Asphalt Pavement Laydown and Asphalt Pavement Laydown and CompactionCompaction
Picture of plant
Compaction of the asphalt mat, typically, has more Compaction of the asphalt mat, typically, has more affect on the life of the pavement than any other affect on the life of the pavement than any other item in asphalt construction.item in asphalt construction.
Adequate Compaction Adequate Compaction Helps Reduce or Retard….Helps Reduce or Retard….
Fatigue CrackingFatigue Cracking RuttingRutting Binder OxidationBinder Oxidation Moisture DamageMoisture Damage Thermal CrackingThermal Cracking
Fatigue Cracking Fatigue Cracking
RuttingRutting
Asphalt Binder Oxidation - Asphalt Binder Oxidation - HardeningHardening
Moisture DamageMoisture Damage
Adequate compaction will help minimize Adequate compaction will help minimize the infiltration of water. the infiltration of water.
Thermal CrackingThermal Cracking
Mixture Items that Affect Compaction Mixture Items that Affect Compaction
Aggregate texture, hardness and shapeAggregate texture, hardness and shape
Asphalt Binder GradeAsphalt Binder Grade
Mixture Properties Mixture Properties – VoidsVoids– Asphalt Binder ContentAsphalt Binder Content
Mixture Temperature and Cooling RateMixture Temperature and Cooling Rate
Field Operations Field Operations that Affect the that Affect the Compaction of the Bituminous MixtureCompaction of the Bituminous Mixture
Types of Rollers and Order they are usedTypes of Rollers and Order they are used
Mode of the Steel RollersMode of the Steel Rollers
– Vibratory mode on or offVibratory mode on or off
– High/Low AmplitudeHigh/Low Amplitude
– High/Low FrequencyHigh/Low Frequency
in most cases the roller should be set to high in most cases the roller should be set to high frequency and low amplitudefrequency and low amplitude
Speed of RollersSpeed of Rollers
Number of Roller PassesNumber of Roller Passes
Number of Roller PassesNumber of Roller Passes
11 33 55 77 99
11 11 33 55 77 99
22 00 11 22 33 44
33 00 11 11 22 33
44 00 11 11 11 22
Num
ber Passes to
Cover P
aver Width
Roller Passes
Minimum Passes on Critical Longitudinal Section
Roller Speed ExampleRoller Speed Example
Given: Given: Plant & Paver Specifics Plant & Paver Specifics
- 12 feet wide- 12 feet wide- 500 tons per hour- 500 tons per hour- 1.5 inch lift- 1.5 inch lift
Roller SpecificsRoller Specifics- minimum 3 passes coverage- minimum 3 passes coverage- roller width is 54 inch- roller width is 54 inch
RequiredRequiredWhat is the minimum roller speed you need to compact the What is the minimum roller speed you need to compact the mat?mat?
Roller Speed AnswerRoller Speed Answer
The speed of the paver is:The speed of the paver is:
500 tons per hour = 500*2000/145 = 6900 cuft per hour500 tons per hour = 500*2000/145 = 6900 cuft per hour
Pavement Cross section = 12 feet * 1.5 inch/12 = 1.5 sqftPavement Cross section = 12 feet * 1.5 inch/12 = 1.5 sqft
Paver speed = (6900 cuft/hr) / 1.5 sqft = 4600 ft/hourPaver speed = (6900 cuft/hr) / 1.5 sqft = 4600 ft/hour
The required roller speed is:The required roller speed is:
Roller Speed = 4600 ft/hour * 9 passes /5280 ft/mi = 7.8 mphRoller Speed = 4600 ft/hour * 9 passes /5280 ft/mi = 7.8 mph
What are the Recommended What are the Recommended Roller Speeds ?Roller Speeds ?
