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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






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 ?