, HFMS-2h, HFMS-2s, CMS-2 or CMS-2h

·Some lIser agencies specify an additional cationic sand mixing grade designated CMS-2s. The CMS-2s is lIsed for sand and silty sand mixes; it contains more solvent than standard CMS grades.

81

7.19 OPEN-GRADED MIX DESIGN METHODS Individual laboratories have developed their own methods for determining optimum aggre­

gate, asphalt and water percentages for open-graded mixes. A procedural outline and design criteria for The Asphalt Institute design method for open­

graded mixes are contained in Part 3, Chapter XII. In general, an attempt is made to use as much asphalt as possible without excessive runoff. The initial asphalt content may be selected from experience or by some test method such as the Surface Capacity test for coarse aggregate (Kc) as determined in the Hveem Method of Mix Design. Subsequent trial batches are made with increasing quantities of asphalt and at varying moisture contents until the optimum asphalt content is determined. Ease of mixing, mixing time, percent coating and moisture content will all affect the emulsion content selected. Usually a minimum of 50 to 75 percent coating is required and moisture contents will range from 0.5 to 3.0 percent. Moisture contents in excess of 3 percent usually cause mixing and coating problems as well as excessive runoff during hauling and placing. Stockpiled aggregates with excessive fines [more than 2 percent passing the 75 f.Lm (No. 200) sieve] often contain more than 3 percent water which is one reason fines should be kept to a minimum. Conventional strength and stability test criteria are not applicable for these mixtures since they have very little cohesive strength. Their stability in service is largely dependent on inter-particle friction and confining pressures.

The best guarantee of success when using open-graded mixes for heavy duty bases and surfaces is strict adherence to weather limitations and quality controls for all materials and mixing plants.

7.20 DENSE-GRADED MIXES Dense-graded aggregate mixtures are graded from the maximum size down to and including

material passing the 75 f.Lm (No. 200) sieve. They embrace a wide variety of aggregate types and gradations and, similarly, can be used for the full range of base and surface pavement types, depending on aggregate quality and equipment. Substantial savings can be realized when locally available, unprocessed aggregates are utilized on lightly traveled roads and in bases for heavy-duty pavements.

7.21 MATERIALS FOR DENSE-GRADED MIXES Samples of all aggregate intended for use in the mixture(s) should be submitted for testing

as previously noted. Recommended aggregate gradation and quality requirements for dense­graded mixes are shown in Table VII-5. MS, CMS, SS, CSS, and HFMS emulsified asphalts are used generally for dense-graded mixes.

7.22 DENSE-GRADED MIX DESIGN METHODS The Centrifuge Kerosene Equivalent (CKE) method is generally used to determine the initial

emulsified asphalt content when formulating dense-graded cold mixes. This value is multiplied by 1.4 to correct for the water in SS and CSS types of emulsion. Subsequent trial batches are made in much the same manner as open-graded mixes with the exception that considerably more water is added to obtain adequate coating and workability of the mix. Generally, complete coating of aggregate particles is not considered necessary for dense-graded mixes. The optimum fluids (water and emulsion) for mixing is compared to that needed for compaction since a wide variation in these values could cause difficulty in placing and compacting the mixture.

82

00 w

TABLE VII-5 AGGREGATES FOR EMULSIFIED DENSE-GRADED ASPHALT MIXTURES

Semi-Processed Sieve Size Crusher, Pit Processed Dense-Graded Aspha It Mixtures

USA Standard Alternative or Bank Run

50mm (2 in.) - 100 - - -

37.5 mm (1-1/2 in.) 100 90-100 100 - -25.0mm .... (1 in.) 80-100 - 90-100 100 -

.c

.~ Q>

19.0mm ~ (3/4 in.) - 60-80 - 90-100 100 12.5mm >- (1/2 in.) - - 60-80 - 90-100 .0

0> C

'" 9.5mm '" (3/8 in.) - - - 60-80 -'" 4.75mm

0-(No.4) 25-85 :20-55 25-60 35-65 45-70 ...

c Q> U ....

2.36mm Q> (No.8) 10-40 15-45 20-50 25-55 0-

1.18mm c (No. 16) - - - - -.Q ... '" "0

600J.Lm ~ (No. 30) - - - - -300J.Lm

t:) (No. 50) 2-16 3-18 3-20 5-20 -

150J.Lm (No. 100) - - - - -75J.Lm (No. 200) 3-15 0-5 1-7 2-8 2-9

Sand Equivalent, Percent 30 min. 35 min. 35 min. 35 min. 35 min.

Los Angeles Rattler - 40 max. 40 max. 40 max. 40 max. @ 500 Revolutions

Percent Crushed Faces - 65 min. 65 min. 65 min. 65 min.

Emulsified Asphalt See Tables 11-1 and 11-2 I I I I I

-

--

-100

90-100 60-80

35-65 -

-6-25

-2-10

35 min.

40 max.

65 min.

Modifications to the Marshall or Hveem procedures are used to compact specimens for density and voids analysis. The compacted and cured specimens may then be further tested to determine Resilient Modulus (MR), Marshall, or Hveem stability values or Resistance (R) Value. The latter test is often used with poorly-graded and marginal aggregates used in emulsified asphalt bases.

Part Three of this manual contains emulsified asphalt-aggregate mix design methods: Chapter XI, Modified Hveem Mix Design (for dense graded mixtures); Chapter XII, Procedural Outline and Design Criteria for Open-Graded Mixes; Chapter XIII, McConnaughay Design Method for Cold Mixtures; and Chapter XIV, Marshall Method for Emulsified Asphalt-Aggregate Cold Mixture Design.

Dense-graded emulsion mixes with SS and CSS emulsions can be improved by the addition of 0.5 to 2.0 percent portland cement during mixing. Excessive amounts should be avoided. The cement serves a fourfold purpose:

1. Workability is improved during mixing and laying.

2. Rapid dehydration of the mix occurs permitting compaction to proceed almost immediately.

3. Higher initial mix stabilities are obtained thereby providing better service under early traffic. Strength properties of the asphalt later overcome the early strength attributed to cement.

4. Retained strengths in a water-saturated condition are higher, providing longer pave­ment life.

As with open-graded mixes, when high quality aggregates are used and adequate equipment and production quality requirements are met, dense-graded emulsion mixes provide strength and durability equal to hot-mix asphalt concrete. Many case histories are available revealing high performance levels with limited maintenance cost after several years of use by heavy logging trucks.

7.23 SAND MIXES Except for aggregate gradation, the same basic principles apply for production of sand-emul­

sion plant mixes as for dense-graded, coarse aggregate emulsion mixes. Sand mixes may be used for either base or surface construction. The mixing, transporting, laydown, and compaction procedures parallel those discussed in Articles 7. 16 and 7.24.

The addition of 1 to 2 percent portland cement will aid in the development of early initial strength. Thorough mixing is essential to uniform distribution of the cement throughout the mixture.

A wide variety of fine aggregates throughout the country has produced satisfactory results. Blending of two, or more, aggregates may be necessary to produce the desirable mix charac­teristics. The gradations in Table VII-6 have been used successfully.

The emulsified asphalt content normally varies within a range of 6 to 15 percent. Types SS-I, SS-lh, CSS-l, CSS-1h or HFMS-2s may be used along with a laboratory-determined amount of mixing water added to the sand.

7.24 LAYDOWN AND COMPACTION OF EMULSIFIED ASPHALT COLD MIXES Laydown procedures for cold plant mixes are similar to those employed for hot mixes. Base

courses may be laid with towed type or self-propelled base spreaders. However, self-propelled pavers

84

TABLE VII·6 SAND·EMULSION MIXES

Total Percent Passing Sieve Size

Poorly-Graded Well-Graded Silty Sands

12.5mm (1/2 in.) 100 100 100

4.75mm (No.4) 75 - 100 75 - 100 75 - 100

300l1m (No. 50) - 15 - 30 -

150l1m (No. 100) - - 15 - 65

7511m (No. 200) 0-12 5 -12 12- 20

Sand Equivalent, percent 30 min. 30 min. 30 min.

Plasticity Index NP NP NP

are recommended for high type or heavy duty surface courses. Cold mixes, generally, are not as workable as hot mixes; and open-graded mixtures, in particular, are extremely tough so mat repairs and handwork should be kept to a minimum. If mix sticks to the screed or tearing of the mat occurs, the problem usually can be corrected at the plant by adjusting mix time or emulsion-water ratio (or content). Heating the screed will not solve the problem but lubricating with diesel oil may help alleviate it. (Installing a diesel spray bar at the leading edge of the screed to apply a light diesel mist when needed has been found helpful.)

Cold mixes have been placed in lifts of 100 mm (4 in.) or more but compaction and curing proceed much more quickly with courses of 50 or 75 mm (2 or 3 in.) compacted thickness. Thick lifts may result in non-uniformly aerated layers. Breaking ofthe emulsion in open-graded mixes usually occurs by the time the mix is placed and, as previously stated, the mixes are tough and extremely stable. Unlike the open-graded mixes, however, the emulsion in dense­graded mixes usually does not break until some time after laydown. This, plus the high moisture content usually required for mixing, often necessitates a waiting period until the mixture develops sufficient stability to support the roller(s). The more rapidly the loss of water occurs, the more quickly the mix can be compacted. Here, again, the use of a small amount of cement in the mix will greatly increase the rate of cure.

Because open-graded mixes are extremely tacky and dense-graded mixes are often low in stability, it has been found advantageous to use static steel-tired rollers for breakdown rolling. There is some concern that too much vibratory rolling may cause migration of asphalt and water in dense-graded mixes. Sometimes, pneumatic-tired rollers are used for breakdown. Either pneumatic- or steel-tired rollers may be used for intermediate rolling and steel-tired rollers are generally used for finish rolling.

Before the initial or breakdown rolling of open-graded mixes, a light application of choke aggregate should be spread uniformly on the pavement surface at the rate of 3-5 kg/m2 (6-1 Olb/yd2

). The aggregate may be coarse, dry sand or the 2. OOmm (No. 10) minus screenings from open-graded aggregate production. The choke material will prevent pick-up of the mix by construction traffic or subsequent rolling.

85

7.25 PRECAUTIONS Dense-graded mixes normally are resistant to water damage during construc­tion. But, if it rains before the mixture is compacted and cured, traffic should be kept off until it cures and the necessary compaction or recompaction ac­complished.

Use only as much mixing water as is needed to disperse the asphalt emulsion and gain good workability. Too much water may retard curing and delay roll­mg.

Do not mix longer than is necessary to disperse the asphalt emulsion. Over­mixing may cause the emulsion to strip from the aggregate or break prematurely.

For faster curing, place asphalt emulsion cold mixes in several thin layers rather than a single thick layer.

Do not seal emulsion cold-mix surfaces too soon. Entrapped mixing water and distillates may create problems.

If raveling occurs under traffic, the loose material should be broomed off as soon as possible to prevent further damage to the surface. If the degree of raveling is increasing, then asphalt enrichment of the surface by a very light fogging with an SS-emulsion diluted at a ratio of about 85 percent water to 15 percent asphalt emulsion may be desirable. The intent is to obtain some penetration so as to avoid a tacky surface and potential pickup by vehicle tires. If the raveling is due to an already tacky surface, then a light blotting with sand will be necessary.

7.26 COLD-MIX SEALS Until the last few years it has been common practice to place a chip seal on new cold­

mix pavements several weeks after construction is finished. Dense-graded mixes usually have low resistance to raveling under traffic until they are fully cured and the same is always true for sand mixes. Open-graded mixes are very tough and raveling is unlikely to occur, but even here the chip seal was felt to be an advantage. This practice is still adhered to by most agencies but on some open-graded projects the chip seal has been eliminated if a positive moisture seal has been provided within or below the pavement structure. On some U.S. Forest Service projects where well-crushed dense-graded ag­gregates have been used in the mix, a fog seal has been used in place of a chip seal. The asphalt emulsion is diluted with water at a ratio of 10 to 20 percent emulsion with 80 to 90 percent water and applied with a distributor or water tanker. Successive applications of this type of seal have also been used on open-graded mixes in an effort to obtain a better moisture seal at the bottom of the open-graded pavement.

A dense-graded mixture is more likely to show reflective cracking than an open­graded mixture. Therefore, the use of an asphalt surface treatment will give some degree

86

of protection from this condition. In addition, it will help against the intrusion of water, which may damage the underlying pavement structure.

c. ASPHALT EMULSION PLANT MIX (HOT)

7.27 MIXING PLANTS • The production of hot plant-mix using asphalt emulsion as' the binder is somewhat

akin to the production of hot mix using-'as'i:ihalt"·c·ement:.- [ower~-iii1xrng time and operatIng temperatures are employed with the emulsion, however. Either a batch type or continuous mix plant may be used. The drum mixer, a type of continuous mix plant, is especially adaptable for this operation. Both base and surface mixtures can be produced.

In addition to reduced mixing temperatures (compared to conventional hot mixes) the high float asphalt emulsion hot mixes appear tO'be superior for two other reasons. One is the modification of the residual asphalt by the emulsifier. The other is that there is less hardening during pugmill mixing because of the high water vapor content that is flashed off when the emulsion water hits the hot aggregate.

7.28 AGGREGATE BLENDING Aggregates can be blended accurately using the controls on the cold feed bins. But, if a

more precise gradation control is desired (as in a batch plant), the aggregates can be screened and reproportioned. In the latter case, the asphalt emulsion and the various ag­gregate sizes are weighed separately into the batch mixer. When a continuous mix plant or drum mix plant is used, all proportioning is done on a volumetric basis. This is achieved by a combination of variable speed belts under each bin and variable gate open­ings. An automatic load-sensing device under the combined aggregate conveyor permits accurate proportioning of the aggregate and the asphalt. Regardless of the blending system used, high quality emulsion mixes require the same degree of quality control in their production that is required for asphalt hot mix. Combinations of aggregates with widely different absorption characteristics should not be used. Otherwise, there may be difficulty in getting a uniform coating over all aggregate particles.

7.29 MIXING As pointed out earlier, emulsion plant mixes may be produced in pugmill or dryer drum

mixers. The procedures are the same as for conventional hot mix. Two temperature ranges are employed-between 49°C and 85°C (120°F and 185°F) for emulsified asphalt warm mixes and 104°C and 127°C (220°F and 260°F) for emulsified asphalt hot mixes. Mixing time is a critical factor. Too little mixing results in non-uniform coating while excessive mixing induces stripping and causes stiffening of the mixture from premature coalescence. In some cases, the addition of about 1 to 2 percent portland cement has accelerated development of initial strength and provided some measure of water resistance.

The asphalt emulsion normally used for warm plant mix is MS-2h, although there may be occasions when a slow-set emulsion could be used. The asphalt emulsion normally used for hot plant mix is HFMS-2h.

87

7.30 PLACING Asphalt emulsion plant mixes are placed with conventional spreading equipment.

Basically, the same procedures that are employed for placement of hot plant-mix can also be used for emulsion mixes. A minimum of delay must be allowed between discharge from the mixer unit and placement.. After breaking has occurred and curing has begun, the mixture may become very difficult to spread without tearing. In order for a smooth mat to be laid, the emulsion mixture must remain workable throughout the spreading operation. Therefore, timely placement is essential for satisfactory results.

7.31 COMPACTION There is no standard procedure for determining the field density of emulsified asphalt

mixtures. The Asphalt Institute recommends that the following be used until a standard proce­dure is adopted:

Divide emulsified asphalt mixture production into lots, each lot equal to the mix produced during one day. Determine the target density for each lot by measuring the average density of six laboratory-prepared specimens representing two randomly chosen sub-samples from trucks delivering mixture to the jobsite. The target density should be reported as dry density.

Determine the compacted density in the field from five randomly located positions in each lot of the compacted mixture. The density of freshly compacted material can be determined using a properly calibrated nuclear density device or other procedure. Density determinations made after a period of curing may be determined on samples obtained from the compacted material by a suitable core-drilling technique. All com­pacted densities should be converted to dry density. It is recommended that the average of the five field density determinations made in each lot be equal to or greater than 95 percent of the average density of the six laboratory-prepared specimens, and that no individual determination be lower than 92 percent.

88

CHAPTER VIII

MISCELLANEOUS ASPHALT EMULSION APPLICATIONS

8.01 GENERAL Previous chapters in this manual have described the use of asphalt emulsion in plant mixes,

mixed-in-place, and various types of treatments and seals. It can also be used for a number of other applications connected with both construction and maintenance of paved surfaces. Its energy-saving advantage and ~~.yer~a~~!L are valid reasons for i~s growing use. This chapter does not cover every possible use. However, it does offer guidelines for the more common miscellaneous uses.

8.02 TACK COAT A tack coat is a ~~" sPF~y ~pn~J!J~pn of diluted aSQh.l!lt emu}sjQn, Figure VIII -I. It

is used to ensure a bond between a surface being paved and the new course. For most overlays, a tack coat is advisable. Perhaps the only exception is when an additional course is placed within two or three days on a freshl~-Jaid asphalt surface. In this case, ~mpl~Jion<!l between the two courses should develop without the use of a tack coat. In all cases: however, the surface must be clean and free of loose material.

The more common emulsion types for tack coats are diluted ~S-I, SS-I h, CSS-l, and CSS-l h. The emulsion is diluted by adding al!_~qual amouni-of waterl To_prevent premature.. bre*i.l}g, the watec is always added to the emulsion, not the ~mulsion to the water. Warm water is used, if practical,and added slowly. But, first, a test dilution is made to be certain that the water to be used is compatible with the emulsion. The diluted material is then applied at a rate of 0.25 to 0.70 litre/m2 (0.05 to 0.15 gal/yd2). ~o I!1~E.~~~~ £2ilt§.Qgq}g,kl11llllied ) to_an area Jh.~!LGa.n.he .. cavered. by.the .. same., day 's operations, . ....

Tack coats should not be applied during periods of cold or wet. \\,'ea~her. ~esults are obtained if the road surface is dry, has Ii.' sur!~ce temperatu~e .Cl~9.Y~,,~!9 (80°F), . andthere is no threat of rain. ! .-The goal is a very th in but uniform coating of asphalt left on the surface when the emulsion has broken. Too much tack coat may create a plane of .sl~PllilR~J).e~ween.tl1et\V()p~vement cQ!!!].es as the asphalt acts as a lubricant rather than an adhesive.<JDmay even create---"Jit spots" or bleeding(on t e surfa ..' .... . '. t, a condition that is not only unsightly, b~t produc~s a c!angerouslyr sl!<;j{.'pavement. Pneumati~~tired rolling of ~ ~k ~"wm ""'\ help spread the asphalt for better coverage. It will also help to lessen the probability of fat spo1L.L) 'After spraying the tack coat, enough time must be allowed for complete breaking to occur

I before the overlay is placed. Traffic should be kept off the tacked area. If that is not possible, vehicle speeds should be kept below 32 km/hr (~9 mph). The freshly-tacked pavement may be too slick for safe driving if excessive speeds are permitted, especially before the emulsion breaks.

A tack coat is also an essential part of ~Q~ pa.t~hin~-perati.on. . First, the area to be patched must be thoroughly cleaned and all loose material removed. Then, a fairly heavy tack coat of asphalt emulsion is sprayed, or painted, over the entire area, including the vertical

89

Figure VIII-1. Applying tack coat. Photo Courtesy of E. 0, Etnyre and Company

sides. The tack helps hold the patch in place and i,mparts a w~~~t1ight seal between the patch and the surrounding pavemenC

8.03 FOG SEAL A fog seal is a light application to an existing surface of a slow-setting asphalt emulsion

diluted with water, similar to a tack coat. It can be diluted in varying proportions up to qne part emulsion to five parts water, but in most cases a 01!~to one dj!'~ is used. (Se,e Par. 8.02) Grades of asphalt emulsion normally used for this purpose are SS-l, SS-l h, CSS-l, or CSS-Ih.

A fog seal can be a Y!ll!!able mainten;!!!<::~ __ aid when used for its intended purpose. It is neither a substitute for an asphalt surface treatment nor a seal coat. It is used to renew old asphalt surfaces that have become dry and embrittled with age and t2-~_eal smaU££~cks and surface voids. The fairly low viscosity diluted emulsion flows easily into the cracks and surface ~ids. It ilia' coats aggregate particles on the surface. This corrective action will prolong pavement life and may delay the time when major maintenance or reconstruction is needed.

The total quantity of fog seal used is normally in the order of 0.45 to 0.70 litre/m2 (0.1 to 0.15 gal/yd2) of diluted material. Exact quantities are determined by the surface texture, dryness, and degree of cracking of the pavement on which the fog seal is sprayed.

The same traffic restraints used with tack coats should be employed with fog seals.

Over-application must be avoided, as this would result in an aspha!.Lp'~ckup by vehicles and possibly a slippery surface. If an excess of emulsion is applied, a light dusting of the affected area with aJJ.T]e §an5!. may remedy the problem.

90

8.04 MULCH TREATMENT Soil erosion caused by water and wind can present a serious problem in the construc­

tion of embankments and flat areas adjacent to highways. The most common method of combating this problem is the use of vegetation to stabilize these areas. But, during the period between the time the seeds are planted and germination takes place they are susceptible to being blown or washed away. Several procedures have been developed to protect the planting until the seeds germinate and a root system forms. One of the most effective is the use of emulsifi,ed asphalt. It leaves a thin membrane over the seeded area or holds a hay or straw mulch in place. Both approaches have been used successfully. Because they differ in procedure each will be discussed separately, although both are designed to achieve the same result.

Emulsified Asphalt Spray Mulch In this system the asphalt emulsion is sprayed directly onto the seeded area, forming a thin

membrane cover. The thin film of asphalt has three beneficial effects:

1. The asphalt cover holds the seeds in place and prevents their loss by the eroding forces of wind and water.

2. Because of its dark color, the asphalt absorbs and holds solar heat during the germination period.

3. The asphalt membrane tends to hold moisture in the soil, thereby promoting faster plant growth.

As the young seedlings emerge from the soil they can easily break through the thin asphalt cover. The membrane eventually disintegrates as the seedlings mature and cover the ground area.

Emulsion 'grades commonly used in this operation are SS-l, SS-l h, CSS-l, or CSS-lh. It is normally applied at a rate of 0.70 to 1.35 litre/m2 (0.15 to 0.30 gallyd2). The exact amount is determined by the nature of the soil and the slope of the area being treated. Special care must be taken to apply the optimum amount of emulsified asphalt. Too little may not hold the soil against erosion by wind and water. Too much emulsion may leave a thick membrane, which would delay growth. The area that is to receive the emulsion spray must be reasonably smooth so that a uniform coating can be applied. Depressions in the surface may collect pools of asphalt and ridges may be coated on one side with virtually no asphalt on the other.

The emulsion can be applied with a hand-held spray nozzle or with an offset distributor bar attached to an asphalt distributor truck.

Emulsified Asphalt Mulch Tie-Down Asphalt emulsion can be used for anchoring straw or hay to a seeded area. There are two

approaches that can be used. In one case the straw or hay mulch is distributed over the prepared area at a rate of 3.3 to

4.5 tonnes/hm2 (1 V2 to 2 tons/acre). The seed is then mixed with water and liquid fertilizer and applied with a hydraulic seeder. A spray application of 0.45 litre/m2 (0.10 gal/yd2

) of asphalt emulsion follows, Figure VIII-2. The emulsion can be applied in a solid pattern or a saw-tooth, checkerboard, or perpendicular line pattern. The solid pattern is most effective, especially when the wind velocity is high. If the amount of mulch is increased above 3.3 to

91

Figure VIII-2. Using emulsified asphalt to tie down mulch.

4.5 tonnes/hm2 (lV2 to 2 tons/acre), the amount of emulsified asphalt applied must be increased proportionately.

A second method begins with the hydraulic application of seed and fertilizer directly to the prepared soil. Then, the mulch and emulsified asphalt are ejected at the same time through a special blower equipped with twin jets. (See completed section. Figure VIII-3.) The two materials are mixed in flight. This is the preferred method as it has at least two advantages:

The mulch and the asphalt emulsion are applied in a single application, which reduces costs and reduces the time required.

It results in better bonding between the emulsion and the hay/straw mulch.

The same types of asphalt emulsion can be used as recommended for the emulsified asphalt spray mulch.

8.05 CRACK FILLER The average maintenance department spends a large amount of time sealing cracks in

pavement surfaces. Depending upon the location and size of the cracks, their maintenance may be thought of as corrective or preventive. In either case the technique for sealing the crack is the same.

Cracking takes many forms, from small hairline cracks to major cracks that may have an opening of as much as 25 millimetres (I in.). Larger cracks, or more severely cracked areas, are

92

Figure VIII-3. Completed section of Interstate with emulsified asphalt mulch on median and close-up. Courtesy of Ohio Department of Transportation

not always correctable by crack filling. Often, it is necessary to completely remove the cracked material and replace with a Full-Depth asphalt patch.

Knowledge of some of the more common types of crack patterns helps determine the proper maintenance procedure. Cracks generally fall into one of the following categories:

Alligator cracks-Interconnected cracks forming a series of small blocks resembling an alligator's skin or chicken wire.

Longitudinal crack-A crack that follows a course approximately parallel to the centerline.

Reflection cracks-Cracks in asphalt overlays that reflect the crack pattern in the pavement structure below.

Shrinkage cracks-Interconnected cracks forming a series of large blocks, usually with sharp corners or angles.

Slippage cracks-Crescent shaped cracks that point in the direction of the thrust of wheels on the pavement surface.

Transverse crack-A crack that follows a course approximately at right angles to the centerline.

93

If a crack results from a defective condition beneath the pavement surface, it is unlike­ly that filling it will be a permanent solution. In many cases, it is necessary to correct the defect in the underlying pavement course to solve the crack problem. This manual only addresses the type of cracks that can be repaired with emulsified asphalt, i.e., longitudinal, reflection, shrinkage, and transverse.

Good maintenance practice calls for sealing as soon as possible after a crack shows up. When it is sealed promptly, the sealing is often the end of the problem. Sometimes the crack continues to widen and sealing applications must be continued until the crack is ar­rested. Failure to seal cracks is an invitation to further damage through freeze-thaw cycles or weakened support caused by intrusion of water. Sealing the cracks with asphalt emulsion is easy and inexpensive; it postpones major maintenance and may avoid it en­tirely.

Before the cracks are filled, they should be cleaned in the following manner:

- A compressed air jet should be used to blowout any loose material in the crack.

- A steel wire brush or router should be used to remove any foreign material that cannot be removed by blowing.

- The entire crack area should be cleaned by brooming.

When the cracks have been thoroughly cleaned they are then ready for sealing. Small cracks [less than 3 mm (118 in.) width] are difficult to seal effectively. For large cracks, an emulsion slurry, or emulsion mixed with sand, should be forced into the crack until it is about 6 to 3 mm (114 to 118 in.) from the surface. After curing has been completed, finish the sealing by filling the remainder of the crack area with emulsified asphalt (Figure VIII -4). The surface should then be sprinkled with a light dusting of dry sand to prevent pickup by traffic.

Emulsion grades SS-l, SS-lh, CSS-l and CSS-lh may be used for crack filling.

8.06J)I~IME COAT A prime coat is a~i~n <?f 1~_\\,yi~~t)'~sph~1t to a granular base in preparation for

an asphalt surface course. The prime coat is designed to perfonn several functions:

To coat and bond loose mineral particles on the surface of the base.

To harden or toughen the surface.

To waterproof the surface of the base.

To plug capillary voids.

To provide adhesion between the base and the next course.

6---(~ In or¥_for._tp_~ Pti.~~!'? satisfy these criteria it needs to penetta.t<? iI.1!~~~~.~as~_~~~rse., At one time it was thought that the use of a prime coat was an essential element of good

pavemenfconstruction. However, in recent years some engineers have eliminated the use of a prime, especially when the asphalt layer(s)(surface and/or base) is 100 mm (4 in.) or more in thickness.

94

Figure VIII-4. Filling crack with emulsified asphalt.

The prime coat is used when a granular base course is to be carried through ari"extended period_(such as the winter months), or when(iVis subjected to ~abIasiveforces of trafflc-!..-­Otherwise, most engineers believe that the cost/benefit ratio of a prime is open to serious questioning. Perhaps this decision can be summed up by saying, "if in doubt, use a prime coat."

1 - Most primes in the past have been some type of cutback asphalt. The use of emulsified asphalt for this purpose is relatively new. §Pedal-pr~cautIQij§ are pecessary when emulsi<?nJ .~ is used. Q]..~ must remember that in _ asphalt emulsion tiny particles of asphalt cemeQt are L

s_usp~nded in water .. The quantity to be used depends upon the nature of the granular base and weather conditions.

The gradation of the aggregate, size of void spaces, and absorption of the aggregate all affect it: -One way to use an emulsion for a prime coat is to scarify the top 5.9 to 75 mm (2 to 3 in.)

__ and mix it in-place. Generally 0.45 to 1.35 litres/m2/25 mm (0.1 to 0.3 gal/yd2/in.) of .s.S_:J, SS~ 1 h, CSS-l or CSS-l h would be used for this purpose. If a layer of base aggregate is to he supplied, the emulsion and compaction water can be mixed at the source.

8.07 DUST PALLIATIVE Research at Iowa State University revt!aled that, on an unpaved road, one vehicle per day

creates 560 kg/ km (one ton per mile) of dust per year. Also, the accident rate is twice as high on unpaved roads. Lack of money or infrequent use may call for some other way to keep dust down or make a road passable in bad weather.

95

The use of emulsified asphalt offers a practical and thrifty solution to these problems. A dilute asphalt emulsion is sprayed directly on the unpaved road surface. This technique is known as dust laying or application of a dust palliative.

When used as a dust palliative, an SS-I, SS-l h, CSS-l, or CSS-l h emulsion is mixed with five or more parts water, by volume. The diluted material is sprayed in repeated light applications on the unpaved surface at the rate of 0.45 to 2.25 litre 1m2 (0.1 to 0.5 gall yd2). The actual quantity applied depends on the condition of the existing surface. Some penetration is expected. Thus, if the road surface is penetrable or contains relatively large surface voids, a greater amount of the dilute emulsion can be applied. The material is applied with an asphalt distributor, following the usual spray application technique.

96

CHAPTER IX

MAINTENANCE MIXES

9.01 PAVEMENT MAINTENANCE Pavement maintenance is a major responsibility of every highway and street department.

From the time construction is completed, all pavements begin deteriorating. Loads are applied by traffic. Temperature and moisture changes cause uneven rates of expansion and contraction of the pavement layers. Pavement weakening may, however, be so gradual that the defects are difficult to notice in the early stages. Therefore, a close inspection of every pavement section should be made regularly to detect the start of trouble. Early detection and correction prevent further deterioration and more expensive maintenance at a later date. Often, weather conditions make temporary repairs advisable to halt further damage until more lasting repairs can be made. In any case, when highway safety is involved, repairs should never be delayed or left undone.

9.02 PATCHING MIXES One of the most time-consuming maintenance functions is the patching of potholes

and weak areas that have developed in a pavement surface. It is generally agreed that the use of high-quality, hot-mixed patching mixtures will produce best results, even though it may cost more. But there is one serious drawback. In many cases, the hot-mix is not ob­tainable from late fall through ~arly sprhig.'Alihough small mixing plants, designed specifically for maintenance operations, are available, they have had limited use. Many maintenance forces, therefore, must rely on some type of s,tockpjle miXHH:~ that mayor may not be heated prior to use.

No matter what type of mix is used, there is no substitute for good construction prac­tices. A dream mixture that can be thrown into a pothole with no preparation, and tamped with the back of a shovel for a permanent patch, is still a dream. Asphalt in Pavement Maintenance, MS-16, The Asphalt Institute, contains a system of making pavement repairs that, when properly followed, will ensure reasonable success.

Maintenance mixes are divided into two types-one for immediate use and one for long-range storage (up to 6 months).

9.03 IMMEDIATE USE MAINTENANCE MIXES Some systems are set up to make immediate use of maintenance mixtures. Such systems

provide more flexibility because either hot or cold mixes can be used. It is common practice for maintenance crews to pick up truck loads of hot mix at the

beginning of a day's operations. By using an insulated cover, the mix may remain workable for a few hours. As its temperature decreases, however, the ability to obtain good compaction also decreases. Likewise, the bond between the individual aggregate particles is diminished.

97

Therefore, patches placed near the end of the day may not be as effective as those placed at the beginning. Some trucks are equipped with a heating device that will keep the mixture warm and workable. By this means the objection to a rapidly cooling mixture can be minimized.

Emulsified asphalt can be used very effectively in the preparation of a mixture for immediate use. The emulsion-aggregate mixture can be mixed in a pugmill and transported to the area where it is to be used. If small quantities are required, it may be mixed by hand at the job site. The application of external heat is not necessary since good coating and adhesion can be obtained otherwise.

Emulsified asphalts used for this purpose include HFMS-2s, CMS-2, and CMS-2h. Aggre­gates should meet quality requirements outlined in previous chapters for asphalt-aggregate mixtures. A wide range of local gradations can be used successfully. Where practicable, one of the gradations in Table IX -1 is suggested.

The amount of asphalt emulsion required for the aggregate gradings specified in Table IX-I nonnally will be in the range of 5 to 10 percent by weight of total mix. Central mix plants, small truck mixers, or hand mixing can be used in the preparation of these mixtures.

Asphalt emulsions containing small amounts of solvents produce the best cold patch mix. The mixture does not gain its full strength until the solvent evaporates, however. Also, patching mixtures should not be placed with an excess amount of mixing water present because that will extend the time before the patch can be opened to traffic.

All mixes described in this article are intended to be used relatively soon after preparation. They are not designed for long term storage.

9.04 STOCKPILE MAINTENANCE MIXES During the cold weather months the most widely-used maintenance mixture is a type drawn

from stockpile storage. It can be produced in late summer and stored in quantity in remote locations for ready use. It is usable for periods up to six months and is easily workable without the use of heat. Nonnally, a thin crust, which can be broken with a shovel, will fonn over the surface of the stockpile. Material immediately beneath the crust will possess the characteris­tics of a freshly made emulsion mix.

The production of stockpile maintenance mixes is a relatively simple operation. Basic equipment required for mixing large quantities includes a pugmill mixer and system for metering correct amounts of aggregate and emulsified asphalt. The metering system may use either volumetric or weight proportioning. Aggregate used in these mixes should meet all quality requirements. Recommended aggregate gradations for stockpile mixes are given in Table IX-I. The amount of emulsion used nonnally is in the range of 5 to 10 percent by weight of total mix. Certain grades of medium-set emulsions are typically used for this purpose.

Stockpile life depends on the formulation of the emulsion used and the aggregate characteristics. Its extended workability comes from using emulsion that contains some portion of solvent. Stockpile life and workability at low temperatures is in direct proportion to the amount of solvent used.

The emulsion supplier's guidelines can be most useful in setting operating procedures and in finding the proportions for each material used.

The completed mixture should be stored in a clean area so that there is no possibility of contamination. A covered storage bin will protect it and will help retain workability.

The specifications for emulsified asphalts (ASTM D 977 and AASHTO M 140) make no mention of a solvent in the emulsion. CRS- and CMS- cationic emulsion specifications (ASTM D 2397 and AASHTO M 208), on the other hand, pennit solvent but restrict the amount.

98

TABLE IX·1 MINERAL AGGREGATE GRADATIONS

Percent Passing by Weight Sieve Size

9.5 mm (3/8 in.) 12.5 mm (1/2 in.) 19.0 mm (3/4 in.)

25.0mm (1 in.) - - 100

19.0mm (3/4 in.) - 100 90 -100

12.5mm (1/2 in.) 100 90 -100 -

9.5mm (3/8 in.) 90 - 100 - 56 - 80

4.75mm (No.4) 55 - 85 44 -74 35 - 65

2.36 mm (No.8) 32 - 67 28 - 58 23 - 49

300llm (No. 50) 7 - 23 5 - 21 5 - 19

751lm (No. 200) 2 - 10 2 - 10 2-8

*From Asphalt in Pavement Maintenance, MS-16, The Asphalt" Institute

Many states have modified these specifications to suit their individual needs. At least two permit up to 25 percent solvent and several permit up to 15 percent. To a degree, the use of solvent in emulsions is contrary to the efforts of EPA and FHW A with respect to environmental al1cl_eO~IgY.£Q!!.~!q~J1!!.i.ons. But improved workability and longer stockpile life 'ffiaY justilytlie ,,, .. addition of the solvent. In most cases, however, the amount of solvent added is considerably less than the amount required for cutback asphalt mixtures of the same stockpile life.

Careful selection, proportioning, and mixing of materials ensure a high-quality, economical maintenance mixture. Coupled with good construction techniques, these mixtures can be used as an effective deterrent to the destructive forces of traffic and weather.

99

CHAPTER X

RECYCLING

10.01 RECYCLING DEFINED Recycling is defined as "the re-use, usually after some processing, of a material that

has already served its first-intended purpose." It can take several forms with respect to pavement recycling. Location of the project, structural requirements of the new pave­ment, availability of other materials, pavement cross-section, and amount of available funding are determining factors as to which recycling method is most appropriate for a specific situation.

10.02 TYPES OF RECYCLING Although there are variations within each method, pavement recycling is classified into

three broad categories:

1. Hot-Mix Recycling-One of several methods where the major portion of the existing pavement structure, including in some cases, the underlying un­treated base material, is removed, sized and mixed hot with added asphalt ce­ment at a central plant. The process may also include the addition of new ag­gregate, a softening agent, or both. The finished product is a hot-mixed asphalt base, binder, or surface course.

2. Cold-Mix Recycling-One of several methods where the entire existing pave­ment structure, including in some cases the underlying untreated base material, is processed in-place or removed and processed at a central plant. The materials are mixed cold and can be re-used as an aggregate base. Asphalt, other materials, or both, can be added during mixing to provide a higher strength base. This process requires that an asphalt surface course be used.

3. Sur/ace Recycling-One of several methods where the surface of an existing asphalt pavement is planed, milled, or heated in place. In the latter case, the pavement may be scarified, remixed, relaid, and rolled. Additionally, asphalt, softening agents, minimal amounts of new asphalt hot-mix, ag­gregates, or combinations of these may be added to obtain desirable mixture and surface characteristics. The finished product may be used as the final sur­face or may, in some instances, be overlaid with an asphalt surface course.

This chapter is not intended to discuss fully all forms of recycling. Rather, its purpose is to describe methods that use emulsified asphalt. Many other publications are available outlining details of the different procedures.

101

Figure X-l. A candidate for recycling.

10.03 CANDIDATES FOR RECYCLING A candidate for recycling usually is an old asphalt pavement (hot-mix, surface treat­

ment, or seal coat) that has become badly cracked because of overstressing, Figure X-I. It can be a city street, a primary or secondary highway, an airport runway, or a parking lot. The cost of resurfacing such a pavement thick enough to prevent reflection cracks could be prohibitive.

Most of these pavement structures have untreated aggregate bases that can be strengthened and upgraded with emulsified asphalt to meet current traffic loads and volumes.

The asphalts in pavements as described have aged and may have become brittle. Some components in the asphalt that determine its physical and chemical characteristics may be lost in the process. Recycling may involve, in part, putting back these components by ad­ding emulsified asphalt.

Some form of recycling may also be used in a curb and gutter section where repeated resurfacings have resulted in a loss of curb depth and draining capacity, Figure X-2. The need in this case would be to retain or regain draining capacity.

10.04 HOT-MIX RECYCLING If asphalt emulsion is used for this purpose, such work should be considered ex­

perimental until a satisfactory procedure is developed. Lower mixing temperatures are necessary if emulsion is used.

102

Figure X-2. Loss of curb depth and draining capacity.

10.05 COLD-MIX RECYCLING Emulsified asphalt is especially suited for cold-mix recycling, Figure X-3. In this method, the

old asphalt pavement is crushed, often in place. An in-place aggregate base also can be incorporated or new aggregates can be added to the old materials and asphalt emulsion added. Then, materials are mixed together, spread to a uniform thickness, and compacted. Although not necessarily required, a softening agent may be used along with the emulsified asphalt. Several different procedures are available to accomplish the same result.

Mixed-in-Place One method that has gained widespread acceptance employs a system known as in­

place mixing. Several types of mechanical devices are available for this purpose. First, the pavement must be crushed or broken into small-size particles. This can be done with a portable hammermill that pulverizes the pavement as it moves forward, Figure X-4. No attempt is made to control gradation, only maximum aggregate size. Material beneath the asphalt pavement (aggregate base) may also be crushed. With especially hard pave­ment a second pass with the hammermill may be necessary. The crushed material may be left in place as it is discharged from the pulverizer or shaped into a windrow.