From Chapter 18 of Hot Mix Paving HandbookFrom Chapter 18 of Hot Mix Paving Handbook
Static Steel WheelStatic Steel Wheel 2 – 3.52 – 3.5 2.5 - 42.5 - 4 3 - 53 - 5
PneumaticPneumatic 2 – 3.52 – 3.5 2.5 - 42.5 - 4 4 - 74 - 7
VibratoryVibratory 2 - 32 - 3 2.5 – 3.52.5 – 3.5 ----
Type of Roller Breakdown Intermediate Finish
Operating Position
Range of Roller Speeds (mph)
You Need More Than 1 Roller !!!You Need More Than 1 Roller !!!
Roller Settings and Roller PatternsRoller Settings and Roller Patterns
Vibratory Steel Roller generally works best in the high Vibratory Steel Roller generally works best in the high frequency and low amplitude modefrequency and low amplitude mode
Typical Rolling Pattern:Typical Rolling Pattern:
– Vibratory Steel Roller as break downVibratory Steel Roller as break down
– Pneumatic Roller as intermediatePneumatic Roller as intermediate
– Static Steel Roller as finish rollerStatic Steel Roller as finish roller
Only Pneumatic rollers should be used when the Only Pneumatic rollers should be used when the temperature of the mat is within the bituminous mixtures temperature of the mat is within the bituminous mixtures “tender zone”“tender zone”
Vibratory BreakdownVibratory Breakdown
Pneumatic BreakdownPneumatic Breakdown
Frequency, f = the number of hertz (cycles/s)--a single cycle Frequency, f = the number of hertz (cycles/s)--a single cycle is one full rotation of the eccentric weight. Frequency = 1/Tis one full rotation of the eccentric weight. Frequency = 1/T
Amplitude, A = the maximum deviation from position at Amplitude, A = the maximum deviation from position at rest -- one-half the total movement.rest -- one-half the total movement.
AmplitudeAmplitude(A)(A)
TimeTime
UU ppD
ow
Do
wnn Time (T) ForTime (T) For
Full CycleFull Cycle
Mo
vem
ent
Mo
vem
ent
AmplitudeAmplitude
DIRECTION OF TRAVELDIRECTION OF TRAVEL
FrequencyFrequency
Impact SpacingImpact Spacing
High FrequencyHigh FrequencyLow FrequencyLow Frequency
Joint CompactionJoint Compaction
Compaction of the Longitudinal Joint is the Weak Link in Compaction of the Longitudinal Joint is the Weak Link in the Paving Processthe Paving Process
Compaction of the Both the Confined and Unconfined Compaction of the Both the Confined and Unconfined Edges is a ChallengeEdges is a Challenge
The Unconfined Edge Needs to be Compacted with the The Unconfined Edge Needs to be Compacted with the Edge of the Steel Roller Over-hanging the Mat by 6 InchesEdge of the Steel Roller Over-hanging the Mat by 6 Inches
If a Pneumatic Roller is used in the Break Down Position, If a Pneumatic Roller is used in the Break Down Position, it Should not be Closer than 6 Inches to the Jointit Should not be Closer than 6 Inches to the Joint
Joint CompactionJoint Compaction
Compaction of the Confined Joint is Best Achieved by Compaction of the Confined Joint is Best Achieved by Rolling on the Hot Mat and Overlapping the Cold Mat by Rolling on the Hot Mat and Overlapping the Cold Mat by 6 Inches6 Inches
Steel Rollers may Tend to Bridge from the Cold Mat and Steel Rollers may Tend to Bridge from the Cold Mat and this May Impede Compaction Right at the Joint. A this May Impede Compaction Right at the Joint. A Pneumatic Roller will be More Effective in Reducing this Pneumatic Roller will be More Effective in Reducing this Bridging.Bridging.
