Lime in AsphaltLime Association of Texas Workshop

H t TXHouston, TX April 9, 2014p

1

Outline Background Types of Distress Benefits of Lime Summary

Long Life Pavement( i if )(5 to 40 Years Increase in Life)

Minimize Premature Pavement Distress

Minimize Rehabilitation and Maintenance

Minimize User Inconvenience (Customer Focused Construction)

Todays Technology/Materials/Contractors

Safe Driving Surface

Design Considerationsg

SafetyThicknessMixture

Safetyy

Work Zone Surface Propertiesp

– Friction– DrainageDrainage– Splash and Spray– Noise– Noise

Thickness Design Fatigue Limit S l t Mi t f Diff t D th i Select Mixture for Different Depth in

Pavement Structure

Friction/Splash/Spray/Noise Permanent deformation Thermal cracking Water Susceptibility

Stiffnessh / High RAP/RAS

Permanent deformation

Fatigue resistance Water susceptibility

MIXTURE DESIGN

Mixture design test parameters use for structuralDESIGN parameters use for structural design input

Designs for different traffic Designs for different traffic level and climates

Specific mixtures for different Specific mixtures for different layers in pavement

N i l i t Nominal maximum aggregate size

P f l d Proper use of recycled materials

b l b d Lab mix-lab compacted vsplant mix-field compacted

Mixture/Structural Design

StiffnessStiffness

Rutting

F ti Fatigue

Thermal cracking

Water susceptibility

Agingg g

Lab mix-lab compacted vsplant mix-field compactedplant mix field compacted

Recycled MaterialsRecycled Materials

RAP/RAS binder stiffness RAP/RAS binder stiffness Uniformity of RAP/RAS Cracking-fatigue,

thermal, reflection Aging

Lime in Asphalt

Several states require lime in all asphalt q pmixtures 5 10% of all asphalt mixtures contain lime 5-10% of all asphalt mixtures contain lime 150,000 tons of lime used in asphalt

mixture per year

11

Summary-Design

Safe surfaces-friction, drainage, splash-ispray, noise

Specific mixtures for different layers Proper use of recycled materials

Outline Background

T f Di Types of Distress Benefits of Lime Summary

Pavement Performance Problems

Raveling Bleeding/Flushing

Transverse Cracking Longitudinal CrackingBleeding/Flushing

Rutting/Shoving Alli C ki

Longitudinal Cracking Reflection Cracking L li d Di Alligator Cracking Localized Distress

14

RavelingRaveling

15

Raveling

16

Bleeding

17

Bleeding

18

Permanent Deformation

High T, Large Load, S i d/Sl L di (L )

19

Sustained/Slow Loading (Large t)Decreases w/Aging

Rutting and Shoving

20

ShovingShoving

21

Fatigue Cracking

22

Fatigue Cracking

23

Fatigue Crackingg g

Intermediate T, Repeated Loading, Fast

24

Loading (Small t)Increases w/Aging

Thermal Crackingg

L T L T R id L di (S ll t)25

Low T, Large T, Rapid Loading (Small t)Increases w/Aging

ThermalThermal Cracking

26

Longitudinal Crackingg g

27

Joint Reflective CrackingPavement Distress - Types

Joint Reflective Cracking

28

StrippingStripping

29

Patchingg

30

CrackCrack Sealing

31

Outline Background T f Di t Types of Distress

Benefits of Lime Summary

Benefits of Using LimeBenefits of Using Lime

Red ce Water S sceptibilitReduce Water SusceptibilityReduce AgingReduce Aging Increase Stiffness of MixtureReduce Plastic Index

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Loss of BondLoss of BondLoss of Strength

Water sensitivity Water susceptibility StrippingStripping

34

StrippingStripping

Loss of adhesionLoss of adhesion between aggregate surface and asphalt cement in thecement in the presence of

i tmoisture

35

Stripping Potential Controlled by:Stripping Potential Controlled by:

Asphalt cement properties Asphalt cement properties Aggregate properties Mixture characteristics Climate Traffic Construction practices Construction practices Pavement design

id ticonsideration36

Asphalt Cement PropertiesAsphalt Cement Properties

Physical propertiesPhysical properties Viscosity T t Temperature Adhesive ability Chemical properties

37

Aggregate PropertiesAggregate Properties

Shape and surface textureShape and surface texture Gradation Fi t t & ti Fines content & properties Coating Absorption Surface chemistrySurface chemistry

38

Mixture CharacteristicsMixture Characteristics

Asphalt cement contentAsphalt cement content Aggregate gradation Ai id t t Air voids content Strength

39

Hot-WetHot Wet

Southeast USSoutheast US High temperature-low viscosity Moisture in summer Bleeding Blistering

40

Cold-DryCold Dry

Freeze-Thaw CyclesFreeze Thaw Cycles Several days of moisture D il f h l Daily freeze-thaw cycles Water expansion Brittle asphalt