The crushed material is now ready for mixing with asphalt emulsion. Several choices are available. Perhaps the simplest is blade mixing with a motor grader. Emulsified asphalt is applied with an asphalt distributor directly to the surface of the crushed

103

Figure X-3. Cold-mix recycling operation. Courtesy Koehring Company. Bomag Division

Figure X-4. Hammermlll pulverizing old pavement.

104

material at the specified rate, determined in the laboratory. Immediately, the recycled ag­gregate and the asphalt emulsion are thoroughly mixed. If necessary, a second applica­tion of asphalt emulsion can be sprayed and the mixing procedure repeated. In some cases water is sprayed on the crushed material before the emulsion application to aid in coating. Or, a softening agent may be used with the emulsion to aid in restoring the original asphalt characteristics. Blade mixing should be continued until thorough mixing and coating have been achieved, the water has been removed, and the mixture is ready for compaction.

Rotary Mixers A more efficient mixing process makes use of a rotary mixer. See Article 7.12 for a

description of these mixers that mix the aggregate and the emulsified asphalt with rotating tiller blades as they move through the material. The rapia rotation of the tiller blades provides a vigorous mixing action. Extra water, emulsified asphalt, and untreated base aggregate, or virgin aggregate may be mixed into the crushed pavement material with this machine. Most rotary mixers are now equipped with spray systems for adding the asphalt emulsion at the time of mixing. When using this type of mixer the following steps are recommended:

Spread the material to be recycled to uniform grade and cross-section with a motor grader.

Thoroughly mix by one or more passes of the mixer. When ready for the asphalt emulsion, the moisture content of the aggregate should not exceed 3 percent. A higher moisture content can be used if laboratory tests show that it will not be harmful when the asphalt emulsion is added.

Travel Plant Still another type of mixer unit is a travel plant. One type contains its own pugmill, ag­

gregate storage bins, and emulsified asphalt storage tanks. This is a self-contained mobile unit capable of mixing and spreading the mixture on the roadbed. In this case, it is necessary that the crushed material be removed from the roadbed. It is usually stockpiled away from the job site and transported to the travel plant where it is discharged into ag­gregate hopper(s). It is then drawn into the pugmill mixer, asphalt emulsion is added, and the two are mixed. The completed mixture is discharged in front of the screed for spreading to the required depth.

Another type moves through a prepared aggregate windrow on the roadbed and adds and mixes the emulsified asphalt as it goes. It discharges to the rear a mixed windrow ready for aeration and spreading.

All types of MS- and SS- emulsions can be used in cold-mix recycling. Laboratory testing should be performed in advance to determine which type and grade best suits the materials and local conditions.

Central Plant Still another method for the cold recycling of existing pavement structures including,

in many cases, the underlying base material, is central plant mixing. The process involves

105

ripping, scarifying, and pulverizing or crushing the pavement layers. If further crushing is needed, the material may be put through a rock crusher.

Samples of the salvaged pavement should be tested in the laboratory to determine aggregate gradations and the amount and consistency of the old asphalt. This gives the basis for deciding if additional aggregate is needed and how much asphalt emulsion must be added to produce a proper, stable mix. Refer to Part Three for an emulsified asphalt mix design test method.

Mixing, placing, and compaction are the same as described in Chapter VII. For additional information, see Asphalt Cold-Mix Recycling, Manual Series No. 21, The Asphalt Institute.

10.06 SURFACE RECYCLING In this method only the upper surface of the old pavement is involved, usually about 20 to

25 mm (3/4 to 1 in.). Open-flame or infrared heat is applied so that the upper surface can be scarified or planed for complete removal. Surface recycling offers many advantages. However, it should not be used in areas where pavement deterioration has been caused by base failure. Correction of the surface only will be a temporary measure unless the source of the problem is dealt with.

Asphalt emulsion frequently is used to enrich the aged asphalt in the scarified surface.

Major equipment items normally required for surface recycling operations are shown in Figure X-5.

10.07 CONCLUSION Experience with recycling is increasing every day. Results to date show it to be a viable

alternative to current maintenance and restoration procedures. Careful selection of the best procedure to suit conditions can result in ample savings. Additionally, recycling appears to offer the potential for emulsions to be used widely, particularly when utilizing in-place untreated base materials to produce a new base with increased strength.

IDIRECT/ON OF TRAVEL)

PAVING TRAIN METHOD

Preheater New mix Remixer Roller

INTEGRAL METHOD

Figure X-5. Heater-overlay methods.

106

PART THREE:

EMULSIFIED ASPHALT-AGGREGATE MIX-DESIGN METHODS

PART THREE

EMULSIFIED ASPHALT-AGGREGATE MIX DESIGN METHODS

There is no universally-accepted emulsified asphalt-aggregate mix-design method; but nearly all of those in use employ some parts, or modifications, of the standard H veem (ASTM D 1560and D 1561 or AASHTO T 246 and T247) or Marshall (ASTM D 1559 or AASHTO T 245) test methods.

Two mix-design methods contained in the first edition of this manual were (1) The Asphalt Institute's Pacific Coast Division Method, based on the Hveem procedure plus a resilient modulus test, and (2) an Illinois method, based on a modified Marshall mix design procedure and a moisture durability test. These laboratory methods were evaluated by the Asphalt Institute as a part ofthe National Cooperative Highway Research Program (NCHRP) Project 9-5, "Design of Emulsified Asphalt Paving Mixtures," and the results of that evaluation are contained in NCB RP Report 259.

The methods contained in this edition generally follow the above with certain modifications suggested by NCB RP Report 259. In addition, an outline and design criteria for The Asphalt Institute design method for open-graded mixes, also from NCBRP Report 259, are included. The McConnaughay method for designing cold mixtures, which has been in use in the Midwestern United States for over three decades has been added to this second edition.

These laboratory design methods will be evaluated periodically as data is accumulated on field performance.

109

CHAPTER XI

MODIFIED HVEEM MIX DESIGN

11.01 SCOPE This method covers the selection, proportioning and testing of aggregates, additives and

emulsified asphalt for dense-graded mixes for pavement construction. It contains California Department of Transportation test methods or modifications of these methods as well as procedures developed within The Asphalt Institute. Criteria to determine the suitability of emulsified asphalt mixes are presented. Procedures for resilient modulus determination are, however, applicable to mixes using emulsified asphalt or paving grade asphalts.

For information on mix-design methods when using paving asphalt (asphalt cement), refer to the The Asphalt Institute publication, Mix Design Methods for Asphalt Concrete, Manual Series No.2 (MS-2).

11.02 OUTLINE OF METHOD a. General

For convenience, the design method is divided into the following parts:

(1) Selection of aggregate and emulsified asphalt

(2) Trial emulsified asphalt content

(3) Mixing test (Determination of optimum fluids content at mixing)

(4) Detennination of optimum fluids content for compaction

(5) Strength testing

(6) Moisture exposure and stability and cohesion testing

(7) Determination of optimum emulsified asphalt content

See Figure XI-l for the testing schedule for this mix design method.

b. Selection of Aggregate and Emulsified Asphalt Aggregates used for emulsified asphalt paving mixtures (Table VII-5) and guidelines

for the selection of emulsified asphalt type are shown in Tables II-I and 11-2 of this Basic Asphalt Emulsion Manual.

c. Trial Emulsified Asphalt Content The Centrifuge Kerosene Equivalent Test (C.K.E.) is used for estimating the emulsified

asphalt contents for trial mixes of aggregates. Ranges of emulsified asphalt content for trial mixes are shown in Table XI-I.

111

:!! ec c::: ; >< 'i"" .....

~ !!1. 3" ec en

D)() en:r ~CD :rOo !!.c::: -cr

tv 3_ -"0 >< ... CD 0. ~CD

::::I en CD cC [ ~ CD 3 c:::

~ ~

S1EP 1 Selection of Mix Proportions + Mixing Test (Optimum Ruids at mixing)

I Use 1.4 x C.K.E. Emulsion Content

l Add water flllCl'eaSing increments) and

Mixing Test Spoon 75% + Okay for Surface ~ & Bowl or Record % Coating --+ addtive O.e., portland cement) Mechanical 50% + Okay for Base

r---+ Record %

~ Reject if Excessively Stiff or

WOlbbity Sloppy

Proceed to Step 2

Step 2 Emulsion Content of 1.4 Kneadng Plus DoWIIe Ruids content of mix with Optimum Ruids for ~ C.K.E. 01 Ratio & Min. 3 PItmger Static Compaction .. highest dry density Compaction Ruids Contents

l Proceed to Step 3

STEP 3 SpecImen Fabrication lor Strength Testfng

1.1, 1.4, and 1.7 C.K.E. Oil Ratio for Emulsion Contents

Optimum Auids for Compaction (from Step 2)

Knealing Plus Double Plunger Static Compaction"

STEP 4 Cure One Specimen in Mold 72 Hrs.

Strength r--- For AI Mixes ~ at 23 ~ 2.8"C (73 , 5'F) Vacuum

f---Desiccate Out of Mold to Pressure Testing of 1 ()'2Omm Hg for 4 Days

STEP 5 MoIsture Exposure and StabIty Testing

Base Mixes I -

+ Vacuum lllunlte Mr specinen Cure second &pI!Cimen (from (from Step 4) 81 23 ~ 2.8"C Step 3) In mold 24 hIS. 81 23 :t

(73 , 5'F) 2.8"C (73 , 5'F)

R·VaIue II 23 , 2.8"C R-Value II 23 , 2.8"C (73 , 5'F) (73 , 5'F)

t C-Value 81 23 1: 2.8"C r-- C-Value 81 23 :t 2.8"C -(73 :t5'F) (73 1: 5'F)

Measure Modulus (Mr) at 23 :t 1.7"C r--- Proceed to Step 5

(73,3'FJ

I Surface Mixes I

Test~(fromStep4) lor ter S-Value 81 H ~N30+1 60 ~ 2.B'C (140 , 5'F)

CohesIometer C-Value 81 60 , H~K100+1 2.8"C (140 :t 5'F)

I ~K I I ~H50+1 100+

Calculate RT Value Accept H 78+

Calculate RT Value Accept H 70+

• Two specimens prepared 81 each emulsified esphaft content lor base mixes. One specimen prepared at each emulsified asphalt content for permanent surface mixes. .. Includes 1 ()'50 blows (25Ops1) kneedlng and up to 40,000 lb. double plunger.

Figure XI-1 (Cont.). Testing schedule for dense-graded emulsified asphalt mixes.

113

d. Mixing Test, Determination of Optimum Fluids Content at Mixing Either a spoon and bowl or mechanical mix is made to determine the coating and

workability of the trial mixtures. The amount of mix water is varied to optimize these properties unless job conditions obviously prevent such optimization. Additives, if used, are premixed with the aggregate prior to conducting the mixing test.

e. Optimum Fluids Content for Compaction Determination of the optimum fluids content (mixing water plus emulsified asphalt)

for compaction and test specimen fabrication are achieved by a light kneading compaction followed by a double plunger static load.

f. Strength Testing The strength of emulsified asphalt mixes is measured by running a final modulus at a

temperature of 23 ± 1. 7°C (73 ± 3°P) after a total of three days mold cure plus four days vacuum desiccation. ** This data is used in conjunction with certain project variables (traffic, regional temperature and curing conditions) and other mix properties (volume percent of asphalt residue and air voids) in determining the pavement thickness require­ments.

g. Moisture Exposure and Stability Testing Base mixes have their strength evaluated before and after vacuum saturation. Base

mixes are tested at 23 ± 2. 8°C (73 ± 5°F) for Resistance R-Value and Cohesiometer C-Value. Surface mixes are tested at 60 ± 2.8°C (140 ± 5°F) for Stabilometer S-Value and Cohesiometer C-Value.

h. Determination of Optimum Emulsion Content Table XI-5 gives design criteria for the two types of emulsified asphalt dense-graded

mIxes.

TABLE XI-1 SELECTION OF EMULSIFIED ASPHALT CONTENT

Type

Processed Dense Graded

Sands Silty Sands Semi-Processed Crusher Pit or Bank Run

Approximate Emulsified Asphalt Content, Percent by Weight of Aggregate *

5.0 - 10.0

4.5 - 8.0

• With porous aggregates the emulsified asphalt content should be increased by a factor of approximately 1.2. Porous aggregates are those which absorb more than 2 percent water by dry weight when tested by ASTM Method C 127 .

•• An alternate procedure, that shortens the laboratory curing time, is to cure for one day in mold at room temperature followed by one day out of mold in oven at 37.8°C (100°F).

114

11.03 AGGREGATES FOR EMULSIFIED ASPHALT MIXES a. General

The types of materials that are suitable for emulsified asphalt treatment include sand, blast furnace slag, coral, volcanic cinder, gravel, ore tailings-, crushed ledge stone or rock, reclaimed aggregate or other inert material.

b. Selection Aggregates meeting the requirements of Table VII-5 of this Basic Asphalt Emulsion

Manual are among those suitable for emulsified asphalt mixes. All of these aggregates are acceptable for bases and also for temporary surfaces for at least light traffic. (For mix design purposes, temporary surfaces are treated as base mixes.) However, for perma­nent surfaces, the processed dense-graded or open-graded aggregates plus a surface treat­ment will be required.

11.04 ASPHALTS a. General

Two types of emulsified asphalt are used for mixing. These are designated as slow setting (SS) and medium (MS). ASTM specifications for these asphalt materials are given in Tables II-I and 11-2 of this manual.

11.05 MIX PROPORTIONS a. General

The amount of emulsified asphalt is estimated for trial mixes of dense-graded aggregates using the Centrifuge Kerosene Equivalent test (C.K.E.).

b. Centrifuge Kerosene Equivalent Test (1) General

The first step in this method of mix design is to determine the approximate asphalt content by the Centrifuge Kerosene Equivalent method. * With a calculated surface area and the factors obtained by the C.K.E. method for a particular aggregate or blend of aggregates, the approximate asphalt content is determined by using a series of charts. These charts are presented herein, accompanied by typical examples to demonstrate their application.

(2) Equipment The equipment and materials required for determining the approximate asphalt content

are as follows: (a) Sample Splitter, small, for obtaining representative samples of fine aggregate. (b) Pans, 114 mm (4V2 in.) diameter x 25 mm (1 in.) deep. (c) Kerosene, 4 litres (1 gal.). (d) Oil, SAE No. 10, lubricating, 4 litres (1 gal.). (e) Beakers, 1500 ml. (f) Metal Funnels, 89 mm (3V2 in.) top diameter, 114 mm (4V2 in.) height, 13 mm

(V2 in.) orifice with piece of2.oo mm (No. 10) sieve soldered to bottom of opening. (g) Timer.

• The development of this method of determining optimum asphalt content is outlined in "Establishing the Oil Content for Dense-Graded Bituminous Mixtures" by F.N. Hveem, California Highways and Public Works, July-August, 1942.

115

(h) Centrifuge, hand-operated, complete with cups, capable of producing 400 times gravity (a power-driven centrifuge is available from Soiltest, Inc., 2205 Lee Street, Evanston, Illinois 60602, Catalog No. AP-275 or equivalent).

(i) Filter Papers, 55 mm diameter (No. 611, Eaton-Dikeman Co., Mt. Holly Springs, Pennsylvania, or equivalent).

(3) Surface Area The gradation of the aggregate of blend of aggregates employed in the mix is used

to calculate the surface area of the aggregates. This calculation consists of multiplying the total percent passing each sieve size by a "surface-area factor" as set forth in Table XI-2. Add the products thus obtained and the total will represent the equivalent surface area of the sample in terms of square metres per kilogram (ft2/1b). It is important to note that all surface-area factors must be used in the calculation. Also, if a different series of sieves is used, different surface-area factors are necessary.

TABLE XI-2 SURFACE AREA FACTORS

Total Percent Passing

Sieve No.

Surface Area

Factor,* ml/kg (ft1/lb.)

Maximum Size

.41 (2)

4.75 2.36 1.18 600 300 150 75 mm mm mm j.Lm j.Lm j.Lm j.Lm

(~o)(~o) ~~) (~~) (~~) (~o~) (~;o)

.41 .82 1.64 2.87 6.14 12.29 32.77 (2) (4) (8) (14) (30) (60) (160)

·Surface area factors shown are applicable only when all the above-listed sieves are used in the sieve analysis.

The following tabulation demonstrates the calculation of surface area by this method.

Sieve Percent S.A. Surface Size Passing x = Factor Area

19.0 mm (3/4 in.) loo} .41 (2) .41 (2) 9.5 mm (3/8 in.) 90

4.75 mm (No.4) 7S .41 (2) .31 (1.5) 2.36 mm (No.8) 60 .82 (4) .49 (2.4) 1.18 mm (No. 16) 4S 1.64 (8) .74 (3.6) 600 j.Lm (No. 30) 35 2.87 (14) 1.00 (4.9) 300 j.Lm (No. SO) 2S 6.14 (30) 1.54 (7.5) 150 j.Lm (No. 100) 18 12.29 (60) 2.21 (10.8) 75 j.Lm (No. 200) 10 32.77 (160) 3.28 (16.0)

Surface Area 9.98 mI/kg (48.7 ftI/lb)

116

(4) C.K.E. Procedure

(a) Place exactly lOOg of dry aggregate (representative of the passing 4.75 mm [No.4] material being used) in the tared centrifuge cup assembly fitted with a screen and a disk of filter paper.

(b) Place bottom of centrifuge cup in kerosene until the aggregate becomes saturated.

(c) Centrifuge the saturated sample for 2 minutes at a force of 400 times gravity. (For the suggested centrifuge this force can be developed by turning the handle approximately 45 revolutions per minute.)

(d) Weigh sample after centrifuging and determine the amount of kerosene re­tained as a percent of the dry aggregate weight; this value is called the Cen­trifuge Kerosene Equivalent (C.K.E.). (Note: Duplicate samples are always prepared in order to balance the centrifuge and to check results. The average of the two C.K.E. values is used unless there is a large discrepancy, in which case the test is rerun.)

(e) If the apparent specific gravity of samples is greater than 2.70 or less than 2.60 make a correction to the C.K.E. value using the formula at the bottom of the chart in Figure XI-2.

(5) Surface Capacity Test for Coarse Aggregate

(a) Place into a metal funnel, exactly lOOg of dry aggregate passing the 9.5mm (3/8 in.) sieve and retained on the 4.75 mm (No.4) sieve (this fraction is con­sidered to be representative of the coarse aggregate in the mix).

(b) Immerse sample and funnel in a beaker containing SAE No. 10 lubricating oil at room temperature for 5 minutes.

(c) Drain for 2 minutes. (d) Remove funnel and sample from oil and drain for 15 minutes at a temperature of

60°C (140°F). (e) Weigh the sample after draining and determine the amount of oil retained as a

percent of the dry aggregate weight. (Note: Duplicate samples are prepared to check results. Average value is used unless there is a large discrepancy, in which case the test is rerun.)

(f) If the apparent specific gravity is greater than 2.70 or less than 2.60 make a correction to the percent oil retained using the formula at the bottom of the chart in Figure XI-3.

117

(6) Estimated Optimum Emulsified Asphalt Content

(a) Using the C.K.E. value obtained and the chart in Figure XI-2, determine the value Kf (surface constant for fine material).

(b) Using the percent oil retained and the chart in Figure XI-3, determine the value Ke (surface constant for coarse material).

(c) Using the values obtained for Kf and Ke and chart in Figure XI-4, determine the value Km (surface constant for fine-coarse aggregate combined). Km = Kf + cor­rection to Kf. The correction to Kfobtained from Figure XI-4 is positive if (Ke - Kf)

is positive and is negative if (Ke - Kf) is negative. (d) The next step is to determine the approximate asphalt ratio for the mix based on

cutback asphalts of RC-250, MC-250 and SC-250 grades. With values obtained for Km, Surface Area and average specific gravity use CASE 2 procedures of chart in Figure XI-5 to determine the oil ratio.

(7) Example

To demonstrate the use of the charts in Figures XI-3 through XI-7, assume the following conditions apply to a paving mix using emulsified asphalt.

Apparent Specific Gravity, coarse Apparent Specific Gravity, fine Percent Passing 4.75 mm (No.4)

Avg. Sp. Gr. = 100

~+~ 2.45 2.64

Surface Area of Aggregate Grading

C.K.E. Percent Oil Retained, coarse

(corrected for specific gravity, this value is 1.7 percent. See Figure XI-3)

From Figure XI-2 determine Kf as 1.25. From Figure XI-3 determine Kc as 0.8. From Figure XI-4 determine Km as 1.15.

= 2.45 = 2.64

= 45 = 2.53

=

= =

6.6 m2jkg (32.4 ft2flb)

5.6 1.9

From Figure XI-5 determine the oil ratio for liquid asphalt as 5.2 percent.

118

CHART FOR DETERMINING Kf FROM C.K.E.

m 2 ft2 'Surface area, - = 0.204816-

kg Ib

sp. gr. fine C.K.E. Corrected = C.K.E. x 2.65

NOTE: Do not confuse this correction to C.K.E. with that used in Fig. XI-3

Figure XI-2. Chart for determining surface constant for fine material, Kfl from C.K.E., Hveem method of design.

119

3.0

2.8 2.6

2.4

2.2

2.0

~u 1.8

;. 1.6 z 4(

!;;1.4 z o u w 1.2 u 4( u.

~ 1.0 I/)

.8

/ L

/ L

/ L

/ /

/ V

/ /

V ~ .,

V / j

1.5 2 3 4 5 6 789 PER CENT OIL RETAINED· CORRECTED FOR SP. GR. OF AGGREGoHE

Material Used: Aggregate - Passing 9.5 mm (3/8"), Ret 4.75 mm (#4) Sieve

Oil- SAE 10

% Oil Ret. Corrected = % Oil Ret. x sp. gr. of Coarse Aggregate

2.65

Figure XI-3. Chart for determining surface constant for coarse material, Kc, from coarse aggregate abs_orption, Hveem

method of design.

120

CHART FOR COMBINING Kf AND Kc TO DETERMINE Km

If (Ke - Kfl is neg., corr. i If (Ke - Kfl is pos., corr. i Km = Kf + corr. to Kf

N.= I <0 ..-co ~ 0 C\I 0

II

N

EI ni Q) .... «l Q) 0 «l -.... :J

(/) •

.0

Cl ~

300

200

... :e i . 100

.:: 90 !l 80 $ 70

t 60

g 50 ca ... o 40 ca ~ ca III 30 I.)

-e :2

CI) 20

10

/ /1/ ,9 r/ ~; / 0.8 s neg.

/~ r/ V~ ./ 0.7 s pos. h 17/ V V~ r/ 0.6

~ 'l "/ /~ ~ -0 0.5

~~ 0-~ t/': ~ '/ 0.4 / ",;;::;

~ ~ ~ ~ / ~ . <b,(.0V ~>~~~ 0.3

, ,/".",./ '/ /

h~~V~ ~ V V V V V V V 0.2

/~~V~'i~ / /

~ ~ ~ ~ ~ ~ V V

l1V ~ ~ ~ ~ ~ V

~ V V V V ~ ~ ~ V V V 0.1

~ ~ V V 7 ~ ~ / / / V / / / / / V / / / , ,I

j , \ \ \ \ 1\

\ 1\ \ '1-' \ 1\ \ \ \ 1\ 1\\\ , 1\ \ ,

\ ~~\ 1\ 1\' l\j 113.

~ \ \ \ ~~ ~ \I

\~ \ \ 1\ ~~'8 \ \ ~ \ \

\ ~ \ \ \ \ \\ r\ \ \ 1 \ \ \

\ \ , \ 1\ \ \ \ ~ \ [\ \ \ \ ,

~ \ \ \ 1\' l\ \

\ \ 1\ ~ ~ ~' l\ ~

..z o ... c o .~ .. 8

Rgure XI-4. Chart for combining Kf and Kc to determine surface constant for combined aggregate, Km, Hveem method of design.

121

-tv tv

:II ca C ; >< ~ o

3::T 9 _.! !~­(') Co g ; ~ iU)() ~ ~ 0 a :::1:3 0<-0 ~CDC oCD~ 23::l D> ca o 3 ~ CD 2. D> -:::l. _~

3 ::T m ~8.~ o 0 ;; 9.0-~ a. ~ ~CDa. D> 2!. CD =-ca::l g ? j

! &

= -0 ::T

!

• 2 0 :; 100 / / & 90 /./ ~~- ///V cT 70 /. / / / /

.:: 60 0 ..IV g - '!o',(,/]V V V « 50 .".""~

~Oj V~"'·· .. '/ ./ .. 40 O'? ~~~~V1 :!! <::>'/V v ",. « - c"Q''-''..t. /

~ 30 "/ VVVV

-o -

~ ~~vvv ~VV/V

20JA 20 VVV"V V

15 vv V

15 ~~~V/ .... V B 20

10 VVV .. vVV 15

~ 10 v/ ./ " ~9 / ./ 6- ......-:.// 10 '!: 8 ,,:~~/ / ::;...-:,...-: ....... ", 9

! 7 0 ~«'/ ').~ v V ~:;...-::~/ ./ .... ~ * ~ 6 ~ / ').V V ~~~~~./ / 6 ~ ~ ~ V" \~ ......::~~ v:: v......-: v / V 5 rr. ~ 5 ~ .... ~%~ ~~?::::: ::::/Vt::-~ 4 0 ~ 4 k:~~~:::::'~/V //V""'"

~/'/././~~/V / 1, 3 3

2

v//:::::VVi ~ V ~///VV ./// ....... V

(+1 H 2 B

CHART FOR COMPUT1NG APPROXIMATE BITUMEN RATIO (ABA) FOR DENSE

GRADED ASPtW..T MIXTURES

Case 1. Given C.K.E., sp. gr. of aggregate and percent passing 4.75mm (#4) sieve.

Correct C.K.E. as indicated by scale E. Find corrected C.K.E. on scale A. Find percent aggregate passing 4.75mm (#4) sieve on scale C. Intersection of straight line with scale B = oil ratio.

Case 2. Given surface area, sp. gr. and Km of aggregate.

Find surface area on scale D. Proceed horizontally to curve corresponding to sp. gr. of aggregate. Then down to curve corresponding to Km' Then horizontally to scale B for oil ratio.

Oil ratio = Ibs. of oil ~er iOO Ibs. of aggregate and applies directly to oil of SC -250 MC - 250 and RC - 250 grades. A correction must be made for heavier cutback or paving asphalts.

1.5 1.0 0.5 0.3 0.1 0 0.1 0.3 0.5 E (Correction to C.K.E.) m 2 ft2

A II.!IIIIIIIIII'I,I' , ,I, , , 'i' i " i' i , ' , i i • Surface Area, kg = 0.204816ib

1.6 1.8 2.0 2.2 2.4 2.6 :>.8 3.0 3.2

Sp. Gr. of Aggregate

C 100 90 80 ..

> ., 70 iii 60 ~

:tI,

50 E E

40 I/)

roo: -t

30 '" c: "ii tf. ..

20 .. 8. f 8l « *-

10 C

Figure XI-6. Apparatus for Hveem C.K.E. tests.

c. Emulsified Asphalt Content for Trial Mixes

The trial emulsified asphalt content for dense-graded mixes is equal to 1.4 x CKE oil ratio, and is adjusted to a 60 percent residue as follows:

Correct Emulsified Asphalt Content

= (1.4 x CKE Oil Ratio) x 60

Emulsion Residue, %

d. Mixing Test, Determination of Optimum Fluids Content at Mixing (1) General

This test measures the ability of the emulsified asphalt to uniformly disperse throughout the mix. It also allows the laboratory technician to judge the mix worka­bility. A number of variables have been found to influence asphalt dispersion and these are listed in Table XI-3.

TABLE XI-3 VARIABLES AFFECTING ASPHALT DISPERSION

Variable

Aggregate

Emulsified Asphalt

Mixing Water

Mixing Operations

Factors Influencing

Surface area (fines) Porosity Roughness

Amount

Type

Oil Distillate

Amount

Temperature

Mix Cycle

124

To Improve Asphalt Dispersion

Decrease Decrease Decrease

Increase

Use anionics with calcareous aggregates (limestone).

Use cationics with siliceous aggregates.

Increase with MS-types.

Increase with SS-types.

Decrease with most MS-types.

Decrease to reduce asphalt runoff.

Decrease with SS-types to prevent coalescence during the mixing cycle.

I ncrease with MS-types.

Optimize. Insufficient mixing may give poor coating.

Excessive mixing may induce stripping.

(2) Equipment (a) Balance. 5,OOOg minimum capacity and accurate to within ± 0.5 g. (b) Mixing Equipment. preferably mechanized and capable of producing intimate

mixtures of the job aggregate, water and asphalt. Hand mixing, if used, must be sufficiently thorough to uniformly disperse the water and emulsified asphalt throughout the aggregate.

(c) Hot Plate or 110 ± 5° C (230 ± 9° F) oven. (d) Supply of round bottom mixing bowls (approximately 5 litre (5 qt.) capacity). (e) Supply of 250 mm (10 in.) metal kitchen mixing spoons. ([) A one-hundred millilitre glass graduate.

(3) Procedure (a) Obtain representative samples of each emulsified asphalt to be considered for

the project. (b) Obtain representative samples of the job aggregate or aggregate blend. (c) Determine the moisture content on the aggregate according to ASTM D 2216

procedure and record. (d) Prepare the remainder of the aggregate by drying to constant weight at 60°C

(l40°F). Separate into sizes using the following sieves: 25.0 mm, 19.0 mm, 12.5 mm, 9.5 mm, and 4.75 mm (1 in., 3/4 in., 112 in., 3/8 in. and No.4).

(e) Weigh out a sufficient number of batches of the job aggregate for mixing tests. The batch weight shall be based on the nominal maximum size particle in the aggregate - see below:

Nominal Maximum Particle Size

25.0mm (1 in.) 19.0mm (3/4 in.) 12.5 mm (1/2 in.) 4.75 mm (No.4)

Batch Weight

2,000 grams minimum 1,200 grams minimum

750 grams minimum 500 grams minimum

Note: These batches should be prepared by reblending exact fractions of plus 4.75 mm (No.4) material with minus 4.75 mm (No.4) material to match the grading analysis of the whole sample.

(f) Put one batch of aggregate in the mixing bowl and incorporate the additive (Le., cement) if specified.

(g) Add and incorporate the minimum amount of mixing water required to achieve coating. Normally this is just enough to darken the aggregate.

Note: In areas where the addition or removal of water is uneconomical, mixes should be made at the in-<)itu moisture content.

125

(h) The emulsified asphalt, in an amount as detennined by the "correct emulsified asphalt content" of Par. 11.05 (c), is added to the damp aggregate and mixed. The mix cycle should simulate field mixing operations (generally a I-minute cycle* with a laboratory mechanical mixer or a 2-minute spoon bowl mix is sufficient). Judge the suitability of the finished mix by the unifonnity of the color (best judged by drying a small portion of the batch on a hot plate). Spottiness denotes an unsatisfactory mix (usually due to insufficient water or improper mixing properties of the emulsion). Mixes which strip or stiffen excessively on mixing are also considered unsatisfactory. If unsatisfactory, re-run a new batch with an additional increment of water and observe for suitability as before. Repeat until a satisfactory­appearing mix is obtained. Mixes which become excessively soupy with additional water and segregate on standing are considered unsatisfactory.

(i) Selection of the emulsified asphalt for the project shall be based upon the following considerations:

1) Coating. As close as possible to 100 percent coating is preferred. Mixes will be considered suitable if they have a minimum of 75 percent coating if used as a surface and 50 percent if used as a base.

2) Workability. The mix should be workable. Mixes which are excessively stiff or sloppy should be rejected.

3) Job Conditions. The availability of water at the construction site, mixing process and anticipated rate of the emulsion mixture cure will also influence the selection of the type and grade of emulsified asphalt.

(j) The total fluids content at mixing of the satisfactory mix is computed by adding percentages of the asphalt emulsion, added mixing water and natural water content of the aggregate. It is expressed as weight percent of dry aggregate. This optimum fluids content at mixing is used for establishing weight proportions of subsequent batches.

11.06 OPTIMUM FLUIDS CONTENT FOR COMPACTION a. General

The optimum fluids content for compaction is detennined as well as the fabrication of all test specimens using a light kneading compaction followed by a double plunger static load.

b. Equipment

(1) Mechanical compactor, meeting the requirements of ASTM Method D 1561, "Com­paction of Test Specimens of Bituminous Mixtures by Means of California Kneading Compactor. ' ,

(2) Compactor accessories; 101.6 mm (4 in.) diameter x 127 mm (5 in.) high stainless steel molds, and a mold holder.

(3) Compression testing machine, 222 kN (50,000 lb.) capacity. (4) Tw%l/ower rams; one ram 101.2 mm (3.985 in.) outside diameter x 139.7 mm

(5.5 in.) high, and the other ram 101.2 mm (.3.985 in.) outside diameter x 38.1 mm (1.5 in.) high.

(5) Special/eeder trough, 100 mm (4 in.) wide and 405 mm (16 in.) long.

* Mixing time may be shortened to 30 seconds if segregation in the mixture is noticed.

126

Figure XI-7. Transfer of mix to mold.

Figure XI-S. Rodding mix in mold. Figure XI-g. Mechanical kneading compactor.

127

(6) Metal paddle to fit feeder trough. (7) Bullet-nosed steel rod, 9.5 mm (% in.) diameter by 405 mm (16 in.) long. (8) A devicefor measuring the height of test specimens to the nearest 0.25 mm (0.01 in.). (9) Metal plate, 6.4 mm (1/4 in.) thick, approximately 9.5 mm (3Js in.) wide and 63.5 mm

(21/2 in.) long.

c. Optimum Fluids for Compaction ( 1) Prepare a mix at the fluids content as developed by the procedures of Par. 11.05. (2) Weigh at least three batches of approximately 1,200 grams each of this mix for the

fluids-density curve specimens. One batch will be compacted immediately with the remaining batches loose-cured (aerated) prior to compaction so as to produce lower fluids contents (minimum of 3 points required to establish optimum). As a first step in the compaction of all specimens, the mix will be spread uniformly on the feeder trough as shown in Figure XI-7. Using paddle, push one-half of the mix into the mold. Rod the mix 20 times in the center of the mass and 20 times around the edge with a bullet-nosed steel rod 9.5 mm (3/8 in.) diameter. 405 mm (16 in.) long (Figure XI-8). Then, push the remainder of the mix into the mold and repeat the rodding procedure.

(3) Place a mold in the mold holder. Slide the metal insert plate [Item 11.06 b.(9)] under the bottom edge of mold. Note: This is used to give temporary support during the preliminary compaction step.

(4) Place the mold holder containing the mix into the kneading compactor (Figure XI-9).

(5) Start the compactor and adjust the tamper foot pressure to 1.7 M Pa (250 psi). Apply approximately 20 tamping blows at 1. 7 M Pa (250 psi) pressure to ac­complish preliminary consolidation of the mix. The exact number of blows to accomplish the initial compaction shall be determined by observation. The number of blows may vary between 10 and 50, depending upon the type of material. In some instances with sandy or unstable material, it may not be possi­ble to accomplish compaction in the mechanical compactor because of the un­due movement of these mixtures under the compactor foot. Discontinue com­paction if the compactor foot penetrates more than 6.5 mm (l /4 in.) or if fluids exude from the base of the compaction mold, and proceed to step (6).

Note: Occasionally, the mix may adhere to the compactor foot. When this occurs, stop the compactor and clean the foot. Use heat on the compactor foot only if necessary to prevent sticking.

(6) Remove the mold from the holder and apply a 178 kN (40,000 lb.) static load by the double plunger method, in which a free-fitting plunger is placed below the sample as well as on top. Load at a rate of about 1.3 mm/min (0.05 in.lmin) and maintain the full load for one minute and release. Reduce the level of the static load if excess fluids exude from the compaction mold and proceed to step (7).

(7) Specimens shall be cured for one day in the mold at room temperature and then extruded. After extrusion, the bulk specific gravities of the specimens are determined by displacement in water (ASTM D 1188 or D 2726).

(8) A plot is made of dry density versus fluids content at compaction. The fluids content resulting in the highest dry density is optimum for compaction.

128

d. Specimen Fabrication for Strength Testing (1) Use approved mix as developed following the procedures of Par. 11.05 for strength

test specimens. This would include trial mixes at emulsified asphalt contents of 1.1, 1.4 and 1.7 times the C.K.E. Oil Ratio adjusted to a 60 percent residue.

(2) Weigh sufficient mix (approximately 1.150 grams) to fabricate each 101.6 mm (4 in.) diameter specimen, 63.5 mm (2.5 in.) in height, and loose cure (aerate) the mix to the optimum fluids content determined by the procedures of Par. 11.06c. Two specimens will be required at each of the trial emulsified asphalt contents selected for bases and temporary wearing surfaces, while only one specimen for each trial emulsified asphalt content is required for permanent surfaces.

11.07 STRENGTH TESTING a. General

The rate at which emulsified asphalt mixes cure or develop tensile strength is important. A number of factors including the aggregate gradation, type and amount of emulsion, type and amount of additive, construction and climatic conditions must be assessed by the engineer in determining the rate of tensile strength development. This procedure measures one strength parameter of the mix using the Resilient Modulus Test which is the final modulus (Mf ). The curing procedure used in defining this strength is given.

b. Equipment Resilient Modulus apparatus and support equipment as manufactured by Retsina Com­

pany, 601 Brush Street, Oakland, California 94607.

c. Procedure ( 1) One of the two specimens compacted at each asphalt content using the procedures

of Par. 11.06 will be cured by placing the mold in a horizontal postion for a total of 72 hours at a temperature of 23 ± 2.SoC (73 ± 5°F).

(2) Remove the specimen(s) from the mold and vacuum desiccate for 4 days (Figure XI-II). Adjust the total pressure to 10-20 mm of Hg. (Note: Fill the bottom of the desiccator with Drierite to facilitate removal of water. If the Drierite is spent, indicated by pink color, replace with fresh Drierite and desiccate for an additional day.)

(3) Determine the specimen's final modulus (Mf ) at 23 ± 1.7°C (73 ± 3°F) as outlined below.

(a) Resilient Modulus Test, Mr.

The equipment used for determining M r consists of a repetitive loading device which applies a 0.1 second pulsed load every 3 seconds across the diameter of the test specimen (Figure XI-IO). The horizontal response to the applied load is measured by a pair of transducers mounted in a yoke that is clamped to the specimen (Figure XI -II). The electrical output from the transducers is amplified and shown on a recording meter designed to hold the deflection long enough for the operator to record the reading.

(b) Calibration

Primary calibration of the instrument is made with a Lansing Instrument Differential Translator. Secondary and load calibration is made with a proving ring. Calibration details are supplied by the instrument manufacturer.

129

(c) Temperature Control

The Mr of an asphalt treated mix is dependent on the stiffness of the asphalt binder. Consequently the M r is quite dependent on the temperature of the specimen. Equilib­rate all specimens and the yoke assembly at least 2 hours at the temperatures of 23 ± 1. 7°C (73 ± 3°F) before testing.

(d) Me Measurements

1) Place the yoke assembly on the holder (Figure XI-12). 2) Back out the thumb screw so that the transducer levers are clear. Back out the

four clamping screws and gently insert the 100 mm (4-in.) diameter sample into the center of the yoke. Place the sample squarely on the centering strip. Gently tighten the four clamping screws, keeping the sample centered and square in the yoke. Use only enough pressure to keep the yoke from falling off the sample (Figure XI-13).

3) Place the assembly in the loading device and align on the centering strip. (Note: Do not lift by the yoke.)

4) Lift the loading shaft and place the top loading block on the specimen, 3.14 radians (180°) from the bottom centering strip. Allow the shaft to seat against the ball on top of the loading block (Figure XI-14).

5) Zero the recording meter. Set the multiplier knob to 100 and tum on the meter. Adjust the zero control until the meter reads just above zero (Figure XI-15).

6) Tighten one of the transducer advancement screws until an increased meter reading of about 1.0 is obtained. Tighten the advancement screw on the other transducer until an additional increase of 1.0 is obtained on the meter.

