rational method for rcc design-ml

8/13/2019 Rational Method for RCC Design-ML

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A RATIONAL METHOD FOR RCC DESIGNLuis Eloy Feo C. [email protected]

Caracas, Venezuela/ Ciudad de Panam, Panam

ABSTRACT. After years of experience using the RCC (Roller Compacted Concrete) in dam construction, a rational or logical method formixtures design has not been developed yet. Some experts, depending on the country of origin and their particular experiences, aim to asimilar approach on concrete design while others, to a lesser extent, have been placing the focus on soils. However, none of these are based

on a rational design method where the inputs, external variables controls, a standardized process and a predictable response corresponding to

mechanistic reasoning are clearly established. This shortcoming converts the design in a trial and errorprocess, leaving the production-placement control stage subject to decisions that sometimes are not oriented to meet the desired goals. In order to design, is requiredconsensus in some input elements, which exists at least in the case of the characteristics of the mixture components. The same cannot be said

about the compaction energy, where a standardization based on experience is necessary. Once these input elements are defined, it onlyremains to control the external variables that can affect the RCC production: handling lapses, temperature and relative moisture; and the

properties that have an influence in the functionality of geomaterials, being these the void ratios in the compacted mixture. The experiencesgained so far using RCC allows this approach.

INTRODUCTION

The handling of petrous material as inputs to civil

construction has lead to the comprehension of thevariables that govern the behavior and the expected

response from the processed material, namelyconventional concrete, asphalt, cement-bentonite,

filling soils and -the case of study of this paper- theRCC. All of these materials have in common the fact

that the main input is an aggregate of mineral origin,

so the differences are related to the binding agentused. These materials are best known as

geomaterials.

For instance, the improvement of the Marshall essay

for the design of asphalt mixtures required years of

practical experiencing and laboratory tests, to reach aconsensus regarding which void properties satisfy the

functionality of the asphalts in terms of workability,durability and mechanical response.

At the beginning of this century, people tried to

migrate from Marshall essay to the Superpave

evaluation, nevertheless in both cases the three mainproperties defining the asphalt response in terms of

workability and durability are the void ratios

remaining after the compaction of the mixtures: totalvoids in mix or trapped air (Vt), filled void (%VF) and

voids of mineral aggregates (VMA).

In order to ensure these variables, and considering

that the energy of confection of the briquettes isstandardized, the amount of binding agent is

determined as a dependant variable.

In this case, the binding agent is asphaltic liquid,

which has very stable properties. This means themeasurable mechanical properties (stability and

flow) are only verified at the end of the design

process. Nevertheless in the case of RCC thprinciple is still the same, some addition

considerations must be taken into account.

After more than 30 years using the RCC for da

construction, it is understood that the capacity of tmaterial to be handled is as important as t

compression resistance, and above any consideratio

the capacity to guarantee the interlayer union durinthe placement stage. So, assuming consensus in t

components characteristics and a specific energy f

the construction of tests specimens, the function

characteristics should be governed by the amount binding and the mechanical response associated

the quality of it, defining the binding as the pas

containing all the fine particles that migrate durin

the process of compaction and fill the void spaces, described in the diagram at Figure 01.

For the first case, functional requirements, addition

research works and the successful experiences usinRCC must be noted, in order to establish the range

variation of the variables already mentioned: tot

void (Vt), filled void (%VF) and mineral aggregavoid (VMA).

In the second case, determining the quality of t

paste, it is used the known proportion between t

compressive strength and the ratio a: (c+pconsidering into the cementitious material t

properties of mineral supplements (p), sometim

required in the RCC to meet other properties such alkali-aggregate reaction, heat of hydratio

production costs, or even the need to increase th

paste volume for functional purposes.

This way, knowing the amount of paste and quality by functional and mechanical requiremen

both solutions are combined to obtain a theoretic


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design that allows starting a test program leading to

the optimal mixture, noting that this only depends onlocal variables and economic considerations.

Vt= Total voids ortrapped voids in the

mix.

VMA= Voids in the

Mineral Aggregate.

%VF= Voids Filled =

VP/VMA

VM; MM= Volume andMass of Mineral

Vp; Mp= Volume andMass of Paste

Vassd; Massd= Volume

and Mass of Aggregates,Saturated-Surface-Dry

(Including Filler)

Vc; Mc= Volume andMass of Cement.

Vw; Mw= Volume andMass of Free-Water

Va; Ma= Volume andMass of Additive

Vf; Mf= Volume and

Mass of Mineral

Supplement.

V#200; M#200= Volume

and Mass of Passing

#200

Total Mass

Total VolumeGi= Specific Mass for

each component= Mi/Vi

GSSD= Specific Mass of

Aggregates Compounds

(Saturated-Surface-Dry)

Figure 01, Phase diagram for RCC

Although this article does not expand on the subject,

for this approach it is necessary to control external

variables that affect production and the end result of

a mixture of RCC. These variables are the maximumtime that the mixture can be worked once

components are combined, the relative moisture andthe temperature at which the design mixtures aremade.