Rolling from the Cold Side is No Longer RecommendedRolling from the Cold Side is No Longer Recommended
Raking of the Joint is Not RecommendedRaking of the Joint is Not Recommended
LOWLOWHIGH HIGH
LOWLOWHIGHHIGH
THINTHINTHICKTHICK
Base TemperatureBase Temperature
Mix TemperatureMix Temperature
Factors Affecting Rolling TimeFactors Affecting Rolling Time
Mat ThicknessMat Thickness
allows allows LESS LESS timetime
allows allows MORE MORE timetime
FACTORSFACTORS
Time for Compaction ExerciseTime for Compaction Exercise
Time to Cool to 175F
Mixture Temp 270F
Mixture Temp 310F
Mixture Temp 270F
Mixture Temp 310F
Mixture Temp 270F
Mixture Temp 310F
Air/Base Temp
Mat Thickness 1 inch Mat Thickness 2 inch Mat Thickness 3 inch
Your Guess
32F Actual Time
Your Guess
60F Actual Time
Your Guess
90F Actual Time
(Values determined using “Pave Cool”. Sky overcast. Wind speed 15 mph)
Paver OperationsPaver Operations
Paver OperationsPaver Operations
The primary objective of the paver is to place a The primary objective of the paver is to place a bituminous mixture on the roadway, in a manner bituminous mixture on the roadway, in a manner that results in mat that has an even distribution of that results in mat that has an even distribution of temperature, thickness and pre-compaction, in temperature, thickness and pre-compaction, in both the longitudinal and transverse directions. both the longitudinal and transverse directions.
Mix Placement ConcernsMix Placement Concerns
Even and steady flow of mixture into the paver hopperEven and steady flow of mixture into the paver hopper
Even and steady flow of mixture to the paverEven and steady flow of mixture to the paver
Even and steady flow of mixture through the paver and in Even and steady flow of mixture through the paver and in
front of the paver screedfront of the paver screed
The appropriate angle of attack of the screed needs to be The appropriate angle of attack of the screed needs to be set and frequent adjustments minimizedset and frequent adjustments minimized
Flow of Mixture to the PaverFlow of Mixture to the Paver
Flow of Mixture into the Paver HopperFlow of Mixture into the Paver Hopper
Paver Hopper and Flow GatesPaver Hopper and Flow Gates
Flow Gates set to Allow Flow Gates set to Allow Uniform Material Flow to the Auger Uniform Material Flow to the Auger
Operating the ScreedOperating the Screed
What Affects the Thickness of the What Affects the Thickness of the Bituminous Being PavedBituminous Being Paved
If the paver speed, the height of material behind the screed, If the paver speed, the height of material behind the screed, and tow point height are held constant, there is only one and tow point height are held constant, there is only one screed angle of attack that will give you the desired mat screed angle of attack that will give you the desired mat thickness. thickness.
Paver SchematicPaver Schematic
TOW POINTTOW POINT
Primary purpose of automatic screed control is to Primary purpose of automatic screed control is to produce a smooth asphalt pavement layer.produce a smooth asphalt pavement layer.– Smoother than a screed operator can accomplish by Smoother than a screed operator can accomplish by
continually changing the setting of the thickness control cranks.continually changing the setting of the thickness control cranks.
Automatics Screed ControlsAutomatics Screed Controls
Automatics Screed ControlsAutomatics Screed Controls
Automatic Screed Functions by:Automatic Screed Functions by:– maintaining the elevation of the screed tow points in maintaining the elevation of the screed tow points in
relation to a reference other than that of the wheelbase relation to a reference other than that of the wheelbase of the paver itself.of the paver itself.
» Elevation of the tow point is kept at a constant elevation in Elevation of the tow point is kept at a constant elevation in relation to a given grade reference.relation to a given grade reference.
The automatics don’t allow the relative position of the tow point The automatics don’t allow the relative position of the tow point to change even though the tractor unit is moving up and down.to change even though the tractor unit is moving up and down.
Automatics of the PaverAutomatics of the Paver
The paver operator controls the angle of attack of The paver operator controls the angle of attack of the screed.the screed.
The automatic controls on the paver control the The automatic controls on the paver control the tow point height.tow point height.
Checking the Mat ThicknessChecking the Mat Thickness
Adjusting the ThicknessAdjusting the Thickness
Screed Reaction TimeScreed Reaction Time
The screed reacts to change in angle of The screed reacts to change in angle of attack over 5 tow arm lengths.attack over 5 tow arm lengths.