7) Set the pressure regulator to the desired load (Figure XI -16). Some instruments use manometers to measure the air pressure--others use pressure transducers. Choice of load depends on the strength of the specimen. Usually 0.33 kN (75 lb.) is used on sound dry specimens having modulus values ranging from 6.89 x 105

to 3.45 X 107 kPa (105 to 5 X 106 psi). However, lower pressures may be required to minimize specimen damage. MR values as low as 3.45 x 104 kPa (5 x 103 psi) can be measured.

8) Reset the zero knob to just above zero, i.e., until both the high and low pilot lights are out.

9) Set the mode switch to operate. 10) Record the deflection in microinches on the meter. If the reading is out of

range change the multiplier to a higher or lower value. Reset the zero knob if one of the zero indicator pilot lights is on and make another measurement.

11) More complete operating details are supplied by the instrument manufacturer.

12) Rotate the sample 1.57 rad (90°) and repeat measurements. Deflection readings should normally agree within 10 percent. Sometimes a specimen is non-isotropic and a larger difference exists.

130

Figure XI·11. Transducers and Mryoke.

131

Figure XI·10. Resilient modulus device.

Figure XI-13. Tightening Mrclamping screws.

132

Figure XI-12. Mr yoke on holder.

Figure XI-14. Seating Mr specimen on loading block.

13) Calculate the M r as follows:

S.1. Metric U.S. Customary

Mr 1000 P ('Y + 0.2734) = 623.4K. Mr = P ('Y + 0.2734) = o 6234R.. = tA tA tA . tA

P = dynamic load in kN (lb)

'Y = 0.35 (assumed for Poisson's ratio)

t = thickness of specimen, mm (in.)

A = deflection in I-Lm (microinches) obtained by multiplying the meter reading by the multiplier.

4 6

~\ \ \ , ,\ \ \ \ \ \ \ IIIIII1111111II 111,l o ~\\\ I///h 10 ~0 ~~/

MICROINCHES

WESTON

Figure XI-1S. Adjusting Mr recording meter.

133

Figure XI-16. Adjusting Mr pressure regulator.

Sample Calculation:

S.1. Metric

P = 0.333 616 6kN t = 63.5mm

-7 6. = 3.81 x 10 ~m

623.4 x 0.3 336 166 Mr=

63.5 x 3.81 x 10-7

Mr = 8596383 kPa

P = t =

6. =

Mr

Mr

U.S. Customary

75lb 2.5 in. 15 micro inches

0.6234 x 75

= 10-6 2.5 x 15 x

= 1,246,800psi

(4) Measure the bulk specific gravity of the specimen according to ASTM D 1188 or D 2726.

(5) Calculate the volume of air and asphalt as follows:

Where:

Va = 100 - (Vb + Vsa>

Vb = Wb. 100 Gb Vmb

Vsa = Ws . 100 Gsa Vmb

Vmb = Wm Gmb

W - WeRe b - 100

Va = Volume of air (percent of total mix)

Vb = Volume of asphalt in mix (percent of total mix)

V sa = Volume of aggregate (by apparent specific gravity percent of total mix)

V mb = Bulk volume of compacted mix

Wb = Weight of asphalt

134

Gb = Specific gravity of asphalt

W s = Weight of dry aggregate

W m = Weight of dry compacted mix

Gmb = Bulk specific gravity of dry compacted mix

Gsa = Aggregate apparent specific gravity

We = Weight of emulsified asphalt

Re = Percent residue of emulsified asphalt, expressed as a whole number.

11.08 MOISTURE EXPOSURE AND STABILITY AND COHESION TESTING a. General

Dense-graded mixtures used in the base course or as a temporary wearing surface are evaluated for early strength and fully-cured strength after vacuum saturation.

b. Vacuum Saturation (1) General

This test simulates the effect of prolonged exposure to subsurface water on dense­graded base mixtures.

(2) Equipment (a) Vacuum apparatus shown in Figure XI-17.

Figure XI-17. Vacuum manometer and desicator.

135

(b) Vacuum pump capable of pulling 100 mm of Hg.

(3) Procedure (a) Record the weight, AB, of the specimen from the resilient modulus testing. (b) Place the specimen into the vacuum apparatus and cover with water (desiccant

should be removed from the vacuum apparatus before filling with water). (c) Evacuate the desiccator to 100 mm of Hg and hold for one hour. (d) Slowly release the vacuum and allow the specimen to soak in water for one hour. (e) Remove the specimen, surface dry, reweigh and record this weight as Aw. (f) Determine the Stabilometer (R-value) and Cohesiometer (C-value) as subsequently

described. (g) Dry the entire specimen to constant weight at 110 ± 5°C (230 ± 9°F), cool to

room temperature and weigh. Record this weight as AD. (h) Calculate percent Moisture Pick-up, P, by the specimen during vacuum saturation

as follows: Aw _ AB P = x 100.

c. Resistance R-Value Test (1) General

AD

This test is used to measure the stability or bearing capacity of dense-graded base mixtures at a test temperature of 23 ± 2.8°C (73 ± 5°F). An early Resistance R-value is determined on "early cure" specimens fabricated by the procedures of Par. 11.06 after curing in the mold in a horizontal position for a total of 24 hours at a temperature of 23 ± 2.8°C (73 ± 5°F) (no moisture exposure). Also, this test is performed on the "fully cured" specimens that are vacuum saturated as described in Par. 11.08 (b).

(2) Equipment (a) Hveem stabilometer and accessories (see Figure XI-I8). (b) Testing machine, 222 kN (50,000 lb.) capacity.

Figure XI-18. Hveem stablometer.

136

(3) Procedure (a) Calibrate the displacement of the stabilometer by the following procedure:

I) Adjust bronze nut on stabilometer stage base so that the top of the stage is 89 mm (31/2 in.) below the bottom of the upper tapered ring. Perform all tests at this stage setting.

2) Put a metal dummy specimen in place in the stabilometer. Apply a load of from 0.445 to 0.89 kN (100 to 200 lb.) on the testing machine dial to the dummy specimen to make certain the dummy is held firmly in place. Crank the pump to a pressure of exactly 34.5 kPa (5 psi). Tap the stabilometer dial lightly with fingers in order to be sure the needle is resting on 34.5 kPa (5 psi) pressure. Adjust the turns indicator dial to zero.

Tum pump handle at approximately two turns per second until the stabilometer reads 689 kPa (100 psi). The turns indicator dial should then read 2.00 + 0.05 turns. If it does not, the air in the cell must be adjusted by means of the rubber bulb, and the displacement measurement must be repeated after each air change until the proper number of turns is obtained. Release horizontal and vertical pressures and remove dummy specimen. The stabilometer is now ready for testing specimens.

3) Adjust testing machine to give a constant movement of 1.3 mm (0.05 in.) per minute with no load applied. The hydraulic machines must be run several minutes before oil warms sufficiently to maintain a constant speed.

(b) Transfer the specimens to the stabilometer.

(c) Place follower on top of specimen and crank pump to give a horizontal pressure of 34.5 kPa (5 psi). [The 34.5 kPa (5 psi) pressure should be exact as a deviation of only 7 kPa (l psi) has considerable effect on the final value.]

(d) Start vertical movement of testing machine platen at speed of 1.3 mm (0.05 in.) per minute, and record the stabilometer gauge readings when the vertical forces are 2.224, 4.448, and 8.896 kN (500, 1,000 and 2;000 lb.) total load. [Vertical pressures are 276,552, and 1,103 kPa (40,80 and 160 psi).]

(e) Stop vertical loading exactly at 8.896 kN (2,000 lb.) and immediately reduce to a load of 4.448 kN (1,000 lb.)

(f) Tum the displacement pump so that the horizontal pressure is reduced to exactly 34.5 kPa (5 psi). This will result in a further reduction in the vertical loading reading which is normal and for which no compensation is made. Set the turns displacement indicator dial to zero. Tum pump handle at approximately two turns per second until the stabilometer gauge reads 689 kPa (100 psi).

During this operation, the vertical load registered on the testing machine will increase and in some cases exceed the initial 4.448 kN (1,000 lb.) load. As before, these changes in testing machine loading are characteristic and no adjustment or compensation is required.

(g) Record the number of turns indicated on the dial as the displacement of the specimen. The turns indicator dial reads in 0.0254 mm (0.001 in.) and each 2.54 mm (0.1 in.) is equal to one tum. Thus, a reading of 6.35 mm (0.250 in.) indicates that 2.50 turns were made with the displacement pump.

137

(h) Calculate the Resistance R-value from the following formula:

R = 100 _ 100

2.5 (Pv _ 1) + 1 D Ph

Where: P v = 1 103 kPa ( 160 psi) vertical pressure D = turns displacement reading

Ph = horizontal pressure [stabilometer gauge reading for 1 103 kPa(16Opsi ) vertical pressure)]

The chart for determining R-value from stabilometer data (Figure XI-19) is normally used to solve the above formula.

(i) Every attempt should have been made to fabricate test specimens having an overall height between 62 mm (2.45 in.) and 65 mm (2.55 in.). However, if for some reason this was not possible, the R-value should be corrected as indicated on the chart for correcting R-values to height of 64 mm (2.5 in.). (Figure XI-20.)

(j) Upon completion of R -value determination, remove the specimen and immediately test for cohesiometer value (Par. 11.08f).

d. Stabilometer S-Value (1) General

This test measures the stability or bearing capacity of compacted fully cured permanent dense-graded surface mixes (no moisture exposure).

(2) Equipment (a) Hveem stabilometer and accessories (see Figure XI-18). (b) Testing machine, 222 kN (50,000 lb.) capacity.

(3) Procedure (a) Place the specimens for test in 60 ± 2.8°C (140 ± 5°F) oven for 2 hours before

testing. (b) Calibrate the displacement of the stabilometer (see Par. 11.08d (3». (c) Transfer the specimen to the stabilometer. (d) Start vertical movement of testing machine platen at speed of 1.3 mm (0.05 in.)

per min., and record the stabilometer gauge readings when the vertical forces are 2.224, 4.448 and each 4.448 kN (500, 1,000 and each 1,000 lb.) thereafter up to 22.24 kN (5,000 lb.).

(e) Stop vertical loading exactly at 26.69 kN (6,000 lb.) and immediately reduce the load to 4.448 kN (1,000 lb.).

(f) Tum the displacement pump so that the horizontal pressure is reduced to exactly 34.5 kPa (5 psi). This will result in a further reduction in the vertical loading reading which is normal and for which no compensation is made. Set the turns displacement indicator dial to zero. Tum pump handle at approximately two turns per second until the stabilometer gauge reads 689 kPa (100 psi).

138

5.0 1.0 155

2

3

4.5 150 4

5

140

4.0 10

100 130 R = 100 -

::(~- 1) + 1 120 d Ph 20

3.5 110 where Py = 160psi

.;;; 30 100 c..

0 0 90 ... II .s= 80 CI.. ..

GI o ;:, ... ;; 70 ...

C GI

E a: 60 II

'" III Q. . !e 50 0 .. E

40 ;:, I-

I 'tl

30

2.5

20

90

10

2.0 5

Figure XI-19. Chart for determining R-value from stabllometer data; multiply psi by 6.894 757 to obtain kPa.

139

-.;;; .g-GI .. i ... GI

ct: ii .. :I !J

I .s=

CI..

o ILl ~ o ILl Q:; Q:;

o o

ILl :::> ..J c(

> I

Q:;

R-VALUE BEFORE HEIGHT CORRECTION

Figure XI-20. Chart for correcting R-values to height of 63.5 mm (2.50 in.); multiply in. by 25.4 to obtain mm

80

During this operation the vertical load registered on the testing machine will increase and in some cases exceed the initial 4.448 kN (1,000 lb.) load. As before, these changes in testing machine loading are characteristic and no ad­justment or compensation is required.

(g) Record the number of turns indicated on the dial as the displacement of the specimen. The turns indicator dial reads in 0.0254mm(0.001 in.) and each 2.54 mm (0.1 in.) is equal to one turn. Thus, a reading of 6.35 mm (0.250 in.) in­dicates that 2.50 turns were made with the displacement pump. This measure­ment is known as turns displacement of the specimen.

140

(h) Calculate the stabilometer S-value from the following formula:

S 22.2

+ 0.222

Where: S = stabilometer value D2 = displacement on specimen (turns) Pv = vertical pressure [typically 2 758 kPa (400

psi) = 22.24 kN (5,000 lb.) total load] Ph = horizontal pressure - stabilometer pressure gauge

reading taken at the instant Pv is 2 758 kPa (400 psi) or 22.24 kN (5,000 lb.) total load

(i) Every attempt should have been made to fabricate test specimens having an overall height between 62 mm (2.45 in.) and 65 mm (2.55 in.). However, iffor some reason this was not possible, the S-value should be corrected as indicated on the chart for correcting S-values to a height of 64 mm (2.5 in.) (Figure XI-2I).

(j) Upon completion of S-value determination, remove specimen and immediately test for cohesiometer value (Par. II.08f).

e. Cohesiometer Test (1) General

This test provides a measure of the cohesive resistance or tensile strength of the compacted mixture.

(2) Equipment (a) Cohesiometer (see Figure XI-22).

(3) Procedure (a) Cohesiometer tests are performed on the same specimens previously tested in the

stabilometer. (b) Calibrate cohesiometer device so that the shot (or liquid) will flow into the receiving

bucket at the end of760 mm (30 in.) lever arm at the rate of 1800 ± 20gperminute. (c) Adjust heating unit in cabinet of cohesiometer device to maintain a temperature of

23 ± 2.8°C (73 ± 5°F) for testing base and 60 ± 2.8°C (140 ± 5°F) for surface mixes.

(d) Lock device in position with release pin. Clamp firmly in position, centered, and with top plates parallel with top surface of specimen .. Permit temperature in cohesiometer cabinet to equilibrate to the desired temperature before starting the test.

(e) Pull release pin and allow shot flow to continue until the specimen breaks, indicated by a sudden drop of beam.

141

CHART FOR CORRECTING STABILOMETER VALUES TO SPECIMEN HEIGHT OF 64 mm (2.50 in.)

Height correction should be made using the table and chart below.

Example: Overall height of 69 mm (2.74 in.) select correc­tion curve "B". Stabilometer value uncorrected = 35 Stabilometer value corrected = 38.

Overall Specimen Ht. Correction Curve

71 mm to 76mm (2.80 in. to 3.00 in.) A 66mm to 70mm (2.60 in. to 2.79 in.) B 61mm to 65mm (2.40 in. to 2.59 in.) C 56mm to 60mm (2.20 in. to 2.39 in.) D 51mm to 55mm (2.00 in. to 2.19 in.) E

ABC 0 E 50r-------~------~------~------._~_,r_~_r~--1

~ • • • t • • • .

• •.. I ....

--t--------- .--.-.- ~-- --_ .... - -- ----+-- ~ ---. • ••• t . . • • • •••••••.•• t·' •..

.• • • • j .••..... t • • ••• , ••••

~ 40~.~.-.-.r,.-.-.-.~.-.-.-.'~.-.. --+-.. -.-.-.-.-.. -.+-~~~~--~~~~------~ Q) •.•• 1 •••• ... . ....... . u Q) ~ ~

o

.•••• f ••••

• - .• + • - ... - ••. t ..•. ..... I .•..

· . . . ~ . . . . .------t----' · ... , -- .. · ... ; ....

• ••• 1 •••• • ••• t ••.•

· ... , .. ' .

U 30~·_·_·_·~t._._._.~._._.,_.~._. '-'-'+-~~~~~~-?~--~--~--~--1

Q)

::J

~ ~

Q)

• ... t ..•. .... ! ....

• ••• t •••• ----+_.

: : : : I : : : : · ..• I' ..• .... j ••••

• ••• I ••.•

• •.• I, . , •

.. .. t .. •• · ........ - . -.... t····~ · ... t· ...

.. - . ! ... ·l-:-· .. t ••• ~-•• t ••• ' •• - ..... ...

· .•• I •.•• - ~ •• -

~ 20~.-.-.-.r.-·-.-.r---~~~~+-~+-.-.. -.-t-.-.-.. ~.-.-.. -,-.-.-.. ~.'-.-.. ~.-_.-._-~~~ E . . . . . . . . . . . . . t • . ., •••• I . . .. . .•• -+ ~. - •• o . . . . j • . • . . . . . • • . .. .... t • • •• •••• t ~.:- .-,'.' • .•. t . • . . . ..••.•...... i . .. . --

.,--+---+----r--.~-+---_+_~~

-g : : : : I : : :: ::::::::: - ····1···· .... , ... . en I 0 r---+--:~~~-ifI'C---+---t----+-. _. '_',-' _. _. '-+--' ... I ... .

: : : : I : : : :

• ••• t •••• · ... I .... • ••• + .•.• · ..• t . - .•

. . .. .... .... , .... : : : : I : : :: :::: j : : : : - --.- t .••• • . ••. . •• ,,- •.•. I •.•• • , •• f • • •• • ••• I .. +.

10 20 30 40 50 60 Stabilometer Value Before Height Correction

Figure XI-21. Chart for correcting stabllometer values to effective specimen height of 64 mm (2.5 in.).

142

(f) In the event that the specimen is flexible or ductile rather than brittle, the flow of shot is stopped when the end of the 760 mm (30 in.) beam has lowered 13 mm (112 in.) from horizontal.

(g) Weigh shot caught in receiving bucket to the nearest gram and record as shot weight.

(h) Calculate cohesiometer value, C, as:

L C = ______________ _ W (0.20H + 0.044H2)

Where: C = cohesiometer value (g per mm (in.) width corrected to a 75 mm (3 in.) height

L = weight of shot in grams W = diameter or width of specimen in mm (in.) H = height of specimen in mm (in.)

Cohesiometer values may also be obtained by mUltiplying the weight of shot necessary to break the specimen by factors established for various heights of 100 mm (4 in.) diameter (or width) specimens. The factors used are shown in Table XI-4.

TABLE 4 MULTIPLYING FACTORS FOR COHESIOMETER VALUES

Heigh,t Factor Height Factor mm in. mm in.

56 2.20 0.382 64 2.50 0.322 57 2.25 0.371 65 2.55 0.313 58 2.30 0.360 66 2.60 0.305 60 2.35 0.349 67 2.65 0.297 61 2.40 0.340 69 2.70 0.290 62 2.45 0.331 70 2.75 0.283

Example: Assume that it takes 600 g of shot to break

g. Resistance R t Value

a certain specimen which has a 100 mm (4 in.) diameter and 64 mm (2.50 in.) height. Cohesiometer value = 600 x 0.322 = 193.

Calculate the Resistance Rt Value for base and temporary wearing surfaces ac­cording to the following formula:

Rt = R + 0.05 C R = Resistance R-Value [23 ± 2.8°C (73 ± 5°F)] C = Cohesiometer C-Value [23 ± 2.8°C (73 ± 5°F)]

143

STATIONAlY PlATES r---- "'OVAllE PlATfS

SHOT SVPl'tY

COUNTEI. 1~~~~rr==~===~=======;~L-WEIGHT , SHOT

TEST - __ ~--V- CONTIOI SPECIMEN

Figure XI-22. Diagrammatic sketch showing principal features of the Hveem cohesiometer.

:::::::1«:: IllUSTRATION Of MANNEI IN WHICH SPECIMEN BlEAU

11.09 DETERMINATION OF OPTIMUM EMULSIFIED ASPHALT CONTENT An optimum emulsified asphalt content is established on the basis of the best combination

of stability, density and maximum resistance to water in addition to meeting the minimum requirements of Table XI-5.

144

TABLE XI-5 DESIGN CRITERIA FOR EMULSIFIED ASPHALT-AGGREGATE MIXES

Base Test Property Mixtures

RESISTANCE Rt-VALUE EarlyCureB 70 min. at (23 ± 2.8°C) (73 ± 5°F)

Fully cured and 78 min. water immersedb

STABILOMETER S-VALUE NA at (60 ± 2.8°C) (140 ± 5°F)

COHESIOMETER C-VALUE EarlyCureB 50min. at (23 ± 2.8°C) ( 73 ± 5°F)

Fully cured and water immersed b

100 min.

COHEISIOMETER C-VALUE NA at (60 ± 2.8°C) (140 ± 5°F)

AGGREGATE COATING (%) 50min.

a Cured in mold for total of 24 hours at temperature of 23 ± 2.8°C (73 ± 5°F).

Surface Mixtures

NA

NA

30min.

N.A.

NA

100min.

75min.

b Cured in mold for total of 72 hours at temperature of 23 ± 2.8°C (73 ± 5°F) vacuum desiccated for 4 days followed by water immersion for one hour under vacuum and one hour without vacuum.

N A Not Applicable

NOTE: Besides meeting the above requirements, the mix must be reasonably workable (Le., not too stiff or sloppy).

145

CHAPTER XII

PROCEDURAL OUTLINE AND DESIGN CRITERIA FOR THE ASPHALT INSTITUTE DESIGN METHOD

FOR OPEN-GRADED MIXES

12.01 SCOPE This outline covers the design of open-graded emulsified asphalt mixtures for base and

surface courses. Design criteria for open-graded mixtures are also presented.

12.02 AGGREGATES Aggregate for open-graded emulsified asphalt pavements should be sound, clean and free

from flat and elongated pieces. The selected aggregate may be any mineral that meets the requirements of the American Society for Testing and Materials (ASTM) Standard D 692, with the following amendments:

1. Not less than 65 percent by weight of material must have at least one fractured face.

2. Loss when subjected to the Los Angeles Abrasion Test must not be greater than 40 percent.

Recommended gradations for open-graded emulsion mixtures are shown in Table VII-4, Chapter VII, of this Basic Asphalt Emulsion Manual.

12.03 ASPHALTS Two types of emulsified asphalt are used for mixing. These are designated as slow setting

(SS) and medium setting (MS). Specifications (ASTM) for these asphalt materials are given in Tables II-I and 11-2 of this manual.

12.04 SELECTION OF TRIAL EMULSION CONTENT The emulsified asphalt content for trial mixes for open-graded aggregates shall be as specified

in Table XII-l. Trial mixes should be prepared to determine the maximum emulsified asphalt content that can be used within the range that meets the mix-design requirements.

TABLE XII-1 SELECTION OF EMULSIFIED ASPHALT AMOUNT

Type Approximate Emulsified Asphalt

Open Graded

Coarse Medium Fine

Content, Percent by Weight of Aggregate·

4.5 - 6.5 5.0 -7.0 6.0 - 8.0

• With porous aggregates the emulsified asphalt content should be increased by a factor of approximately 1.2. Porous aggregates are those which absorb more than 2 percent water by dry weight when tested by ASTM Method C 127.

147

Figure XU-1. Wire screen funnel.

12.05 MIXING TEST This test measures the ability of the emulsified asphalt to uniformly disperse throughout

the mix. It also allows the laboratory technician to judge the mix workability. A number of variables have been found to influence asphalt dispersion and these are listed in Table XI-3 of Method A.

For a given emulsion content, add enough water to just darken the aggregate (the amount of which is a function of nominal maximum particle size). Then add the selected amount of emulsion and mix for 30 seconds using a mechanical mixer. Immediately pour or spoon the mixture into an 850 J.Lm (No. 20) mesh wire screen funnel that has been positioned over a tared litre (quart) container. (See Figure XII-I.)

Allow the mix to drain for 30 minutes. Remove the mix from the funnel and judge it for coating and workability. Place the container with the runoff in a 110 ± 5°C (230 ± 9°F) oven and dry to a constant weight. Determine the final weight and compute the runoff as:

Runoff, % = Final Weight - Tared Weight x 100 Batch Aggregate Weight

If the three characteristics (coating, workability and runoff) arejudged to be unsatisfactory, increase the water content in fixed increments until a satisfactory mix is obtained.

The process is repeated for each trial emulsion content. The objective is to determine the maximum emulsified asphalt content that can be used within the range that meets the mix design requirements. (Note: The mixing fluids content [asphalt and water] for open-graded mixes is assumed to be at optimum for compaction.)

148

12.06 MIX CURING AND RESILIENT MODULUS TESTING Prepare two specimens at the emulsion and water content established as optimum in the

mixing test. Compact them using the kneading compactor followed by a 178 kN (40,000 lb.) double-plunger static load (see Par. 11.06c).

One specimen is cured for 72 hours in the mold at room conditions and then vacuum desiccated (with a residual pressure of 10 to 20 mm of Hg) for four additional days. This specimen is then tested for diametrial resilient modulus, Mr. (The Mr is not part of the actual mix design since criteria have not been established. It may be used for establishing pavement layer thickness. See Par. 11.07, Strength Testing, Method A.)

12.07 WASHOFF TEST (Open-graded mixes are evaluated for damage by surface water if rain is a possibility on a

project within a short period after laydown. Damage from washoff as a result of rainfall is generally not a problem after 24 hours under favorable curing conditions.)

The second specimen, from Par. 12.06 above, is cured for 24 hours in the mold at room conditions and subjected to the washoff test. This involves placing the specimen, while still in its mold, on a 125 mm (5 in.) square 850 fJ.m (No. 20) mesh wire screen supported by a pedestal, and then pouring 200 cm3 of water over the sample and collecting the washoff in a tared container. After allowing the specimen to drain for 30 minutes, the washoff is dried to a constant weight in an oven at a temperature of 110 ± 5°C (230 ± 9°P). The residue weight after drying is computed as the' 'residual asphalt washoff. " The percent of washoff is computed as:

Washoff, % = Wt. of Residual Asphalt Washoff x 100 Wt. of Aggregate in Specimen

12.08 DESIGN CRITERIA To be acceptable, the mix must satisfy the design criteria as follows:

Coating, percent Runoff, percent Washoff, percent Combined (runoff & washoff), percent

* Usually requires a surface treatment. (See Chapter VII.)

149

Base Mixture

50.0 min. 0.5 max. 0.5 max. 0.5 max.

Surface Mixture * 75.0min. 0.5 max. 0.5 max. 0.5 max.

CHAPTER XIII

PROCEDURAL OUTLINE AND DESIGN CRITERIA FOR THE McCONNAUGHAV

DESIGN METHOD FOR COLD MIXTURES

13.01 SCOPE This outline covers the design procedure and criteria for open- and dense-graded emulsified

asphalt cold mixtures.

13.02 AGGREGATES Dense-graded aggregates meeting requirements of Table VII-5 of this Basic Asphalt Emulsion

Manual are among those suitable for emulsified asphalt mixtures. (Generally, gradations containing appreciable fines may require aeration.)

For open-graded mixtures, aggregates should conform to the requirements of Par. 12.02, and Table VII-4, this manual.

13.03 ASPHALTS Two types of emulsified asphalt are used for mixing. These are designated as slow setting

(SS) and medium setting (MS). Specifications (ASTM) for these asphalt materials are given in Tables II-I and II-2 of this manual. The McConnaughay method, while not limited, has been applied for the most part to mixtures made with high float (HFMS) type of emulsion.

13.04 PART A-DETERMINATION OF EMULSIFIED ASPHALT CONTENT AND CURED MIX STABILITY

This procedure is used to determine the emulsified asphalt content and to indicate the H veem * stability of the mixture in its cured state. A minimum of three (3) emulsified asphalt contents should be tested.

For average traffic conditions, Hveem stability values above 30 are recommended. However, successful results with local aggregates yielding lower H veem stabilities have been experienced on low volume roads. Generally well-graded aggregates will develop Hveem stabilities in the 35 to 45 range.

1. Determine the residue content of the emulsion to be used by ASTM D 244, "Residue and Oil Distillate by Distillation." (See Appendix B.)

2. Estimate an initial emulsified asphalt content based on dry aggregate weight as follows:

a. A (Base Mix) = [(0.06 x B) + (0.01 x C)] x 100 OR

A (Surface Mix) = [(0.07 x B + (0.03 x C)] x 100

b. E = A 1(1.00 - A) X 100 R

* For a description of the Hveem and Marshall test, see Mix Design Methods for Asphalt Concrete and Other Hot-Mix Types, Manual Series No.2, The Asphalt Institute.

151

Where: A = Percent residue based on dry weight of mix B = Percent passing 4.75 mm (No.4) sieve C = 100 minus percent passing 4.75 mm (No.4) sieve R = Percent residue by distillation (Step 1) E = Percent emulsion based on dry weight of aggregate

Note: This procedure is for obtaining an estimate only and does not apply to open-graded aggregates.

Example: Estimate the initial emulsified asphalt content for a base mix where: (1) the graded aggregate has 60% passing the No.4 sieve and (2) the residual content of the emulsified asphalt is 68%.

a. A (Base Mix) = [(0.06 xO.60) + (0.01 x (1.00 - 0.60»] x 100 = 4.0%

b. E = 0.04/(1.00 - 0.04) x 100 = 6.13% 0.68

After determining the asphalt emulsion content required for the aggregate, weigh the required amount of emulsion on to the cold pre-weighted aggregate. (Dry weight plus moisture content.) The aggregate should be used at its natural moisture content.

3. Mix the emulsion and aggregate by hand for 30 seconds. Evaluate the aggregate coating. * Test for water resistance with a small portion of the resulting mix. * If coating and water resistance are satisfactory for the intended use of the mix, proceed to Step 4. If not, another emulsion should be selected.

4. Heat this mixture to 121°C (250°F) with continual mixing.

5. Compact the mixture at 110°C (230°F) using the Marshall hammer. (Apply 50 blows to each side of the specimen.)

6. Allow the sample to cool in the mold for a minimum of 1 hour.

7. Place the sample while still in the mold in an 60°C (140°F) oven for 2 hours.

8. Test the specimen in the Hveem stabilometer in accordance with ASTM D 1560 "Resistance to Deformation and Cohesion of Bituminous Mixtures by Means of Hveem Apparatus. "

13.05 PART B-INITIAL STABILITY (PARTIALLY CURED) The following procedure is used to determine the initial strength of the mixture; that is,

after the mixture has been placed and compacted. As noted in the procedure, if the moisture is excessive, it may be necessary to aerate the mixture prior to compaction.

This part of the procedure may be omitted if past experience has shown that the mix has sufficient stability to carry initial anticipated traffic without undue distress.

1. Determine the residue content of the emulsion to be used by ASTM D 244, "Residue and Oil Distillate by Distillation."

2. Determine moisture content of the aggregate.

3. Estimate the initial emulsified asphalt content (Par. 13.04, Step 2). After determining the emulsified asphalt content required for the aggregate, weigh the required amount of emulsion on to the cold aggregate. (The aggregate should be used at its natural moisture content.)

• ASTM D 244, Residue and Oil Distillate by Distillation, Section on "Coating Ability and Water Resistance"

152

4. Determine the proper emulsion which will provide for satisfactory coating ability and water resistance on the aggregate, as per Par. 13.04, Step 3.

Mix the emulsion and aggregate for 30 seconds. Note the percentage of the aggregate that is coated. Continue mixing for an additional 21/2 minutes.

5. Compact the mixture at ambient temperature using the Marshall hammer. (Apply 50 blows to each side of the specimen.) If moisture is excessive, it may be necessary to aerate the mixture prior to compaction.

6. Remove the base plate and paper discs and place the mold containing the compacted specimen on a perforated shelf in a forced draft oven at 60°C (140°F) for 48 hours.

7. After removal from the oven and while the specimen is still at 60°C (140°F) temperature, apply a static load of 178 kN (40,000 lbs.), by the double plunger method, in which a free-fitting plunger is placed below the sample as well as on top. Load at the rate of about 1.3 mrnlmin. (0.05 in.lmin.) and maintain the full load for one minute and release.

8. Allow the sample to cool in the mold for a minimum of 1 hour.

9. Test the specimen in the Hveem stabilometer in accordance with ASTM D 1560, except that the test is performed at ambient* temperature.

13.06 DESIGN CRITERIA To be acceptable for average traffic conditions the mixture must satisfy the following criteria:

Par. 13.04 Par. 13.05 (Part A) (Part B)

Minimum Minimum

Hveem Stabilometer, S-Value at60 ± 2.8°C(140 ± 5°F) 30 at 23 ± 2.8°C (73 ± 5°F) 30

Aggregate Coating (%) Fair Fair Water Resistance ** Fair Fair

* 23 ± 2.SOC (73 ± 5°F) ** The water resistance may be waived/or slow setting (SS and CSS) emulsions.

153

CHAPTER XIV

MARSHALL METHOD FOR EMULSIFIED ASPHALT·AGGREGATE COLD MIXTURE DESIGN

14.01 SCOPE This design method for cold-mix emulsified asphalt-aggregate paving mixtures is based on

research conducted at the University of Illinois using a modified Marshall method of mix design and a moisture durability test. The method and recommended test criteria are applicable to base course mixtures for low traffic volume pavements containing emulsified asphalt and dense-graded mineral aggregates with maximum sizes of 25 mm (1 in.) or less. This design is recommended for road mixes or plant mixes prepared at ambient temperatures. The procedures contain certain modifications suggested by NCHRP Report 259, "Design of Emulsified Asphalt Paving Mixtures."

14.02 OUTLINE OF METHOD The design procedure involves the following major parts: (1) Aggregate quality tests. (2) Emulsified asphalt quality tests. (3) Type and approximate amount of emulsified asphalt. (4) Water content at mixing and at compaction. (5) Variation of residual asphalt content. (6) Selection of optimum asphalt content. The optimum asphalt content is chosen as the

percentage of emulsified asphalt at which the paving mixture best satisfies all of the design criteria.

14.03 OBJECTIVE Provide an adequate amount of residual asphalt to economically stabilize granular materials to:

- Give required strength or stability to withstand repeated load applications (compres­sive and flexural) without excessive permanent deformation or fatigue cracking.

- Render the mixture sufficiently insensitive to moisture effects.

14.04 AGGREGATES FOR EMULSIFIED ASPHALT MIXES Aggregate properties are the determining factor in many of the choices made concerning

the optimum mixture. Thorough testing of the aggregate therefore is necessary. A wide range of materials are suitable for use with emulsified asphalt including crushed stone, rock, gravel, sand, silty sand, sandy gravel, slag, reclaimed aggregate, ore tailings, or otherinert materials.

Aggregates meeting the requirements of Table VII-5 of this Basic Asphalt Emulsion Manual are among those suitable for emulsified asphalt mixes.

14.05 EMULSIFIED ASPHALTS Two general types of emulsified asphalt are used for mixing. These are designated as slow

setting (SS) and medium setting (MS). ASTM specifications for these asphalt materials are given in Tables II-I and 11-2 of this manual.

Selection of emulsified asphalt type and grade for use on a particular project is based in part on the ability of the emulsion to adequately coat the job aggregate. Some factors which affect this selection are:

155

(1) Aggregate type. (2) Aggregate gradation and characteristics of the fines. (3) Anticipated water content of the aggregate. (4) A vail ability of water at the construction site. More than one emulsified asphalt type is often acceptable for a given aggregate, and the

selection should be based on mixture properties determined by comparative mixture designs. Additional factors that cannot be evaluated at the time of design of the mixture, but which should be accounted for at the time of construction are:

(1) Anticipated weather at the time of construction. (2) Type of mixing process. (3) Construction equipment selected and field procedures used.

14.06 APPROXIMATE AMOUNT OF EMULSIFIED ASPHALT The amount of emulsified asphalt is estimated for trial mixes of dense graded aggregates

using the Centrifuge Kerosene Equivalent test (C.K.E.). The equipment and procedures for running the C.K.E. test are contained in Chapter XI

"Modified Hveem Mix Design," Par. 11.05 band c.

If C.K.E. equipment is not available, an approximation of the emulsified asphalt content for trial mixes can be made by the following formula:

P = 0.05A + 0.1 B + (j.5e

where P = Percent* by weight of emulsified asphalt, based on weight of graded mineral aggregate

A = Percent* of mineral aggregate retained on 2.36 mm (No.8) sieve

B = Percent* of mineral aggregate passing 2.36 mm (No.8) sieve and retained on 75 Il-m (No. 200) sieve

C = Percent* of mineral aggregate passing 75 Il-m (No. 200) sieve.

*Expressed as a whole number.

14,07 COATING TEST Preliminary evaluation of each emulsified asphalt selected for mixture design is accomplished

through a coating test. The trial residual asphalt content as determined in Par. 11.06 is combined with the job aggregate, and coating is visually estimated as a percentage of the total area. An emulsified asphalt's ability to coat an aggregate is usually sensitive to the premix water content of the aggregate. This is especially true for aggregates containing a high percentage of material passing a 75 IJ..m (No. 200) sieve, where insufficient pre-mixing water results in balling of the asphalt with the fines and insufficient coating. For this reason, the coating test is performed at varying aggregate water contents. Emulsified asphalts which do not pass the coating test are not considered further. Detailed procedures for the coating test are listed below.

(1) Equipment (a) Balance 5,000 g minimum capacity and accurate to within ± 0.5 g. (b) Laboratory mixing equipment, preferably mechanized and capable of producing inti­

mate mixtures of the job aggregate, water and emulsified asphalt. Hand mixing, if used, must be sufficiently thorough to uniformly disperse the water and emulsion throughout the aggregate.

(c) Hot plate or 100° ± 5°C (230° ± 9°F) oven.

156

(d) Pans, metal, approximately 200 x 355 x 50 mm (8 x 14 x 2 in.). (e) Supply of metal kitchen mixing spoons (approximately 250 mm (10 in.». (t) A one-hundred millilitre glass graduate.

(2) Procedure (a) Obtain representative samples of each emulsified asphalt considered for the project. (b) Obtain representative samples of the job aggregate or aggregate blend. (c) Prepare the aggregate by air drying until it is easily separated into sizes using the

following sieves: 25.0 mm (1 in.), 19.0 mm (3/4 in.), 12.5 mm (112 in.), 9.5 mm (3/8 in.), and 4.75 mm (No.4) sieve. Dry until the portion passing the 4.75 mm (No.4) sieve has a free-flowing consistency. Any suitable means of drying which does not heat the aggregate in excess of 60°C (140°F) or cause degradation of the particles may be used. The aggregate should be stirred frequently to prevent crusting or fonnulation of hard lumps.

(d) Detennine the moisture content on a combined sample of the air-dried aggregate according to ASTM Test Method D 2216, "Laboratory Detennination of Moisture Content of Soil," and record.

(e) Prepare a sufficient number of batches of the air-dried job aggregate for trial mixes. The batch mass should be approximately 1200 g (oven dry basis). These batches should be prepared by reblending exact fractions of material retained on 25.0 mm (1 in.), 19.0 mm(3/4 in.), 12.5 mm(l/2 in.), 9.5 mm(3/8 in.) and 4.75 mm(No. 4) sieves with material passing 4.75 mm (No.4) sieve to match the grading analysis of the whole sample.

(f) Place one batch of aggregate in the mixing bowl of the mechanical mixer. Incorporate X percent of water by dry weight of aggregate in excess of the air dried water content. Water should be added in a thin stream and the aggregate mixed until the water is thoroughly dispersed. (Sixty seconds of mixing time is sufficient.) Select the initial X percentage water by the following criteria:

1. Medium setting (HFMS, CMS and other solvent containing asphalt emulsions). Initial trial may be mixed without the addition of any water (i.e., air dry condition). 2. Slow setting (SS and CSS) asphalt emulsions. Often require a higher water content to produce satisfactory mixes; start the coating test at about 3 percent added water.

With aggregates containing clay, the aggregate should be placed in a sealed container for a minimum of 15 hours prior to the addition of emulsified asphalt.

(g) Add the amount of emulsified asphalt (percent by weight of dry aggregate) as deter­mined in Par. 14.06. The emulsion should be added in a thin stream to minimize the tendency of the asphalt to ball up with the fine aggregate. A one-minute mixing process* is usually satisfactory. If hand mixing is used, it should be sufficiently thorough to disperse the asphalt throughout the mixture.

(h) Calculate the free water content of the aggregate at mixing by combining the moisture content of the aggregate as detennined in Step (d) with the percentage of water added in Step (f).

*Mixing time should be shortened to 30 seconds if segregation of asphalt-fines mixture from coarse aggregate is noticed.

157

Example: Water content of [air dried] aggregate = 0.5 percent Percentage of water added prior to addition of emulsified asphalt = 3.0 percent Total premix water before mixing with emulsified asphalt = 3.5 percent.

(i) Allow the mixtures to air dry with the aid of an electric fan. Prepare a new batch by repeating Steps (t), (g) and (h) with an additional increment of 1 percent water by weight of dry aggregate. Mixes which become soupy or segregate on standing are considered unacceptable. When this occurs proceed to Step (j).