MATERIALS PROPERTIES

The minimum characteristics that the RCC

constituent materials should have, are very similar tothose known for other geomaterials. The convention

is to use the specifications (ASTM or other) that

apply to conventional concrete, with some exceptio

and in some cases with more flexibility. In thsection, we only will refer to these exceptions

other relevant issues.

Cement: Some countries have abandoned t

production of cement according to ASTM C-15which classifies the cements according to the

chemical composition. Based on environment

requirements, some companies in some countrihave adopted the manufacturing pattern based

ASTM-C1157, that take into account t

performance parameters instead of the chemic

composition of cement. In either case, the cement be used for the manufacture of RCC should be low

alkali content, less than 1%. Additionally, the heat

hydration must be low.

Aggregates Quality: Although the specifications fselection of aggregates for RCC production tend

be more flexible than those applied for tconventional concrete, in general terms the durabilishould be guaranteed against chemical an

atmospheric agents, as well as minimum mechanic

resistance in order to avoid excess breakdown durinhandling, mixing and placement.

The most important exception in the selection

aggregates relates to the potential reactivity tes

between the cement and alkalis. The variostandardized tests to evaluate this parameter ha

two extremes: either they are very slow to gi

reliable results or are severe, with tendencies disqualify many potential sources of aggregates.

this regard it must be remembered that the doses

cement in RCC are much lower than those used

conventional concrete, so a critical judgment required when deciding the applicability of the

standards. The recommendation is to ma

adjustments to these tests for RCC designconsidering in each case the actual workin

conditions of the mixture.

Fine particles: There are RCC design specificatiowith plastic fines up to 6%, unacceptable values fconventional concrete. At this point the design

must make a judicious balance of additional cos

associated to the increase in the cement amount this usually related to the use of plastic fines in th

mix.

The same happens to non plastic fines, where the

are no limits in the amount of fines included in RC


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mixtures, the opposite case to the conventional

concrete mixture.

GRADING CURVE

The selection of the gradation to be used on the

design process must meet the following criteria: 1)

minimize the stockpiles of component materials; 2)the combined mixture of RCC must guarantee the

consistency in every stage of production, storage and

handling and also should be considered the way of

supply: by truck or by conveyor belt; 3) The mixturemust meet the higher density and the lower void

amount; 4) It is recommended to use the biggest size

available, taking into account that as the higher themaximum size (NMSA), the bigger the tendency to

segregate.

The design manual USACE (Ref. 11) recommends

the use of ideal combinations for the stockpiles ofcoarse aggregates, fine aggregates and combined

aggregates.

On the other hand, Brazilians used as typical curve

for combined aggregates, the following expression:

%Ppasante= (d/NMSA)1/3

x 1005%

with NMSA, maximum particle sizebetween 50 - 60 mm

d, sieve size.

COMPACTION ENERGY

There are several ways of making RCC testspecimens for laboratory testing. Of these, only two

are standardized: using the vibrating hammer (ASTM

C1435) and the vibrating table (ASTM C1176). Forboth tests there is not an energy pattern that unifies

them.

This energy cannot be a random selection, as it

should be a mirror of the energy used in-field, andthe nature of this depends only on the equipment

used for compaction. It is also widely known thatexcess energy in compaction of geomaterials iscounterproductive, as it can lead to material fatigue.

For instance, the energy associated to Modified

Proctor test (ASTM D1557), is known as a

successful energy to achieve adequate levels of soilcompaction and it is characterized by a value of

2.700 kN-m/m3, or in terms of mass 275.510 5.900

kg-m/m3. In the case of preparation of Marshall testspecimens (ASTM D2926 and ASTM D5581), the

energy varies from a minimum of 403.200 kg-m/m

for low traffic roads up to 605.000 kg-m/m3 frailway medium-high traffic.

For now, and in the absence of data that allows us

discriminate other energy levels for different types

RCC mixtures, we recommend setting the energy fthe construction of test specimens to a lev

equivalent to the Modified Proctor, i.e. 275.510

5.900 kg-m/m3.

The energy setting for each type of instrument usto make specimens requires knowledge of the ma

frequency and amplitude of impacts. For examp

the Tamper-06 Jet Toku (www.tamcotools.comwith a mass of 18 kg, has an impact rate of 60

strokes / min and an amplitude of impact equal to

"(140 mm). It would require 20 sec compaction b

each of the 3 layers forming a cylinder with diameter of 15 cm and height of 30 cm:

AMOUNT OF PASTE

The void properties that govern the behavior of RC

are shown below. The values used to set the rang

of variation were based on a review of variospecifications for projects, the exchange

information with experts and laboratory testing in th

scope of this work. It is necessary to conduct an hoc research to review and adapt these values.