65% of change occurs in the first tow arm 65% of change occurs in the first tow arm length.length.
35% of change occurs in the last 4 tow arm 35% of change occurs in the last 4 tow arm lengths.lengths.
How Long Does it Take the Screed How Long Does it Take the Screed to React to an Adjustment of the to React to an Adjustment of the
Thickness Control ScrewThickness Control Screw
What do the Automatics What do the Automatics on a Paver do? on a Paver do?
Contract Special Provisions Contract Special Provisions
S-135 (2350) PLANT MIXED ASPHALT PAVEMENT For 2003 Construction Season REVISED 12/18/02 SP2000-126
Mn/DOT 2350 and Mn/DOT 2360 are hereby deleted from the Mn/DOT Standard Specifications and replaced with the attached Combined 2360/2350 (Gyratory/Marshall Design) Specification.
S-135.1 Mix Designation Numbers for the bituminous mixtures on this Project are as follows: The Designer needs to fill in the numbers here. Examples of what is needed are:
Type LV 2 Wearing Course -LVWE25030B Type MV 2 Wearing Course -MVWE25035B Type LV 3 Non-Wearing Course -LVNW35030B Type MV 3 Non-Wearing Course -MVNW35035B
S-135.2 Mix Designations for bituminous mixtures contain the following information:
(1) The first two digits indicate the mixture design type: MV = Medium Volume, LV = Low Volume
(2) The third and fourth digits indicate the course:
WE = Wearing and Shoulder Wearing Course NW = Non-Wearing Course
(3) The fifth digit indicates the maximum aggregate size:
2 = 25.0mm [1 inch], 19.0 mm [3/4 inch] nominal size 3 = 19.0mm [3/4 inch], 12.5 mm [1/2 inch] nominal size 4 = 12.5mm [1/2 inch], 9.5 mm [3/8 inch] nominal size 5 = 9.5mm [3/8 inch], 4.75 mm nominal size (Marshall design only)
(4) The sixth and seventh digit indicates the Marshall design blows:
50 blow design for both LV and MV mixtures
(5) The last two digits indicate the air void requirement. 35 = 3.5% air voids (for MV only), 30 = 3.0% air voids (for LV only).
(6) The letter after the mix designation identifies the performance grade of asphalt cement.
A = PG 52 - 34 B = PG 58 - 28 C = PG 58 - 34 D = PG 58 - 40 E = PG 64 - 28 F = PG 64 - 34 G = PG 64 - 40 H = PG 70 - 28 I = PG 70 - 34 L = PG 64 - 22
The Designer needs to let Special Provisions know how pavement smoothness will be evaluated. S-135.3 Pavement smoothness requirements will be evaluated by Table 2360.7-C6A or 2360.7-C6B or
2360.7-C6C. OR
S-135.4 Pavement smoothness requirements of 2360.7C will not apply on this Project. The requirements
of 2360.7B (Straight edge specification) will apply. S-135.5 The attached Combined 2360/2350 (Gyratory/Marshall Design) Specification is hereby
modified with the following:
(A) Modify 2360.4F (2a)1 to read: 1. Percent passing on sieves listed in Table 2360.2-E and the following sieves: 1.18 mm (#16), 0.600 mm (#30), 0.300 mm (#50), and 0.150 mm (#100). The test results for these additional sieves may be included on the daily Test Summary Sheet or on a separate Summary Sheet. If the test results for the additional sieves are recorded on a separate Summary Sheet, the test results must be identified such that there is a direct and easy correlation with the test results of the sieves listed in Table 2360.2-E and the other mixture property tests for that sample.
S-135.6 BASIS OF PAYMENT
Payment for the accepted quantities of asphalt mixture used in each course at the Contract prices per unit of material shall be compensation in full for all costs of constructing the asphalt surfacing as specified, including the costs of furnishing and incorporating any asphalt binder, mineral filler, hydrated lime, or anti-stripping additives that may be permitted or required.
If the Marshall design density at the recommended or established asphalt content is in excess of 2565 kg/m 3 [160 pounds per cubic foot], payment for mixture will be calculated at the following percent of the contracted unit price.