(j) Rate the appearance of the surface dry mixtures by visually estimating the total aggregate surface area that is coated with asphalt. For each pre-mix water content at mixing, record the estimate of the coating as a percentage of the total area. Aggregate coating in excess of 50 percent shall be considered acceptable (see Note 1). If the mixture does not attain 50 percent coating at any water content, the emulsion shall be rejected from further consideration. If the coating appears borderline, the mixture may be evaluated by the full mixture design procedure.

(k) For medium setting (HFMS, CMS and other solvent-containing asphalt emulsions) emulsions, use sufficient premix water to give optimum dispersion of the emulsified asphalt. In some cases, excessive premix water may cause stripping of the asphalt from the aggregate. Where this occurs, use only as much water as needed to give at least 50 percent coating. All subsequent mixing shall be done at the water content that produces maximum coating without stripping (see Note 2).

(1) Slow setting (SS and CSS) asphalt emulsion mixtures generally exhibit increased coating as the pre-mix water content is incrementally increased. At some point, sufficient water is available for optimum dispersion of the asphalt and additional increments of water do not improve coating. This result shall be the minimum pre-mix water content required for mixing. All subsequent mixing in the design process shall be done at the minimum pre-mix water content.

NOTE 1: It is important to recognize that 100 percent coating common to hot-mixed materials is desirable but not required. Sufficient asphalt to produce 100 percent coating may result in an excessively high asphalt content. NOTE 2: Some combinations of aggregate and emulsified asphalt are not significantly affected by a variation of water content at mixing. In these cases, mixing may be allowed at or above the optimum water content as determined for compaction.

14.08 OPTIMUM WATER CONTENT AT COMPACTION Mixture properties are closely related to the density of the compacted specimens. Thus, it

is necessary to optimize the water content at compaction to maximize the desired mixture properties. This must be done for each combination of emulsified asphalt, type and grade, and aggregate type considered for each project.

The mixture design procedure utilizes standard Marshall specimens in the evaluation of compacted mixture properties. To obtain reliable results, triplicate specimens are prepared for each water content at compaction.

158

a. EQUIPMENT The equipment required for the preparation of test specimens is as follows:

(1) Scoop, for batching aggregate. (2) Thermometer, armored, glass or dial type with metal stem, lOoC (500 P) to 65.5°C

(1500 P). (3) Balance, 10 kg capacity, sensitive to ± 1 g for aggregate and aerating mixtures. (4) Balance, 2 kg capacity, sensitive to ±0.1 g for compacted specimens and bulk

density determination. (5) Mixing spoon, large. (6) Spatulas, small and large. (7) Mechanical mixer, capacity to handle 2500 g.

*(8) Compaction pedestal consisting of an 200 x 200 x 460 mm (8 x 8 x 18 in.) wooden post capped with a 305 x 305 x 25 mm (12 x 12 x 1 in.) steel plate. The wooden post should be oak, yellow pine or other wood having a density of 673 to 769 kg/m3 (42 to 48 Ib/ft3). The wooden post should be secured by four angle brackets to a solid concrete slab. The steel cap should be firmly fastened to the post. The pedestal should be installed so that the post is plumb, the cap level, and the entire assembly is free from movement during compaction.

*(9) Compaction mold consisting of base plate, forming mold, and collar extension. The forming mold has an inside diameter of 101.6 mm (4 in.) and height of approximately 76 mm (3 in.); the base plate and collar extension are designed to be interchangeable with either end of the forming mold.

*( 10) Compaction hammer consisting of a flat circular tamping face 98.4 mm (3% in.) diameter and equipped with a 4.5 kg (10 Ib) mass constructed to obtain a specified 457 mm (18 in.) height of drop.

*( 11) Mold holder, consisting of spring tension device designed to hold compaction mold in place on compaction pedestal.

(12) Extrusion jack or Arbor press for extruding compacted specimens from mold. (13) Gloves, welders, for handling hot equipment; gloves, rubber, for removing speci­

mens from oven. (14) Marking crayons for identifying test specimens. (15) Pans, metal, approximately 200 x 355 x 50 mm (8 x 14 x 2 in.) for batching

aggregates. (16) Oven, forced draft, capable of maintaining a temperature of 110 ± 2.8°C (230 ±

2.8°P) for determining moisture contents.

b. PREPARATION OF TEST SPECIMENS (1) Number of specimens. Prepare three specimens for each water content at compaction

to be evaluated. Generally, three increments of water content one percent apart are sufficient to define the stability (density) / water content at compaction curve.

(2) Preparation of molds and hammer. Thoroughly clean the specimen mold assemblies and the face of the compaction hammer. Place a piece of waxed paper cut to size in the bottom of the mold before placing mixture in the mold.

*Marshall test apparatus should confonn to requirements of ASTM test method D 1559.

159

(3) Preparation of aggregate. Recombine each size fraction of the aggregate to produce a total aggregate mass of 1.2 kg for each batch. Place the pans in a well ventilated area and determine the temperature of the aggregate. The temperature should be adjusted to 22.2 ± 1.7°C (72 ± 3°F) prior to mixing.

(4) Calculations. Four calculations are required for each combination of aggregate and asphalt: mass of aggregate, emulsified asphalt, added pre-mixing water and water loss for compaction. The following formulas are used for the calculations.

(a) Mass of air dried aggregate added a 100 _ b x 100

(b) Mass of emulsified asphalt = a : c

(c) Mass of pre-mixing water added = a~ - b _ e ; C) 100

(d) Mass of water loss for compaction -- a(fl00-g)

where a b c d e f g

Example:

= = = =

= = =

mass of dry aggregate percent water content of air-dried aggregate desired residual asphalt content, percent weight dry aggregate percent residual asphalt in the emulsion percent water in emulsified asphalt = 100 - d percent pre-mix water content at mixing (mass dry aggregate) percent water content at compaction (mass dry aggregate)

mass of dry aggregate = a = 1200 g percent water content of air-dried aggregate = b = 0.5 percent desired residual asphalt content = c = 4.0 percent percent residual asphalt in the emulsified asphalt = d = 65 percent percent water in emulsified asphalt = e = 35 percent percent pre-mix water content at mixing = f = 5.0 percent percent water content at compaction = g = 3.5 percent

(a) Mass of air-dried aggregate added = 1~2~~.5 x 100 = 1206 g.

(b) Mass of emulsified asphalt = 12006

; 4.0 = 74 g.

(c) Mass of added pre-mixing water = 1200(5.0 - 0.5 _ 35 x 4.0)1100 = 28 g. 65

(d) Mass of water loss for compaction = 1200(5.0 - 3.5) = 18 g. 100

Appropriate input values for the previous formulas are discussed in subsequent sections.

160

(5) Addition of pre-mixing water. Place the air dried aggregate in the mechanical mixer. Calculate the total amount of free water that needs to be added to achieve the optimum pre-mixing water as determined in the coating test. (Par. 14.07).

Measure the volume of added water in a graduated cylinder. The temperature of the water shall be 22.2 ± I. 7°C (72 ± 3°F). Add the water in a slow stream and mix for 1 ± 0.5 minutes or until the water is thoroughly dispersed throughout the aggregate. For aggregates containing clay the material shall be placed in a sealed container for a minimum of 15 hours (see Note below). Determine the mass of emulsified asphalt container and record. Add the emulsified asphalt to the moistened aggregate in a thin stream as the material is mixing. Reweigh the emulsified asphalt container periodically to ensure the required mass of emulsified asphalt is not exceeded. A one minute mixing time using a mechanical mixer should be sufficient. Excessive mixing tends to strip the asphalt from the aggregate and should be avoided.

(6) Aeration to reduce the water content of the mixture to get maximum density (see Par. 14.08b (1). If the desired water content at compaction differs from the optimum mixing water content, aeration is required. Remove all material from the mixing bowl and blade and place in an aeration pan. Distribute the mixture in the pan such that the depth does not exceed 25 millimetres (1 in.). Record the mass of the mixture and pan. The required loss to reach the desired compaction water content is calculated by equation (4)(d). The required loss is subtracted from the recorded mass of mixture and pan and that mass recorded. A fan may be used to aerate the mixture. Stir and weigh the mixture every 10 ± 0.5 minutes until the calculated required water loss is complete. The mixture is now ready for compaction.

NOTE: If coating of the aggregate is not sensitive to the water content at mixing as determined in the coating test (Par. 14.07), the aggregate may be mixed at the desired water content at compaction, emulsion added, and the mixture compacted immediately.

(7) Compaction of specimens. For specimens to be tested in the modified Marshall stability test use standard Marshall forming molds. Assemble the base plate, Marshall forming mold, and collar extension. Cover the base plate with a piece of waxed paper cut to size and place mixture in the mold assembly (see Note). Spade the mixture with a small spatula 15 times around the perimeter and 10 times over the interior. Place a second piece of waxed paper cut to size over the top of the mixture. Repeat this process for the remaining mold assemblies.

Place the first mold assembly on the compaction pedestal in the mold holder and apply 50 blows with the compaction hammer. Remove the collar and base plate, reverse the mold and reassemble. Apply the same number of compaction blows to the face of the reversed specimen. Repeat the process for the remaining mold as­semblies. Remove the collars, base plates, and paper from all specimens. Specimens are now ready for curing.

161

NOTE: Generally it is desirable to prepare a single trial specimen for each type of aggregate considered for the job prior to compacting the test specimens. Should the height of the extruded trial specimen fall outside thelimitsof63.S ± 6 mm(2.5 ± 0.251n.), the amount of mixture per specimen may be adjusted as follows:

Adjusted mass of aggregate per specimen =

or for U.S. Customary Units:

Adjusted weight of aggregate =

63.5 ( mass of aggregate used) (specimen height (mm) obtained)

2.5 (weight of aggregate used) (specimen height (in.) obtained)

(8) Curing of specimens. Cure for 1 day in the mold at room temperature, with molds on their edge for equal ventilation on both sides, and then extrude. After extrusion, the bulk specific gravities of the specimens are determined by displacement in water (ASTM D 1188 or D 2726).

(9) A plot is made of dry density versus fluids content at compaction. The fluids content resulting in the highest density is optimum for compaction. (See "Mix Design Cal­culations" for use with Table XIV-I).

If further definition of results is required, batches with an additional water content at compaction may be prepared. The optimum water content at compaction shall be used on all subsequent compaction regardless of the residual asphalt content.

14.09 VARIATION OF RESIDUAL ASPHALT CONTENT In determining the optimum residual asphalt content for a particular aggregate and emulsified

asphalt combination, a series of test specimens are prepared over a range of residual asphalt contents, using the previously established optimum water contents for mixing and compaction.

Test mixtures are prepared in one percent increments of residual asphalt content with two increments on either side of the trial asphalt content determined in Par. 14.06. If further definition of test results is required, increments farther away from the trial residual asphalt content are prepared.

a. EQUIPMENT The equipment required for preparation of specimens is listed under Equipment, Par.

14.08a.

b. PREPARATION OF SPECIMENS Use the Procedure for Preparation of Specimens listed in Par. 14.08b. Additional instructions

and clarifications presented below correspond to the appropriate Sections of 14.08b.

162

(1) Number of specimens. Prepare six specimens for each residual asphalt content. (2) Preparation of molds and hammer. No change. (3) Preparation of aggregate. Use a total aggregate mass of 1.2 kg for each specimen batch. (4) Calculations. No change. (5) Addition of mixing water. Note that the optimum total compaction water is used for

all asphalt contents. As the residual asphalt content increases, the amount of water contributed by the emulsion increases. Thus, the amount of pre-mix water added will be reduced as the residual asphalt content is increased. Vary the residual asphalt content on successive batches to yield five one-percent increments (the trial residual asphalt content and one and two percent increments both sides of the trial).

(6) Aeration to reduce the water content of the mixtures. No change. (7) Compaction of specimens. No change. (S) Curing of specimens. Cure for 1 day in the mold at room temperature, extrude and

cure for 1 day out of mold in oven at 3SoC (100°F).

14.10 TEST PROCEDURE

To complete the mix design, the following tests and analyses are made from data obtained from the compacted specimens:

Bulk Specific Gravity. Modified Marshall Stability and Flow of Dry Specimens at 22.2 ± 1. 1°C (72 ± 2°F). Soaked Stability and Flow after vacuum saturation and immersion. Density and Voids Analysis. Moisture Absorption.

Table XIV -1 is a detailed data sheet that can be used to record pertinent data and perform calculations.

a. EQUIPMENT The equipment required for the testing of the 102mm (4 in.) diameter x 64mm

(2-112 in.) height speci mens is as follows: (1) Marshall Testing Machine. A compression testing device. It is designed to apply

loads of test specimens through semicircular testing heads at a constant rate of strain of (50.Smm) (2 in.) per minute. It is equipped with a calibrated proving ring for determining the applied testing load, a Marshall stability testing head for use in testing the specimen and a Marshall flow meter for determining the amount of strain at the maximum load for the test. A universal testing machine equipped with suitable load and deformation indicating devices may be used instead of the Marshall testing frame.

(2) Water Bath. At least 610 x 915 x 155mm (24 x 36 x 6 in.) and thermostatically controlled at 22.2 ± 1.1 0 C (72 ± 20 F).

(3) Pans, either 229 x 229 mm (9 x 9 in.) or 254mm (10 in.) in diameter and 25mm (1 in.) deep capable of containing failed specimens for moisture content determination.

(4) Balances 1500g capacity equipped for bulk density determination. (5) Towel, cloth for drying samples during bulk density determination. (6) Vacuum pump, vacuum desiccator and manometer. (See Chapter XI, Par. 11.0S.)

163

b. BULK SPECIFIC GRAVITY DETERMINATION The method used for determination is ASTM D 2726, "Bulk Specific Gravity and

Density of Compacted Bituminous Mixtures Using Saturated Surface-Dry Specimens" or ASTM D 1188, "Bulk Specific Gravity and Density of Compacted Bituminous Mixtures Using Paraffin-Coated Specimens."

TABLE XIV-1 EMULSIFIED ASPHALT MIXTURE DATA SHEET (Use for specimens containing a single residual asphalt content)

ASPHALT AGGREGATE

Type & Grade Source rd. Asphalt in Emulsion % Type

Asphalt Spec. Gra. (B) Apparent Spec. Grav. (C)

Residual Asphalt % in Mi xture (A)

MIXING AND COMPACTION TESTING

Total Mix Water % Dry Spec. Test Date Added Mix Water 9 Rotate Soak Spec. Date Water at Compaction % Soak Spec. Test Date Compac t i OJ) Da te

COMPACTED SPECIMEN DATA Dry Soaked 1 2 3 4 5 6

Bul k Density

Mass in Air (D) >< >< >< Mass in Water (E) >< >< >< Mass SSD (F) >< >< >< BSG - compacted mix (G) >< >< >< Dry BSG - compacted mix >< >< >< Thickness Stabil ity

Dial Load Adjusted Stability (S) Flow Moisture Content Mass of specimen (H)

Mass of oven-dry specimen (I)

Tare (J)

Moisture content (K) Moisture absorbed >< >< >< Maximum Total Voids - % XlXX

164

c. MODIFIED STABILITY AND FLOW TESTS After determining the bulk specific gravity on six cured specimens, test three of them

for stability and flow as follows: (In the selection of test specimens, the three retained for water conditioning should have the same average density as the three tested dry.) (I) Determine mass of cured specimens and record in column' 'Mass of Specimen (H)" (2) Thoroughly clean the guide rods and inside surfaces of the test heads prior to making

the test, and lubricate the guide rods so that the upper test head slides freely over them. The testing head temperature is maintained between (21.1 and 23.3°C) (70 and 74°P) using a water bath when required. Check the load measuring device for zero "adjustment. "

(3) Place one of the three specimens on the lower testing head into position and center complete assembly in the loading device. Place the flow meter over marked guide rod.

(4) Apply testing load to specimen at constant rate of deformation of (50.8 mm) (2 in.) per minute until failure is obtained. The total number of newtons (pounds) required to produce failure of the specimen at 22.2 ± 1.1°C (72 ± 2°P) shall be recorded as its modified Marshall stability value.

(5) While the stability test is in progress, hold the flow meter firmly in position over the guide rod and remove it the instant the maximum load starts to decrease. Note and record the indicated flow value in units of 0.25mm (0.01 in.)

(6) Place the failed specimens in tared pans taking care to make sure all of the of the specimen is put into the pan. The specimens are broken up and put in an oven at 93 + 6° C (200 + 10° F). The specimens are removed after 24 hours, reweighed, and the masses recorded under the heading "Mass of Oven Dried Specimen." The mass of the water is corrected by su btracting the mass of water absorbed during bulk specific gravity determination. The mass of the water absorbed can be determined by subtracting the mass of the dry specimens from the mass of the SSD specimen. Prom the data obtained above, a water content at testing is determined.

MIX DESIGN CALCULATIONS POR USE WITH TABLE XIV-I

G (bulk specific gravity) = _p D -E

G 'fi') G (100 + A) d (dry bulk Specl IC gravity = X (100 + A + K)

Dry density, Kg/m2 = 1,000 Gd (lb/ftJ = Gd K 62.4) , mass of water, g

K (water content at testmg), % = f d' X (100 + A) mass 0 ry mixture, g

_ [(100 + A+K 100), (100 + A + K)] 100 VMA % - - - -:- X ,7< G C G

[(100 + A + K 100 A) (100 + A + K)] V (total voids), % = G - C - Ii + G X 100

[(K X 1(0) (100 + A + K)] Air Voids, % = V - L + G

165

Percent stability loss - 3 3 x 100

Moisture absorbed =

where: D = mass of specimen in air, g; E = mass of specimen in water, g; F = mass of specimen in saturated surface-dry (SSD) condition, g; A = asphalt residue as percent of dry aggregate mass; B = specific gravity of asphalt; C = apparent specific gravity of aggregate; L = specific gravity ofwater;and S = adjusted stability

Note: Letters A through S refer to identical letters in parentheses in Table X/V-J

d. SOAKED STABILITY AND FLOW TESTS After testing three of the six cured specimens for each residual asphalt content, the remaining

three specimens are subjected to vacuum saturation and immersion. (1) Each specimen is separately placed into the vacuum apparatus (See Chapter XI, from

Par. 11.08b. (2), and covered with water (desiccant should be removed from the vacuum apparatus before filling with water).

(2) Evacuate the desiccator to l00mm of Hg and hold for one hour. (3) Slowly release the vacuum and allow specimen to soak in water for one hour. (4) The specimens are then tested in modified Marshall stability and moisture content

determination as outlined in Section c.

e. DENSITY AND VOIDS ANALYSIS A density and voids analysis is conducted as follows:

(1) Detennine each unit weight by multiplying the bulk specific gravity by 62.4 (for unit weight in kg/m3 multiply by 1000).

(2) After detennining water content at testing, aggregate apparent specific gravity, asphalt specific gravity, and mix bulk specific gravity, voids can be calculated as shown under' 'Mix Design Calculations for use with Table XIV-I. "

Voids are calculated for each specimen. Any values that are more than 50 percent from the average of the three specimens should not be used.

14.11 INTERPRETATION OF TEST DATA The stability, flow, voids, bulk density, and moisture content data are prepared as follows:

(1) Measured stability values for specimens that depart from the standard 63.5mm (2-1 /2 in.) thickness shall be converted to an equivalent 63.5mm (2-1/2 in.) value by means of a conversion factor. Applicable correlation ratios to convert the measured stability values are set forth in Table XIV-2. Note that the conversion may be made on the basis of either measured thickness or measured volume.

166

TABLE XIV-2 STABILITY CORRELATION RATIOS -

Volume of Approximate Thickness Correlation Specimen of Specimen Ratio

cm3 mm in.

457 to 470 57.2 2 114 1.19 471 to 482 58.7 25/16 1.14 483 to 495 60.3 2 3/8 1.09 496 to 508 61.9 2 7116 1.04 509 to 522 63.5 2 112 1.00 523 to 535 64.0 2 9/16 0.96 536 to 546 65.1 2 5/8 0.93 547 to 559 66.7 211116 0.89 560 to 573 68.3 2 3/4 0.86

NOTES: I. The measured stability of a specimen multipled by the ratio for the thickness of the specimen equals the

corrected stability for a 63.S mm (2 1!2-in.) specimen. 2. Volume-thickness relationship is based on a specimen diameter of 101.6 mm (4 in.).

(2) Average the flow values and the converted stability values for all specimens of a given asphalt content. Values that are obviously in error shall not be included in the average.

(3) Prepare a separate graphical plot for the following factors as illustrated in Figure XIV-I.

(a) Dry and soaked stability versus residual asphalt content. (b) Percent stability loss versus residual asphalt content [calculated by (Dry Stability

-Wet Stability) lOO/Dry Stability] (c) Dry bulk density (corrected for moisture) versus residual asphalt content. (d) Percent moisture absorbed versus residual asphalt content. (e) Percent total voids (air plus moisture) versus residual asphalt content.

In each graphical plot, connect the data with a smooth curve that provides the best fit for all values.

a. TRENDS AND RELATIONS OF TEST DATA The test property curves as previously plotted have been found to vary copsiderably

between aggregate types and gradations, but typical curves are shown in Figure XIV-I. General trends are described as follows: (1) Soaked stability will generally show a peak at a particular residual asphalt content

while dry stability will generally show a continually decreasing curve with increasing residual asphalt content. Some mixes may show a continual increase in soaked stability over the range of asphalt content evaluated, which indicates the increased beneficial effect of additional asphalt content on soaked stability.

(2) Percent loss of stability (computed by [dry stability - soaked stability] tOO/dry stability) generally decreases as residual asphalt content increases.

(3) Dry bulk density usually peaks at a particular residual asphalt content.

167

(4) Percent moisture absorbed during the soak test decreases with increased residual asphalt content.

(5) Percent total voids (air plus moisture) decreases as residual asphalt content increases.

b. DETERMINATION OF OPTIMUM ASPHALT CONTENT (1) Mixture must provide an adequate stability when tested in a "soaked" condition to

provide adequate resistance to traffic load during wet seasons. (2) The percent loss of stability of the mixture when tested "soaked" as opposed to

"dry" should not be excessive. A high loss is indicative of the mixture having high moisture susceptibility and may cause disintegration during wet seasons.

(3) The total voids within the mixture should be within an acceptable range to prevent either excessive pennanent deformation and moisture absorption (for too high void content), or bleeding of the residual asphalt from the mixture (for a low void content).

(4) Moisture absorption into the mixture should not be excessive to minimize the potential of stripping or weakening the bond between residual asphalt and agregate.

(5) Residual asphalt should provide adequate coating of the aggregate and should be resistant to stripping or abrasion.

The optimum residual asphalt content for the paving mixture is determined from the data obtained as presented. The optimum residual asphalt content is chosen that provides maximum soaked stability, but is adjusted either up or down depending on moisture absorption, percent loss of stability, total voids, and coating of aggregates. Design criteria for each of these values is given in Table XIV-3. If the residual asphalt content at the peak of the soaked stability curve provides for adequate moisture absorption, percent loss of stability, total voids, and aggregate coating, it is selected as the optimum asphalt content. This value must meet minimum stability requirements, however, as given in Table XIV-3, or the mix is rejected. If one or more criteria cannot be met, the mix should be considered inadequate.

If no peak in residual asphalt content versus soaked stability or other properties is developed, the optimum emulsion content should be established based on the best combinations of such properties as Marshall stability of both cured and immersed specimens, percent stability loss and dry density, with particular attention to the effects of water on specimen properties.

TABLE XIV-3 EMULSIFIED ASPHALT-AGGREGATE MIXTURE DESIGN CRITERIA

Test Property

Stability, N (Ib) at 22.2°C (72°F) Paving Mixtures

Percent Stability Loss After vacuum saturation and immersion

Aggregate Coating (percent)

Minimum Maximum

2224 (500)

50

50

168

II

~

II ~ Cl

Optimum

.. Residual Asphalt, %

(a)

" Residual Asphalt, %

(c)

t c o

~ C)

a .J::.

ilo Ci5 eft. :: o

..J

I L--_____ --J

.. ~ 0

-0 CD

~I ~ ·0 :!

Residual Asphalt, % (e)

.. Residual Asphalt, %

(b)

.. Residual Asphalt, %

(d)

Figure XIV-1. Typical emulsified asphalt-aggregate mixture design plots.

169

APPENDIX A

GLOSSARY AGGREGATE

Aggregate: A hard inert mineral material, such as gravel, crushed rock, slag, or sand. Coarse Aggregate: Aggregate retained on the 2.36mm (No.8) sieve. Fine Aggregate: Aggregate passing the 2.36mm (No.8) sieve. Sand: Fine aggregate resulting from natural disintegration and abrasion of rock or

processing of completely friable sandstone. Dense-Graded Aggregate: Aggregate that is graded from the maximum size down through

filler with the object of obtaining an asphalt mix with a controlled void content and high stability. Open-Graded Aggregate: Aggregate containing little or no mineral filler or in which

the void spaces in the compacted aggregate are relatively large. Sandy Soil: A material consisting essentially of fine aggregate particles smaller than

2.00mm (No. 10) sieve and usually containing material passing a 75 J.lm (No. 2(0) sieve. This material usually exhibits plasticity characteristics.

ASPHALT Asphalt: "A dark brown to black cementitious material in which the predominating

constituents are bitumens which occur in nature or are obtained in petroleum processing" (ASTM Designation D 8). Asphalt is a constituent in varying proportions of most crude petroleums.

Asphalt Cement: Asphalt that is refined to meet specifications for paving, industrial, and special purposes. It requires heat to make it fluid.

Asphalt Prime Coat: An application of asphalt primer to an absorbent surface. It is used to prepare an untreated base for an asphalt surface. The prime penetrates or is mix­ed into the surface of the base and plugs the voids, hardens the top and helps bind it to the overlying asphalt course.

Asphalt Primer: A fluid asphalt of low viscosity (highly liquid) that penetrates into a non-bituminous surface upon application.

Asphalt Seal Coat: A thin asphalt surface treatment applied to an existing asphalt surface. Asphalt Surface Treatment: Application of asphalt materials to any type of road surface,

with or without a cover of mineral aggregate, that produces an increase in thickness of usually less than 25mm (1 in.)

Cutback Asphalt: Asphalt cement that has been liquefied by blending with petroleum solvents.

Emulsified Asphalt: An emulsion of asphalt cement and water which contains a small amount of an emulsifying agent. Emulsified asphalt droplets may be of either the anionic (negative charge) or cationic (positive charge) type, depending upon the emulsifying agent.

171

EQUIPMENT Aggregate Spreaders: Machines for spreading aggregate evenly at a controlled rate on

a surface. Mechanical Spreaders: Spreader boxes mounted on wheels. The spreaders are attached

to, and are pushed by, the dump trucks. Self-Propelled Spreaders: Spreaders with their own power units, and two hoppers. The

spreader pulls the truck as it dumps its load into the receiving hopper. The aggregate is moved forward by conveyor belts to the spreading hopper.

Tail Gate Spreaders: Boxes with adjustable openings, which attach to and suspend from the tail gates of dump trucks.

Whirl Spreaders: Spreaders that attach to or are built on to dump trucks. Aggregate is fed on to the spreader disc through an adjustable opening and the speed of the disc is ad­justable to control the width of spread.

Aggregate Trucks: Trucks equipped with hydraulic lifts to dump the aggregate into the spreader.

Asphalt Distributor: A truck, or a trailer, with an insulated tank and a heating system. The distributor is made to apply asphalt to a surface in an even spread and at a uniform rate for the whole load.

Power Sweeper: A power operated rotary broom used to clean loose material from the pavement.

Pneumatic- Tired Rollers: Rollers, usually two-axled and self-propelled, with a number of tires spaced so their tracks overlap while giving kneading compaction.

Steel- Tired Static Rollers: Tandem, or three-wheel, rollers with cylindrical steel rolls that apply their weight directly to the pavement.

Travel Plants: Travel plants are self-propelled pugmill plants that proportion and mix aggregates and asphalt as they move along the road. There are three general types of travel plants:

1. One that moves through a prepared aggregate windrow on the roadbed, adds and mixes the asphalt as it goes and discharges to the rear a mixed windrow ready for aeration and spreading.

2. One that receives aggregate into its hopper from haul trucks, adds and mixes asphalt, and spreads the mix to the rear as it moves along the roadbed.

3. Batch mixing units, such as slurry machines, that haul materials to the site then mix and apply the materials.

TYPES OF ASPHALT SURFACE TREATMENTS AND MIXES Asphalt Emulsion Mix (Hot): A mixture of emulsified asphalt materials and mineral aggregate

usually prepared in a conventional hot-mix plant or drum mixer at a temperature of not more than (127°C) (260°F). It is spread and compacted at the job site at a temperature above (93°C( (200°F).

Pavement Base and Surface: The lower or underlying pavement course atop the subbase or subgrade and the top of wearing course.

172

Plant Mix (Cold): A mixture of emulsified asphalt and mineral aggregate prepared in a central mixing plant and spread and compacted at the job site when the mixture is at or near ambient temperature.

Asphalt Application: The application of sprayed asphalt coatings not involving the use of aggregates.

Asphalt-Aggregate Applications: Applications of asphalt material to a prepared ag­gregate base or pavement surface followed by the application of aggregate.

Maintenance Mix: A mixture of asphalt material and mineral aggregate for use in relatively small areas to patch holes, depressions, and distressed areas in existing pavements. Appropriate hand or mechanical methods are used in placing and compac­ting the mix.

Single Surface Treatment: A single application of asphalt to any kind of road surface (ol1ow~d immediately 12Y-a single layer of aggregate of as uniform size as practicable. The thickness of the treatment is about the same as the nominal maximum size aggregate par­ticles. A single surface treatment is used as a wearing and waterproofing course.

Multiple Surface Treatment: Two or more surface treatments placed one on the other. The aggregate maximum size of each successive treatment is usually one-half that of the previous one, and the total thickness is about the same as the nominal maximum size aggregate particles of the first course. Or, a multiple surface treatment may be a series of single treatments that produces a pavement course up to 25mm (1 in.) or more in thickness. A mUltiple surface treatment is a denser wearing and waterproofing course than a single surface treatment, and it adds some strength.

Seal Coat: A thin surface treatment used to improve the texture of and waterproof an asphalt surface. Depending on the purpose, seal coats mayor may not be covered with aggregate. The main types of seal coats are aggregate seals, fog seals, emulsion slurry seals, and sand seals.

Aggregate Seal: Usually the same as single surface treatment, see above.

Fog Seal: A light application of slow-setting asphalt emulsion diluted with water. It is used to renew old asphalt surfaces, seal small cracks and surface voids and inhibit raveling.

Emulsion Slurry Seal: A mixture of emulsified asphalt, well-graded fine ag­gregate, mineral filler, and water. It is used to fill cracks and sealed areas of old pavements, to restore a uniform surface texture, to seal the surface to prevent moisture and air intrusion into the pavement, and to provide skid resistance.

Sand Seal: An application of asphalt material covered with fine aggregate. It may be used to improve the skid resistance of slippery pavements and to seal against air and water intrusion.

Prime Coat: An application of\low viscosity fluig asphalt to an absorbent surface. It is used to prepare an untreated base=Tor an asphalt surface. The prime penetrates into the base and plugs the voids, hardens ~e".top and helps ~!lg)j/ to the overlying asphalt course.

Tack Coat: A very light application of asphalt emulsion diluted with water. It is used to ensure ~9r!d)etween the surface being paved and the overlying course.

173

Dust Laying: Diluted slow-setting emulsion, sprayed on an untreated surface to prevent dust. The asphalt penetrates and coats the fine particles to relieve the dust nuisance temporarily. This treatment also is called dust palliative.

Road Oiling: Similar to dust laying except that usually it is done as a part of a planned build-up of low-cost road surfaces over several years. Each application of asphalt may be mechanically mixed with the material being treated or allowed to penetrate.

Mulch Treatment: A spray application of asphalt material used to temporarily stabilize a recently-seeded area. The asphalt material can be applied to the soil or to a straw or hay mulch as a tie-down.

Crack Filler: Asphalt material used to fill and seal cracks in existing pavement.

174

APPENDIX B

TESTING EMULSIFIED ASPHALT (ASTM D 244)

Reprinted with permission, from the Annual Book of ASTM Standards, copyright American Society for Test­ing and Materials, 1916 Race Street, Philadelphia, PA 19103

Standard Methods of Testing

EMULSIFIED ASPHAL TS1 ~t Designation: D 244 - 86

This standard is issued under the fixed designation D 244: the number immediately following the designation indicates the year of original adoption or. in the case of revision. the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (tl indicates an editorial change since the last revision or reapproval.

1. Scope

1.1 The methods given under the headings titled Composition, Consistency, Stability, and Examination of Residue cover the examination of asphalt emulsions composed principally of a semisolid or liquid asphaltic base, water, and an emulsifying agent. The methods cover the follow­ing tests:

Test

Composition: Water Content. Residue by Distillate. Identification of Oil Distillate by Micro

Distillation Residue by Evaporation Particle Charge of Emulsified Asphalts

Consistency: Viscosity (Saybolt Furol) ..

Stability:

Sections

4 to 8 9 to 13

14 to 16 17 to 21

.. 22 to 24

25 to 27

Demulsibility . . 28 to 31 Settlement . 32 to 35 Cement Mixing. . .. 36 to 40 Sieve Test .... 41 to 44 Coating 45 to 46 Miscibility with Water 47 Freezing. 48 Coating Ability and Water Resistance ... 49 to 54 Storage Stability of Asphalt Emulsion .. 55 to 61

Examination of Residue. . .. 62 to 67 Classification Test for Rapid Setting Cationic

Emulsified Asphalt. . .. 68 to 73 Field Coating Test on Emulsified Asphalts 74 to 78 Emulsified Asphalt/Job Aggregate Coating

Test . . . . . . . . . . . . . . . . . . . .. 79 to 85 Weight per Gallon of Emulsified Asphalt 86 to 91

1.2 This standard may involve hazardous ma­terials. operations. and equipment. This standard does not purport to address all of the safety prob­lems associated with its use. It is the responsibil­ity of whoever uses this standard to consult and extablish appropriate safety and health practices and determine the applicability of regulatory lim i-tat ions prior to use.

2. Referenced Documents

2.1 ASTM Standards: C 150 Specification for Portland Cementl C 190 Test Method for Tensile Strength of

Hydraulic Cement Mortars2

D 5 Test Method for Penetration of Bitumi­nous Materials3

D6 Test Method for Loss on Heating of Oil and Asphaltic Compounds4

D 70 Test Method for Specific Gravity of Semi­Solid Bituminous Materials)

D 86 Method for Distillation of Petroleum Products5

D 88 Test Method for Saybolt Viscositl D 113 Test Method for Ductility of Bitumi­

nous Materials) D 128 Methods for Analysis of Lubricating

Grease5

D 139 Method of Roat Test for Bituminous Materials)

D 140 Methods of Sampling Bituminous Materials3

D 2042 Test Method for Solubility of Asphalt Materials in Trichloroethylene3

D 3289 Test Method for Specific Gravity or Density of Semi-Solid and Solid Bituminous Materials by Nickel Crucible)

E I Specification for ASTM Thermometers6

1 These methods are under the jurisdiction of ASTM Com­mittee D-4 on Road and ~aving Materials and are the direct responsibility of Subcommittee D04.42 on Emulsified Asphalt Tests.

Current edition approved March 27. 1986. Published May. 1986. Originally published as D 244 - 26 T. Last previous edi­tion D 244 - 85.

1 Annual Book ofASTM Standards. Vol 04.01. l Annual Book of ASTM Standards. Vol 04.03. • Annual Book of ASTM Standards, Vol 04.04. I Annual Book of ASTM Standards. Vol 05.01. • Annual Book of ASTM Standards. Vols 05.03 and 14.01.

175

E I I Specification for Wire-Cloth Sieves for Testing Purposes2

E 145 Specification for Gravity-Convection and Forced-Ventilation Ovens7

Sample Conditioning for Testing

3.1 All emulsions with viscosity requirements

0244

of 122°F (50°C) should be heated to 122 ± SOF (50 ± 3°C) in the original sample container in a 160°F water bath or oven. The container should be vented to relieve pressure. After the sample reaches 122 ± 5°F (50 ± 3°C), stir the sample to achieve homoger eity.

COMPOSITION

WATER CONTENT

4. Apparatus and Materials

4.1 ,Hetal Still-The metal still (Fig. I(a)) shall be a vertical cylindrical vessel, preferably of copper, having a faced flange at the top to which the head is tightly attached by means of a clamp. The head shall be made of metal, preferably brass or copper, and shall be provided with a tubula­tion I in. (25.4 mm) in inside diameter.

4.2 Glass Still-Tl)e glass still (Fig. I (b)) shall be a short-neck, round-bottom flask, made of well-annealed glass, and having an approximate capacity of 500 mL.

4.3 lIeat Souree-The heat source used with the metal still shall be a ring gas burner of 4-in. (100-mm) inside diameter or an electric mantle heater. The heat source for the glass still shall be either an ordinary gas burner or an electric heater.

4.4 Condenser-The condenser shall be a wa­ter-cooled reflux glass-tube type, having a jacket not less than 153/4 in. (400 mm) in length, with an inner tube 3fs to III in. (9.5 to 12.7 mm) in outside diameter. The end of the condenser shall be ground to an angle of 30 ± SO from the vertical axis of the condenser.

4.5 Trap-The trap shall be made of annealed glass constructed in accordance with Fig. I(c) and shall be graduated in O.IO-mL divisions from o to 2 mL, and in 0.20-mL divisions from 2 to 25 mL.

4.6 Solvent-Xylol or other petroleum distil­late conforming to the following distillation re­quirements: 98 % distills between 248 and 482°F (120 and 250·C). This distillation shall be con­ducted in accordance with Method D 86.

5. Sample

5.1 Obtain a representative sample of the ma­terial for test using standard procedures as spec­ified in Methods D 140.

176

NOTi I-The ditriculties in obtaining representative samples for this determination are unusually great, so that the importance of sampling cannot be too strongly emphasized.

6. Procedure

6.1 When the material to be tested contains less than 25 % water, place 100 ± 0.1 g of sample in the still. When the material contains more than 25 % water, use a 50 ± O.I-g sample. Thor­oughly mix the sample to be tested with 200 mL of solvent by swirling, taking proper care to avoid any loss of material.

6.2 Connect the still, trap, and condenser by means of tight-fitting corks as shown in Fig. I (a)

or (h). Adjust the end of the condenser in the trap to a position which will allow the end to be submerged to a depth of not more than 0.04 in. (I mm) below the surface of the liquid in the trap after distillation conditions have been estab­lished. When using the metal still, insert a heaVy paper gasket, moistened with the solvent, be­tween the lid and flange before attaching the clamp.

6.3 When the ring burner is used with the metal still, place it about 3 in. (76.2 mm) above the bottom of the still at the beginning of the distillation, and gradually lower it as the distilla­tion proceeds. Regulate the heat so that the con­densate falls from the end of the condenser at a rate of from 2 to 5 drops per second. Continue the distillation at the specified rate until no water is visible on any part of the apparatus and a constant volume of water is obtained in the trap. Remove any persistent ring of condensed water in the condenser tube by increasing the rate of distillation for a few minutes.

7. Calculation and Report

7.1 Calculate the water content as follows:

Water content, % = (AlB) x 100

J Annual Book o/ASTM Srandards, Vol 14.02.

where: A = volume of water in trap, mL, and B = original weight of sample, g.

7.2 Report the result as " ... water weight per­cent, ASTM D 244.

8. Precision

8.1 The following criteria should be used for judging the acceptability of results (95 % proba­bility):

8.1.1 Duplicate results by the same operator should not be considered suspect unless they differ by more than the following amount:

Water Content. weight % 30 to 50

Repeatability. weight % 0.8

8.1.2 The results submitted by each of two laboratories should not be considered suspect unless they differ by more than the following amount:

Water Content. weight %

30 to 50

Reproducibility. weight %

2.0

RESIDUE AND OIL DISTILLATE BY DISTILLATION

9. Scope

9.1 This method covers the quantitative de­termination of residue and oil distillate in asphalt emulsions composed principally of a semisolid or liquid asphaltic base, water, and an emulsify­ing agent.

10. Significance and Use

10.1 This method can be used for quantitative determination of residue and oil distillates in asphalt emulsions for specification acceptance. service evaluation, control, and research. This method can also be used to obtain residue and oil distillate for further testing.

II. Apparatus

11.1 Aluminum-Alloy Still.8 (see Fig. 2), ap­proximately 91/2 in. (241.3 mm) in height by 3% in. (95.3 mm) in inside diameter with one 43/~_ in. (l21-mm) inside diameter ring burner,9 hav­ing holes on the inner periphery and having three spacers, to ensure centering of burner around the still (see Fig. 3).