Total voids (trapped air) in mix (Vt):

A high content of voids decreases density, increas

permeability and as a consequence, decreases t

durability of the compacted RCC. In the case of RCthere is not a functional limitation for the minimu

level of voids, so the limit is constituted by th

physical barrier representing the saturation curvwhich depends only on the particle shape and si

distribution. The maximum allowable air voids ratis set to 4%, a value that can be reached wi

conventional energy levels used in - field and abovwhich, the RCC guarantee their mechanic

properties, while the minimum level is set at 1

since it is a value achievable in laboratory with thselected energy level, corresponding

approximately 275.510 kg-m/m3.


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Voids of mineral aggregate ratio (VMA):

The compacted mixture needs to have enough

intergranular space to contain the paste, guaranteeingthat all particles are coated. The volume of paste

(Mp, Vp in Figure 01) must be sufficient to ensure

not only the coating but also the effective bondingbetween layers. However, the amount of paste cannot

be exceeded because it reduces the workability of the

mixture, increasing the amount of adhered materialinside trucks and compaction equipment, causing

operational problems.

In the first years of experience in design of mixtures

with the RCC, this variable (VMA) was between 18%and 20%, although designs are reported with ranges

as high as 28% (Ref. 10). The trend in the design of

RCC mixtures in recent years has been restricting

this variable to a range between 22 and 24%.

Filled voids ratio (%VF):

This parameter, at least for high traffic asphalt is

used to limit the maximum VMA value. Because the

RCC does not have this restriction, with experimentaldata to constrain this variable and for the purposes of

this study, limits are set outside the range of

influence, which is determined by the above

parameters (see Equation 10).

The determination of the optimal volume of paste

(Mp and Vp) which guarantees the void properties

(Vt, %VF and VMA), has a mathematical solution for

the asphalt case (Ref. 08). Based on this, somevariations can be done to model the RCC case.

Definitions (see Figure 01):

(1)

(2)

(3)

(4)

(5)

(6)

(7)

(

(

(1

After combining and grouping these equations, thr

functions result, based on unit weight Uw=f(Pp):

(

(

(

If each of this functions is represented in the pla

Uw Pp for limit values of void ratios (%Vt, %

and %VMA), it can be obtained, assuming hypothetical RCC with Gp=1,86 kg/m

3and GM= 2,

kg/m3, the Figure 02.

The optimal amount of paste and the density

RCC that satisfy the void ratios is the centroid of thresulting polygon. To assure this, there are up to

nine possible combinations based on the 10 verticderived from Figure 03, with the conditions shown Table 01.

Then, the determination of each vertex is made wi

the equations 11 to 16, evaluated in the limit valu

of the void ratios (%Vt, %VFand %VMA).

Figure 02, Polygon of voids


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Figure 03, vertices of polyvoid (see Ref. 08)

# Querya I II III IV V VI VII VIII IX

1 Uw5>Uw1 x x x

2 Uw2>Uw6 x x x x x x

3 Uw7>Uw3 x x x X x x

4 Uw8>Uw4 x x x X x x

Vertices thatmake the

polygon

1,2,9,7,4

5,2,9,7,4,1

0

5,6,7,4,10

5,2,3,8

5,6,7,8

5,2,9,7,8

5,2,3,4,10

1,6,7,4

1,2,3,4

Table 01 (see Ref. 08)

Pp Ec.# Uw

(14)(12)

(13)

(15)(11)

(12)

(16)

(11)

(13)

Finally, these definitions derived from the Figure 01are introduced:

(17)

(18)

(19)

The specific weight for compound materials

obtained by using the following generic formula:

(2

From which can be obtained the specific gravity

the paste (GP) and the mineral fraction (GM):

(2

with X= initial assumed proportions.

(2

For the particular case where the design is nrestricted by the filled voids ratio (%VF), and with established range for VMA (between 22 and 24%) an

Vt (between 1% and 4%), exists only one solution f

the optimal paste percentage and the density th

satisfies the void specification

(2

(2

PASTE QUALITY

To determine the quality of the paste that guarantthe expected mechanical properties of the mixture,

is used the known correlation between ratio =a/

and the compression resistance.

The guide 207.5R.11 published by ACI (Ref. 0

offers a general ratio for RCC mixtures with Vetime below 45 seconds (See Figure 04).

Although this guide does not specify details about th

degree of compaction of the test specime

considered, it makes reference to the standard ASTC1435 (about construction of test specimens), so w

assume this relation (Figure 04) is valid for the vo

parameters established in this paper.


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Figure 04 (from Ref. 01)

Additionally, we use as a reference the parameters

listed in the document ACI 214R-02 (Ref. 02) todetermine the maximizing factors of the design

resistance against the nominal resistance, consideringthe dispersion of the results in terms of the qualitycontrol and the allowable fraction defective, adopting

the criteria defined in Table 02 and affecting the

design resistance according to Equation 25.