% Payment = {100 - [{100 x (Marshall design Density - 2565)} / 2565]} % Payment = {100 - [{100 x (Marshall design Density - 160)} / 160]} ENGLISH
In the absence of Contract items covering shoulder surfacing and other special construction, the accepted quantities of material used for these purposes will be included for payment with the wearing course materials.
The Contractor is responsible to complete yield checks and monitor thickness determinations so that the constructed dimensions correspond with the required Plan dimensions throughout the entire length of the project. The tolerances for lift thickness shown in 2360.7A and B, Thickness and Surface Smoothness Requirement is for occasional variations and not for continuous over-running or under-running, unless Ordered or Authorized by the Engineer.
S-135.7 Payment for the item of asphalt mixture production at the Contract unit price of mixture produced
shall be compensation in full for all costs of producing the mixture and loading it on board the Department's trucks at the mixing plant. The provisions of Mn/DOT 1903 are modified to the extent that the Department will not make a price adjustment in the event of increased or decreased quantities of asphalt mixture items. Payment for plant mixed asphalt surface will be made on the basis of the following schedule:
Item No. Item Unit 2350.501 Type (1) (2) Wearing Course Mixture ((4))...............................................................metric ton [ton] 2350.502 Type (1)(2) Non Wearing Course Mixture ((4)) ........................................................metric ton [ton] 2350.503 Type (1)(2)(3) Course Mixture ((4)), (5) mm (inch) thick .................... square meter [square yard] 2350.504 Type (1)(2)(3) Course Mixture ((4)) ................................................................... [square yard inch] 2350.505 Type (1)(2) Bituminous Mixture for Specified Purpose.............................................metric ton [ton] 2350.506 Type (1)(2) Bituminous Mixture Production...............................................…..….....metric ton [ton] (1) Traffic Level Designation (LV or MV as appropriate). (2) Aggregate size designation, as per Table 2360.2-E. (3) "Wearing" or "Non Wearing" as appropriate. (4) AC binder grade designation. (5) Specified lift thickness.
Bituminous Web PageBituminous Web Page
www.mrr.dot.state.mn.us/pavement/bituminous/bituminous.asp
REVISED modified
INCENTIVE / DISINCENTIVE WORKSHEET 2360 2360SUPERPAVE
S.P. HWY. 99PAVED 6/15/2003 CORED 6/15/2003 TON TYPE ENGLISH
INCENT/DISINC RATIO= 0.86 MAX. DENSITY TONS = 1800 REQ'D DENSITY= 92.0 TOTAL TONS PAVED = 2100 Max Sp.G.= 2.435 MIN. AIR VOIDS = 3.5 LOTS REQUIRED = 4 BID PRICE= $24.34 DESIGN AIR VOIDS = 4 TONS PER LOT= 450.00 MIX TYPE SPWE
MANUAL OVERRIDE LOTS = 0101 102 103 104200 400 1200 1900400 800 700 200343 686 600 1712.80 3.70 4.40 2.90
BULK AVE. BULK % AIR VOID TONS PAY
LOT CORE # BULK SP.G SpG. USED Sp GRAV. DENSITY USED REPRESENT. FACTOR
22 22.1 2.296 2.296 2.306 94.7 2.80 342.8 low voids22.2 2.315 2.315 3.70 107.1 4%
COMP 22.1 2.310
23 23.1 2.193 2.193 2.201 90.4 3.70 450.0 -9%23.2 2.252 2.208
COMP 23.2 2.208 COMPANION CORE USED
24 24.1 2.287 2.287 2.281 93.7 3.70 128.6 4%24.2 2.275 2.275 4.40 321.4 4%
COMP 24.1 2.280
25 25.1 2.311 2.275 2.280 93.6 4.40 278.6 4%25.2 2.285 2.285 2.90 171.4 low voids
COMP 25.1 2.275 COMPANION CORE USED
TOTAL = TOTAL = TOTAL =