NOTE 2-Residue by distillation results obtained with iron stills in accordance with Method D 244 - 66 are acceptable. Similarly results obtained with as-in. (127-mm) ring burner as in subsequent issues of D 244 are acceptable.

0244

11.2 Connection Apparatus. consisting of a glass connecting tube, tin shield. and water­cooled glass condenser tube with a metal or borosilicate glass jacket.

11.3 Graduated Cylinder. lOO-mL, with grad­uation intervals of 1.0 mL.

11.4 Thermometer-Two ASTM Low-Distil­lation Thermometers, graduated either in Fahr­enheit or Celsius degrees as specified, having a range from 30 to 580·F or - 2 to + 300·C, respec­tively, and conforming to the requirements for Thermometer 7F or 7C as prescribed in Specifi­cation E I.

NOTE 3-For details of the assembly of apparatus for the distillation test, see Fig. 4.

11.5 Balance. capable of weighing 3500 g to within ±O.I g.

12. Procedure

12.1 Weigh 200 ± 0.1 g of a representative sample of the emulsion in the previously weighed aluminum-alloy still (including lid, clamp, ther­mometers and gasket, if gasket is used).

12.2 Use a gasket of oiled paper between the still and its cover, or grind the joint to a tight fit. Securely clamp the cover on the still.

12.3 Insert a thermometer through a cork, in each of the small holes provided in the cover. Adjust these thermometers so that the end of the bulb of one is 1/4 in. (6.4 mm) from the bottom of the still and the bulb of the other is approxi­mately 6 1/2 in. (165.1 mm) from the bottom of the still.

12.4 Place the ring burner around the still about 6 in. (152.4 mm) from the bottom of the still. Apply heat by lighting this burner and ad­justing to low flame. Also apply just enough heat from a bunsen burner to the connecting tube to prevent condensation of water in this tube.

12.5 Move the ring burner approximately level with the bottom when the temperature can be read on the lower thermometer, approxi­mately 420°F (2 I S·C). Increase the temperature to 500 ± 10°F (260 ± 5°C), maintaining it at this temperature for 15 min. Complete the total dis­tillation in 60 ± 15 min from the first application of heat.

• Available from P & H Electronics. 442 Columbia St.. Lafayette. IN 4790 I. Koehler Instruments, Inc., 168-56 Douglas Ave., Jamaica. NY 11433. and Humboldt Mfg. Co .. 7300 w. Agatite Ave .. Chicago. IL 60656.

• Available from Humboldt Manufacturing Co .. Catalog No. H-1876. 7302 w. Agatite Ave., Chicago. IL 60656.

177

NOTE 4-The location of the burner at the start of the test is flexible. It may be raised to decrease chance of foam-over or lowered to middle of still for emulsion containing no solvent. A sudden change in temperature reading of upper thermometer indicates foam on bulb. Remove heat until foaming ceases.

12.6 Immediately at the expiration of the heating period, again weigh the stilI and acces­sories as described in 12.1. Calculate and report the percentage residue by distillation. Record the volume of oil distillate to the nearest 112 mL. Calculate and report the oil distillate as a volume percentage on the total emulsion. Save this oil distillate if identification is desired.

NOTE 5-The aluminum-alloy still at room temper­ature (9.1) weighs 1.5 g more than at 500°F (260°C). Correct for this error by adding 1.5 g to gross weight obtained in 12.6 prior to calculating the percentage of residue by distillation.

12.7 Remove the cover from the stilI, stir, and immediately pour suitable portions of the residue into an 8-oz tin or into suitable molds and con­tail1ers for making the required tests. Permit the residue in the molds and containers to cool, uncovered, to room temperature, and thereafter test as described in Sections 66 to 71. If there is foreign matter in the residue, the material shall be poured through a No. 50 (300-llm) sieve prior to pouring into the test molds and containers.

13. Precision

13.1 The following criteria should be used for judging the acceptability of results (95 % proba­bility):

13.1.1 Duplicate results by the same operator should not be considered suspect unless they differ by more than the following amount:

Residue by Distillation. weight %

50 to 70

Repeatability. weight %

1.0

13.1.2 The results submitted by each of two laboratories should not be considered suspect unless they differ by more than the following amount:

Residue by Distillation. weight %

50 to 70

Reproducibility. weight %

2.0

13.2 The precision for penetration of residue from distillation by this method is the same as that shown in Section 69.

0244

IDENTIFICATION OF OIL DISTILLATE BY MICRO-DISTILLATION

14. Apparatus

14.1 Apparatus shall be in accordance with Method D 86, with the following exceptions:

14.1.1 Flask. 10-mL. 1O

14. J.2 Graduated Cylinder. JO-mL, gradua­tion interval 1/10 mL.

14.1.3 Condenser. borosilicate glass, IOO-mm jacket. 1 1

15. Procedure

15.1 Redistill a JO-mL sample of the oil dis­ti1Iate under prescribed conditions of Method D 86, using Group 2 Test Conditions in Table I with the following exceptions: Diameter of hole in flask support.

in. (mm) Temperature at start of test:

Flask and thermometer Graduate and 10-mL charge

16. Calculations and Reporting

0.75 (19)

not above ambient not above ambient

16.1 Calculations and reporting shall be in accordance with Method D 86, where applicable.

NOTE 6-Better identification of the solvent con­tained in the emulsion is possible if a larger condenser is used with ice water for the cooling medium during the distillation of the emulsion.

RESIDUE BY EV APORA TION

17. Apparatus

17.1 Beakers. low form, lOOO-mL capacity, made of borosilicate glass or aluminum.

17.2 Glass Rods. with flame-polished ends, 1/4

in. (6.4 mm) in diameter and 7 in. (177.8 mm) in length.

17.3 Balance, capable of weighing 500 g to within ±O.I g.

17.4 Oven, conforming to Specification E 145, Type lB.

17.5 Sieve-A No. 50 (300-llm) sieve con­forming to Specification Ell.

IS. Procedure A

18.1 Use procedure A when determination of the percentage of residue only is required.

18.2 Weigh 50 ± 0.1 g of thoroughly mixed,

10 Arthur H. Thomas Co. Catalog No. 5395 flask has been found satisfactory for this purpose.

" Arthur H. Thomas Co. Catalog No. 3906 condenser has been found satisfactory for this purpose.

178

emulsified asphalt into each of three beakers, each beaker having previously been weighed with a glass rod. Place the beakers containing the rods and sample in the oven, the temperature of which has been adjusted to 325 ± 5°F (163 ± 2.S"C), for 2 h. At the end of this period remove each beaker and stir the residue thoroughly. Replace in the oven for I h, then remove the beakers from the oven, allow to cool to room tempera­ture, and weigh, with the rods.

NOTE 7 -Care must be taken to prevent loss of asphalt from the beaker through foaming or spattering, or both. Also, the placing of beakers and emulsion samples in a cold or warm oven and bringing the oven and sample up to a temperature of 32soF (l63"C) together is permissible. If preferred, preliminary evap­oration of water may be accomplished by careful heat­ing on a hot plate. followed by oven treatment at 32soF for I h.

19. Calculation and Report

19.1 Calculate the percentage of residue on each beaker as follows:

Residue. % = 2(A - B)

where: A = weight of beaker, rod, and residue, g, and B = tare weight of beaker and rod, g.

19.2 Report the percentage of residue by evap­oration as the average of the three results.

20. Procedure B

20.1 Use procedure B when tests on the resi­due from the emulsion are required.

20.2 Proceed in accordance with IS.2 using four 50 ± O.I-g samples. After the calculation for percentage of residue, replace the beakers in the oven until the asphalt residue is sufficiently fluid to pass through a No. 50 (300-~m) sieve (usually requiring 15 to 30 min). Pour the residue through the No. 50 (300-~m) sieve into suitable con­tainers and molds for making such tests as de­sired, as described in Sections 66 to 70.

Non 8-As the method for residue by evaporation described in Sections 17 to 20 tends to give an asphaltic residue lower in penetration and ductility than the distillation method described in Sections II to 13. material may be accepted but shall not be rejected as failing to meet specifications containing requirements for determination of residue by distillation. on data obtained by evaporation. If residue from evaporation fails to meet the requirements for properties specified for residue from distillation, tests shall be rerun using the distillation method.

0244

21. Precision

21.1 The following criteria should be used for judging the acceptability of results (95 % proba­bility):

21.1.1 Duplicate results by the same operator should not be considered suspect unless they differ by more than the following amount:

Residue by Evaporation. weight %

50 to 70

Repeatability. weight %

0.4

21.1.2 The results submitted by each of two laboratories should not be considered suspect unless they diff~r by more than the following amount:

Residue by Evaporation. weight %

50 to 70

Reproducibility, weight %

0.8

PARTICLE CHARGE OF EMULSIFIED ASPHALTS

NOTE 9-This test is made to identify cationic emul­sions. Positively charged particles are classified as cati­onic.

22. Apparatus

22.1 Current Source. of 12-V direct current, a milliammeter, and a variable resistor. (See Figs. 5 and 6.)

22.2 Plates-Two stainless steel plates I in. (25.4 mm) by 4 in. (101.6 mm), insulated from each other and rigidly held parallel 1/2 in. (12.7 mm) apart. (See Fig. 5.)

22.3 Beaker. 150 or 250-mL.

23. Procedure

23.1 Pour the emulsion to be tested into the 150 or 250-mL beaker to a height that will allow the electrodes to be immersed I in. (25.4 mm) in the emulsion.

23.2 Connect the electrodes, which have been cleaned and dried, to the doc current source and insert them into the emulsion to a depth of I in. (25.4 mm).

23.3 Adjust the current to at least S rnA with the variable resistor and start timing with a suit­able timing device equipped with a second hand.

NOTE 10-The 8 rnA is a minimum current value­higher current levels may be specified. Current used shall be reported.

23.4 When the current drops to 2 rnA, or at the end of 30 min, whichever occurs first, discon-

179

nect the current source, and gently wash the electrodes in running water.

23.5 Observe the asphalt deposit on the elec­trodes. A cationic emulsion will deposit an ap­preciable layer of asphalt on the cathode (nega­tive electrode) while the anode (positive elec-

0244

trode) will be relatively clean.

24. Report

24.1 Report the test results in terms of the determined polarity (positive or negative) as de­fined in 23.S.

CONSISTENCY TEST

VISCOSITY

25. Apparatus

2S.1 Viscometer-A Saybolt Furol viscome­ter conforming to the requirements specified in Test Method D 88.

2S.2 Sieve-A No. 20 (8S0-jlm) sieve or a 20-mesh strainer of wire cloth, framed or unframed.

2S.3 Thermometers-ASTM No. 17F or 17C for tests at 77°F (2S°C) and ASTM No. 19F or 19C for tests at 122°F (SO°C), conforming to the requirements of Specification E I.

2S.4 Water Bath. capable of maintaining the required testing temperature within the limits specified in Table 2 of Test Method D 88.

26. Procedure

26.1 Tests at 77"F (25"C}-Stir the sample thoroughly without incorporating bubbles and pour it into a 4-oz (118-mL) bottle. Place the bottle in the water bath at 77°F (2S°C) for 30 min and mix the sample in the bottle by inverting it several times slowly enough to prevent bubble formation. Pour the sample into the viscometer through the No. 20 (8S0-jlm) sieve or 20-mesh strainer, allowing a small portion to flow through the outlet tube to waste. Place the cork in posi­tion, fill the viscometer and, without again stir­ring the sample, determine the viscosity as pre­scribed in Test Method D 88.

26.2 Tests at 122"F (50°C}-Clean and dry the viscometer and insert the cork. Heat the emulsion sample to 122 ± SOF (SO ± 3°C) in a 160 ± 5°F (71 ± 3°C) water bath or oven. Stir the sample thoroughly without incorporating bubbles, and then pour approximately 100 mL into a 400-mL glass beaker. Immerse the bottom of the beaker containing the emulsion approxi­mately 2 in. (SO.8 mm) below the level of a 160 ± SOF (71 ± 3°C) water bath. Hold the beaker upright and stir the emulsion with a wide circular

motion at a rate of 60 rpm with the thermometer to obtain uniform temperature distribution. Avoid incorporation of bubbles. Heat the emul­sion in the water bath to 124.S ± O.soF (S1.4 ± O.3"e). Immediately pour the emulsion through the No. 20 (8S0-jlm) sieve or 20-mesh strainer into the viscometer until it is above the overflow rim. Stir the emulsion in the viscometer at 60 rpm with the thermometer until the test temper­ature is attained, avoiding bubble formation. Ad­just the bath temperature until the emulsion temperature remains constant for I min at 122 ± O.loF (SO ± O.OS"C). Withdraw the thermom­eter. Quickly remove the excess emulsion from the gallery with a suction pipet. Determine the viscosity as described in Test Method D 88. Re­port the results to t:le nearest full second.

NOTE II-While the Saybolt Furol viscometer is not used for petroleum products and lubricants when the time of flow is less than 25 s, this instrument is satisfactory for testing emulsified asphalt when the time of flow is not less than 20 s.

27. Precision

27.1 The following criteria should be used for judging the acceptability of results (9S % proba­bility):

27.1.1 Duplicate results by the same operator should not be considered suspect unless they differ by more than the following amount:

Test Tempera­ture. "F

77 122

Viscosity. s

20 to 100 75 to 400

Repeatability. % of the mean

5 9.6

27.1.2 The results submitted by each of two laboratories should not be considered suspect unless they differ by more than the fOllowing amount:

Test Tempera­ture. OF

77 122

180

Viscosity. s

20 to 100 75 to 400

Reproducibility. % of the mean

15 21

4t 0244

STABILITY TESTS

OEMVLSIBILITY

28. Apparatus and Heagents

28.1 Wire Cloth-Three pieces of No. 14 (1.40-mm) wire cloth approximately 5 in. (127.0 mm) square, unframed. having wire diameters and openings that conform to Specification Ell.

28.2 Beakers-Three metal beakers of 600-mL capacity each.

28.3 Rods-Three metal rods with rounded ends, approximately 5/16 in. (7.9 mm) in diameter.

28.4 Buret-A 50-mL glass buret graduated in O.I-mL intervals.

28.5 Calcium Chloride Solution (I. rt g/L)­Dissolve 1.11 g of calcium chloride (CaCh) in water and dIlute to I L. The 1.11 giL calcium chloride solution shall be standardized to be a 0.02 N ± 0.00 I normal solution of calcium chlo­ride in water.

28.6 Calciwn Chloride Solution (5.55 g/L)­Dissolve 5.55 g ofCaCh in water and dilute to I L. The 55.5 gil calcium chloride solution shall be standardized to be a 0.1 N ± 0.00 I normal solution of calcium chloride in water.

28.7 Dioctyl Sodium Su/fosuccinate Solution (8.00 g/L)-Dissolve 8.00 g of dioctyl sodium sulfosuccinate in 992 g ofwaler.

28.8 Balance. capable of weighing 500 g to within ±O.I g.

29. Procedure

29.1 Determine the percentage of residue by distillation as described in Section 12.

29.2 Record the weight of each assembly of beaker, rod, and wire cloth.

29.3 Weigh 100 ± 0.1 g of the emulsified asphalt into each of three 600-mL beakers in the weighed assemblies. Bring the weighed sample of emulsion and the proper reagent to a temperature of 77 ± I.O°F (25 ± 0.5°C). Over a period of approximately 2 min, add to each beaker, from a buret, 35 mL ofCaCh solution (1.11 giL) (Note 14) for rapid setting emulsions, or 50 mL of CaCh solution (5.55 giL) for mixing-type emul­sions. While adding the CaCh solution, stir the contents of the beaker continuously and vigor­ously, kneading any lumps against the sides of the beaker to ensure thorough mixing of the reagent with the emulsion. Continue kneading any lumps for an additional 2 min after the

addition of the CaCh solution.

NOTE 12-When testing cationic emulsions, use 35 mL of dioctyl sodium sulfosuccinate solution (0.8 %) instead of 35 mL of CaCh solution (1.11 giL).

29.4 Decant the mixture of any unbroken emulsion and reagent onto the wire cloth. Rinse the beaker containing the sample and metal rod with distilled water. Knead and break up all lumps, and continue washing the beaker, rod, and wire cloth until the wash water drains clear. Place the wire cloth enclosing the asphalt in the beaker with the metal rod. Place the assembly in a 325°F ( 163°C) drying oven and dry to constant weight.

30. Calculation

30.1 Subtract the tare weight of the beaker, rod, and wire cloth from the weight of the dried assembly to obtain the demulsibility residue. Cal­culate the demulsibility as follows:

Demulsibility, % = (A/B) x 100

where: A = average weight of demulsibility residue

from the three tests of each sample of emul­sified asphalt, and

B = weight of residue by distillation in 100 g of the emulsified asphalt.

31. Precision

31.1 The following criteria should be used for judging the acceptability of results of tests on RS emulsions (95 % probability):

NOTE 13-Precision does not apply when using dioctyl sodium sulfosuccinate solution in the testing of cationic emulsions for demulsibility.

31.1.1 Duplicate results by the same operator should not be considered suspect unless they differ by more than the following amount:

Demulsibility, weight %

30 to 100

Repeatability, % of the mean

5

31.1.2 The results submitted by each of two laboratories should not be considered suspect unless they differ by more than the following amount:

181

Demulsibility, weight %

30 to 100

Reproducibility. % of the mearr

30

SETILEMENT

32. Apparatus

32.1 Cylinders-Two.500-mL glass cylinders, with pressed or molded glass bases and cork or glass stoppers, having an outside diameter of 50 ±5mm.

32.2 Glass Pipet-A 60-mL siphon glass-tube pipet of optional form.

32.3 Balance. capable of weighing 500 g to within ±O.I g.

33. Procedure

33.1 Place a 500-mL representative sample in each of the two glass cylinders. Stopper the cyl­inders and allow them to stand undisturbed at laboratory air temperature, for 5 days. After standing for this period, remove approximately the top 55 mL of emulsion by means of a pipet or siphon without disturbing the balance. Mix each portion thoroughly. Weigh 50 g of each sample into separate weighed IOOO-mUow-form glass beakers, and determine the asphaltic residue by evaporation in accordance with Section IS.

33.2 After removal of the top sample, siphon off approximately the next 390 mL from each of the cylinders. Thoroughly mix the emulsion re­maining in the cylinders and weigh 50 g into separate weighed IOOO-mL low-form beakers. Determine the asphaltic residue of these samples in accordance with Section IS.

NOTE 14-lf the emulsion contains appreciable amounts of oil distillate as determined by distiJlation (see 12.6), the settlement value may be calculated from the difference in the percentage of water content be­tween the top and bottom samples as determined by the procedure described in Section 6.

34. Calculation

34.1 Calculate the settlement as follows:

Settlement, % (5 days) = B - A

where: A = average of the percentage of residues from

the top samples, and B = average of the percentage of residues from

the bottom samples.

35. Precision

35.1 The following criteria should be used for judging the acceptability of results (95 % proba­bility):

35.1.1 Duplicate results by the same operator

0244

should not be considered suspect unless they differ by more than the following amount:

Settlement. weight %

o to 1.0 above 1.0

Repeatability

0.4 weight % 5 % of the mean

35.1.2 The results submitted by each of two laboratories should not be considered suspect unless they differ by more than the following amount:

Settlement. weight %

o to 1.0 above 1.0

Reproducibility

0.8 weight % 10 % of the mean

CEMENT MIXING

36. Apparatus

36.1 Sieves-A No. SO (ISO-Ilm) sieve and a 3-in. (76.2-mm) diameter No. 14 (1.40-mm) sieve, made of wire cloth conforming to Specifi­cation Ell.

36.2 Dish-A round-bottom iron dish or a kitchen saucepan of approximately 500-mL ca­pacity.

36.3 Stirring Rod-A steel rod with rounded ends, approximately 1/2 in. (13 mm) in diameter.

36.4 Graduate-A 100-mL graduated cylin­der.

36.:; Balance. capable of weighing 500 g to within ±O.I g.

37. Cement

37.1 High-early-strength portland cement conforming to the requirements for Type III portland cement in Specification C 150 and hav­ing a minimum specific surface'area of 1900 cm2

/

g, as measured by the Wagner Turbidimeter.

38. Procedure

3S.1 Dilute the emulsion with distilled water to a residue of 55 %, as determined by distillation or by evaporation for 3 h at 325°F (163°C).

3S.2 Sieve a portion of the cement through the No. SO (IS0-llm) sieve. Weigh 50 ± 0.1 g of the cement passing the No. SO (IS0-llm) sieve into the iron dish or saucepan.

38.3 Bring the ingredients and apparatus to a temperature of approximately 77°F (25°C) before mixing. Add 100 mL of the diluted emulsion to the cement and stir the mixture at once with the steel rod, using a circular motion at a rate of 60 rpm. At the end of the I-min mixing period, add 150 mL of distilled water, and continue the stir-

182

ring for 3 min. 38.4 Pour the mixture through a weighed No.

14 (1.40-mm) sieve. Use repeated washings to completely remove material from the mixing bowl. Pour these over the sieve, and rinse the sieve using distilled water held at a height of approximately 6 in. (IS2.4 mm) until the water is clear. Place the sieve in a weighed shallow pan, heat at 32soF (163°C) in an oven, and weigh. Repeat the heating and weighing until successive weights differ by no more than 0.1 g.

39. Report

39.1 Report the weight, in grams, of the ma­terial retained on the sieve and in the pan as the percentage of break in the cement mixing test.

40. Precision

40.1 The following criteria should be used for judging the acceptability of results (9S % proba­bility):

40.1.1 Duplicate results by the same operator should not be considered suspect unless they differ by more than the following amount:

Cement Mixing. weight %

o to 2

Repeatability. weight %

0.2

40.1.2 The results submitted by each of two laboratories should not be considered suspect unless they differ by more than the following amount:

Cement Mixing. weight %

o to 2

Reproducibility. weight %

0.4

SIEVE TEST

41. Apparatus and Reagents 41.1 Sieve-A sieve having a 3-in. (76.2-mm)

frame conforming to Section 3.4 of Specification E II. and having a No. 20 (8S0-l1m) wire sieve cloth.

41.2 Pan-A tin box cover or shallow metal pan of appropriate size to fit over the bottom of the standard sieve.

41.3 Sodium Oleate Solution (2 %)-Dissolve 2 g of pure sodium oleate in distilled water and dilute to 100 mL.

NOTE IS-Replace sodium oleate solution with dis­tilled water in testing cationic emulsions.

41.4 Balances, capable of weighing 2000 g to within ± I g, and SOO g to within ±O.I g.

42. Procedure

42.1 The temperature at which the sieve test

0244

should be performed is related to the emulsion viscosity. For those materials whose viscosity is 100 s or less at 77°F (2S°C), perform the test at room temperature. For those materials whose viscosity is more than 100 s at 77°F (2S°C) and those whose viscosity is specified at 122°F (SO°C), use a test temperature of 122 ± SOF (SO ± 3°C). If heating is necessary the emulsion, in a closed container, may be placed in an oven or water bath, followed by stirring to achieve homogene­ity.

42.2 Record the weight of the sieve and pan and wet the wire cloth with the 2 % sodium oleate solution. Weigh 1000 g of the emulsified asphalt into a suitable container and pour it through the sieve. Wash the container and the residue on the sieve with the sodium oleate solution until the washings run clear. Place the pan under the sieve and heat for 2 h in a 220°F (lOS°C) drying oven. Cool in a desiccator, and weigh the sieve, pan and residue.

43. Calculation

43.1 Calculate the percentage of sample re­tained on the sieve as follows:

Sample retained, % = (B - A)/IO

where: A = weight of sieve and pan, g, and B = weight of sieve, pan, and residue, g.

44. Precision

44.1 The following criteria should be used for jUdging the acceptability of results (9S % proba­bility):

44.1.1 Duplicate results by the same operator should not be considered suspect unless they differ by more than the following amount:

Sieve Test. weight %

OtoO.1

Repeatability. weight %

0.03

44.1.2 The results submitted by each of two laboratories should not be considered suspect unless they differ by more than the following amount:

Sieve Test. weight %

o to 0.1

Reproducibility. weight %

0.08

COATING TEST

NOTE 16-This test is applicable only to emulsions containing an asphalt base of semisolid consistency. It is not applicable to the rapid-setting type of emulsions.

45. Apparatus and Material

4S.1 Sieves-Standard 3/4-in. (I9.0-mm) and

183

1/4-in. (6.3-mm) sieves conforming to Specifica­tion E II.

45.2 Spatllla-A steel spatula or its equiva­lent. having a blade approximately 8 in. (203.2 mm) in length.

45.3 Dish-A round-bottom iron dish or a kitchen saucepan. of approximately l-qt (I-l) capacity.

45.4 St one-A suppl y of reference stone (hard limestone. trap rock. or other type) which has been washed with water and dried before using. All stone shall pass through the standard %-in. (l9.0-mm) screen and not more than 5 % shall pass through the 1/4-in. (6.3-mm) screen.

Non l7-Each laboratory shall select its own ref­erence stone supply. the source of which is not apt to change: this is to obviate rapid changes in the character of reference stone used in anyone laboratory.

45.5 Balance. capable of weighing 1000 g to within ± 0.1 g.

46. Procedure

46.1 Weigh 465 ± 0.1 g of stone into the metal pan. Add 35 ± 0.1 g of the emulsion to the stone in the pan. and mix vigorously with the spatula for 3 min.

46.2 Record whether or not there is apprecia­ble separation of the asphaltic base from the water of the emulsion. and whether or not the stone is uniformly and thoroughly coated with the emulsion.

MISCIBILITY WITH WATER

NOTE 18-This test is not applicable to the rapid­setting type of emulsions.

47. Procedure

47.1 Gradually add 150 ml of distilled water. with constant stirring. to 50 ml of the emulsion in a 400-ml glass beaker. The temperature should be between 70 and 77°F (21 and 25T). Allow the mixture to stand for 2 h; then examine it for any appreciable coagulation of the asphalt content of the emulsion.

FREEZING TEST

48. Procedure

48.1 Place approximately 400 g of the emul­sion in a clean metal container, such as a I-pt (500-ml) press-top can.

48.2 Expose the emulsion in the closed con-

0244

tainer to an air temperature of O°F (-17.8°C) for 12 (or more) consecutive hours.

48.3 At the expiration of the freezing period. permit the emulsion to thaw by exposure of the container to ambient temperature.

48.4 Repeat the freezing and thawing periods until the emulsion will have been subjected to three cycles of freezing and thawing.

48.5 After the third cycle, the emulsion may be homogeneous or may have separated into distinct layers which cannot be rendered homo­geneous by stirring at laboratory temperature.

48.6 Report the result of this test as either "Homogeneous" or "Broken."

COATING ABILITY AND WATER RESISTANCE

NOTE 19-This method covers the determination of the ability of an asphalt emulsion to (/) coat an aggre­gate thoroughly. (2) withstand a mixing action while remaining as a film on the aggregate. and (3) resist the washing action of water after completion of the mixing. The method is primarily intended to aid in the identi­fication of asphalt emulsions suitable for mixing with coarse-~raded calcareous aggregates. (See Note 20 for application of the method to other aggregates.)

49. Apparatus

49.1 Mixing Pan-A white-enameled kitchen saucepan with handle, of approximately 3-qt (3-l) capacity.

49.2 Mixing Blade-A putty knife with a 11/4 by 3 Ih-in. (31.8 by 88.9-mm) steel blade with rounded corners. A 10-in. (254.0-mm) kitchen mixing spoon may be used as an alternative.

49.3 Sieves-Standard %-in. (19.0-mm) and No.4 (4.75-mm) sieves conforming to Specifi­cation Ell.

49.4 Constant-Head Water Spraying Appara­tlls-An apparatus for applying tap water in a spray under a constant head of 2 ft, 61h in. (774.7 mm) (Figs. 7 and 8). The water shall issue from the apparatus in a low-velocity spray.

49.5 Thermometer-An ASTM low Soften­ing Point Thermometer I:'F (or 15C), having a range from 30 to 180°F (or -2 to 80°C) and conforming to the requirements in Specification E I.

49.6 Balance, capable of weighing 1000 g to within ± 0.1 g.

49.7 Pipet, of IO-ml capacity.

50. Materials

50.1 Aggregate-Standard reference aggre-

184

gate l2 shall be a laboratory-washed and air-dried limestone aggregate graded to pass the )/4-in. (19.0-mm) sieve and be retained on the No.4 (4.75-mm) sieve.

NOTE 20-Aggregates other than limestone may be used provided calcium carbonate is omitted throughout the method. Laboratory washing and air-drying of such aggregates shan also be omitted.

50.2 Calcium Carbonate-Chemically pure, precipitated calcium carbonate (CaCO) shall be used as a dust to be mixed with the standard reference aggregate.

50.3 Water-Tap water of not over 250 ppm CaCO) hardness for spraying over the sample.

SI. Sample

51.1 The sample shall be representative of the asphalt emulsion to be tested.

S2. Procedure for Tests with Dry Aggregate

52.1 Carry out the test at 75 ± 10"F (23.9 ± 5SC).

52.2 Weigh 461 g of the air-dried, graded ref­erence aggregate in the mixing pan.

52.3 Weigh 4.0 g ofCaC03 dust in the mixing pan and mix with the 461 g of aggregate for approximately I min by means of a mixing blade to obtain a uniform film of dust on the aggregate particles.

NOTE 21-The total weight of aggregate and dust shall equal 465 g. If no calcium carbonate is included, the weight of aggregate alone shall be 465 g.

52.4 Weigh 35 g of the asphalt emulsion into the aggregate in the pan and mix vigorously with the mixing blade for 5 min using a tossing action created by a back-and-forth motion in an ellip­tical path of the mixing blade or spoon. At the end of the mixing period, tilt the pan and permit any excess emulsion not on the aggregate to drain from the pan.

52.5 Remove approximately one half of the mixture from the pan and place it on absorbent paper and evaluate the coating.

52.6 Immediately spray the mixture remain­ing in the pan with tap water from the conStant­head water spraying apparatus to cover the mix­ture. The distance from the sprayhead to the sample shall be 12 ± 3 in. (305 ± 75 mm). Then carefully pour ofT the water. Continue spraying and pouring ofT the water until the overflow water runs clear. Carefully drain ofT the water in the pan. Scoop the mixture from the mixing pan on

0244

to absorbent paper for evaluation of coating re­tention in the washing test.

52.7 Evaluate the mixture immediately by vis­ual estimation as to the total aggregate surface area that is coated with asphalt.

52.8 Repeat the evaluation by visual estima­tion of the coating of aggregate surface area by asphalt after the mixture has been surface air­dried in the laboratory at room temperature. A fan may be used for drying if desired.

S3. Procedure for Tests with Wet Aggregate

53.1 Proceed in accordance with 52.1 to 52.3. 53.2 Pipet 9.3 mL of water to the aggregate

and CaCO) dust mixture into the mixing pan and mix thoroughly to obtain uniform wetting.

53.3 Continue in accordance with 52.4 to 52.8.

54. Interpretation of Results

54.1 Evaluate and report the following infor­mation for tests with both dry and wet aggregate:

54.1.1 At the end of the mixing period, record the coating of the total aggregate surface area by the asphalt emulsion as good, fair, or poor, where a rating of "good" means fully coated by the asphalt emulsion exclusive of pinholes and sharp edges of the aggregate, a rating of "fair" coating applies to the condition of an excess of coated area over uncoated area, and a rating of "poor" applies to the condition of an excess of uncoated area over coated area.

54.1.2 After spraying with water, record the coating of the total aggregate surface area by the asphalt as good, fair, or poor.

54.1.3 After air-drying in the laboratory, re­cord the coating of the total aggregate surface area by the asphalt as good, fair, or poor.

54.1.4 Comments about the results of the test may be included in the evaluation.

STORAGE STABILITY OF ASPHALT EMULSION

SS. Scope

55.1 This method relates to the ability of an asphalt emulsion to remain as a uniform disper .. sion during storage. It is applicable to asphalt emulsions composed principally of a semisolid or liquid asphaltic base, water, and an emulsify­ing agent.

12 Limestone from the Monon Stone Co. of Monon, IN, has been found suitable as reference agrepte.

185

56. Summary of Method

56.1 The method determines the difference in asphalt content of samples taken from the top and bottom of material placed in undisturbed simulated storage for 24 h. The result is expressed as the difference between the average percent of residue from top and bottom samples taken from two storage cylinders.

57. Significance and Use

57.1 This method is useful for determining in a comparatively short time the storage stability of an asphalt emulsion. It is a measure of the permanence of the dispersion as related to time, but it is not to be construed to have significance as a measure of other stability aspects involved in use.

58. Apparatps

58.1 Cylinders-Two 5OO-mL glass cylinders, with pressed or molded glass bases and cork or glass stoppers, having an outside diameter of 50 ± 5 mm, and having 5-mL graduations.

58.2 Glass Pipet-A 60-mL siphon glass-tube pipet of optional form.

58.3 Balance. capable of weighing 500 g to within ±O.I g.

59. Procedure

59.1 Bring the asphalt emulsion to room tem­perature, 70 to 80°F (21 to 27"C). Place a 500-mL representative sample in each of the two glass cylinders. Stopper the cylinders and allow them to stand undisturbed, at laboratory air tempera­ture 70 to 80°F (21 to 27"C), for 24 h. After standing for this period, remove approximately 55 mL from the top of the emulsion by means of the pipet or siphon without disturbing the balance. Thoroughly mix each portion.

59.2 Weigh 50 ± 0.1 g of each sample into separately weighed lOOO-mL glass or aluminum beakers, each beaker having previously been weighed with a 1/4-in. (6-mm) diameter by 7-in. (178-mm) glass rod. Adjust the temperature of the oven to 325 ± 5°F (163 ± 2.8°C). Then place the beakers containing the rods and sample in

0244

the oven for 2 h. At the end of this period remove each beaker and thoroughly stir the residue. Re­place in the oven for I h, then remove the beakers from the oven, allow to cool to room tempera­ture, and weigh, with the rods (see Note 7).

59.3 After removal of the top sample, siphon off the next 390 mL (approximate) from each of the cylinders. Thoroughly mix the emulsion re­maining in the cylinders and weigh 50 g into separate weighed lOOO-mL glass or aluminum beakers. Determine dIe asphaltic residue of these samples in accordance with 59.2.

60. Calculation

60.1 Calculate the storage stability as the nu­merical difference between the average percent­age of asphaltic residue found in the two top samples and that found in the two bottom sam­ples.

6 J. Precision

61.1 Repeatability-The repeatability stand­ard deviation is 0.2 %. The average difference between two results, obtained by the same oper­ator with the same equipment, but not concur­rently, will be approximately 0.2 %. Two such values should be considered suspect (95 % con­fidence level) if they differ by more than 0.5 %.

61.2 Reproducibility-The reproducibility standard deviation is 0.2 %. The average differ­ence between two results obtained by operators in different laboratories will be approximately 0.3 %. Two such values should be considered suspect (95 % confidence level) if they differ by more than 0.6 %.

NOTE 22-lf this method of test is performed using only one cylinder instead of two for each determination as specified in the method. then the following precision criteria should be used:

Repeatability, %

Standard deviation 0.2 A verage difference 0.3 Suspect criterion O.S

Reproducibility. %

Standard deviation 0.2 Average difference 0.3 Suspect criterion 0.6

EXAMINATION OF RESIDUE

62. Specific Gravity

62.1 Determine the specific gravity on a rep­resentative portion of the residue in accordance with Test Method 070 or Test Method 03289.

63. Ash Content

63.1 Determine the ash on a representative portion of the residue in accordance with the rapid routine method of ash determination, as

186

described in Section 5 of Methods D 12S.

64. Solubility in Trichloroethylene

64.1 Determine the solubility in trichloroeth­ylene on a representative portion of the residue in accordance with Test Method D 2042.

65. Penetration

65.1 Determine the penetration on a repre­sentative portion of the residue in accordance with Test Method D 5.

65.2 Precision-The following criteria should be used for judging the acceptability of results (95 % probability):

65.2.1 Duplicate results by the same operator should not be considered suspect unless they differ by more than the following amount:

Penetration of Residue. range

80 to 200

Repeatability. points

15

65.2.2 The results submitted by each of two

0244

laboratories should not be considered suspect unless they differ by more than the following amount:

Penetration of Residue. range

80 to 200

66. Ductility

Reproducibility. points

30

66. I Determine the ductility on a representa­tive portion of the residue in accordance with Test Method D 113.

67. Float Test

67.1 Determine the float test on a represent­ative portion of the residue in accordance with Method D 139 except revise Section 3.2 of Method D 139 as follows: Pour the residue into the collar at or near 500°F (260°C) preferably. directly from the still. If the residue has been allowed to cool below SOO"F (260°C). reheat it to 500°F (260°C) with stirring and pour into the collar.

CLASSIFICATION TEST FOR RAPID SETTING CATIONIC EMULSIFIED ASPHALT

68. Scope

6S. I This method covers a procedure for dis­tinguishing rapid-setting cationic emulsified as­phalts from other types by their failure to coat a specific Ottawa sand-portland cement (Type III) mixture.

69. Apparatus

69.1 Mixing Pan-A white enameled kitchen saucepan with handle. of approximately 3-qt (3-L) capacity.

69.2 Mixing Tool-A IO-in. (250-mm) kitchen mixing spoon.

69.3 Thermometer-An ASTM Low Soften­ing Point Thermometer 15F (or 15C) having a range from 30 to ISO°F (or -2 to SO°C) and conforming to the requirements in Section 3 of Specification E I.

69.4 Balance. capable of weighing 200 g to within ± 0.1 g.

70. Materials 70. I AK,I?re,l?ale-Standard reference aggre­

gate shall be 20 to 30-mesh Standard Ottawa Sand (see Test Method C 190).

70.2 Hi,l?h-Early Slren,l?lh Porlland Cement.

conforming to Type III portland cement in Spec­ification C 150. and having a minimum specific surface area of 1900 cm2/g.

71. Sample

71.1 Obtain a representative sample of the cationic emulsion for test.

72. Procedure

72.1 Test at 77 ± 9°F (25 ± 5°C). 72.2 Weigh 461 g of air-dry. 20 to 30-mesh

Standard Ottawa Sand in the mixing pan. 72.3 Weigh 4.0 g of Type III portland cement

in the mixing pan. Mix with the 461 g of 20 to 30-mesh Ottawa sand for approximately I min using the mixing tool to obtain a uniform distri­bution of the cement on the sand particles.

72.4 Weigh 35 g of the asphalt emulsion into the Ottawa sand-portland cement mixture. Mix vigorously with the mixing spoon for approxi­mately 2'12 min using a combined stirring and kneading action. At the end of the mixing period, tilt the pan and drain from the pan any excess emulsion not on the aggregate.

72.5 Place a representative quantity of the completed mixture on absorbent paper. Visually

187

estimate as soon as possible the amount of un­coated and coated area in the mixture.

73. Interpretation of Results

73.1 From the evaluation made in 72.5 at the

0244

end of the mixing period, record the coating of the total aggregate surface area by the asphalt emulsion. An excess of uncoated area over a coated area shall be considered as a passing rating for rapid setting cationic emulsions.

FIELD COATING TEST ON EMULSIFIED ASPHALTS

74. Scope

74.1 This test is proposed for use at the project site to determine (1) the ability of an asphalt emulsion to coat the job aggregate; (2) the ability of the emulsion to withstand mixing; and (3) the water resistance of emulsion-coated aggregate.

75. Summary of Method

75.1 A measured amount of the job aggregate is hand-mixed with a measured amount of the emulsion supplied to the job. The ability of the emulsion to remain as a coating during a 5-min mixing cycle is observed. The resistance offered by the coating to wash-off is determined by re­peated filling with water and emptying a con­tainer of the coated aggregate.

76. Apparatus

76.1 Metal Containers, I-pt W2-L) capacity (friction-top pint cans).

76.2 Metal Porcelain Saucepan, 2112 to 3-qt (2 112 to 3-L), equipped with a handle.

76.3 Dispensing Graduate, 50-mL capacity, preferably plastic.

76.4 Serving Spoon, long-handled.

77. Procedure

77.1 Derim the I-pt (lh-L) can. 77.2 Fill the can level with the job aggregate

deleting any sizes above 3/. in. (19 mm).