41

TrafficTraffic

V l ADT Volume – ADT Heavy vehicles

42

Construction PracticesConstruction Practices

Quality controlQuality control Compaction - air voids J i t d it & ti Joint density & segregation Time of year

43

Water

44

Water

Fabric Chip Seal

Water45

Water

Water

Water

46

Water Susceptibility Water sensitivity Stripping Water damage Loss of Strength in the presence of

moisture– Adhesion between asphalt binder and

aggregategg g– Loss of strength in asphalt binder

47

Anti Strip AgentsAnti-Strip Agents

Liquids amines/di amines Liquids-amines/di-amines Solids-lime/portland cement/by-

products

48

Antistrip AdditivesLiquid Antistrip Agents

Chemical Compounds Containing Amines (Basic Chemical Compounds Containing Amines (Basic Compounds Derived from Ammonia)

Heat Stability

0 5 % Generally0.5 % Generally

May Change AC Properties (Soften)

Heat AC, Add Liquid Antistrip, Mix for 2 Min

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Antistrip AdditivesLime

Hydrated Lime - Ca(OH)Hydrated Lime Ca(OH) Bonding of the Calcium with the Silicates in

A tAggregate And/or Interaction or Modification of the Acidic

Portions of AC 1 to 1.5% Generally1 to 1.5% Generally Dry Mixed w/ Hot Aggregate or Damp Aggregate

Immediately before AC Added and MixedImmediately before AC Added and Mixed 50

Water Sensitivity TestsWater Sensitivity-Tests

Boil Test (ASTM D3625)(Tex-503-C) Immersion Compression (ASTM D1075)Immersion Compression (ASTM D1075) Tensile Strength Ratio (AASHTO T 283) Hamburg (Tex-242-F)

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TSR and Hamburg

AASHTO T283AASHTO T283 Modified LottmanTest (TSR)– 1 Freeze-Thaw

(F/T) Cycle

Resilient Modulus Test (MR)

b Hamburg Wheel-Tracking Device (HWTT)52

Resilient Modulus Test ResultsUniversity of Nevada Reno StudyUniversity of Nevada, Reno Study

Resilient Modulus 77F (Ksi)

250

300Truckee, CA Grass Valley, CA

150

200

Before

100

150 Lottman

After Lotmann

0

50

0 1 2 0 1 2

53Percent Hydrated Lime (%)

Resilient Modulus Test ResultsUniversity of Nevada Reno StudyUniversity of Nevada, Reno Study

Resilient Modulus 77F (Ksi)400

( )

Mammoth, CA Moreno, CA

300

Before

100

200 Lottman

After Lotmann

0

100 Lotmann

00 1 2 0 1 2

54Percent Hydrated Lime (%)

Types of Lime Added to Dry AggregateUniversity of Nevada Reno StudyUniversity of Nevada, Reno Study

Resilient Modulus 77F (Ksi)

400

500

( )

300

400

200

Before Lottman

After

0

100Lotmann

0Control Hyd. Lime I Hyd. Lime II Quicklime Dolomitic

55

Deeth ReconstructionState of Nevada Test Results

500

State of Nevada Test ResultsResilient Modulus (KSI)

300

400 Original

200

300 Vacuum SaturatedLottman

0

100

0No PCC, 5.5% FA, 5.5% AC

1.5 % PCC, 5.5% AC

1.5% PCC, 3.0% FA, 6.0% AC

2.0% PCC, 2.5% FA, 6.0% AC6.0% AC 6.0% AC

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Water Sensitivityy

After asphalt chemistry After asphalt chemistry After aggregate surface chemistry After coatings

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After Aggregate Surface

CA++Asphalt

CA++Asphalt

CA++

CA++

Initial coating Long term coating

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Long term coating Adhesion cohesion

Hamburg Test Results (Nebraska Study)

0B1_1.0% Screenings-1st PairB1_1.0% Screenings-2nd PairB1_1.0% Screenings-AverageB2 1.0% Dry Lime-1st Pair

-4

n (m

m)

B2_1.0% Dry Lime 1st PairB2_1.0% Dry Lime-2nd PairB2_1.0% Dry Lime-AverageB3_1.0% Lime Slurry-1st PairB3_1.0% Lime Slurry-2nd PairB3 1 0% Lime Slurry-Average

-8

Impr

essi

on

B3_1.0% Lime Slurry Average

B1 Stripping Point approx. 1,800 passes

-12

Max

imum

B2 Stripping Point approx. 4,300 passes

B3 Stripping Point approx. 2,200 passes

-16

papp o , 00 passes

0 1000 2000 3000 4000 5000 6000 7000 8000

No. of Passes

Moisture Sensitivity Dynamic Modulus (E*)

Un-Treated_UnagedLi id t t d U d

Un-Treated_UnagedLi id t t d U d0H

z,ks

i

0Hz,

ksi

Liquid-treated_UnagedLime-treated_Unaged

Liquid-treated_UnagedLime-treated_Unaged

104

F an

d 10

104

F an

d 10

odul

us E

*at

odul

us E

*at

60

CaliforniaTexas

Dyna

mic

Mo

Dyna

mic

Mo

Number of F-T Cycles Number of F-T Cycles

...But without Embrittlement at Low Temperature

70/100 + mixed filler w/ 40% lime70/100 + limestone filler

Temperature

No 70/100 + limestone filler70/100

No negativeeffect on cracking

ess

(Pa)