(25)

where:

Fcr Design resistancefc Nominal resistance

V Coefficient of Variation (Table 02)

Z Typified variable of the normal distribution for thepermitted fraction defective according Table 03

Quality control Coefficient of variation (V)

Excellent 5%

Very good 10%

Good 15%

Fair 20%

Poor 25%

Table 02, Coefficient of variation for the expected

quality control

Quantil or Defective Fraction Z

2% 2,054

5% 1,645

9% 1,340

10% 1,282

15% 1,036

20% 0,842

Table 03, Variable z for established quantiles

correction

For different aggregates to those considered in Figu04, it is recommended to adjust the value obtained b

using =w/c, with those factors shown in Table 0and 05.

Max. Size (NMSA) 1 2 2 3

KRFactor 1,15 1,1 1,05 1

Table 04, KRFactor for NMSA correction

Crushed

from

quarries

Semi-

crushed

Natural grav

or boulders

Crushed sand 1 0,97 0,95

Natural sand 0,97 0,95 0,93

Table 05, factor KAfor type of aggregate

Correction due to the type of cement

The curves in Figure 04 are values obtained for

Type II Cement, ASTM C150.

The use of different cements involves an adjustmeconsidering the proportional relation betwe

concrete resistances as a function of the cemen

resistance, measured in normalized mortaaccording the ASTM C109/C109M.

(

Where:

q Adjustment factor of curves, Figure 04

Rgrout cement Strength of grout cement at 3 or 7 days (Mp

Rgrout type II Strength of grout cement Type II, ASTC150, as follow:

10 Mpa at 3 days/ 17 Mpa at 7 days

Coarse

Fine


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Correction due to plastic fines or pozzolanic activity of

non-plastic fines

Sometimes it is not possible to avoid the presence ofplastic fines in the aggregates, causing an additional water

demand and therefore the need to increase the amount ofcement. This amount is increased proportionally to thepercentage of fines passing the sieve # 200 and the plastic

index (Ip) of these, up to a maximum value of Ip = 25.

Also, it is considered that the presence of non-plastic fineswith pozzolanic activity can decrease the demand forcement. In this case, the decrease is proportional to thepozzolanic index of the combination of all the fines

present in the aggregates including, if applicable, themineral supplement used. This Pozzolanic Activity Index(PAI), should be determined according to ASTM C311and affected by an empiric factor, which, within the scope

of this paper, is = 0,50.

CALCULATION PROCESS

Currently the company is participating in the design of theRCC mixture for the dam Cuira, located in MirandaState, Venezuela. This dam will have a height of 135 m

and an estimated volume of RCC close to 1MM m3. Thefollowing sequence, describes the design process usingthe experimental data and results obtained to date withone of the available aggregate sources, taken from thecrushing of rocks characterized as metavolcanicdetritic-

lithic sandstones (metatuffs).

Step 1, Combination of aggregates: The aggregates aregrouped in stockpiles characterized with the specific

gravities and grain sizes shown in Table 06.

Step 2 Design Strength: To check against the availableresults, the mixture is analyzed at 28 days, with anaverage value of 6,95 MPa expected.

Assuming a defective fraction of 10% and a qualitycontrol "Outstanding", the following results are obtained

from Tables 02 and 03:

V, Coefficient of Variation = 10% Z, Standardized Variable = 1,282

Fcr= 7,43 Mpa (Equation 26)

Step 3, Water / Cementitious Material ratio: A designstrength ofFcr= 7,43 MPa, is entered in Figure 04 (curvecorresponding to 28 days) to obtain an initial value of thewater / cementitious material:

calculus= (4,1202/7,43)^(1/1,724)= 0,711

Step 4, Adjustments to water / cementitious material: The

result obtained from the previous step must be adjustedaccording to the characteristics of the aggregates, finesproperties and cement.

Aggrega-

tes

Specific

Gravity

(SSD;

kg/m3)

Grain Size

(%passing)

% Combined

Grain Size

(% passing)

Gravel 1 2.725 (d/22,3mm)^0,86

(R2=0,962)

25 (d/37,9 mm)^

(R2= 0,991)

Passing #200

7,84%

Moisture:1,92

Gravel 2 2.775 (d/37,7mm)^2,71

(R2=0,994)

27

CrushedSand

2.737 (d/5,6mm)0,48

(R2=0992)48

d: sieve opening size;R : Coefficient of the curve fitting.

Table 06, composition of Cuira RCC mixture

Step 4.1, Aggregates:

Maximum size of Aggregate (NMSA): 2 ", of Table 0KR= 1,1

Crushed Aggregates: Table 05 KA= 1

Step 4.2, Fines Properties: The combined aggregate have7,84% of non-plastic fines (rock dust) with a Pozzolan

Activity Index (PAI) of 62%.

In order to estimate the amount of fines in the final mixtu

is necessary to have a first estimate of the composition the mixture based on an assumed percentage of paste anthe water / cementitious materialratio specified in step 3.