77.3 Measure out 50 mL of emulsified as­phalt.

77.4 Dump the aggregate (77 .2) and the emul­sion (77.3) into the porcelain saucepan.

77.5 Hand mix vigorously for 5 min with the long-handled spoon.

77.6 Observe (1) whether the stone is fully coated with the emulsion and rate the coating as good, fair or poor-a rating of good means fully coated by the asphalt emulsion exclusive of pin­holes and sharp edges of the aggregate, a rating of fair applies to the condition of an excess of coated area over uncoated area, and a rating of poor applies to the condition of an excess of uncoated area over coated area; and (2) the pres­ence, if any, of free water which denotes break­down of the emulsion.

77.7 Refill the I-pt (l12-L) can with the coated stone.

77.8 Set the can of coated stone upright in the porcelain saucepan.

77.9 Fill the can with water and pour off. Repeat this step five times.

77.10 Dump the contents of the can onto newspapers. Repeat the observations made in 77.6 and record.

78. Report

78.1 Report the observations made in 77.6 and 77.10 as the results from this test.

EMULSIFIED ASPHALT/JOB AGGREGATE COATING TEST

79. Scope

79.1 This test method may be used to identify the adequacy of slow setting grade of emulsified asphalt to mix with and coat a dense and fine­graded job aggregate. It is a laboratory test method of screening emulsion candidates for mixing with and coating job aggregates and is not to be construed as a mix design test method.

80. Significance and Use

80.1 The conditions of the test are designed

to identify the adequacy of emulsified asphalt, slow-setting grade (CSS-D2397 and SS-D977) for mixing with and coating dense-graded aggregate and fine-graded aggregate.

81. Summary of Method

81.1 A weighed amount of dry job aggregate is hand-mixed with a weighed amount of water for prewetting the aggregate. The wetted aggre­gate is then hand-mixed with a weighed amount of emulsified asphalt of known asphalt-cement

188

content until maximum coating of the job aggre­gate is obtained. (Mix time is usually 15 to 120 s.) The adequacy of emulsified asphalt for mixing with job aggregate is determined by using various amounts of water and emulsified asphalt until a maximum coating of the job aggregate is ob­tained. This coating is rated as good. fair. or poor.

82. Apparatus

82.1 Containers-A IOOO-mL glass beaker. a I-qt (I.O-L) friction-tip metal can, or lOOO-mL stainless steel beaker or bowl.

82.2 Mixing Tool-A steel spatula or its equivalent. having a blade approximately 8 in. (203.2 mm) in length.

82.3 Balance. capable of weighing 1000 g to within ±O.I g.

83. Procedure

83.1 Weigh 300 g of dry job aggregate into the container and add water basis dry weight of aggregate. Immediately begin to mix vigorously for I min or until all aggregate surfaces subjec­tively appear to be wetted (as a guide. 2 to 8 % water for dense-graded aggregate and 4 to 12 % water for fine-graded aggregate). The natural moisture in a job aggregate may be used in the test if predetermined. Additional water may then be added. if necessary. to obtain the desired level of water to be used for prewetting the aggregate.

83.2 Add the emulsion and immediately begin to mix vigorously. scraping sides and bottom of container. for 15 to 120 s or until maximum

0244

coating has been attained (as a guide, basis dry weight of aggregate. 3 to 7 % Asphalt Cement (A/C) residue for dense aggregate and 4 to 8 % AIC residue for fine aggregate). Example: 8 % emulsion at 60 % solids would be equivalent to 4.8 % asphalt cement residue in the mix.

83.3 If mix appears to be too dry and insuffi­ciently coated repeat 83.1 and 83.2 using an increased amount of water or emulsified asphalt, or both. If mix appears to be too wet from excessive water or emulsified asphalt, or both. repeat 83.1 and 83.2 using less water or emulsi­fied asphalt. or both.

83.4 For each job aggregate mix observe and record the amount of aggregate prewetting water and asphalt cement residue from the emulsified asphalt and note the one mix which provides the best aggregate coating.

83.5 Rate the best coating as good. fair. or poor using the ratings as defined in Section 54.

84. Report

84.1 Report the observations made in 83.2 and 83.3 relating to amount of aggregate pre­wetting water and residual asphalt needed for best obtainable aggregate coating.

84.2 Report the maximum coating achieved as good, fair, or poor in accordance with Section 54.

85. Precision

85.1 The usual methods of analysis for preci­sion cannot be applied to this test method be­cause it is only semiquantitative.

WEIGHT PER GALLON OF EMULSIFIED ASPHALT

86. Scope

86.1 This test method is used to determine the weight per gallon of emulsified asphalt used in highway construction. This unit weight i!> com­puted by determining the weight of an asphalt emulsion contained in a standard measure of known volume.

NOli: 23-The calculation of Imperial Gallon Weight may be made by using proper conversion fac­tors.

87. Apparatus

87.1 Weight-per-Gallon Clip-Stainless steel measure of known standard volume (83.2 ml),

87.2 Balance. accurate to 0.01 g. 87.3 Water Bath. constant-temperature.

maintained at 77°F (25°C).

88. Procedure

88.1 Stir the emulsion sample and place in a constant-temperature water bath maintained at 77 ± 1°F (25 ± OSC) for approximately I h.

88.2 Place the measure and its cap on the balance. tare. and zero the balance.

88.3 Remove the emulsion sample from the bath and stir, using care to avoid trapping air in the sample. If necessary. strain through a No. 20 (850-l1m) sieve to remove any skin or film that might be present in the emulsion.

189

88.4 Bring the measure to approximately 77°F (25°C) and pour the emulsion into the measure, filling it completely.

88.5 Start placing the cap into the measure and remove, with a clean dry rag or paper, the excess emulsion oozing through the orifice in the cap.

88.6 When the cap is placed on tightly, clean the measure carefully, weigh on the tared balance to the nearest 0.0 I g, and record.

89, Calculation

89.1 Calculate the weight per gallon of emul­sion as follows:

W= G/IO

where: W = unit weight of emulsion, Ib/gal, and G = weight of emulsion in measure, g.

90, Report

90.1 Report the unit weight of emulsion in

0244

pounds per gallon to the nearest 0.0 I Ib at 77°F (25°C).

91. Precision

91.1 The following criteria should be used for judging the acceptability of results (95 % proba­bility):

91.1.1 Duplicate results by the same operator should not be considered suspect unless they differ by more than the following amount:

Unit Weight

Pounds per gallon at 77'F (25'C)

Repeatability

0.019

91.1.2 The results submitted by each of two laboratories should not be considered suspect unless they differ by more than the following amount:

Unit Weight Reproducibility

Pounds per gallon at 77'F (25'C) 0.034

NOTE 24-Weight per gallon at 77'F (25'C) may be translated to weight per gallon at 60'F (15.6·C) by using a multiplier of 1.00475.

--r-

A -45 to 55 mm B - 14 to 16 mm C-12to 16mm D - 235 to 255 mm

. :

(6)

E" 25 to 38 mm F - 186 to 194 mm H-18tol9mm

FIG. I Apparatus for Determinioa Water

190

~~ 0244

I" lor I 0 - 2 Hoi ..

Clomp -

f Center Drill

9t'

I

I I

I f' Atumlf,um Plote

Alloy 3003-H14

in.

I 4"~

"-- Cost Aluminum AllOY 319

r 0 x 2·r Lon9 Steel Rod

COSI Aluminum Alloy 319

t~ Aluminum Plote

Alloy 3003 - H 14

__ Standard 4"A1umlr'lum Tube Alloy 3003- H 14

Metric Equivalents

mm

3.2 4.S 9.5

12.7 14.3 15.9 19.1 25.4 41.3 44.5 57.2 63.5

101.6 130.2 15S.S IS4.2 241.3

NOTE-The still cover may be machined from Rolled Aluminum Plate Alloy 3003-H 14.

FIG. 2 Aluminum-Alloy Still

191

in. mm

,","'M"'" \

6"

4t 0244

Mat'flol: erO,I Finilh: BriQht Nlck'i SPECIFY TYPE OF GAS

FOR PROPER ORIFICl

FIG. J Rinl Burner with o41/.-in. (I21-mm) Inside Diameter

, 6f

r-- 13{ -------1

~r'l 'f~~ I f-------- ------------,

L£mm_:_-- -1~ , DETAIL OF TIN SHIELD

U~l,-=-,

Metric Equivalents

'I. 1/. Jlh 2 3 4 S 6 6'h 91f, 9'h 13'/, IS

6.4 19.1 2~.4 38.1 SO.8 76.2 101.6 127.0 IS2.4 16~.1 231.8 241.3 3S2.4 381.0

FIG. 4 Apparatus Assembly for Distillatioa Telt of Emulsl8ed Asphalts

192

1A 1>-_--.T1

C1-S00 IIF 2S-V capacitor D I-silicon diode RI-47 n. I-W .esistor R2-5000!l potentiometer R3-6800 n. '/.-W resistor

4~ 0244

FIG. 5 Particle Charge Tester

R

o Low

o-f.;.;;Ml=-.L ___ ~ To CATHODE

+

TO ANODE

R4-meter shunt (determined by type of meter used) SI-2-pole. 3-position rotary switch T 1-12.6-V filament transformer M 1-0 to 100mA milliameter

FIG. 6 Particle Charge Tester Circuit Diagram

193

Inl't

4IDtt 0244

Male Coupling

:S/.Pip. Valy'

I in. '" 25.4 mm 8 in. - 230.2 mm 2 in. - 50.8 mm I ft - 304.8 mm 6 in. - 152.4 mm I ft 10J/. in. - 577.9 mm

7lf. in. - 196.9 mm 2 ft I'll in. - 650.2 mm 2 ft 6'11 in. '" 774.7 mm

NOTE-Use galvanized steel sheeting for the tank. All joints and litting attachments shall be soldered and shall be watertight. All couplings shall be standard brass garden hose littings. The J/ .. in. (19-mm) pipe valve shall be placed as close as possible to the bottom of the tank. allowing space to shut ofT the valve. The tank shall be placed on a suitable stand. so that the distance from the bottom of th~ spray head to the top of the test sample is 3 ft ± I in. (0.9 m ± 25.4 mm).

FIG. 7 Conslanl-Head Flow Tank

194

BOTTOM VIEWS

4--_ 4" Dia (101.6 mm)

4~ 0244

Flange Sol dered to Bottom of Tank

/ H = lr ~"NiPPle )1 %. Coupl i ng and Nipple to be E Inserted Between Flange-Nipple E and 3/4" Pipe Valve to Lower Valve O'l Handle for Eas'ler Regulation ~

~ It) ,... .!! N N o z '0

~ (; (l)

Holes in Spray Nozzle Approximately 0.05"( 1.3 mm) in Diameter, Spacing I

I

~ .¥ c: ~ as Shown. I 'II I Adopter from 3/4" Pipe to

_ Male Garden Hose Coupling

I I

I

-o E o --o (l)