Beneficialeffect on

cracking

Stif

fne rutting

70/100 bitumen versus temperature

data from Wortelboeret al. (ESHA/LCPC),

E&E 1996

APA (under Water) Test Results24

B0_No AdditiveB1_1.0% ScreeningsB2_1.0% Dry LimeB3 1 0% Lime Slurry (Concentration Ratio = 0 33)

16

20

)

B3_1.0% Lime Slurry (Concentration Ratio 0.33)B4_1.0% Lime Slurry (Concentration Ratio = 0.22)B5_1.0% Lime Slurry (Concentration Ratio = 0.13)

APA Rutting Failure

12

16

epth

(mm

)

Criteria

8Rut

De

0

4

00 1000 2000 3000 4000 5000 6000 7000 8000

Strokes

Mechanisms: Filler Effect on Softening Point90

ratu

re C 90

80Hydrated LimeLimestoneGraywacke

ng T

empe

r

70

60

Graywacke

all S

ofte

nin 60

50

ng a

nd B

a

40

30

Hydrated lime added to the bitumen has a substantially greater

Rin 0 10 20 30 40 50 60 70 80

Filler Content (wt. %)

Hydrated lime added to the bitumen has a substantially greater impact in reducing the softening point of asphalt binder than does filler from graywacke or limestone source. Why?

Aging IndexWestern Research Institute

0% 10% 20%Log Aging Index

Western Research Institute

2.5

30% 10% 20%

2

1

1.5

0

0.5

0Boscan Ca. Central W. Texas Maya N. Slope Mays

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Additive Effect on the Hardening of AsphaltUt h DOT Fi ld St d

6000Viscosity – Stokes at 140F

Utah DOT – Field Study

5000

6000

3000

4000

2000

3000

No Additive

0

1000HydratedLime

0 1 2 3 4 5 6 7 8Time in Years

Hydrated Lime Improves Mixture Stiffness at HighMixture Stiffness at High

TemperatureStiffening effect = better rutting resistance

12

8

10

(%)

rut depth of AC 14

data from 4

6

rut d

epth

LCPC 1999

0

2

10 100 1 000 10 000 100 00010 100 1,000 10,000 100,000loading cycles

AC 14 35/50 AC 14 35/50 + 1.25% lime

Comparison of Fatigue Life1.0

AAD-1 AAM-1 AAD-1+HL AAD-1+LS AAM-1+HL

%)

Nf = A(strain)-B

Stra

in (%

S

0.11.E+03 1.E+04 1.E+05

Fatigue life

Resistance to Thermal CrackingThermal Stress Restrained Specimen (TSRST)

0 F T 6 F TState Mix

0 F-T 6 F-T

Fracture Stress (psi)

Fracture Temp (C)

Fracture Stress (psi)

Fracture Temp (C)

U d 368 24 333 24

AL

Un-treated 368 -24 333 -24

Liquid-treated 345 -26 304 -29

Lime-treated 406 -24 424 -27

CA

Un-treated 303 -10 210 -11

Liquid-treated 329 -11 300 -17

Lime-treated 404 -13 381 -13Lime treated 404 13 381 13

IL

Un-treated 375 -13 232 -16

Liquid-treated 275 -14 251 -16

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Lime-treated 426 -18 377 -16

Resistance to Thermal Crackingh l i d i ( )Thermal Stress Restrained Specimen (TSRST)

(Cont’d)

0 F T 6 F TState Mix

0 F-T 6 F-T

Fracture Stress (psi)

Fracture Temp (C)

Fracture Stress (psi)

Fracture Temp (C)

U d 292 19 126 25

SC

Un-treated 292 -19 126 -25

Liquid-treated 268 -17 229 -28

Lime-treated 311 -17 198 -15

TX

Un-treated 287 -19 210 -20

Liquid-treated 277 -19 235 -20

Lime-treated 353 -17 377 -18Lime treated 353 17 377 18

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OUTLINE Background T f Di t Types of Distress Benefits of Lime

Summary

Summary

Improve Performance Improve Performance Balance Pavement Thickness Design and

Mi D iMixture Design Lime offers some help

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Pavement Distress Lime Benefits

• Reduce AgingRaveling • Reduce Aging• Improved Resistance to Water

Bleeding • Increased Stiffness• Improved Resistance to Water

Rutting • Increased Stiffness• Improved Resistance to WaterImproved Resistance to Water

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Pavement Distress Lime Benefits

• Increased StiffnessFatigue Cracking • Increased Stiffness• Improved Resistance to Water

Thermal Cracking • Aging

Reflective Cracking • AgingReflective Cracking • Aging

Stripping • Improved Resistance to WaterI d Stiffpp g • Increased Stiffness

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