With an assumed percentage of paste Pp = 18% andcalculated = 0,711; a preliminary dose is calculated usithe following equations derived from Figure 01 (letters P V, equations 27 to 33, are auxiliary variables):

E

(2

Note: %Abs.: weighted absorption of aggregates

(2

(2

(2

(3

(3

(3


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(33)

(34)

(35)

(36)

(37)

(38)

(39)

So, the non plastic fines represent an amount of equivalentcement that can be determined as follows:

Adjust for equivalent cement: PAI x Passing#200_1 x

= 0,62 x 176,24 x 0,50= 54,64 kg

Step 4.3, Cement Properties: A Type II Cement is used(ASTM C150), resulting in a KC=1.

Finally, the water / cementitious materialratio is adjustedas follows:

adjusted= (Estimated_Water_1/(Estimated_Cement_1-Equivalent_Cement))*Kr*Ka*Kc = 118,1/(166,2-54,64)*1.1*1*1 = 1,164

Paso 5, Recalculation of doses::The doses of cement, waterand aggregates are recalculated using the same equations

than Step 4.2 but with adjusted.

Estimated_Cement_2 (kg) 128,3

Estimated_Water_2 (kg) 149,4

Aggregate_Volume_2 (lt) 809,9

Aggregate_Mass_2 (kg) 2.222

Passing #200_2 (kg) 172,2

Filler_2 (kg) 0

Below, the following parameters are determined:

Equation 18:TMD= 149,4 kgwater/m

3 + 128,3 kgcement/m3 + 2.222

kgaggregates/m3= 2.499,7 kg/m3

Equation 21:

Equation 22:

Step 6, Determination of the optimal percentage of pasWith the void specifications shown in Table 07, the resuobtained in Step 5 (GP' and GM') and Equations 11 to 1the 10 vertices from Figure 03 can be determined. STable 08.

Trapped voidsin mixture, Vt

(%)

Voids in MineralAggregate VMA

(%)

Void filledwith paste

VF(%)

Minimum 1% 22% 81,8%

Maximum 4% 24% 95,8%

Table 07, Voids specifications for Cuira RCC

Pp Uw

Equation

14

14,2% 2.437

16,2% 2.496

14,8% 2.518

12,9% 2.463

Equation

15

14,4% 2.444

16,2% 2.496

14,7% 2.516

12,9% 2.463

Equation

16

12,9% 2.463

16,2% 2.496

Table 08, Polivoid, first iteration Cuira design

With this, it can be verified that the Case V (Table 01)

satisfied; resulting the voids polygon as a figure formed vertices 5, 6, 7 and 8. The centroid of the polygon is thaverage of its vertices, from which can be calculated:

%Pastecalculated: 14,57% and Uw: 2.480 kg/m3

As the Filled Void (Vf) specifications does not restrict tdesign, the result can be verified by using equations 23 a24.

Step 7, Iteration: Repeat the process from Step 4.2 un%PasteAssumed=% Pastecalculated.

By performing several iterations with a spreadshe

(available to the reader via e-mail at [email protected] %Paste converges to 14,73%; while the obtaindosage corresponds to the indicated in Table 09, where apresented the proportions used in the actual design and tresults obtained at compression 28 days later. This desi


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was not tested in the equipment VeBe but we can confirmthat the preparation of the samples was successful,obtaining an adequate interlayer binding.

It was also verified others RCC designs for different source

of aggregates, including those within the scope of thiswork, other known successful design and even designsavailable in the literature (Ref. 10).

Dose forCalculation Real Dose

(by m3)

Gravel 1 (SSD) 588,67 Kg 587,62 Kg

Gravel 2 (SSD) 635,76 Kg 634,63 Kg

Crauhed Sand (SSD) 1.130,25 Kg 1.128,24 Kg

Water 117,75 Kg 117,29 Kg

Cement 75,03 Kg 80,00 Kg

a/c 1,569 1,466

Average Resistance(Mpa) Prediction Real

28 days 7,43 7,4390 days 14,13 10,23

180 days 17,18 Pending

28 days 20,23 Pending

Table 09, Cuira RCC design by calculation vs real dose

The prediction in all designs was quite tight. However, theexperimental nature of the proposed method warrants thatthe results obtained are considered only as a reference tostart a testing program that will lead to the final design.

According to our experience, the optimal values of

moisture tend to be in the range of (+1% to +1.5%) pointsabove the optimal moisture of the combined aggregates(without cement) taken from the Modified Proctor test(ASTM D1557), therefore a final testing program can fit

into an array of pre-designs considering this range ofmoisture.

Note: When dosing, an adjustment that considers theactual moisture of the aggregates should be done.

QUALITY CONTROL

One of the advantages of the design method proposed is toprovide rational references for the quality control of theRCC.

This control should aim to ensure both parameters of the

mixture produced, expressed in quantity and quality ofpaste, as well as specified void parameters, being these

directly dependent on the placement. The production of amixture similar to that established in the design isguaranteed by meeting these three parameters

simultaneously.

Production Control

A previous definition of the lots to control is required (volume or frequency). After this, it is necessary measure the following parameters in the RCC mixture.