E e -.r:. -C7I c: ~

Knurled Fittinq ~ Female Couplino :0

~~~~~ ~

11\

~ Spray Nozzle

NOTE I-A Speakman, Model 235S, all brass, fixed shower head has been found acceptable. NoT!' 2-Existing 4·in. (10 1.6-mm) diameter shower heads may continue to be used.

FIG. 8 Valve and Nozzle Assembly for Constant-Head Flow Tank

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights. and the risk of infringement of such rights. are entirely their own responsibility.

This standard is subject to revision at any time by the responsible technical commillee and must be reviewed every five years and if not revised. either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will rl'ceive careful consideration at a ml'l'ting of thl' rl'sponsibll' tl'chnical commilll'l'. which you may alll'nd. If you fl'elthat your comments havl' not rl'cl'ivl'd a fair hl'aring you should make your views known to the ASTM Commilll'l' on Standards. 1916 Race St., Philadl'lphia, PA 19103.

195

APPENDIX C

MISCELLANEOUS TABLES

197

TABLE C-1 TEMPERATURE-VOLUME CORRECTIONS FOR EMULSIFIED ASPHALTS

Oct OF M* Oct of M* Oct of

10.0 50 1.00250 35.0 95 0.99125 60.0 140 10.6 51 1.00225 35.6 96 0.99100 60.6 141 11.1 52 1.00200 36.1 97 0.99075 61.1 142 11.7 53 1.00175 36.7 98 0.99050 61.7 143 12.2 54 1.00150 37.2 99 0.99025 62.2 144

12.8 55 1.00125 37.8 100 0.99000 62.8 145 13.3 56 1.00100 38.3 101 0.98975 63.3 146 13.9 57 1.00075 38.9 102 0.98950 63.9 147 14.4 58 1.00050 39.4 103 0.98925 64.4 148 15.0 59 1.00025 40.0 104 0.98900 65.0 149

15.6 60 1.00000 40.6 105 0.98875 65.6 150

16.1 61 0.99975 41.1 106 0.98850 66.1 151 16.7 62 0.99950 41.7 107 0.98825 66.7 152 17.2 63 0.99925 42.2 108 0.98800 67.2 153 17.8 64 0.99900 42.8 109 0.98775 67.8 154

18.3 65 0.99875 43.3 110 0.98750 68.3 155 68.9 156 18.9 66 0.99850 43.9 111 0.98725 69.4 157 19.4 67 0.99825 44.4 112 0.98700

20.0 68 0.99800 45.0 113 0.98675 70.0 158

20.6 69 0.99775 45.6 114 0.98650 70.6 159

71.1 160 21.1 70 0.99750 46.1 115 0.98625 71.7 161 21.7 71 0.99725 46.7 116 0.98600 72.2 162 22.2 72 0.99700 47.2 117 0.98575 72.8 163 22.8 73 0.99675 47.8 118 0.98550 73.3 164 23.3 74 0.99650 48.3 119 0.98525

73.9 165 23.9 75 0.99625 48.9 120 0.98500 74.4 166 24.4 76 0.99600 49.4 121 0.98475 75.0 167 25.0 77 0.99575 50.0 122 0.98450 75.6 168 25.6 78 0.99550 50.6 123 0.98425 76.1 169 26.1 79 0.99525 51.1 124 0.98400

76.7 170 26.7 80 0.99500 51.7 125 0.98375 77.2 171 27.2 81 0.99475 52.2 126 0.98350 77.8 172 27.8 82 0.99450 52.8 127 0.98325 78.3 173 28.3 83 0.99425 53.3 128 0.98300 78.9 174 28.9 84 0.99400 53.9 129 0.98275 79.4 175 29.4 85 0.99375 54.4 130 0.98250 80.0 176 30.0 86 0.99350 55.0 131 0.98225 80.6 177 30.6 87 0.99325 55.6 132 0.98200 81.1 178 31.1 88 0.99300 56.1 133 0.98175 81.7 179 31.7 89 0.99275 56.7 134 0.98150 82.2 180

32.2 90 0.99250 57.2 135 0.98125 82.8 181

32.8 91 0.99225 57.8 136 0.98100 83.3 182

33.3 92 0.99200 58.3 137 0.98075 83.9 183

33.9 93 0.99175 58.9 138 0.98050 84.4 184

34.4 94 0.99150 59.4 139 0.98025 85.0 185

Legend: t = observed temperature in degrees Celsius (Fahrenheit) M = multiplier for correcting volumes to the basis of 15.ft C (60°F)

*Multiplier (M) for ° C is a close approx imation.

198

M*

0.98000 0.97975 0.97950 0.97925 0.97900

0.97875 0.97850 0.97825 0.97800 0.97775

0.97750 0.97725 0.97700 0.97675 0.97650

0.97625 0.97600 0.97575 0.97550 0.97525

0.97500 0.97475 0.97450 0.97425 0.97400

0.97375 0.97350 0.97325 0.97300 0.97275

0.97250 0.97225 0.97200 0.97175 0.97150

0.97125 0.97100 0.97075 0.97050 0.97025

0.97000 0.96975 0.96950 0.96925 0.96900

0.96875

TABLE C-2 MASS PER CUBIC METRE OF DRY MINERAL AGGREGATES OF DIFFERENT SPECIFIC GRAVITY AND VARIOUS VOID CONTENTS

Specific Voids - Percent

Gravity 16 20 25 30 36 40 46

2.0 1700 1600 1500 1400 1300 1200 1100 2.1 1786 1680 1575 1470 1366 1260 11,55

CI) 2.2 1870 1760 1650 1640 1430 1320 1210 .. t: 2.3 1955 1840 1725 1610 1495 1380 1265 ~ u 2.4 2040 1920 1800 1680 1560 1440 1320

:.0 a 2.5 2126 2000 1876 1750 1625 1600 1375

~ 2.6 2210 2080 1960 1820 1690 1560 1430 Q.

2.7 2295 2160 2025 1890 1755 1620 1485 E III 2.8 2380 2240 2100 1960 1820 1680 1640 .. .2 2.9 2466 2320 2175 2030 1885 1740 1595 ~ 3.0 2560 2400 2250 2100 1950 1800 1650

3.1 2635 2480 2326 2170 2015 1860 1705 3.2 2720 2560 2400 2240 2080 1920 1760

1. The Specific Gravity of commonly used road construction aggregates normally is within the following ranges:

Granite 2.6-2.9 Sandstone 2.0-2.7 Gravel 2.5-2.7 Traprock 2.7-3.2 Limestone 2.1-2.B Blast Furnace Sand (Quartzite) 2.5-2.7 Slag 2.0-2.5

2. Data contained in this table are appliCllble to dry mineral aggregates in either the loose or compacted state, and the void content should be selected accordingly. Preferably, both the void content and specific gravity should be determined in the laboratory.

3. The formula for computation of data in the table above is as follows:

kg/m3

G(100- V) W - 1000 x ----

100

where: W - Weight per cubic metre G == Specific gravity V = Air void content, percent

199

50

1000 1050 1100 1150 1200 1250 1300 1350 1400 1450 1500 1550 1600

65

900 945 990

1036 1080 1125 1170 1215 1.260 1305 1350 1395 1440

TABLE C-2a WEIGHT PER CUBIC FOOT AND PER CUBIC YARD OF DRY MINERAL AGGREGATES OF DIFFERENT SPECIFIC GRAVITY AND VARIOUS

VOID CONTENTS

.,.11e VOIDS-PERCENT 8r •• 11f

11 20 21 .0 15 40 41 ~ II -.:- 2.0 106.1 99.8 93.6 87.4 81.1 74.9 68.6 62.4 56.2 0 0 2.1 111.4 104.8 98.3 91.7 85.2 78.6 72.1 65.5 59.0 II. 2.2 116.7 109.8 103.0 96.1 89.2 82.4 75.5 68.6 61.8

" '2.3 122.0 114.8 107.6 100.5 93.3 86.1 78.9 71.8 64.6 ii 2.4 127.3 119.8 112.3 104.8 97.3 89.9 82.4 74.9 67.4 ::I

2.5 132.6 124.8 117.0 109.2 101.4 93.6 85.8 78.0 70.2 " IC 2.6 137.9 129.8 121.7 113.6 105.5 97.3 89.2 81.1 73.0 III 2.7 143.2 134.8 126.4 117.9 109.5 101.1 92.7 84.2 75.8 .. 2.8 148.5 139.8 131.0 122.3 113.6 104.8 96.1 87.4 78.6 • 2.9 153.8 144.8 135.7 126.7 117.6 108.6 99.5 90.5 81.4 a z 3.0 159.1 149.8 140.4 131.0 121.7 112.3 103.0 93.6 84.2 ::I 3.1 164.4 154.8 145.1 135.4 125.7 116.1 106.4 96.7 87.0 0 .. 3.2 169.7 159.7 149.8 139.8 129.8 119.8 109.8 99.8 89.9 - - - - - - -a 2.0 2860 2700 2530 2360 2190 2020 1850 1680 1520

= 2.1 3010 2830 2650 2480 2300 2120 1950 1770 1590

)- 2.2 3150 2970 2780 2590 2410 2220 2040 1850 1670

" 2.3 3290 3100 2910 2710 2520 2330 2130 1940 1740 ii 2.4 3440 3240 3030 2830 2630 2430 2220 2020 1820 ::I 2.5 3580 3370 3160 2950 2740 2530 2320 2110 1900 " IC 2.6 3720 3500 3290 3070 2850 2630 2410 2190 1970 III 2.7 3870 3640 3410 3180 2960 2730 2500 2270 2050 .. 2.8 4010 3770 3540 3300 3070 2830 2590 2360 2120 .. 2.9 4150 3910 3660 3420 3180 2930 2690 2440 2200 a

3.0 4300 4040 3790 3540 3290 3030 2780 2530 2270 z ~ 3.1 4440 4180 3920 3660 3400 3130 2870 2610 2350 0 3.2 4580 4310 4040 3770 3500 3230 2970 2700 2430 ..

1. The Specific Gravity of commonly used road construction aggregates normally is within the following ranges:

Granite 2.6-2.9 Sandstone 2.0-2.7 Gravel 2.5-2.7 Traprock 2.7-3.2 Limestone 2.1-2.8 Blast Furnace Sand (Quartzite) 2.5-2.7 Slag 2.0-2.5

2. Data contained in this table are applicable to dry mineral aggregates in either the loose or compacted state, and the void content should be selected accordingly. Preferably, both the void content and specific gravity should be determined in the laboratory.

3. The formulas for computation of data in table above are as follows:

Ib/fr3

and

Where: W = Wt. per cu ft W = Wt. per cu yd G = Specific gravity

G(100- V) W = 62.4 x = O. 624 G(100 - V)

100

G(100- V) W = 27 x 62.4 x 16.85G(100 - V)

100

V = Air void content, percent

200

TABLE C-3 LINEAR MEASUREMENT COVERED BY TANK OF ANY CAPACITY FOR VARIOUS WIDTHS AND RATES OF APPLICATION

To compute the number of linear feet (metres) that will be covered by a tank of any capacity, for various widths and rates of application, use the applicable formula:

C S.1. Metric: L = -

RW

9C U. S. Customary: L = -

RW

where: L = No. of linear metres (feet) that will be covered C = Capacityoftankin litres (gallons) (or quantity of asphaltin tank) R = Rate of application in litres per sq. metre (gallons per sq. yard)

W = Width of application in metres (feet).

201

Lltres per Sq.

Metre

0.45 0.68 0.91 1.13 1.36 1.58 1.81 2.04 2.26 2.72 3.17 3.62 4.07 4.53 5.66 6.79 7.92 9.05

TABLE C-4 LINER METRES COVERED BY 4000 LITRE TANK OF ASPHALT FOR VARIOUS WIDTHS AND LlTRES PER

SQUARE METRE

Width-Metres

0.5 1.0 1.5 2.0 3.0 4.0 5.0 6.0

1m8 8889 5926 4444 2963 2222 1778 1481 11765 5882 3922 2941 1961 1471 1176 980 8791 4396 2930 2198 1465 1099 879 733 7080 3540 2360 1no 1180 885 708 590 5882 2941 1Q61 1471 980 735 588 490 5063 2532 1688 1266 844 633 506 422 4420 2210 1473 1105 737 552 442 368 3922 1961 1307 980 654 490 392 327 3540 1nO 1180 885 590 442 354 295 2941 1471 980 735 490 368 294 245 2524 1262 841 631 421 315 252 210 2210 1105 737 552 368 276 221 184 1966 983 655 491 328 246 197 164 1766 883 589 442 294 221 in 147 1413 707 471 353 236 in 141 118 1178 589 393 295 196 147 118 98 1010 505 337 253 168 126 101 84 884 442 295 221 147 110 88 74

NOTE: See Table C-3 for formula used for calculation.

Gals. per Sq. Yd. 1 -- ---

0.10 90000 0,15 60000 0,20 45000 0,25 36000 0.30 30000 0.35 25714 0,40 22500 0.45 20000 O.SO 18000 0.55 16364 0.60 15000 0.65 13846 0.70 12857 0.15 12000 0.80 11250 0.85 10588 0.90 10000 0.95 9474 1.00 9000 1.10 8182 1.20 7500 1.25 7200 1.30 6923 1.40 6429 1. SO 6000 1. 75 5143 2.00 4500 2.25 4000 2.SO 3600 2.75 3213 3.00 3000

TABLE C-4a LINEAR FEET COVERED BY 1000-GALLON TANK OF EMULSIFIED ASPHALT FOR VARIOUS WIDTHS AND RATES

WIDTH-FEET

I 2 6 7 8 9 10 11 12 14 16 18 20 --- --- --- --- --- --- ------ --- '-- --- --~-- -

45000 15000 12857 11250 10000 9000 8182 7500 6429 5625 5000 4500 30000 10000 8m 7500 6667 6000 5455 5000 4286 3750 JJJJ 3000 22500 7500 6429 5625 5000 4500 4091 3750 3214 2813 2500 2250 18000 6000 5143 4500 4000 3600 3273 3000 2571 2250 2000 1800 15000 5000 4286 37SO 3J33 3000 2727 2500 2143 1875 1661 1500 12857 4286 3673 3214 2857 2571 2338 2143 1837 1607 1429 1286 11250 31SO 32t-4 2813 2500 2250 2045 1815 1607 1406 12SO 1115 10000 3333 la57 2500 2222 2000 1818 1661 1429 1250 1111 1000 9000 3000 2571 2250 2000 1800 1636 1500 1286 1125 1000 900 8182 2127 2338 2046 1818 1636 1488 1364 1169 1023 909 818 7500 2500 2143 1875 1667 1500 1364 1250 1071 938 833 150 6923 2308 1918 1731 1538 1385 1259 1154 989 865 769 692 6429 2143 1837 1607 1429 1286 1169 1071 918 804 714 643 6000 2000 1714 1500 1333 1200 1091 1000 857 7SO 661 600 5625 1815 1607 1406 1250 1125 1023 938 804 103 625 563 5294 1765 1513 1324 1116 1059 963 882 756 662 588 529 5000 1667 1429 1250 III 1 1000 909 833 714 625 ,56 500 4737 1579 1353 1184 1053 947 861 789 616 592 526 473 4500 1500 1286 1125 1000 900 818 750 643 563 500 450 4091 1364 ll69 1023 909 818 744 682 584 5ll 454 409 37SO 1250 1071 938 833 750 682 625 535 469 416 315 3600 1200 1029 900 800 720 655 600 514 450 400 360 3462 ll54 989 866 769 692 629 517 494 433 384 346 3215 1072 918 804 714 643 584 536 459 402 357 321 300Cl 1000 857 750 667 600 545 500 429 375 333 300 2571 857 735 643 571 514 468 I 429 367 321 286 251 2250 7SO 643 563 500 450 409

I 315 321 281 250 225

2000 667 571 500 444 400 364 333 286 250 222 200 1800 600 514 4SO 400 360 321 300 257 225 200 180 1636 545 468 409 364 327 298 272 234 204 182 163 1500 500 429 315 333 300 273 250 214 181 161 ISO

NOTE: See Table C-3 for formula used for calculation. For metric conversion factors refer to Table C-10.

202

7.0

1270 840 628 506 420 362 316 280 253 210 180 158 140 126 101 84 72 63

22 24 --- ---

4091 3750 2727 2500 2045 1875 1636 1500 1363 1250 1169 1011 1022 931 909 833 818 150 144 682 682 625 629 511 584 535 545 500 511 46~ 481 441 454 416 430 394 409 315 312 341 341 312 327 300 314 288 292 268 212 250 234 214 204 181 182 166 163 150 149 136 136 125

TABLE C-5 LlTRES OF ASPHALT REQUIRED PER 50 LINEAR METRES; VARIOUS WIDTHS AND LITRES PER SQUARE METRE

L1tres per Sq.

Metre 0.5 1.0 1.5

0.45 11.3 22.5 33.8 0.68 17.0 34.0 51.0 0.91 22.8 45.5 68.3 1.13 28.3 56.5 84.8 1.36 34.0 68.0 102. 1.58 39.5 79.0 119. 1.81 45.3 90.5 136. 2.04 51.0 102. 153. 2.26 56.5 113. 170. 2.72 68.0 136. 204. 3.17 79.3 159. 238. 3.62 90.5 181. 272. 4.07 102. 204. 305. 4.53 113. 227. 340. 5.66 142. 283. 425. 6.79 170. 340. 509. 7.92 198. 396. 594. 9.05 226. 453. 679.

NOTE: Formula used for calculation: Q=50 WR where: Q = Quantity of asphalt required per 50 metres.

W=Width of application in metres.

Width-Metres

2.0 3.0 4.0 5.0

45.0 67.5 90.0 113. 68.0 102. 136. 170. 91.0 137. 182. 228.

113. 170. 226. 283. 136. 204. 272. 340. 158. 237. 316. 395. 181. 272. 362. 453. 204. 306. 408. 510. 226. 339. 452. 565. 272. 408. 544. 680. 317. 476. 634. 793. 362. 543. 724. 905. 407. 611. 814. 1018. 453. 680. 906. 1133. 566. 849. 1132. 1415. 679. 1019. 1358. 1698. 792. 1188. 1584. 1980. 905. 1358. 1810. 2263.

R= Rate of application in litres per square metre. Application rates for mtermediate widths can be determined by adding columnar values or by use of above formula.

6.0

135. 204. 273. 339. 408. 474. 543. 612. 678. 816. 951.

1086. 1221. 1359. 1698. 2037. 2376. 2715.

7.0

158. 238. 319. 396. 476. 553. 634. 714. 791. 952.

1110. 1267. 1425. 1586. 1981. 23n. 2m. 3168.

TABLE C-5a GALLONS OF EMULSIFIED ASPHALT REQUIRED PER 100 LINEAR FEET: VARIOUS WIDTHS AND RATES

Gill. WIDTn-fEET per Sq. Yd. I 2 6 7 I • 10 _1_1 _1_1_2 _ 14

0.10 \.I 2.2 6.7 7.' I.' 10.0 11.1 12.2 13.1 15.6 0.15 1.7 3.3 10.0 11.7 13.3 15.0 16.7 18.3 20.0 23.3 0.20 2.2 4.4 13.3 15.6 17.' 20.0 22.2 24.4 26.7 31.1 0.·25 2.' 5.6 16.7 ".4 22.2 25.0 27.' 30.6 n.3 38.9 0.30 U 6.7 20.0 23.3 26.7 30.0 n.3 36.7 40.0 46.7 0.35 3.9 7.' 23.3 27.2 31.1 35.0 3I.t 42.8 46.7 54.4 0.40 4.4 1.9 26.7 31.1 35.6 40.0 44.4 4a.9 53.3 62.2 0.45 5.0 10.0 30.0 35.0 40.0 45.0 50.0 55.0 60.0 70.0 0.50 5.6 11.1 n.3 3'.9 44.4 50.0 55.5 61.1 66.7 17.' 0.55 6.1 12.2 36.7 42.a 4a.t 55.0 61.1 67.2 7U as.5 0.60 6.7 13.3 40.0 46.7 53.3 60.0 66.7 71.3 80.0 93.3 0.65 7.2 14.4 41.3 50.6 57.' 65.0 72.2 79.4 86.7 101. 0.70 7.' 15.6 46.7 54.4 62.2 70.0 17.a a5.5 91.3 109. 0.75 a.3 16.7 50.0 58.3 66.7 75.0 .3.3 tl.7 100. 117. 0.80 '.9 17.' 53.3 62.2 71.1 80.0 .... 97.' 107. 124. 0.a5 9.4 la.9 56.7 66.1 75.5 as.O 14.4 104. m. 132. O.to 10.0 20.0 60.0 70.0 80.0 to.O 100. 110. 120. 140. 0.95 10.6 21.1 63.3 73.9 14 .• 95.0 106. 1\6. m. 14 •• 1.00 11.1 22.2 66.7 17.' ".9 100. III. 122. 133. 156. 1.10 12.2 24.4 71.3 85.5 97.' 110. 122. 134. 147. 171. 1.20 13.3 26.7 80.0 93.3 107. 120. ID. 147. 160. 187. 1.25 13.9 27.' 83.3 97.2 III. 125. 139. 153. 167. 1M. 1.30 14.4 2I.t 16.7 101. 116. 130. 144. 1St. 173. 202. 1.40 15.6 31.1 93.3 109. 124. 140. 156. 171. 117. 21a. 1.50 16.7 D.3 100. 117. ID. 150. 167. 183. 200. m. 1.75 19.4 3a.t 117. 136. 156. 175. 1M. 214. 21:. 272. 2.00 22.2 44.4 m. 156. 17a. 200. m. 244. 267. 31 I. 2.25 25.0 50.0 150. 175. 200. 225. 250. 275. 300. 350. 2.50 27.' 55.6 167. 1M. 222. 250. 27 •• 306. Dl. '19, 2.75 30.6 61.1 183. 214; 244. 275. 306. m. 367. 42 •• 3.00 D.3 66.7 200. m. 267. 300. 3D. 367. 400. 467.

tOOW Note: Formula used for calculation: Q = -- R = "."WR

9

Where: Q = Quantity of asphalt required, in gallons per 100 ft. R = Rate of application in gallons per sq. yd. W ~ Width of application, in feet

203

16 \I 20 22

17.' 20.0 22.2 24.4 26.7 30.0 n.3 36.7 35.6 40.0 44.4 48.9 44.4 50.0 55.6 61.1 53.3 60.0 66.7 73.3 62.2 70.0 17.' as.5 71.1 80.0 ".9 11.' 80.0 to.O 100. 110. ".9 100. III. 122. 97.' 110. 122. 134.

107. 120. m. 147. 115. 130. 144. 159. 124. 140. 156. 171. ID. 150. 167. 183. 142. 160 . 17 •. 196. 151. 170. In. 208. 160. 180. 200. 220. 169. Ito. 211. 232. 17 •. 200. 222. 244. 196. 220. 244. 269. 213. 240. 267. 293. 222. 250. 27 •• 306. 230. 260. 218. 311. 24t. 280. 31 I. 342. 267. 300. lD. 367, 311. 350. In. 427. 156. 400. 444. 4". 400. 450. 500. 550. 444. 500. 556. 611. .n. 550. 611. 672. m. 600. 667. m.

24

26.7 40.0 53.3 66.7 80.0 93.3

107. 120. m. 147. 160. 173. 1.7. 200. 213. 227. 240. 253. 267. 293. 320. 333. 347. 373. 400. 467. 511. 600. 667. 713. 100.

TABLE C-6 MEGAGRAMS OF MATERIAL REQUIRED PER KILOMETRE FOR VARIOUS WIDTHS AND KILOGRAMS PER SQUARE METRE

kg/m2 1 2 3 4 5

5 5.0 10.0 15.0 20.0 25.0 10 10.0 20.0 30.0 40.0 50.0 20 20.0 40.0 60.0 80.0 100.0 30 30.0 60.0 90.0 120.0 150.0 40 40.0 80.0 120.0 160.0 200.0 50 50.0 100.0 150.0 200.0 250.0 60 60.0 120.0 180.0 240.0 300.0 70 70.0 140.0 210.0 280.0 350.0 80 80.0 160.0 240.0 320.0 400.0 90 90.0 180.0 270.0 360.0 450.0

100 100.0 200.0 300.0 400.0 500.0 200 200.0 400.0 600.0 800.0 1000.0 300 300.0 600.0 900.0 1200.0 1500.0 400 400.0 800.0 1200.0 1600.0 2000.0 500 500.0 1000.0 1500.0 2000.0 2500.0

NOTE: Fonnula used for calculation: M=RWL where: M = Mass of material, megagrams per kilometre

R= Rate of application, kg/m2 W=Width of application, metres L=Length of section, 1 kilometre

Width-Metres

6 7 8 9 10 15

30.0 35.0 40.0 45.0 50.0 75.0 60.0 70.0 80.0 90.0 100.0 150.0

120.0 140.0 160.0 180.0 200.0 300.0 180.0 210.0 240.0 270.0 300.0 450.0 240.0 280.0 320.0 360.0 400.0 600.0 300.0 350.0 400.0 450.0 500.0 750.0 360.0 420.0 480.0 540.0 600.0 900.0 420.0 490.0 560.0 630.0 700.0 1050.0 480.0 560.0 640.0 720.0 800.0 1200.0 540.0 630.0 720.0 810.0 900.0 1350.0 600.0 700.0 800.0 900.0 1000.0 1500.0

1400.0 1600.0 1800.0 2000.0 3000.0 3000.0 1800.0 2100.0 2400.0 2700.0 3000.0 4500.0 2400.0 2800.0 3200.0 3600.0 4000.0 6000.0 3000.0 3500.0 4000.0 4500.0 5000.0 7500.0

TABLE C-6a TONS OF AGGREGATE REQUIRED PER MILE FOR VARIOUS WIDTHS AND RATES

Spread Spread Width (in Feet)

Rate 8 9 10 12 16 18

Tons Tons Tons Tons Tons Tons

20

100.0 200.0 400.0 600.0 800.0

1000.0 1200.0 1400.0 1600.0 1800.0 2000.0 4000.0 6000.0 8000.0

10000.0

20

Tons Ib/yd2

Per Mile Per Mile Per Mile Per Mile Per Mile Per Mile Per Mile

5 12 13 15 18 23 26 29 10 23 26 29 35 47 53 59 15 35 40 44 53 70 79 88 20 47 53 59 70 94 106 117 25 59 66 73 88 117 132 147 30 70 79 88 106 141 158 176 35 82 92 103 123 164 185 205 40 94 106 117 141 188 211 235 45 106 119 132 158 211 238 264 50 117 132 147 176 235 264 293 60 141 158 176 211 282 317 352 75 176 198 220 264 352 396 440

100 235 264 293 352 469 528 587 150 352 396 440 528 704 792 880 200 469 528 587 704 939 1056 1173 250 587 660 733 880 1173 1320 1467 300 704 792 880 1056 1408 1584 1760

204

Percent Depth Filled

1 2 3 4 5 6 7 8 9

10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

TABLE C-7 QUANTITIES AT DEPTHS IN CYLINDRICAL TANKS IN A HORIZONTAL POSITION

Percent Percent Percent Percent Percent Percent of Depth of Depth of Depth

Capacity Filled Capacity Filled Capacity Filled

0.20 26 20.73 51 51.27 76 0.50 27 21.86 52 52.55 71 0.90 28 23.00 53 53.81 78 1.34 29 24.07 54 55.08 79 1.87 30 25.31 55 56.34 80 2.45 31 26.48 56 57.60 81 3.07 32 27.66 57 58.86 82 3.74 33 28.84 58 60.11 83 4.45 34 30.03 59 61.36 84 5.20 35 31.19 60 62.61 85 5.98 36 32.44 61 63.86 86 6.80 37 33.66 62 65.10 87 7.64 38 34.90 63 66.34 88 8.50 39 36.14 64 67.56 89 9.40 40 37.39 65 68.81 90

10.32 41 38.64 66 69.97 91 11.27 42 39.89 67 71.16 92 12.24 43 41.14 68 72.34 93 13.23 44 42.40 69 73.52 94 14.23 45 43.66 70 74.69 95 15.26 46 44.92 71 75.93 96 16.32 47 46.19 72 71.00 97 17.40 48 47.45 73 78.14 98 18.50 49 48.73 74 79.27 99 19.61 50 50.00 75 80.39

205

Percent of

Capacity

81.50 82.60 83.68 84.74 85.71 86.71 87.76 88.73 89.68 90.60 91.50 92.36 93.20 94.02 94.80 95.55 96.26 96.93 97.55 98.13 98.66 99.10 99.50 99.80

TABLE C-8 AREA IN SQUARE METRES OF ROAD SURFACE FOR VARIOUS ROAD WIDTHS

Per Road Lineal Per Per Width Metre 50m Kilometre

2m 2 100 2.000 2.5 2.5 125 2.500 3 3 150 3.000 3.5 3.5 175 3.500 4 4 200 4.000 4.5 4.5 225 4.500 5 5 250 5.000 5.5 5.5 275 5.500 6 6 300 6.000 6.5 6.5 325 6.500 7 7 350 7.000 7.5 7.5 375 7.500 8 8 400 8.000 8.5 8.& 425 8.500 9 9 450 9.000 9.5 9.5 475 9.500

10 10 500 10.000 10.5 10.5 525 10.500 11 11 550 11.000 11.5 11.5 575 11.500 12 12 600 12.000 15 15 750 15.000 20 20 1.000 20.000 25 25 1.250 25.000

TABLE C-8a AREA IN SQUARE YARDS OF ROAD SURFACE FOR VARIOUS ROAD WIDTHS

Per Road Lineal Per Per Width Foot 100 ft Mile

6ft 0.67 66.67 3.520 7 0.78 n.78 4.107 8 0.89 88.89 4.693 9 1.00 100.00 5.280

10 1.11 111.11 5.867 11 1.22 122.22 6.453 12 1.33 133.33 7.040 13 1.44 144.44 7.627 14 1.56 155.56 8.213 15 1.67 166.n 8.800 16 1.78 1n.78 9.387 17 1.89 188.89 9.973 18 2.00 200.00 10.560 20 2.22 222.22 11.733 22 2.44 244.44 12.907 24 2.67 266.67 14.080 25 2.78 2n.78 14.667 26 2.89 288.89 15.253 28 3.11 311.11 16.427 30 3.33 333.33 17.600 32 3.56 355.56 18.n3 34 3.78 3n.78 19.947 36 4.00 400.00 21.120 38 4.22 422.22 22.293 40 4.44 444.44 23.467 50 5.56 555.56 29.333 60 6.67 666.67 35.200 70 7.78 m.78 41.067 75 8.33 833.33 44.000 80 8.89 888.89 46.933

206

TABLE C-g TEMPERATURE CONVERSION CHART

Fahrenheit to Degrees Celsius

OF °c of °c of °c -9 -23 31 -1 71 22 -8 -22 32 0* 72 22 -7 -22 33 1 73 23 -6 -21 34 1 74 23 -5 -21 35 2 75 24 -4 -20* 36 2 76 24 -3 -19 37 3 77 25* -2 -19 38 3 78 26 -1 -18 39 4 79 26 0 -18 40 4 80 27

1 -17 41 5* 81 27 2 -17 42 6 82 28 3 -16 43 6 83 28 4 -16 44 7 84 29 5 -15* 45 7 85 29 6 -14 46 8 86 30* 7 -14 47 8 87 31 8 -13 48 9 88 31 9 -13 49 9 89 32

10 -12 50 10* 90 32

11 -12 51 11 91 33 12 -11 52 11 92 33 13 -11 53 12 93 34 14 -10* 54 12 94 34 15 -9 55 13 95 35* 16 -9 56 13 96 36 17 -8 57 14 97 36 18 -8 58 14 98 37 19 -7 59 15* 99 37 20 -7 60 16 100 38

21 -6 61 16 101 38 22 -6 62 17 102 39 23 -5* 63 17 103 39 24 -4 64 18 104 40* 25 -4 65 18 105 41 26 -3 66 19 106 41 27 -3 67 19 107 42 28 -2 68 20* 108 42 29 -2 69 21 109 43 30 -1 70 21 110 43

*These are exact conversions.

Examples: 25' F is -4°C (minus four degrees Celsius) 7SoF is 2ftC; 10~F is 42°C

207

of °c 111 44 112 44 113 45* 114 46 115 46 116 47 117 47 118 48 119 49 120 49

121 49 122 50* 123 51 124 51 125 52 126 52 127 53 128 53 129 54 130 54

131 55* 132 56 133 56 134 57 135 57 136 58 137 58 138 59 139 59 140 60*

141 61 142 61 143 62 144 62 145 63 146 63 147 64 148 64 149 65* 150 66

of °c 151 66 152 67 153 67 154 68 155 68 156 69 157 69 158 70* 159 71 160 71

161 72 162 72 163 73 164 73 165 74 166 74 167 75* 168 76 169 76 170 77

171 77 172 78 173 78 174 79 175 79 176 80* 177 81 178 81 179 82 180 82

181 83 182 83 183 84 184 84 185 85*

TABLE C-10 CONVERSION FACTORS:

To convert from

acre ..... . acre. . . . . . . . ..... .

Atmosphere Itechnical = lkgf/cm 2)

barrel (42 gaL) . . . . . . BTU (Intwnational Table) bushel .. dyne .......... . dyne/centimetre 2 .... .

Fahrenheit (temperature) foot . foot 2 .

footJ.

foot·pound·force . foot/minute .. foot/second 2 ..

galion (U.S. liquid) .

galion/minute ... gallon/yard 2 ..

horsepower (electric) inch . inch 2 .

inch2 .

inchJ . inch/second inch of mercury (60°F) inch/second2 .

kilogram (kg) . kip (1 000 Ibl)

kip/inch 2 ..

mile (U$. statute) mile2 .....

mile/hour. . . minute (angle) ounce· force . ounce-mass.

ounce· fluid

pint (U.S. liquid) . poise (absolute viscosity) .

pound· force (lbf) .

pound·force·inch . pound·forcelfoot2 . .

pound.force/inch 2 (psi)

pound·mass '" pound·masslfoot2

pound·mass/footJ

pound·mass/inchJ

pound·mass/yard 2

pound·,mass/yardJ .

pound·mass/gallon IU.S. liquid)

psi ....... . quan (U.S. liquid) ton (metric) . Ion hhorl·2 OOOlb) ton (long-2 240 Ib) . ton'mass/yardJ . yard . yard2

yard J

U.S. CUSTOMARY TO METRIC UNITS

metre2 (m2 ) .

hectometre2 (hm2 )

To

kilapascal (kPa) .. .. decimetreJ (dm J ) or litre (I)

kilojoule (kJ) ... decimetreJ (dm J ) . micronewton (pN) . pascal (Pa) . Cels,u, fe) . metre (m) .. metre2 (m 2 ) .

{metreJ ImJ) .

· litre (I) ...

joule (J) metre/second (m/s) metre/second2 Im/,2)

{decimetreJ (dmJ) or litre (I)

metreJ (m J ) ........ . decimetreJ/second (dmJ/s) Or Ittre/second (lIs) decimetreJ /metre 2 (dm J /m 2 ) or litre!metre 2 (11m 2 )

kilowan (kW) . millimetre (mm) . centimetre2 Icm2 ) . millimet,e2 (mm2 )

centimetreJ (cmJ) metre/second (m!s) pascal (Pa). . metre!second2 (m/5 2 )

ton (metric)

kilonewton (kN) . megapascal (MPa) kilometre (km) .. kilometre2 (km2 )

kilometrelhour (kmlhr) radian (rad). newton (N) ... . gram (g) ..... .

{centimetreJ (cmJ)

litre (I) ..... .

litre (I) ..... .

pascal·second (Pa·s)

{newton (N) .... k il onewton (k N) . newton·metre (N.m) . pascal (p.) ...

kilopascal (kPa) ... kilogram (kg) .. . ..

· kilogram/metre2 (kg/m2 ) .

{kilogram/metreJ (kg/mJ) .•.

· megagram/metreJ (Mg/m") . kilogram/decimet,eJ (kg/dm J )

kilogram/metre2 (kg/m2 ) .

kilogram/metreJ (kg/m J )

{ kilogram/metreJ (kg/mJ )' ...

· kilogram/decimetreJ (kg!dmJ ) kilopascal (kPa). "" decimetr.3 (dm J ) or litre (I)

kilogram (kg) kilogram (kg) •.. kilogram (kg) .... kilogram!metreJ (kg!mJ ) metre (m) .. metre 2 (m2 ) . metreJ (mJ) .

208

Multiply bV

4046.856 · . 0.404 686 · 98.06650 · 158.9873

· 1.055056 35.2391 to.OOO 0

· 0.100 0 . te = 1t,-32)/1.8

0.304 SO · 0.092903 · 0.02B 317 2B.3170

1.355B18 0.00508 0.30480 3.785412 0.003785 0.06309 4.527314 0.7460

25.400 0 · 6.45160

· 645.1600 .16.38706

· . 0.02540 .3376.85

0.02540 0.00100 4.448222 6.894 757 1.609 344 2.589988 1.609 344 0.000290 89 0.2780139

28.34952 29.57353

0.029574 0.473 1765 0.100 000 4.448222 0.004448 0.1129848

47.88026 6.894 757 0.4535924 4.882428

16.01846 · 0.D16018 27.67990

· 0.542 492 0.593276

· 119.8264 0.119826

· . 6.894 757 · . 0.9463529

. 1000.000 0

. .907.184 7

.1016.0461

.1186.5527 0.91440 0.8361274 0.764554 9

D.Ol SCOPE

APPENDIXD

STANDARD METHOD OF TEST FOR UNIT WEIGHT OF AGGREGATE AASHTO DESIGNATION: T 19*

ASTM DESIGNATION: C 29*

0.01.1 This method covers the determination of the usnit weight of fine, coarse, or mixed aggregates.

Note 1: The values stated in V. S. customary units are to be regarded as the standard, The metric equivalents of V.S. customary units may be approximate.

D.02 APPARATUS D.02.1 Balance-A balance or scale accurate within 0.1 percent of the test load at any point

within the range of use. The range of use shall be considered to extend from the mass (weight) of the measure empty to the mass (weight) of the measure plus its contents at 1600 kg/m3 (100 Ib/ft3

).

0.02.2 Measure-A cylindrical metal measure, preferably provided with handles. It shall be watertight, with the top and bottom true and even, preferably machined to accurate dimensions on the inside, and sufficiently rigid to retain its form under rough usage. The top rim shall be smooth and plane within 0.25 mm (0.01 in.) and shall be parallel to the bottom within 0.009 radian (0.5 deg.) (Note 2). Measures of the two larger sizes listed in Table 0-1 or 0-2 shall be reinforced around the top with a metal band, to provide an overall wall thickness of not less than (5 mm) (0.20 in.) in the upper 38 mm (1 112 in.) The capacity and dimensions of the measure shall conform to the limits in Table E-l or E-2 (Note 3).

Note 2: The top rim is satisfactorily plane if a 0.25 mm (0.01 in.) feeler gauge cannot be inserted between the rim and piece of 6 nun (114 in.) or thicker plate glass laid over the measure. The top and bottom are satisfactorily parallel if the slope between pieces of plate glass in contact with the top and bottom does not exceed 1 percent in any direction.

Note 3: Dimensional tolerances and thicknesses of metal prescribed here are intended to be applied to measures acquired after January 1, 1968. Measures acquired before that date may conform either to this standard or to Section 2(c) of Test Method ASTM C 29-60.

D.03 SAMPLE 0.03.1 The sample of aggregate shall be dried to essentially constant weight, preferably in

an oven, at 105 to 110°C (220 to 230°F) and thoroughly mixed.

*Note: Only the portion of this test method required to determine the loose weight of an aggregate is reproduced here.

209

TABLE 0-1 DIMENSIONS OF MEASURES*

Thicknesses of Size of Inside Diameter Inside Height metal, min. mm Aggregate

Capacity, litres mm mm max, mm** Bottom Wall

3 155 ± 2 160 ± 2 5.0 2.5 12.5 10 205 ± 2 305 ± 2 5.0 2.5 25 15 255 ± 2 295 ± 2 5.0 3.0 40 30 ·355 ± 2 305 ± 2 5.0 3.0 100

*The indicated size of container may be used to test aggregates of a maximum size equal to or smaller than that listed.

**Based on sieves with square openings.

TABLE 0-2 DIMENSIONS OF MEASURES, U.S. CUSTOMARY SYSTEM*

Thicknesses of Size of Inside Diameter Inside Height metal, min. in. Aggregate.

Capacity, tt3 in. in. max. in.** Bottom Wall

1/10 6.0 ± 0.1 6.1 ± 0.1 0.20 0.10 1/2 1/3 8.0 ± 0.1 11.5 ± 0.1 0.20 0.10 1 1/2 10.0 ± 0.1 11.0 ± 0.1 0.20 0.12 1 1/2 1 14.0 ± 0.1 11.2 ± 0.1 0.20 0.12 4

*The indicated size of container may be used to test aggregates of a maximum nominal size equal to or smaller than that listed.

**Based on sieves with square openings.

D.04 CALIBRATION OF MEASURE D.04.1 Fill the measure with water at room temperature and cover with a piece of plate

glass in such a way as to eliminate bubbles and excess water. D.04.1 Determine the net weight of water in the measure to an accuracy of ± 0.1 percent D.04.3 Measure the temperature of the water and determine its unit weight, from Table

D-3, interpolating if necessary. D.04.4 Calculate the factor for the measure by dividing the unit weight of the water by the

weight required to fill the measure.

LOOSE WEIGHT DETERMINATION

n.os SHOVELING PROCEDURE D.OS.l The shoveling procedure is applicable to aggregates having a maximum size of 100

mm (4 in.) or less. D.OS.I.l Fill the measure to overflowing by means of shovel or scoop, discharging the aggre­

gate from a height not to exceed (50 mm) (2 in.) above the top of the measure. Exercise care to prevent, so far as possible, segregation of the particle sizes of which

210

TABLE 0-3 UNIT WEIGHT OF WATER

Temperature Ib/ft3 kg/m3 Deg.F Deg.C

60 15.6 62.366 999.01 65 18.3 62.336 998.54 70 21.1 62.301 997.97

(73.4) (23.0) (62.274) (997.54) 75 23.9 62.261 997.32 80 26.7 62.216 996.59 85 29.4 62.166 995.83

the sample is composed. Level the surface of the aggregate with the fingers or a straightedge in such a way that any slight projections of the larger pieces of the coarse aggregate approximately balance the larger voids in the surface below the top of the measure.

D. 05. 1.2 Weigh the measure and its contents and record the net weight of the aggregate to the nearest 0.1 percent. Multiply this weight by the factor calculated as described in 4.4. The product is the loose unit weight of the aggregate.

0.06 REPRODUCIBILITY OF RESULTS D.06.1 Results by an operator using the same sample and procedure should check within 1

percent.

211

APPENDIX E

BIBLIOGRAPHY

A BRIEF INTRODUCTION TO ASPHALT AND SOME OF ITS USES, Manual Series No.5, 8th Ed., The Asphalt Institute, College Park, Maryland, 1984

AJOUR, A.M., "Chemical Aspects of the Formulation of Bituminous Emulsion," World Congress on Slurry Seal, Madrid, Spain, February 1977

ANDERSON, JOHN, "Asphalt Emulsions in Paving Mixes: Open Graded and Dense Graded," Second Annual Meeting, Asphalt Emulsion Manufacturers Association, March 4, 1975

AROSURF-CATIONIC ASPHALT EMULSIFIERS, Ashland Chemical Company, Columbus, Ohio

ASH, ROBERT, "Dust Control and Stage Construction Using Asphalt Emulsion," First Annual Meeting, Asphalt Emulsion Manufacturers Association, Washington, D.C., January 28, 1974

ASPHALT COLD-MIX MANUAL, Manual Series No. 14, The Asphalt Institute, College Park, Maryland, 1977

ASPHALT EMULSION AND THE CHARLOTTE COLLOID MILL, Chemicolloid Laboratories, Inc., May 1977

ASPHALT EMULSION SPECIFICATIONS, Elf Aquitaine Asphalt, Inc., St. Louis, Missouri, 1985

ASPHALT IN PAVEMENT MAINTENANCE, Manual Series No. 16, 2nd Ed. The Asphalt Institute, College Park, Maryland, 1983

ASPHALT MULCH TREATMENT, Information Series No. 161, The Asphalt Institute, College Park, Maryland, January 1973

ASPHALT OVER LA YS FOR HIGHWAY AND STREET REHABILITATION, Manual Series No. 17, 2nd Ed. The Asphalt Institute, College Park, Maryland, 1983

ASPHALT SURFACE TREATMENTS-SPECIFICATIONS, Educational Series No. 11, The Asphalt Institute, College Park, Maryland, 1982

ASPHALT SURFACE TREATMENTS-CONSTRUCTION TECHNIQUES, Educational Series No. 12, The Asphalt Institute, College Park, Maryland, 1982

BAN, STEPHEN, and HARDIN, JACK, "The Properties of Asphalt Emulsion Residue," Fifth Annual Meeting, Asphalt Emulsion Manufacturers Association, Atlanta, Ga., March 1, 1978

BENEDICT, C. ROBERT, "Design and Control of Slurry Seal Mixes," Fourth Annual Meeting, Asphalt Emulsion Manufacturers Association, Phoenix, Arizona, March 1, 1977

BENEDICT, C. ROBERT, "Machine-Laid Travel Plant Emulsion Mixes," First Annual Meeting, Asphalt Emulsion Manufacturers Association, January 29, 1971 .

BENEDICT, C. ROBERT, "Quick-set, Quick-Cure Slurry Seal Systems-State ofthe Art," Proc. ISSA R&D Committee Symposium, Atlanta, Ga., February 13, 1978

BENEDICT, C. ROBERT, "An Introduction to the Potential Uses of a Loaded Wheel Tester for the Traffic Count Design of Slurry Seal," Proc. 13th Annual ISSA Convention, Las Vegas, February 1975

BERRY, BILL, "Chip Seal With RS-2 and Plio Pave L-170," Region IV Meeting, Asphalt Emulsion Manufacturers Ass'ociation, Chula Vista, California, July 8, 1975

213

BETENSON, WADE B., "Emulsified Asphalt Pavement at South Holden Interchange Ramps," Utah Department of Transportation

"BITUMINOUS EMULSIONS FOR HIGHWAY PAVEMENTS," Synthesis of Highway Practice Report No. 30, Transportation Research Board, National Cooperative Highway Research Program, Washington, D.C.

BITUMULS FOR BASE CONSTRUCTION, American Bitumuls & Asphalt Company, San Francisco, CA

BITUMULS MIX MANUAL, Chevron, U.S.A., Asphalt Division, San Francisco, CA, January 1977

BURTON, JAMES A., "Seal Coats are an Engineering Challenge," The Asphalt Paving Workshop, North Platte, Nebraska, March 4-5, 1976

BYRNE, JOSEPH, "Oil Industry Outlook, 1975," Second Annual Meeting, Asphalt Emulsion Manufacturers Association, San Diego, CA, March 5, 1975

CALDWELL, DONALD L., "Use of Portable Mixing Plants in Asphalt Emulsion Surface Mixes and Base Stabilization," Second Annual Meeting, Asphalt Emulsion Manufacturers Association, San Diego, CA, March 5, 1975

CHUCK-HOLE PATCHING WITH ASPHALT EMULSION, Phillips Petroleum Company, Bartlesville, Oklahoma, June 1976

COLD-MIX ASPHALT-STABILIZED BASE MIXER FOR PUG MILL PA VING, Calenco Equipment Company, Jacksonville, IL

COYNE, L.D., "Design and Construction of Emulsified Asphalt Open Graded Mixes and Overlays,"Twenty-Third Annual Road Builders' Clinic, Moscow, Idaho, March 17, 1972

COYNE, L.D. and RIPPLE, R.M., "Emulsified Asphalt Mix Design and Construction," Annual Meeting of The Association of Asphalt Paving Technologists, Phoenix, Arizona, February 1975

COYNE, L.D., "Emulsion Stabilization Mix Design," Transportation Research Board Meeting Washington, D.C., January 19, 1976

DARTER, MICHAEL I. and DEVOS, ALOIS J., "Structural Analysis of Asphaltic Cold Mixtures Used in Pavement Bases," Project IHR-505, Illinois Cooperative Highway Research Program, University of Illinois, Urbana, Illinois, August 1977

DARTER, MICHAEL I, and DEVOS, ALOIS J., "Structural Analysis of Asphaltic Cold Mixtures Used in Pavement Bases," Project IHR-505 (Research Report 505-4), Illinois Cooperative Highway Research Program, University of Illinois, Urbana, Illinois, April 1977

DARTER, MICHAEL I., WILKEY, PATRICK L., AHLFIELD, STEVEN L., and WASILL, RICHARD G., "Development of Emulsified Asphalt-Aggregate Cold Mixture Design Procedures," Project IHR-505 (Research Report 505-5), Illinois Cooperative Highway Research Program, University of Illinois, Urbana, Illinois, February 1978

DA Y, ALVYN J., "Manufacture and Use of Asphalt Emulsions (Paving)," Ohio Asphalt Paving Conference, Columbus, Ohio, February 26, 1976

DELP, LARUE, "The Use of Emulsions in The State of Kansas," Third Annual Meeting, Asphalt Emulsion Manufacturers Association, Toronto, Canada, April 26-28, 1976

DESIGN TECHNICAL BULLETINS-1984, International Slurry Seal Association, Washington, D.C.

DO'S AND DON'TS OF ASPHALT EMULSION HANDLING, Asphalt Emulsion Manufacturers Association, Washington, D.C.

214

DOTY, RO BER TN., "Cal Trans and Emulsions: Past, Present, and Future," Second Annual Meeting, Asphalt Emulsion Manufacturers Association, San Diego, CA, March 5, 1975

DOUGHERTY, H.D., "Servicing Slurry Seal Construction Using Bitumuls QS-h Emulsified Asphalt," Technical Paper No. 159, Chevron Asphalt Company, January 16, 1970

DRAPER, HOMER L., "Asphalt Emulsion Mill Setting Versus Particle Size,.· 1978 Annual Meeting, Asphalt Emulsion Manufacturers Association, Atlanta, GA., February 26-March 1, 1978

DUNNING, R.L. AND TURNER, F.E., "Asphalt Emulsion Stabilized Soils as a Base Material in Roads," Annual Meeting of Association of Asphalt Paving Technologists, Philadelphia, Pennsylvania, February 15-17, 1965

DUNNING, ROBERT L., "Rubber in Asphalt Emulsion Systems and Their Rheological Behavior," Second Annual Meeting, Asphalt Emulsion Manufacturers Association, San Diego, CA, March 5, 1975

DYBALSKI, JACK N., "Asphalt Emulsions," 1975 Iowa Asphalt Paving Conference, Ames, Iowa, March 20, 1975

DYBALSKI, JACK N., "Soil Stabilization and Other Cold Mixes with Cationic Asphalt Emulsions," First Annual Meeting, Asphalt Emulsion Manufacturers Association, Wash­ington, D.C., January 28, 1974

DYBALSKI, JACK N., "The Chemistry of Asphalt Emulsion," Fifty-Fifth Annual Meeting, Transportation Research Board, Washington, D.C., January 1976

"EMULSIFIED ASPHALT SINGLE SEAL COAT OR SURFACE TREATMENT," Guide Specification 102.0, Asphalt Emulsion Manufacturers Association, Washington, D.C.

EMULSIFIED ASPHALT MULTIPLE APPLICATION SEAL COAT OR SURFACE TREATMENT (ARMOR COA 1)," Guide Specification 103.0, Asphalt Emulsion Manufacturers Association, Washington, D.C.

"EMULSIFIED ASPHALT SAND SEAL," Guide Specification 104.0, Asphalt Emulsion Manufacturers Association, Washington, D. C.

EPPS, JON A., LITTLE, DALLAS N., and GALLA WAY, BOB M., "Use of Asphalt Emulsions in Pavement Recycling," Fourth Annual Meeting, Asphalt Emulsion Manufacturers Association, Phoenix, Arizona, March 1, 1977

FERGUSON, JOHN, "Emulsified Asphalt Used· for Seal Coats," Third Annual Meeting, Asphalt Emulsion Manufacturers Association, Toronto, Canada, April 26-28, 1976

FONG, GENE K., "Mix Design Methods for Base and Surface Courses Using Emulsified Asphalt-A State-of-the Art Report," Unpublished Report, Paving and Structural Group, Department of Transportation, Federal Highway Administration, July 1978

FOREST SERVICE GENERAL PROVISIONS & STANDARD SPECIFICATIONS FOR CONSTRUCTION OF ROADS & BRIDGES, U.S. Department of Agriculture Washington, D.C., 1977

FOSTER, CHARLES R., An Assessment of the Role of Emulsified Asphalts in Reducing Air Pollution and Conserving Energy in Pavement Construction, National Asphalt Pavement Association, Riverdale, Maryland, December 2, 1975

FOSTER, CHARLES R., The Future for Hot-Mix Asphalt Paving, National Asphalt Pavement Association, Riverdale, Maryland, December 1977

215

GAGAN, PETER, "High Float Emulsion," Fourth Annual Meeting, Asphalt Emulsion Manufacturers Association, Phoenix, Arizona, March 1, 1977

GODWIN, LENFORD N., "Slurry Seal Surface Treatments," Instruction Report 5-75-1, U.S. Army Engineers Waterways Experiment Station, Vicksburg, Mississippi, June 1975

GOETZ, W.H., "Developments in the Use of Emulsified Bitumen in the United States," Proceedings, Second Conference on Asphalt Pavements for Southern Africa, Durban, Republic of South Africa, July 29-August 2, 1974

GOODRICH, J.L., FERM, R.L. and ROGERS, E.D., "Practical Quick-Set Slurry Seal Coats," Technical Paper No. 150, Chevron Asphalt Company, San Francisco, CA, January 8, 1969

GORDILLO, JAIME, "Cationic Emulsions Based on Elastomeric Asphalt Used in Spain for Surface Treatments," Fifth Annual Meeting, Asphalt Emulsion Manufacturers Association, Atlanta, Georgia, February 28, 1978

HALLSTEAD, WOODROW J., "Opportunities and Problems for Increased Use of Asphalt Emulsions," First Annual Meeting, Asphalt Emulsion Manufacturers Association, Washington, D.C., January 27-29, 1974

HA TFIELD, RICHARD D., "Solvent and Solventless Emulsions," Fifth Annual Meeting, Asphalt Emulsion Manufacturers Association, Atlanta, Georgia, February 27, 1978

HENSLEY, M.J.and EPPS, JON, "The Design and Construction of Heavy Haul Roads," Fifth Annual Meeting, Asphalt Emulsion Manufacturers Association, Atlanta, Georgia, February 27, 1978

HERRIN, MORELAND, DARTER, MICHAEL I., and ISHAI, ILAN, "Determination of Feasible Testing Methods for Asphalt-Aggregate Cold Mix Bases," Project IHR-505, Illinois Cooperative Highway Research Program, University of Illinois, Urbana, Illinois, March 1974

HICKS, R.G., and WILLIAMSON, RONALD, "Use of Open Graded Emulsion Mixes in the Pacific Northwest," Fourth Annual Meeting, Asphalt Emulsion Manufacturers Association, Phoenix, Arizona, March I, 1977

HOlBERG, ARNOLD J., "A Survey of Asphalts-Types, Composition, Manufacture and Properties," First Annual Meeting, Asphalt Emulsion Manufacturers Association, Sheraton-Carlton Hotel, Washington, D.C., January 28, 1974

HUFFMAN, JOHN E., "An Overview of the Uses of Asphalt Emulsion in Paving and Pavement Maintenance," Second Annual Meeting, Asphalt Emulsion Manufacturers Association, San Diego, CA, March 4, 1975

HUFFMAN, JOHN E., "Emulsified Asphalts in Paving and Maintenance," Canadian Technical Asphalt Association, Toronto, Canada, November 24-26, 1975

HUFFMAN, JOHN E., "Emulsified Asphalt Paving-Proper Construction Practices," Third Annual Meeting, Asphalt Emulsion Manufacturers Association, Toronto, Ontario, April 26-28, 1976

HUFFMAN, JOHN E., Outline for Technical Training on Emulsified Asphalts, Pacific Coast Division, The Asphalt Institute, June 1974

HUTCHINSON, C. BRYCE, "Technical Aspects of CRS-2 for Seal Coating," Fifth Annual Meeting, Asphalt Emulsion Manufacturers Association, Atlanta, Georgia, February 27, 1978

216

ISHAI, ILAN, HERRIN, MORELAND, and LEVERENZ, DAVID G., "Failure Modes and Required Properties in Asphalt-Aggregate Cold Mix Bases," Project IH R-505, Illinois Cooperative Highway Research Program, University of Illinois, Urbana, Illinois, August 1973

JOHNSON, EUGENE M, "Road Programs" Region III Meeting, Asphalt Emulsion Manufacturers Association, Des Plaines, Illinois, October 1, 1975

KANDHAL, PRITHVI, Let's Get Acquainted with Asphalt Emulsions, Bureau of Materials, Testing and Research Information Report, Pennsylvania Department of Transportation, Harrisburg, April 1974

KARl, W.J., Emulsified Asphalt: Properties and Uses, Chevron Asphalt Company, U.S.A., September 11, 1975

KARl, W.J., "Design of Emulsified Asphalt Treated Base Courses," Technical Paper No. 155 Chevron Asphalt Company, San Francisco, CA, July 28, 1969

KARl, W.J., "Replacement of Cutbacks with Emulsified Asphalt," Chevron Asphalt Company, San Francisco, CA

KENNEDY, DOUGLAS 0., "Emulsion Basics-Mixes," Third Annual Meeting, Asphalt Emulsion Manufacturer~ Association, Toronto, Canada, April 26-28, 1976

KENNEDY, DOUGLAS, "Sand Seal," Technical Subcommittee IB, Asphalt Emulsion Manufacturers Association, Washington, D.C.

KIR W AN, FRANCIS M., and MADAY, CLARENCE, "Air Quality and Energy Conservation Benefits from Using Emulsions to Replace Asphalt Cutbacks in Certain Paving Operations," EPA-450/2-78-004, U.S. Environmental Protection Agency, Research Triangle Park, N.C., January 1978

KOCH, DONALD, "Emulsion Basics: Seal Coats, Surface Treatments, Slurry Seal, and Tack Coats," Third Annual Meeting, Asphalt Emulsion Manufacturers Association, Toronto, Canada, April 26-28, 1976

LANDISE, CYRIL c., "World Use of Asphalt Emulsion," Second Annual Meeting, Asphalt Emulsion Manufacturers Association, San Diego, CA, March 5, 1975

"LES EMULSIONS DE BITUME," Special w., Ministere de L' Amenagement du Territoire, de L' Equipement et des Transports, Bulletin de Liaison des Laboratories des Ponts et Chaussees, June 1974