CHK'D BY DATE :
PLANT # : REC.# :
NOTES
MIX DESIGNATION : SPWEB440F 1 2002-0123
$813.63 -$985.75 -$172.12
DATA ENTERED BY : dan boerner joe thomas 3/21/2003
INCENTIVE THIS SHEET DISINCENTIVE THIS SHEET INCENTIVE / DISINCENTIVE
$0.00
$312.94
$271.21
$125.17
$104.31
-$985.75
INDIVIDUAL VOIDS
INCENTIVE
DISINCENTIVE
$0.00
SAMPLE NUMBER
SAMPLE TON #
TONS REPRESENTED
MAX DENSITY TONS
SPEC. YEAR "2004"
2352-121 CONTRACTOR: w orlds best paving
(english)
S.P. EngineerContractor
10+50.00 End Station 92+50.00 Length Paved 820092+50.00 End Station 10+50.00 Length Paved 8200
End Station Length Paved 0End Station Length Paved 0End Station Length Paved 0End Station Length Paved 0End Station Length Paved 0End Station Length Paved 0
1800 Lots Required 4 Total Length Paved 16400450 Required Lot Length 4100 Lane Width Paved 14.0
Comp Lot Random Lot Distance Lane Lane Station of RandomTonnage # Length Name Core #
Lot Number Lot Core 22.1 Comp 0.34 4100 1390 Lane 1 west bound 24+40 0.73
1 22 Core 22.2 450 0.00 4100 9 Lane 1 west bound 10+59 0.27
1 Lot Core 23.1 0.72 4100 2941 Lane 1 west bound 80+91 0.81
23 Core 23.2 Comp 450 0.09 4100 361 Lane 1 west bound 55+11 0.95
2 Lot Core 24.1 Comp 0.26 4100 1049 Lane 2 east bound 82+01 0.04
2 24 Core 24.2 450 0.85 4100 3474 Lane 2 east bound 57+76 0.92
Lot Core 25.1 Comp 0.42 4100 1709 Lane 2 east bound 34+41 0.32
3 25 Core 25.2 450 0.94 4100 3870 Lane 2 east bound 12+80 0.10
3 Lot Core 0.60 0.20
Core 0.87 0.62
4 Lot Core 0.29 0.73
4 Core 0.58 0.21
Remarks
5 Daily Production5 Lot
16 26 3
47 57 6
# 0F COMPANIONS CORES =
50% TOTAL CORES
BITUMINOUS CORING LOG
2352-121 T. H. 99 Richard Andersonworld's best paving Plant #1
Lane Lane NameLane 1 west bound Begin Station
Lane 2 east bound Begin Station
Lane 3 Begin Station
Lane 4 Begin Station
Lane 5 Begin Station
Lane 6 Begin Station
Lane 7 Begin Station
Lane 8 Begin Station
Total Tons Paved
Tons Per Lot
English Tons
0-600
>5000Street Inspector
601-10001001-16001601-36003601-5000
Common Errors When Using Spread Common Errors When Using Spread SheetsSheets
Most common error happens when the macros are Most common error happens when the macros are disabled due to the security setting being set to disabled due to the security setting being set to highhigh
Set the security level to “low”Set the security level to “low”– Move cursor to the menu on top and under the “Tools” Move cursor to the menu on top and under the “Tools”
menu, pick Tools: Macro: Security menu, pick Tools: Macro: Security – In the security dialog box, set the security level to In the security dialog box, set the security level to
“low” and press “OK”“low” and press “OK”
Common Errors When Using Spread Common Errors When Using Spread SheetsSheets
Problems with creating random numbersProblems with creating random numbers The two versions of the core locations spread The two versions of the core locations spread
sheets use random number functions to pick the sheets use random number functions to pick the core locations. The program must make a core locations. The program must make a decision whether or not be make new random decision whether or not be make new random numbers. Read the instructions for the spread numbers. Read the instructions for the spread sheet to be sure that the random numbers are being sheet to be sure that the random numbers are being treated properly.treated properly.
Questions ?Questions ?