Theoretical Maximum Density (TMD): In this regarthe ASTM D2041 can be used. Alternatively it can used the DMA Brazilian test (Ref. 03), which simpler but less accurate.

As a reference, it has been observed that the TMD an asphalt mixture for airport runways (Ref. 04) in

plant with a rigorous quality control reached maximudifferences of 30 kg/m3 inter-daily and 70 kg/m3 intweekly even with aggregates from quarries. Th

variation would be much greater if the aggregates wederived from sedimentary sources.

Percentage of Paste, Pp: Represents all the material thpasses through the sieve #200. It is recommended use the ASTM C117.

Specific Gravity of Mineral (GM), in Saturated-SurfacDry (SSD): it corresponds to all the material retainby the sieve #200. It is recommended to use the ASTC127.

By measuring these parameters, the specific gravity of tpaste (GP) in SSD condition can be calculated. This allow

control of the composition and therefore the quality of tpaste:

(4

Also, for each lot, samples must be taken in order prepare the test specimens for further tests of resistancKnowing the GM and GP and the true density of the tesspecimens, the Void Properties can be determined (s

Equations 41 to 44). The actual density can be obtainby dividing the mass of the specimen by its volumdetermined this by the actual dimensions measured withprecision of three decimal places. This alternaticalculation based on real measurements, it is easier

voids determination according to ASTM C231.

Placement Control:Control of the placed material is performed by measurinthe density at site (Uw) with a Nuclear Densimeter (ND

to obtain the following relationships:

(4

(42


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(43)

(44)

=(10)

Nevertheless, it should be advised that the ND might notbe so accurate in order to measure real density to qualitycontrol purposes under this scope. In that case core drilledshould be taken after a period later than setting and

hardening time, usually more than 3 days, leaving the useof the ND only for the placement control stage.

CONCLUSIONS

A design method combining the accumulated experiences

in the use of RCC with design and quality control ofasphaltic mixtures is proposed.

The basic approach is to get a suitable amount of paste

that ensures an effective interlayer bonding. The knownexperience, as well as the actual trend, suggests thatvariable Voids of Mineral Aggregate Ratio (VMA)should be limited in a range between 22-24%. However, it

is necessary to have more experimental evidence toconclude on the relationship between VeBe time and

VMA specification.

The method offers an accurate prediction of themechanical response of the mixture, based on thestandardization of the energy used for the confection of

tests specimens and uniformed properties of components.

In addition, to better the goal of prediction, it was takeninto account the fines characteristics, ranging fromplastic fines to non-plastic fines with puzolanic activity.

This prediction allows closing the whole spectrum ofpossible combinations, representing an appropriatestarting point in a testing program or a reference in theeconomic evaluation of a mixture of RCC.

The alternative variable to define a pre-designs matrix isthe optimal moisture of the aggregates, obtainedexperimentally before combining them with cement. This

is because the final moisture of the RCC mixtures tends tobe in a range between +1 and +1,5% points above the

optimum water content of the ASTM D1557, measured onthe aggregates without cement.

Another advantage offered by the proposed method is the

rationalization of the quality control, as the design basedon voids specifications minimizes the disputes oftenobserved in field between Contractor and Inspector.

The worksheets needed for the design, dosage and qualicontrol, as well as all the detailed information in rega

with this investigation, can be requested to [email protected].

REFERENCES[01] American Concrete Institute (2012) ACI 207.5R-11 Report

Roller-Compacted Mass Concrete. USA.

[02] American Concrete Institute (2002) ACI 214.R-02 Evaluationstrength test result of concrete. USA.

[03] Andrade, M.A.S.; Pimenta, M.A., Bittencourt, R.M.; FonseA.C.; Fontoura, J.T.F y Andrade, W.P..(2003) DMA, a simpdevice for measuring unit water in RCC mixtures. ProceedingsFourth International Symposium on Roller Compacted Concr

(RCC) Dams, 17- 19 November 2003, Madrid, Spain.[04] Ingeniera Geotcnica Prego (2008-2010) Informes de control

calidad para la construccin de pistas del Aeropuerto Jos AntonAnzotegui. Trabajos contratados con Consorcio Wydoca p

PDVSA. Edo. Anzotegui, Venezuela.[05] Lamont, J.F y Pielert, J.H.(2006) Significance of test a

properties of concrete and concrete-making materials. ASTInternational standard worldwide, STP 169D. Bridgeport, NJ, US

[06] Lpez, J.E.; Schrader, E. y Gackel, L. (2012) RCC D

construction conveyors or trucks. Proceedings of SiInternational Symposium on Roller Compacted Concrete (RCDams, 23- 25 Octuber 2012, Zaragoza, Spain.

[07] Porrero S., J; Ramos R., C; Grases G., Jos y Velazco G.J. (20Manual del Concreto Estructural, conforme con la Nomra Cove1753-03. SIDETUR, Venezuela.

[08] Snchez-Leal, F. (2010) Manual Digital Seminario Suelos

Mezclas Asflticas RAMCODES, Supertraining RAMCODES 20Barquisimeto, Venezuela.