"LES EMULSIONS DE BITUME ET LEURS APPLICATIONS ROUTIERES," Syndicat des Fabricants d' Emulsions Routieres de Bitume, Paris, France, 1976

LIGNOCHEMICAL EMULSIFIERS AND STABILIZERS FOR ASPHALT, Westvaco, Polychemicals Department, North Charleston, South Carolina

LINDBERG, H.A., AND MENDENHALL, W., "Welcome to the Highway Fraternity," First Annual Meeting, Asphalt Emulsion Manufacturers Association, Sheraton Carlton Hotel, Washington, D.C., January 28, 1974

McCONNAUGHA Y, K.E., INC., Emulsified Asphalt Plants and Processes, LaFayette, Indiana

McCONNAUGHAY, K.E., Improving Asphalts by Means of the Emulsification Process, LaFayette, Indiana .

McCONNAUGHAY, K.E., Join the Move to Emulsified Asphalts, LaFayette, Indiana McCONN AUG HA Y, K.E., Inc., Repair Pavement Cracks by Sealing with Asphalt Emulsion,

LaFayette, Indiana McCONNAUGHAY, K.E., Save Fuel: Pave Cold with McConnaughay High-Float Emulsified

Asphalt, LaFayette, Indiana

217

McCOY, PA UL, "Asphalt Emulsions Manufacture and Use in Road Construction," presented at University of Wisconsin, Institute on Bituminous Roads, February 14, 1962

McLEAN, J.A. and McLEOD, NORMAN W., "Heater-Planer and Slurry Seal for the Rehabilitation of Runways at Camp Borden, Ontario," Third Annual Meeting, Asphalt Emulsion Manufacturers Association, April 27-29, 1976

McLEOD, NORMAN, W., "Basic Principles for the Design and Construction of Seal Coats and Surface Treatments with Cutback Asphalts and Asphalt Cements," Supplement to Association of Asphalt Paving Technologists Proceedings, Volume 29, 1960

McLEOD, NORMAN' W., Seal Coat and Sur/ace Treatment Construction and Design Using Asphalt Emulsions, Asphalt Emulsion Manufacturers Association, Washington, D.C.

McLEOD, NORMAN, "Single and Multiple Chip Seals," Technical Subcommittee lA, Asphalt Emulsion Manufacturers Association

McLURE, GROVER,JR., "Use of Emulsified Asphalt on a Limited Budget," Fifth Annual Meeting Asphalt Emulsion Manufacturers Association, Atlanta, Georgia, February 26, 1978

McLURE, GROVER c., "Use of Emulsified Asphalt on a Limited Budget," Fifth Annual Meeting, Asphalt Emulsion Manufacturers Association, Atlanta, Georgia, March I, 1978

McQUEEN, JAMES A., and WALLER, H.F., JR., 'The Use of Emulsion (For 'Drag Seal') in North Carolina," Fifth Annual Meeting, Asphalt Emulsion Manufacturers Association, Atlanta, Georgia, February 26 - March 1, 1978

MARAIS, C.P., "A New Outlook on the Design of Single Surface Treatments," First Conference on Asphalt Pavements/or Southern Africa, National Institute for Road Research, South African Council for Scientific and Industrial Research, Pretoria, July 1969

MAREK, CHARLES R., and HERRIN, MORELAND, "Voids Concept for Design of Seal Coats and Surface Treatments," Highway Research Record No. 361, pp. 20-36, Highway Research Board, Washington, D.C.

MEIER, W.R., JR., "Asphalt Emulsion Construction on the Navajo Reservation." Engineer, Navajo Area Bureau of Indian Affairs

MEIER, W.R., JR., "Design and Construction Techniques for Emulsified Asphalt Roads on the Navajo Reservation," Fourth Annual Meeting, Asphalt Emulsion Manufacturers Association, Phoenix, Arizona, March 1, 1977

MERTENS, E. W., and BORG FELDT, M.J., "Cationic Asphalt Emulsions," ABA CO Technical Publication No. 113, California Research Corporation, American Bitumuls and Asphalt Company

MULLINS, TROY E., "Predicting Mechanical Stability of Emulsions," Fifth Annual Meeting, Asphalt Emulsion Manufacturers Association, Atlanta, Georgia, February 28, 1978

O'BRIEN, LOUIS G., "The Use of Motor Pavers in Penndot," Third Annual Meeting, Asphalt Emulsion Manufacturers Association, Toronto, Canada, April 26-28, 1976

PAVING HANDBOOK, Chevron Asphalt Company, San Francisco, CA, 1973 POLLOCK, JAMES, 'The Contractor, The Emulsion Maker, and the Job/' Second Annual

Meeting, Asphalt Emulsion Manufacturers Association, San Diego, CA, March 4, 1975 PRIMES, Technical Committee IlIA Report, Hans Schreuders, Chairman, Asphalt Emulsion

Manufacturers Association, Washington, D.C. PRINCIPLES AND PRACTICE OF BITUMINOUS SURFACING, Volume /, Sprayed Work,

National Association of Australian State Road Authorities, Sydney, New South Wales (1965)

PUBMILL PAVING WITH PORTA PUGG TWIN 78, Calenco Equipment Company, Jacksonville, Illinois

218

PUZINAUSKAS, V.P. and JESTER, R.N., "Design of Emulsified Asphalt Paving Mixtures," Report No. 259, Transportation Research Board, National Cooperative Cooperative Highway Research Program, Washington, D.C., 1983

RECOMMENDED PERFORMANCE GUIDELINES, Asphalt Emulsion Manufacturers Association, Washington, D.C., 1981

REDICOTE REFERENCE MANUAL, ARMAK Highway Chemicals Department, Chicago, Illinois

RICHARDSON, E.S., and LIDDLE, W.A., "Experience in the Pacific Northwest with Open­Graded Emulsified Asphalt Pavements," Implementation Package 74-3, U.S. Department of Transportation, Federal Highway Administration, Office of Research and Development, July 1974

RIPPLE, R.M., BLUM, DAVID, and OSWALD, HOYT, "Bitumuls Base Treatment Construction Using Advanced Machines, Methods and Materials," Technical Paper No. 157, Chevron Asphalt Company, San Francisco, CA, October 22, 1969

RIPPLE, R.M., ROGERS, E.D., and GOODRICH, J.L., "Construction Guide for Bitumuls Quick-Set Slurry Seal Coats (Anionic Asphalt Emulsion Type)," Technical Paper No. 149, Chevron Asphalt Company, San Francisco, CA, December 1968

RIPPLE, R.M., and ROGERS, E.D., "Construction Guide for Bitumuls Quick-Set Slurry Seal Coats (Cationic Asphalt Emulsion Type)," Technical Paper No.1 54, Chevron Asphalt Company, San Francisco, CA, May 29, 1969

RIVERA, ING. GUSTAVO, "The Construction ofthe International Airport on the Island of Cozumel Using Only Emulsions," Second Annual Meeting, Asphalt Emulsion Manufacturers Association, San Diego, CA, March 4, 1975

ROGERS, E.D., GOODRICH, J.L., and SCHMITZ, c.G., "Practical Quick-Set Slurry Seal Coats (Cationic Asphalt Emulsion Type)," Technical Paper No. 151, Chevron Asphalt Company, San Francisco, CA, January 8, 1969

SALE, JAMES P., PARKER, FRAZIER, JR., and BARKER, WALTER R., "Engineering Potentials for Membrane Encapsulated Soil Layers," First Annual Meeting, Asphalt Emulsion Manufacturers Association, Washington, D.C., January 28, 1974

SANTUCCI, L.E., "Thickness Design Procedure for Asphalt and Emulsified Asphalt Mixes," Technical Paper No.1 75, Chevron Asphalt Company, San Francisco, CA, September 1, 1976

SCHMIDT, R.J., "A Practical Method for Measuring the Resilient Modulus of Asphalt-Treated Mixes," Technical Paper No. 161, Chevron Asphalt Company, San Francisco, CA

SCHMIDT, R.J., SANTUCCI, LE.D., and COYNE, L.D., "Performance Characteristics of Cement-Modified Asphalt Emulsion Mixes," Technical Paper No.1 66, Chevron Asphalt Company, San Francisco, CA, February 1973

SCHMIDT, R.J., and GRAF, P.E., "The Effect of Water on the Resilient Modulus of Asphalt-Treated Mixes," Technical Paper No. 162, Chevron Asphalt Company, San Francisco, CA, February 1972

SCHREUDERS, HANS G., "Basic Anionic Asphalt Emulsion," Third Annual Meeting, Asphalt Emulsion Manufacturers Association, Toronto, Canada, April 26-28, 1976

SEAL COAT CONSTRUCTION USING CATIONIC ASPHALT EMULSION, Phillips Petroleum Company, Bartlesville, Oklahoma

"SEAL COATS AND SURFACE TREATMENTS," Asphalt Emulsion Users' Newsletter, Volume 1, No. I, Fall 1977

SLURRY SEALING, Construction Leaflet No. 22, The Asphalt Institute, College Park, Maryland, January 1978

219

SLURRY SEAL GUIDE SPECIFICATION, NO. A-105, International Slurry Seal Association, Washington, D.e.

"SLURRY SEAL, RECOMMENDED PRACTICE FOR THE DESIGN, TESTING AND CONSTRUCTION," ASTM Subcommittee Studies

"SOIL STABILIZATION AND GRADED AGGREGATE MIXES," Highway Chemicals Department Technical Service Report, ARMAK, Chicago, Illinois

SPENCER, J.W., "Bituminous Surface Treatments and Seal Coats," Seminar Notes, Cornell University, February 1964

STORING AND HANDLING OF EMULSIFIED ASPHALTS, Construction Leaflet No. 21, The Asphalt Institute, College Park, Maryland 1977

SURFACE TREATMENT MANUAL, MS-5038 (OS-1-86), Chevron U.S.A., Inc., Asphalt Division, San Francisco, CA, 1986

"TACK COATS AND FOG SEALS," Subcommittee IC Report, Don Koch, Chairman, Asphalt Emulsion Manufacturers Association, Washington, D.e.

TENG, T.e., PAUL, "A Construction Report for the Cement Modified Emulsified Asphalt Treated Base Course Project in Calhous County, Mississippi," Report No. FHWA- TS-77-205, Federal Highway Administration, March 1977

TENG, PAUL, "Emulsified Asphalt Stabilization of Sandy Soils in Mississippi," Second Annual Meeting, Asphalt Emulsion Manufacturers Association, San Diego, CA, March 4, 1975

TERRY, EDWARD, "Working with the Federal Highway Administration," Third Annual Meeting, Asphalt Emulsion Manufacturers Association, Toronto, Canada, April 26-28, 1976

TERREL, RONALD L., "The Use of the Drum Mixer with Emulsions," Second Annual Meeting, Asphalt Emulsion Manufacturers Association, San Diego, CA, March 5, 1975

THOMPSON, HARRY J., "Future Trends in Highway Construction in North America," Third Annual Meeting, Asphalt Emulsion Manufacturers Association, Toronto, Canada, April 1976

TOLONEN, WILLIAM J., and PETERS, ROWAN J., "Emulsion Testing Methods and Specifications," First Annual Meeting, Asphalt Emulsion Manufacturers Association, Washington, D.e., January 28, 1974

TRUMBULL, JOHN, "Open Graded Mixes," Technical Subcommittee lIB, Asphalt Emulsion Manufacturers Association Report, Washington, D.e.

WALKER, R.N., "A Method for the Design of Multiple Surface Treatments Based on the Results of Three Road Surfacing Experiments," First Conference on Asphalt Pave­ments/or Southern A/rica, National Institute for Road Research, South African Council for Scientific and Industrical Research, Pretoria, July 1969

WHITNEY, GORDON, F., "Recycling Asphalt Pavements Using the Heater Remix-Slurry Seal Method," Proc., 15th Annual ISSA Convention and First World Congress on Slurry Seal, Madrid, February 1977

WRIGHT, J.R., and MERTENS, E.W., "Theoretical and Practical Aspects of Catholic Asphalt Emulsions," ABA CO Technical Paper 72, California Research Corporation, Presented at Association of Asphalt Paving Technologists' Meeting, Denver, Colorado, January 26-28, 1959

YOUNG, Model SB-804 Slurry Machine, Slurry-Seal Inc., Waco, Texas

220

------------- -- - --- - -- ------

A Absorption

coarse aggregate, of, 120 emulsion, of, 15

Acid, hydrochloric, 13 Acids, fatty, II, 13 Adhesion provided by prime coat, 94 Adhesive properties of emulsions, 38 Adsorption of emulsion, 15 Aeraticn of mix, 77, 79, 163 Aggregate

absorption rates of, 15 air-dried, 160 application methods, 60, 61 asphalt content variation, and, 147 Asphalt Institute design, in, 147 bins used for, 80 calcareous, 124 Cape seal, for, 57 characteristics of, 67 choke, 85 choosing the best, 15 cleanliness of, 47 coarse, in Hveem method, 120 coarse, in mixes, 69 coarse, surface area, test of, 117 coatahility, 70, 126 coating requirements in mix, 145 coating test, and the, 31, 32-33, 188 combinations to be avoided, 87 combined, in Hveem method, 121 compatability of, 70 covering of, emulsion, 47 cubical shape ideal, 47 damp, 16 defined, 171 dirty, 16 drying of, 70 drying to constant weight, 125 electrical charges in surface of, 15 emulsion choice, and,S emulsion coating, 2 emulsion content, and, 114 emulsion mixes, for, 67, 83 emulsion setting rate, and, 16 evaluation of, 70, 71 factors, surface area, 116 field performance, and, 70 fine, in Hveem method, 119 fine, in mixes, 70 gradations in maintenance mixes, 99 grading requirements, 70 hot mixes, in, 87 imported, 72 laboratory evaluation of, 72 laboratory testing of, 54

INDEX

221

local, savings and, 82 loose weight determination, 210 loss of cover, 43, 45, 48 maintenance mixes, in, 98 marginal quality type, 79 Marshall method, in the, 155 mass, table on dry, 199,200 measures for, tables of, 210 moisture content, and, 16, 157 one-size in surface treatments, 54 open-graded mixes, for, 81, 82 pit run, 79 porous, 114 preparation in laboratory specimens, 160 quality tests of, 155 quantity determination in surface treatment, 54 reclaimed, 115 requirements in mix, 67 retention of, 66 selection of, III, 115 shape of, 47 shoveling procedure in weight test, 210 siliceous, 124 size of, 47 slurry seal, for, 57 specific gravity of, 55 spreaders for, 60, 61, 62,172 surface area calculation of, 116 surface treatments, in, 42 tests on, 70 tons per mile requirements, 204 types of, 115 types used in surface treatments, 54, 55 unit weight of, test for, 209-211 water, and, 72 weighing of, 61 weights of, tabulated, 200 wet, tests in, 185

Aggregate emulsion mixes, 67, 88 Air and asphalt calculation, 134 Air bubbles and emulsion stability, 19 Air entrainment, 19 Air jet in crack cleaning, 94 Air voids in mix design, 165 Airport runway recycling, 102 Alligator cracking, 93 Aluminum alloy still, 25 American Association of State Highway and

Transportation Officials, methods of M 140, 7, 39, 98 M 208, 7, 29, 39, 98 TII,71 T 19, 71, 73, 209 T 27,71 T 37,71

T 40,21,22 T44,31 T49,31 T 50,6,31,32,38 T 51, 31 T 59, 25, 26, 27 T 96, 47,51,71 T 104, 71 T 176,51,71 T 228,31 T 245,109 T 246,109 T 247,109

American Society for Testing and Materials, standards of

C 29, 71, 72, 209 C 88,71 C 117,71 C 127, 114, 147 C 131,47, 51, 71 C 136,71 D5,31 D 70, 31 D 113,31 D 139,6,31,32,38 D 140,21,22 D 244,25,26,27,151,152,175-195 D 546, 71 D 692, 69, 147 D 977, 7, 8, 9, 38, 39, 98 D 1188, 128, 134, 162, 164 D 1559, 109 D 1560, 109, 153 D 1561, 109, 126 D 2042, 31 D 2216, 125, 157 D 2397, 7, 10,31,39,51,71,98 D 2419, 51, 71 D 2726, 128, 134, 162, 164 D 3910,53 list of standards, 6, 175

Amines, fatty, II Ammonium salts, fatty quarternary, II Anionic emulsions, 5 Applications of emulsions, miscellaneous, 89, 96 Applications check methods, 59, 66 Arbor press, 159 Armorcoat, 57 Ash content test, 186 Asphalt

asphaltenes, II basic to emulsions, 7 chemical properties of, 7 cold-mix described, 79 colloid, as a, 7 contamination causes listed, 20-22 content determination, 7, 151 content, trial of, III cutbacks,2, 171

222

demand for, 3 dispersion, factors in, 5, 124 droplet size in emulsions, 12 emulsifying procedure, I field performance of, II fractions of, II hardness of, 7 hot mixes, in, I, 87-88 ionic charge in, 7 optimum content determination, I 15, I 18, 168 particle size, 7, 14 personal judgment in selection of, 7 I pump discharge rate, and, 74 purity test, 26, 31 quantity determination in surface treatments

55, 56, 57, 203 residual, plotted percent, 169 residue characteristics, 7 I selection of, 71, III types of, I, 171 varieties and grades of, I volume checking, 66

Asphalt Cold-Mix Recycling (MS-21), 106 Asphalt in Pavement Maintenance (MS-16), 97 Asphalt Institute mix-design methods, 109, 147-149 Asphalt Institute publications

See Bibliography

B Base, strong, surface treatment for, 42 Batch plant, defined, 172 Bibliography, 212-218 Bitumeter, 59 Blade mixing, 77, 78, 79, 103, 105

rolling action, and, 78 Bleeding, 44

causes of, 44 surface treatments, and, 41, 55

Bonding, aggregate-emulsion, 15 Breaking and curing of emulsion, 15-16

indications of, 79 premature, 58

Brittle pavements recycling, 102 Broom, power, 64

use before crack filling, 94 Bulk specific gravity determination, 164 Bunsen burner, 25

c Calcium carbonate dust, 31 Calcium chloride solution, 181

in RS testing, 29 California Division of Highways' tests, I I I California kneading compactor, 126, 127 Cape seal, 48, 56

asphalt for, 59 curing time, 56 emulsion for, 57 uses of. 40

Cationic emulsified asphalts listed, S, 6 Cement, asphalt, defined, 171 Cement mixing test, 8-10, 182 Central mix plant, 105 Centrifuge, hand operated, 116 Chemical coagulation, 16 Chemical emulsifiers, 11-12 Chemical principles and emulsions, 5 Chemistry, emulsion, 5-16 Chevron, U.S.A., Inc., 26,40 Chip seal, 56, 86

uses of, 40 Choke aggregate use, 85 C.K.E. oil ratio, 129 C.K.E. test, 82, III, 112, 113, 115, 156

equipment for, 115, 123 fine material surface constant, 119 procedure, 117

Classification test, 26 Clays, II Climatic conditions and emulsions, 7, 37 CMS-2s,6 CMS emulsions, 16 Coagulation of asphalt test, 30 Coalescence, premature, 87 Coarse aggregates in lIIixe~, 70 Coating test, 8, 10, 31, 32, 33, 156, 183-184 Coating

criteria, 149, 168 field, 188 note on, 158, 161

Cohesiometer calibration of, 141 illustrated, 144 test,68,114. 141. 142. 143.145

Cohesion testing. 135 Cold mixes, 79-87

See also Marshall method; McConnaughay method advantages of, 79-80 laydown of, 84-85 plant for, described, 80 production of, 80 recycling with, 10 I, 103, 104 seals with, 86-87

Colloid mill, 12 Compaction, 78-79

care to be taken in, 79 cold mixes, of, 84, 85 fluids content, and, 114, 126, 128 hot mixes, of, 88 optimum water content at, 158 roller mark elimination, 79 specimens. of, 161 laboratory, mechanical, 126

Composition of emulsified asphalt. test for. 176-177 Compression testing machine. 126 Conservation and emulsions, 2 Consistency test, 180 Constancy test, 26 Constant-head flow tank, illustrated, 195

Construction characteristics test, 26 Construction equipment, I Construction practices in surface treatments, 66 Construction system and emulsion type, 5 Containers, sampling, 22 Contamination

asphalt emulsions, of, 20-22 causes of, 20-22 sampling spigot, and, 22 surface, on, 21 unloading line, from, 22

Continuous mix plant, 87 Conversion charts, customary to metric, 207, 208 Coral as aggregate, 115 Corrosion in equipment, 12 Cost savings and emulsions, 2 Cover aggregate

loss of, 43, 44, 45 quantity calibration, 61 spreading, 65

Cracks causes of, 94 cleaning of, 94, 95 filler for, 39, 92, 174 reflective, 86 types of, 93

Crushed stone, 115 Crushing old pavement, 103 CSS emulsions, 16 Curb depth and recycling, 49, 102 Cured mix stability determination, 151 Curing and breaking of emulsions, 15-16

223

cationic emulsions fastest, 15 mix, Asphalt Institute design, in, 149 rate of, 71 specimen mixes, of, 128 time of, laboratory, 114

Cutback asphalts, 2, 25, 99. 171 emulsions used instead of, 37

o Defect, pavement, 94 Dehydration of mix, 84 Demulsibility test, 8-10, 29, 181 Dense-graded mixes, 82, 84

aggregates for, 151 design methods, 82, 84 durability of, 84 emulsion mixes as, 68 materials for, 82 mixing time in, 86 precautions in use of, 86 procedure modifications for, 84 trial batches of, 82

Density analysis, 166 dry, 88, 165, 167 field, 68, 88 hot mixes, of, 88 voids analysis, and, 163

Desiccator, 135 Design

criteria for emulsion mixes, 45, 147-149 emulsions and, 2

Diesel oil contamination, 20 Dispersion, asphalt, factors in, 124 Distillation test apparatus, 192 Distributor, asphalt, 58, 77, 172

forward speed of, 72, 73, 74 Dolomite aggregate, 15 Do's and don'ts in emulsion storage, 18-19 Double seal, uses of, 40 Double surface treatment, quantities for, 56 Drainage, 81

open-graded mixes, and, 81 recycling, and, 103

Drierite, 129 Drum-mix plant, 87 Dry aggregates mass, table, 199 Dry bulk density, 167 Ductility test, 25, 31, 32, 187 Durability

open-graded mixes, of, 80 test for, 26

Dust binder, 39 Dust laying, 174 Dust palliative, 95 Dust, stockpile, 80

E Electrical charges and emulsion types, 5 Emissions, hydrocarbons, 2 Emulsifying agents, I, 7, 11-12

process, in the, 12-14 setting rate, and the, 16

Emulsions adhesive properties of, 38 aggregate mixes, 67, 88 aggregate types, and, 5 application rate checking, 66, 73 applications, typical, 8-10 asphalt heated in making, 12 ASTM tests for, 175-195 behavior predictability, II breakdown in storage, 17 breaking and curing, 15-16 Cape seal, for, 57 categories of, 5 cationic, 12 cement mixing test, and the, 30 chemical modifiers in, 7 chemical principles, and, 5-16 climatic conditions, and, 7 coalescence of, 6 coating ability test, 31 cold plant mixes, 79-87 composition of, 5 crack filling, for, 92, 94, 95 curing of, 5 design plots for mixes, 169

224

defined, 171 dense-graded mixes, in, 82 design criteria for mixes, 145 diluted, on dusty roads, 96 dilution of, 19 dirty aggregate, and, 16 distributor spraying temperatures, 46 dust palliative, as, 95-96 economic benefit£ of, I electrical charges and types o~ 5) emulsifying agent~ in, 11-12 en~i.'.!g.p!~.c.tice~.!n use of, 67 equIpment used in making, 7 .... fog seal, and, 90, 91 forced air not to be used to agitate, 17 general uses of, tabulated, 39 grades of, 81 harder asphalt in, 6 heat, and, 2 heating in storage, 17 high-float, 6 highway maintenance, and, 2 hot mixes, and, 8:-88 increased use of, 2 ingredients of, 5 ingredients' order of addition, 7 laboratory testing recommended, 37 list of types of, 6, 46 maintenance mixes, in, 2, 97-99 major uses of, 67, 68 manufacturers' formulations, II manufacturing conditions for, 7 manufacturing plant for, 13 Marshall method, in, 155 mass test, 33 materials incompatibility and, 19 medium setting type, 158 miscibility with water test, 30 misconception regarding, 67 mix-design method, 106 mixing ability of, 32 mixing types to be avoided, 19 mixture data sheet, 164 mulch treatment, in, 91, 92 open-graded mixes, 80-82 optimum content determination, 114, 144 overmixing, 18 over-pumping, 18 penetration range of asphalt in, 7 pollution, and, 2 precautions in using, 17 prime coat, for, 94, 95 production of, 12-14 proportioning ingredients, 13 QS grades of, 40 recirculation of, 19 recycling, in, 2, 10 1-106 residue content of, 151 residue examination, 31 retained asphalt test, 30

safety precautions in handling, 23 sampling, 22-23 sand mixes, 84 sand-mixing grade, 6 sand seal, in, 49 selection of amount of, 114, 147 selection of mix type, 79 selection of type of emulsion, 37-40 setting rate factors, 6, 16 sieve test, 30 site storage of, 65 sloshing in transport of, 19 slow-setting, 158 soil stabilization with, 71 solvent content of, 6 solvent-free, 16 specifications for, 6 storage of, 12, 30, 31 studyof,5 substitute for cutback asphalts, 2 success in use of, 38-39 summary of tests on, 26 surface treatments, in, 42 tack coats, 89, 90 tanks' conditions, and, 20 temperatures of, 12, 13 testing data, 175 tests on, 8-10 trial content of, 147 types of, 115 uses of, I, 2, 37-38 variables affecting, 7 viscosity test on, 8-10 volume increase in, I water in, II water resistance of, 31 "why and how" of, 3 wide range of uses of, 79 windrowed aggregate and, 72, 73 working time, and, 16 zeta potential test, 33

Engineering practices essential in emulsion use, 67

Entrapment of moisture, 86 Environmental considerations and

solvents' use, 2, 99 Equipment

C.K.E. test, for, 115 emulsifying, 12, 13 hot-mix emulsion, for, f:8 inspection of, 42 laboratory, 125, 126, 12i, 128, 159 mixing, 125 surface treatment, 58

Evaluation of aggregates, 71 Evaporation, emulsion and, I

F Face shields, safety, 23 Fat spots, 89

225

Fatty acids, II FHW A conservation notices, 2 Field coating test, 32-33 Filler, mineral, 51 Filter papers, 116 Fine aggregates in mixes, 70 Flexibility of open-graded mixes, 80 Float test, 8, 10,31,32, 187 Flow tank, constant-head, 194 Flow test, modified, 165, 166 Fluids

compaction, optimum for, 126, 128 content of mix, III, 114 optimum in Hveem method, 124

Fly ash in slurry seal, 51 Fog seals, 39, 86, 90, 173 Freezing destroys emulsion in storage, 17 Freezing test, 184 Fuel and emulsion use, 2 Full-depth asphalt patch, 93

G Gloves, safety, 23 Granite, specific gravity range of, 199, 200 Grasslands, cold-mix use in, 80 Gravel, 115

specific gravity range of, 31, 73, 199,200

H Hammer, compaction, 159 Hammermill, 103, 104 Hand spray, 58 Handling emulsions, 17,23 Hauling vehicles' contamination, 20 Heater-overlay recycling, 106 HFMS emulsions, ASTM standards for, 38 High-float emulsions, 6 History of emulsions' use, I Hopper type tailgate spreader, 60 Hot Mixes, emulsion, 1,87-88

breaking, and, 88 compaction of, 88 density of, 88 emulsion used in, 87 mixing-time critical, 87 recycling with, 101, 102

Hveem, F.N., 115 Hveem cohesiometer illustrated, 144 Hveem mix design, 82

apparatus for C.K.E. test in, 123 coarse material in, 120 combined aggregate in, 121 emulsion content in trial mixes, 124 fine material in, 119 modified, 111-145 oil ratio chart in, 122 outline of method, III stability value, 84, 151 test method in, 109 testing schedule in, 112

Hveem stabilometer, 67, 136, 138, 153 Hydrated lime, 51 Hydrocarbon solvent, I Hydroplaning, 81

Illinois mix-design method, 109 Imported aggregate, blending of, 72 Improvement, highway, 3 Ingredients in emulsions, 7 Inspection of equipment, 42 International Slurry Seal Association, 52, 53

K Kerosene, I

emulsion storage, in, 18

L Laboratory equipment in Marshall

mix-design method, 156 Laboratory mixes, 70, 125 Laboratory testing recommended, 37 Lansing Instrumental Differential Translator, 129 Laws, conservation, 2 Limestone aggregate, 15

dust, 51 specific gravity range, 199,200

Load-sensing device in hot mixing, 87 Longitudinal cracks, 93 Los Angeles Abrasion Test, 47, 51, 71, 81, 83,147

M Magnesium sulfate, 71 Maintenance

costs of, 2 defined, 173 emulsions in, 2 importance of, 97 mix for, 39 pavement, 97

Maltenes, II Manometer, vacuum, 135 Marshall mix-design method, 84, 155-169

outline of, 155 procedure in, 157

Marshall flow meter, 163 Marshall forming molds, 161 Marshall hammer, 153 Marshall stability test, 67, 84, 163, 165 Marshall test method, 109 Marshall testing frame, 163 Marshall testing machine, 163 Mass test, 33 Materials

coverage requirement tables, 201-204 evaluation, 67 surface treatments, in, 45

McConnaughay mix-design method, 84, 109, 151-153 asphalt residue in, 151, 152 criteria in, 153 emulsion determination in, 153 laboratory procedure in, 152

Mechanical aggregate spreader, 60, 61, 62 Mechanical forces, setting rate and, 16 Medium-setting emulsions, 6

226

Micro-distillation test, 25 Milled-in-place recycling, 101 Mineral filler in slurry sealing, 5 I Miscellaneous applications of emulsions, 89-96 Miscibility with water test, 184 Mix

mold, in, 127 soaked and dry, 168

Mix-Design calculations, 165, 168 Mix-Design Methods/or Asphalt Concrete

(MS-2), III Mixed-in-place, 39, 71

applications rates for, 73 recycling, in, 10 I

Mixers, rotary, 74, 76, 77, 105 Mixers, traveling, 72, 75 Mixes, cold, 70 ,

defined, 1E:ll3-­dense-graded, 82, 84 design criteria for, 145 maintenance, 97-99 open-graded, 80 patching, 97 sand-emulsion, 85 sand, value of, 84 trial, 70

Mixing ability of emulsion, 13, 32 blade, 77, 78 coating, and, 78 reaction, cement-emulsion, 30 test, Asphalt Institute design, in, 148

Modifiers, chemical, 7 Moisture

aggregate, and, 70, 125 exposure to, 113, 135 seal against, 81

Molds, Marshall forming, 161 Mr calculation, 133, 149 M r measurements, 130, 131 Mr pressure regulator, 133 Mr recording meter, 133 Mr test, 67, 84, 129, 130, 131, 132

measurements procedure in, 130 yoke in, 131, 132

MS emulsions' uses, 38, 39 Mulch treatment, 39, 91, 93, 174

asphalt's advantages for, 91 patterns of, 91

Mulcher, twin-jet, 92

N Naphtha, I NCHRP Report 259. 109, 155 Nonionic emulsions, 5

o Oil distillate test, 8, 10, 27, 28, 177-178 Oil ratio chart, H veem mix design, 122 Oil ratio, C.K.E., 129 Open-graded mixes, 80

advantages of, 80 aggregates for, 151 design criteria, 147-149 design of, 82

emulsion mix as, 68 field performance of, 80 materials for, 81 mixing time for, 82 research on, 81 toughness of, 86

Ore tailings as aggregate, 115 Oven for specimens, 159 Overlays, I, 79 Ox blood, II

P Paint striping, 49 Pan, aeration, 161 Particle charge test, 27, 28, 179 Particle charge tester illustrated, 193 Particle distribution in asphalt, 14 Particle-size of asphalt, 14 Patching mixes, I, 97 Pavementrecyding, 101-106

See also Recycling Pavement texture and surface treatment type, 55 Paving train, 106 Penetration test, 25, 31 Pedestal, compaction, 159 Photomicrograph of asphalt particles, 14 Plant-mix. emulsion used in, 39 Plants

cold-mix, 80 defined. 13. 172 travel, 75, 76, 77

Plow attachments on grader. 77 Pneumatic-tired rollers for breakdown. 85 Pollution

atmospheric, 2 eliminated by emulsion mixes, 80

Portland cement mixing test, 30 Portland cement

sand mixes, in, 84, 85 slurry seal, in, 51

Pothole patching, 65 Power broom

clean air standards, and, 64 use of, 64, 65

Precautions in emulsion storage, 18-19 Prime coat, 94-95

defined, 171, 173 uses of, 94

Primer, asphalt, 171 Problem solving, iii Procedure in emulsifying, I Pugmill plants, 172 Pulvimixer,77 Pump

preheating of, 18 speed and pressure in surface treatments, 43 start-up, and, 18

Pugmill mixer, 87 Pulverizing old pavement, 103 Pycnometer used in specific gravity test, 33

Q QS emulsion

grades of, 40 slurry sealing, in, 51

R Rain

dense-graded mixes, and, 86 obviating construction, 66 washoff simulating, 149

Rapid-setting emulsions, 6 asphalt classification test, and, 187

Raveling, 42, 86 slurry seal correcting, 51

Recycling, 2 blade mixing in, 103, 105 candidate pavements for, 102 central plant in, 105 cold-mix for, 101, 103 curb depth and, 102, 103 defined, 10 I drainage, and, 103 emulsion added in, 101-106 experience in, 106 heater-overlay method of, 106 hot-mix type. 101 mixing in, 105 new mix added, 101 rotary mixers in. 105 salvaged materials tests in, 106 softening agent used in, 101. 103 surface type, 101, 106 travel plant in. 105 water added in, 105 windrows in, 103

Reflection cracking, 93 Repairs, pavement, importance of, 97 Residual asphalt content, 155, 169 Residual asphalt in Marshall mix specimen, 160, 162 Residue tests, 8-10, 177-178, 186-187 Residue by distillation test, 25 Residue by evaporation test, 25, 27, 178-179 Residue examination, 31 Retsina Company, California, 129 Resilient modulus

See also Mr

227

Resilient modulus apparatus, 129, 131 Resistance R-Value Test, 136, 137, 138 Ring burners in distillation test, 25, 192 Road oiling, 96, 174 . Road widths and area requirements tables, 206 Roadway travel, U.S., 3 Rock crusher, 106 Rollers, 63

defined, 172 pneumatic-tired, 63 surface treatments, in, 42

Rolling See also Compaction aggregate, 65 slurry sealing, in, 53

Rotary mixers, 105 RS emulsion tests, 29, 32 RS emulsions' uses, 37, 38, 47 Rumble strips, 42 Rumble criteria, 149 Runoff criteria, 149 R-Value, 67, 68, 84, 136, 139, 140, 143, 145

chart for correcting, 140

S SAE No. 10 oil, 117 Safety in cold mixes, 80 Safety precautions in handling emulsions, 23 Salts, inorganic, in asphalt residue, 27 Samples

contaminated,2l-22 freezing, protection from, 23 preservation of, 23 unit weight of aggregate test, for, 209

Sampling emulsions, 17-23 precautions in, 23 spigot and contamination, 22

Sand, 115 specific gravity range, 199,200

Sand-emulsion mixes, 85 Sand equivalent test value, 51, 71 Sand mixes, 84 Sand seals, 39, 49, 173

uses of, 40 Sandy soil defined, 171 Saybolt Furol viscometer, 180 Saybolt Furol viscosity test, 27, 29 Scalping screen on spreader, 61 Scarification and in-place material, 77 Screed problems with, 85 Seal coats, 86

described, 171, 173 types of, 48

Seeding mulch, 91, 92 Selection of emulsion, 37 Sequence of surface treatment operation, 64-65 Serviceability of roadway system, 3 Setting times of emulsions, 6 Settlement test, 182 Short cuts not recommended, 66 Shoulder definition by surface treatment, 42 Shrinkage cracks, 93 Sieve analysis of aggregates, 71 Sieve test, 183 Skid resistance, 49

surface treatments, and, 41 Skin formation in emulsion storage, 18 Slag as aggregate, 115 Slippage cracks, 93 Slow-setting emulsions, 6 Slurry seal, I, 48, 49, 173

228

advantages listed, 49 aggregates for, 57 application of, 51 drag used in, 53 flow diagram of mixer, 50 joints in, 52, 53 low cost of, 49 mix grading, 52 machine for, 50 multi-course use of, 51 pavement geometrics, and, 53 pneumatic-tired rolling and, 53 publications on, 53 ridging and, 52 rolling and, 53 spreader boxes in use of, 51 streaking in, 52 tack coat. and. 52 temperature and, 53 texture of, 53 uses of, 40 wheel damage to, 53

Smoking and emulsion handling, 23 Soaked ability test, 163 Soaps, II Sodium hydroxide, 13 Softening agent, 101 Solubility in trichloroethylene test, 187 Solubility test, 25, 32 Solvents, I

emulsions, in, 2 environmental considerations and, 99 evaporation of, 16 Marshall mix design, in, 158

South African procedure, 56 Specific gravity, bulk determination of, 164 Specific gravity test, 33 Specifications for emulsion, 6

review of, 25 Specimens

equipment for laboratory, and, 159 laboratory fabrication of, 141 laboratory size of, 162 Marshall method, in, 158 preparation of laboratory, 159, 162 use of dummy, 137

Split tension test, 67 Spottiness in mix, 126 Spray applications, 5

historic, I Spray-bars, 43

described, 58 height setting of, 59

Spray-nozzle and surface treatments, 43, 58, 59 Spraying temperatures of emulsions, table of, 46 Spread, uniformity of, 58, 59 Spreaders

aggregate, 60, 61, 62 calibration of, 61 self-propelled, 84

types of, 60, 62 Spreading, 78-79 Squeegee use in slurry sealing, 51 SS emulsified asphalts, 38, 39

cement-mixing test for, 30 Stability

correlation ratios, 167 cured mix, of, 151 emulsion mixes, of, 111 initial, cured, 152 mix, initial of, 84 percent loss of, 167, 168 soaked, test, 166, 167 testing for, 114, 135, 165, 166

Stabilization, 1,71,72 Stabilizer use, 5 Stabilometer, displacement of, 137 StabiJometer values,

chart for correcting, 142 Stage construction, 71 Still, aluminum alloy, 191 Stirring device in storage tanks, 12 Stockpiling maintenance mixes, 98 Storage facilities described, 18 Storage stability test, 8, 10, 30, 31, 185 Storing emulsions, 12, 17-23,

rules in, 17 Streaking illustrated, 43 Str~ngth, retained, 84 Strength tests, 67, 114, 129 Stripping, 124 Structure adjustments eliminated, 49 Surface capacity test, 82 Surface, tacky, 86 Surface treatments, I, 39, 40, 41

abrasion-resistant, 41 advantages of, 41, 46, 106 aggregate quantity determination in, 54 aggregate used in, 41, 42 air intrusion, for, 49 application rate checked in, 59 bleeding pavement, in, 41, 44 Cape seal, 48 choosing emulsion for, 42 clean surface essential, 52 cover aggregate loss in, 43, 44, 45 defined, 171, 172 design of, 54 distributor used in, 58 double type, 48, 56 dusty aggregates in, 47 emulsion used in, 45-46, 68 equipment for, 58 interim measure, as an, 48 materials in, 45 multiple type, 56 not a cure-all, 41 pavement evaluation and, 41 performance of, 46 power broom used in, 64

229

preparation for, 65 problems in, 66 procedure in, 64-65 pump speed, and, 43 quality control in, 45 raveling, and, 42, 48 road condition, and, 55 rollers in, 42, 63 rumble strips, and, 42 safeguards in using, 42 salvage of pavement by, 42 sand seal type, 49 shoulder definition, and, 42 single and double types, 47, 48 single type, 48, 54 skid resistance, for, 49 slurry seal, 48, 50, 51

See also Slurry seal specifications and, 42 spray-bar importance in, 43 streaking in, 43 strong base essential to, 42 temporary, 42 thickness of, 41 triple, 57 types of, 48 uses of, listed, 41-42 voids in, 54 waterproofing, 48 weather, and, 42 weathered surface restoring, 41

Surfactant, emulsion, 14 S-Value testing, 67, 114, 138, 140, 141, 145

T Tables, miscellaneous, 197-208 Tack coat, 30, 39, 52, 89

defined, 173 fat spots in, 89 patching, and, 89 procedures in, 89 rolling of, 89 vehicles on, 89

Tailgate vane spreader, 60 Tank capacity and linear coverage, 201, 202 Tank, distributor, 58 Tanks, 18

conditions of, 20 emulsions, and, 20

Temperature conversion chart, 207 emulsion storage, 17, 18 hot-mix, for, 87 laboratory specimens, and, 160 maintenance mixes, and, 97 maximum, emulsion, 27 premature breaking, and, 58 recycling, in, 102 road surface, 66 slurry sealing, for, 53

storage limits, 17, 18 Temperature-volume corrections table, 198 Tests

aggregates, on, 70 data interpretation, 166-167 emulsions, on 25-33, 175-195 salvaged materials, on, 106 summary of, 26

Tie-down emulsion mulch, 91, 92 Traffic control, 37,42 Traffic densification of emulsion, 26 Traffic increases, I Transducers, pressure-type, 130, 131 Transverse cracks, 93 Traprock, specific gravity range of, 199,200 Travel plants, 75, 76, 77, 105 Trial mixes, 70

Hveem, asphalt content in, 124 Trichloroethylene solubility test, 8-10 Triple seal, uses of, 40 Trucks, 64

with baffle plates, 19

u Unpaved roads, dust palliative used on, 95 U.S. Forest Service projects, 86 U.S. roadway system, asphalt paving on, 2 User-producer planning, 6 Uses of emulsions, 37-38

V Vacuum pump, 163 Vacuum saturation test, 135 Vibratory rolling, 79 Viscometer, 180 Viscosity test, 8-10, 27, 180 VMA,165 Voids analysis, 166 Voids in surface treatments, 54 Volcanic cinder as aggregate, 115

W Washoff test, 149

Water emulsion, in, II impurities in, II intrusion of, 87 pre-mixing, 161 unit weight of, 211

Water bath, 163 Water content test, 176 Water determination apparatus, 190 Water resistance test, 8-10, 31, 32, 184 Waterproofing, emulsion and, I Waterproofing pavelT'ent by surface treatment, 41 Wearing surface, temporary, 68 Weather

construction and, 156 dense-graded mixes, and, 86 surface treatments, and, 42, 66

Weight per gallon test, 189 Whipping-off of aggregate, 44 Whirl spreaders, 172 Windrows, 72

230

blade mixing and, 77, 78 flattened, 78 grading variation in, 78 mixed type, 105 moving of, 78 recycled material in, 103 sizer for, 78 travel plants, and, 75

Windshield damage, 48 Wire-screen funnel illustrated, 148 Workability of mix, 84, 126

z Zeta potential test, 33

SOME IMPORTANT ASPHALT INSTITUTE

TECHNICAL PUBLICATIONS·

Thickness Design-Asphalt Pavements for Highways and Streets (MS-1) Mix Design Methods for Asphalt Concrete and Other Hot-Mix Types (MS-2) Asphalt Plant Manual (MS-3) Introduction to Asphalt (MS-5) Asphalt Pocketbook of Useful Information (MS-6) "{ Asphalt Paving Manual (MS-8) ~ Soils Manual (MS-10) Full-Depth Asphalt Pavements for Air Carrier Airports (MS-11) Asphalt in Hydraulics (MS-12) Asphalt Cold-Mix Manual (MS-14) Drainage of Asphalt Pavement Structures (MS-15) Asphalt in Pavement Maintenance (MS-16) Asphalt Overlays for Highway and Street Rehabilitation (MS-17) Sampling Asphalt Products for Specifications Compliance (MS-18) Basic Asphalt Emulsion Manual (MS-19) Asphalt Hot-Mix Recycling (MS-20) Asphalt Cold-Mix Recycling (MS-21) Principles of Construction of Hot-Mix Asphalt Pavements (MS-22) Thickness DeSign-Asphalt Pavements for Heavy Wheel Loads (MS-23)

Model Construction Specifications for Asphalt Concrete (SS-1) Specifications for Paving and Industrial Asphalts (SS-2) Specifications and Construction Methods for Asphalt Curbs and Gutters

(SS-3)

Asphalt Technology and Construction Practices-Instructor's Guide (ES-1 )

• For a completee catalog of all asphalt publications contact:

ii...SPHALT INSTITUTE

Asphalt Institute Building College Park, MD 20740 USA

Telephone: 301·ASPHALT 301·277 ·4258

231

THE ASPHALT INSTITUTE

ASPHALT INSTITUTE

EXECUTIVE OFFICES AND RESEARCH CENTER Asphalt Institute Building

College Park, Maryland 20740 USA

Telephone 301-ASPHALT 301-277-4258

MEMBERS OF THE ASPHALT INSTITUTE (As of February 5, 1987)

The Asphalt Institute is an international, nonprofit association sponsored by members of the petroleum asphalt Industry to serve both users and producers of asphalt materials through programs of engineering service, research and education. Membership is limited to refiners of asphalt from crude petroleum, and to processors manufacturing finished paving asphalts and/or non-paving asphalts but not starting from crude petroleum. Institute Members provide quality

AMOCO OIL COMPANY, Oak Brook, illinois ASFALTOS ESPANOLES, S.A., Madrid, Spain ASHLAND PETROLEUM CO" Ashland, Kentucky ASPHALT MATERIALS, INC., Indianapolis ATLANTIC REFINING I MARKETING CORP., Southeastern, Pennsylvania "BELCHER OIL COMPANY, Miami, Florida BRITISH PETROLEUM COMPANY, LIMITED, THE, London, England CENEX, Laurel, Montana CHF.VRON U,S.A. INC., San Francisco COMPANIA ESPANOLA DE PETROLEOS, B.A., Madrid, Spain CONOCO INC., Houston EDGINGTON OIL COMPANY,INC., Long Beach, California EGYPTIAN GENERAL PETROLEUM CORP., THE, Cairo, Egypt ELF AQUITAINE, INC., Paris, France ESSO PETROLEUM CANADA, Toronto, Ontario, Canada

A Division of Imperial Oil Limited EXXON COMPANY, U.S.A., Houston HUNTWAY REFINING COMPANY, Wilmington, California HUSKY OIL MARKETING CO., Calgary, Alberta, Canada INDUSTRIA ITALIAN A PETROLl, SpA, Genoa, Italy JORDAN PETROLEUM REFINERY COMPANY LTD., Amman, Jordan KERR-McGEE REFINING CORPORATION, Oklahoma City

Triangle Refining Division KOCH ASPHALT COMPANY, Wichita, Kansas KUKDONG OIL COMPANY, LTD .. Seoul, Korea

products and advocate quality construction and timely maintenance. A total of 44 Members have headquarters in offices in:

United States. 26 Europe 7 Canada ..... 4 Middle East .. 3 South America 1 Asia ......................... 3

MAPCO PETROLEUM, INC" Fairbanks, Alaska MARATHON PETROLEUM COMPANY, Findlay, Ohio MOBIL OIL CORPORATION-MIR Dlv.-Int'l., New York NEWHALL REFINING CO., INC" Newhall, California AB NYNAS PETROLEUM, Stockholm, Sweden OXNARD REFINERY, Oxnard, California PAZ OIL COMPANY, Haifa, Israel PETRO-CANADA PRODUCTS, Toronto, Ontario, Canada PETROPHIL CORPORATION, Makati (Metro Manila), Philippines PHILLIPS 88 COMPANY, Bartlesville, Oklahoma REFINERIA DE PETROLEO CONCON, S.A., Concon, Chile "RICHARDS ASPHALT COMPANY, Savage, Minnesota SHELL INTERNATIONAL PETROLEUM COMPANY LIMITED, London, England SHELL OIL COMPANY, Houston SINGAPORE PETROLEUM CO, PTE. LIMITED, Singapore SOUTHLAND OIL COMPANY, Jackson, Mississippi SUN REFINING AND MARKETING COMPANY, Philadelphia TRUMBULL ASPHALT Dlvilion 01 Owens-Cornlng Flbervlal Corporation,

Summit, Illinois ULTRAMAR CANADA, INC., Montreal, Quebec, Canada U,S. OIL. REFINING COMPANY, Tacoma, Washington "ZIEGLER CHEMICAL. MINERAL CORP., Jericho. New York

*Assocl8te member

ASPHALT INSTITUTE ENGINEERING OFFICES (As of February 5, 1987)

EASTERN REGION:

COLLEGE PARK, MD 20740-Alp"''' Instltule Bldg., (301) 277-4258, District of Columbia

ALBANY, NY 12205-8 Alrtlne Drive, (518) 8811-2335, New York, New Jersey LAWRENCE, MA 01841-101 Ameobury Street, Room LLI, (817) 881-0455,

Connecticut, Maine, Massachusetts, New Hampshire. Rhode Island. Vermont CHICAOO,!L 80018-2400 Eut Devon Avenue, Suite 157, Del Plalneo, (312)

297-511 .. 7, illinois, Wisconsin, Iowa DILLSBURG, PA 17019-P.O. Box 337, (717) 432-5985, Pennsylvania,

Maryland, Delaware INDIANAPOLIS, IN 48240-1010 E .. t 88th Street, (317) 848-9148, Indiana.

Michigan JACKSON, MS 39208-112 OffIce Park Plazo, 8ulte 13, (801) 881-3417,

Louisiana, Mississippi, Tennessee COLUMBUS, OH 43215-50W. Broad 8treet, Suite 1985, (814) 228-3388, Ohio.

Kentucky, West Virginia RALEIGH, NC 27805-2018 Cameron 8treet, Room 217, (919) 828-5998, North

Carolina. South Carolina, Virginia TALLAHASSEE, FL 32303-2839 North Monroe, Station 15, (904) 385-7822,

Florida, Georgia, Alabama

1st Edition DCP IOM279 DCP IOM580 DCP IY.zM285 DCP 3M885 2nd Edition L 7Y.zM 387

WESTERN REGION:

SACRAMENTO, CA 95815-1 832111bute Roed, Suite 214-218, (918) 922"507, Northern California, Hawaii. Nevada

AUSTIN, TX 78750-13894 Reaeerch Boulevard, Sullel, (512) 288-1981, Texas (except Southwelt Texas)

DENVER, CO 80222-5850 East Evans Avenue, Suite 108, (303) 753-1014, Colorado, Montana. Wyoming

MINNEAPOLIS, MN 55422-8100 Golden ""'ley Road, Suite 113, (812) 848-2311, Minnesota. North Dakota, South Dakota. Nebra.ka

NORTH LITTLE ROCK, AR 72118-P.O. Box 4007 (5318 John F. Kennedy Bhrd.), (501) 758-0484, Arksn .... Kansas, Missouri. Oklahoma

OLYMP1A, WA 98502-2828-121h Court, S.W .. Suite No.4, (208) 788-5119, Oregon, Idaho, Washington, Alaska

TEMPE, AZ 85282-201 Eut Southern Avenue, Suite 118, (802) 8211-0448, Arizona, New Mexico, Southwest Texas, U'ah

WEST LAKE VILLAGE, CA 91382-3809 Thou .. nd O.kl Boulevard, Suite 218, (805) 373-5130. Southern California. Southern Nevada

PRINTED IN U.S.A.