[09] Snchez-Leal, F., Garnica, P., Gmez, J. y Prez, N. (200RAMCODES: Metodologia Racional para el Analisis Densificacion y Resistencia de Geomateriales Compactad

Publicacin Tcnica N 200, Instituto Mexicano del TranspoIMT. Quertaro, Mxico.

[10] Rizzo, P; Osterle, J.; Schrader, E. y Gackel, L. (2003) Saluda D

mix design program. Proceedings of Fourth InternatioSymposium on Roller Compacted Concrete (RCC) Dams, 17-

November 2003, Madrid, Spain.[11] US Army Corp of Engineers (2000) EM-1110-2-2006 Rol

Compacted Concrete. Manual of Engineering and Design 1January 2000.


11/15

Attachment 1

Date: Sept., 2013 Design: 002

3 4 22.6

z= 1.282 5%

6.95 Actual Fcr

to 7.43 Mpa

28 DAYS

Voids in mineral

aggregates, VMA(%)

Range for Voids filled

with paste, VF(%)

Voids filled with paste, VF

(%)

22.0% 81.8% 81.8%

24.0% 95.8% 95.8%

Kc 1.00 KR 1.10 KA 1.00

Label Type

Specific gravity (SSD,

ton/m3) % Abs. Proportion (%)

Actual doses

(kg)

Gravel 1 Crushed gravel 2.713 1.19% 25.0% 587.62 Kg

Gravel 2 Crushed gravel 2.766 1.24% 27.0% 634.63 Kg

Sand 1 Crushed sand 2.746 1.10% 48.0% 1128.24 Kg

Sand 2 2.5 Filler/Cement ratio

Filler 2.5 0%

GSSD: 2.743 ton/m3 1.16% 100%Specific gravity

(ton/m3)

1.569 Water_adjusted 1 117.29 kg

1.569 Cement_adjusted 3.15 80.0 kg0.457 Admixture 1.5 0.00 kg

Volume_agreggate: 858.4 lt Passing #200 182.5 kg 182.2 kg

Mass_aggregate: 2354.7 kg Paste (mass) 375.3 kg 379.4 kg

2547.5 kg/m3 Calculed Paste (%) 14.73% 14.89%

%Paste_min 14% 20%

Cont. Camargo-Correa

Cuira, DAM, M iranda State, Venezuela

V=

Setting cementiuos material (Kg):

Type ofcontrol:

Design strength, Fcr (Mpa):

Total voids, Vt (%)

1%

4%

DESIGN OF ROLLER COMPACTED CONCRETE (RCC)

Code of record:

Project:

Contract:

Customer:

%Paste_max

Test age of grout

Comp. Str. (Mpa) of grout, used

cement

Range for % Paste

7.43

Voids specifications

0.711

14.71%

14.73%Assumed Paste (%)

Calculated Paste

(%)

Characteristics of fines

Passing #200

2.65

Aggregate combination (after compliance with specified band)

Assumed Str. grout

ratio

Final ratio w/c:

% Defective fraction:

Minimum

Maximum

Specific gravity of P.

#200 (ton/m3)

Initial Water-

Cementious ratio for

design:

7.84% Liquid limit

0.5

Choose the following parameters

Strength (Mpa)

62%

Final Str. grout ratio

2 Inch

Choose NMSA

58.06

Water-Cementious ratio adjusted:

Plastic index

Characteristics of cement (grout tested as ASTM C 109/C109M)

Final ratio w/(c+p+passing #200):

Cement type Type II, Astm C150

Adjusment to water-cementitious ratio

Theoretical Maximum Density (TMD):

1.569

12.00 1.00

3 DAYS

Final ratio w/(c+p):

Pozzolanic activity

index


12/15

Attachment 2

Date: 2001 Design: 004

7 4 Enter value for Fcr (Mpa): Actual Fcr

19.75 Kg

z= It will be used Fcr value It will be used Fcr value

19.75

to

1 YEAR

Voids in mineral

aggregates, VMA(%)


with paste, VF(%)


(%)

28.0% 85.7% 85.7%

29.0% 96.6% 96.6%

Kc 1.00 KR 1.15 KA 1.00

Label Type



Actual doses

(kg)

Gravel 1 Crushed gravel 2.681 2.00% 49.8% 1070.54 KgGravel 2 2.766



Filler Pozzolan 1.5 1.0% 4.2% 122% 89.07 Kg


(ton/m3)


0.903 Cement_adjusted 3.15 74.2 kg0.613 Admixture 1




%Paste_min 16% 23%


2.005

12.00 1.00

3 DAYS


Pozzolanic activity

index






Strength (Mpa)

90%


1 1/2 Inch

Choose NMSA

79.40


Plastic index


Minimum

Maximum


#200 (ton/m3)

Initial Water-


design:

3.70% Liquid limit

0.5


Calculated Paste

(%)


Passing #200

2.50


Assumed Str. grout

ratio

Final ratio w/c:

19.75


0.722

16.47%


Code of record:

Project:

Contract:

Customer:

%Paste_max

Test age of grout


cement

Primary Mix, 125+150

Range for % Paste

Saluda DAM, Columbia, USA

V=


Type ofcontrol:


Total voids, Vt (%)

1%

4%


13/15

Attachment 3

Date: 2001 Design: 003

7 4 Enter value for Fcr (Mpa): Actual Fcr

23.34 Kg

z= It will be used Fcr value It will be used Fcr value

23.34

to

1 YEAR

Voids in mineral

aggregates, VMA(%)


with paste, VF(%)


(%)

28.8% 86.1% 86.1%

29.8% 96.6% 96.6%

Kc 1.00 KR 1.15 KA 1.00

Label Type



Actual doses

(kg)

Gravel 1 Crushed gravel 2.681 2.00% 49.8% 1056.96 KgGravel 2 2.766



Filler Pozzolan 1.5 1.0% 4.2% 94% 89.07 Kg


(ton/m3)


0.808 Cement_adjusted 3.15 89.1 kg0.557 Admixture 1.5




%Paste_min 17% 23%


1.568

12.00 1.00

3 DAYS


Pozzolanic activity

index






Strength (Mpa)

90%


1 1/2 Inch

Choose NMSA

81.40


Plastic index


Minimum

Maximum


#200 (ton/m3)

Initial Water-


design:

3.99% Liquid limit

0.5


Calculated Paste

(%)


Passing #200

2.50


Assumed Str. grout

ratio

Final ratio w/c:

23.34


0.648

17.50%


Code of record:

Project:

Contract:

Customer:

%Paste_max

Test age of grout


cement

Alternate II Mix, 150+150

Range for % Paste

Saluda DAM, Columbia, USA

V=


Type ofcontrol:


Total voids, Vt (%)

1%

4%


14/15

Attachment 4

Date: Mar. 2007 Design: 002

3 3 22.6

z= 1.282 10%

9.85 Actual Fcr

to 11.30 Mpa

1 YEAR

Voids in mineral

aggregates, VMA(%)


with paste, VF(%)


(%)

18.3% 72.7% 72.7%

19.3% 94.8% 94.8%

Kc 1.00 KR 1.05 KA 0.95

Label Type



Actual doses

(kg)

Gravel 1 Semi crushed gravel 2.57 2.10% 32.0% 720.67 Kg

Gravel 2 Natural gravel 2.55 2.00% 23.0% 517.98 Kg


Sand 2 Natural sand 2.54 2.00% 33.0% Filler/Cement ratio 743.19 Kg

Filler 2.5 0% 0.00 Kg


(ton/m3)


0.873 Cement_adjusted 3.15 83.8 kg0.371 Admixture 1




%Paste_min 10% 16%


Guapo DAM, Miranda State, Venezuela

V=


Type ofcontrol:


Total voids, Vt (%)

1%

5%


Code of record:

Project:

Contract:

Customer:

%Paste_max

Test age of grout


cement

Range for % Paste

11.30


1.032

12.46%


Calculated Paste

(%)


Passing #200 3%

2.54


Assumed Str. grout

ratio

Final ratio w/c:


Minimum

Maximum


#200 (ton/m3)

Initial Water-


design:

5.74% Liquid limit

0.5


Strength (Mpa)


2 1/2 Inch

Choose NMSA

-15.24


Plastic index

Pozzolanic activity

index






0.873

12.00 1.00

3 DAYS



15/15

Attachment 5

Date: August, 2013 Design: Cuira 06

3 4 22.6

z= 1.282 5%

4.93 Actual Fcr

to 5.27 Mpa

28 DAYS

Voids in mineral

aggregates, VMA(%)


with paste, VF(%)


(%)

16.6% 75.9% 75.9%

17.6% 94.3% 94.3%

Kc 1.00 KR 1.15 KA 0.95

Label Type



Actual doses

(kg)



Sand 1 Natural sand 2.711 1.99% 44.0% 1046.94 Kg


Filler 2.5 0%


(ton/m3)


1.196 Cement_adjusted 3.15 80.0 kg0.704 Admixture 0.32 kg 1.5 0.32 kg




%Paste_min 8% 14%






Final ratio w/c:


1.196

12.00 1.00

3 DAYS

70%


1 1/2 Inch

Choose NMSA

20.66


#200 (ton/m3)

Initial Water-


design:

2.49% Liquid limit

0.5

Strength (Mpa)

Plastic index

9.48%


Calculated Paste

(%)

Passing #200

2.65


Range for % Paste

5.27


0.867

Project:

Contract:

Customer:

%Paste_max

Test age of grout


cement


Assumed Str. grout

ratio

Pozzolanic activity

index



Type ofcontrol:


Total voids, Vt (%)

1%

4%


Minimum

Maximum


Cuira, DAM, M iranda State, Venezuela

V=



Code of record:

rational method for rcc design-ml

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