Test to Acess the Potencial for Moisture Damage in Asphalt Mixtures

8/18/2019 Test to Acess the Potencial for Moisture Damage in Asphalt Mixtures

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Tests to Assess the Potential for

Moisture Damage in Asphalt

Mixtures

Tests to Assess the Potential for

Moisture Damage in Asphalt

MixturesMike Anderson

Asphalt Institute Spring 2002 Meeting

Houston, TX


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Moisture Damage TestsMoisture Damage Tests

Pre-SHRPImmersion-Compression Test

Boil Test

Texas Freeze-Thaw Pedestal Test

Swell Test (Hveem)

Lottman Test

Root-Tunnicliff Test


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Moisture Damage TestsMoisture Damage Tests

Post-SHRPEnvironmental Conditioning System

Modified Lottman Test

Root-Tunnicliff Test

Hamburg Wheel Tracking Test


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Modified Lottman TestModified Lottman Test

Standard Procedure AASHTO T-283

Specimen Size

4-inch (100-mm) diameter; 2.5-inch (63-mm) height

6-inch (150-mm) diameter; 3.75-inch (95-mm) height ?

Percentage of Air Voids

Construction air voids

– 7.0 ± 1.0%


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AgingLoose Mix

– 16 hours at 60C in forced draft oven

Compacted Specimen

– 72-96 hours at ambient temperature (20-25C)


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Specimen Conditioning (Conditioned Subset)Partial Vacuum Saturation

– After compacted specimen aging

– Initial saturation of 55-80%


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Specimen Conditioning (continued)Freeze Cycle

– 15 hours at -18C

Thaw Cycle

– 24 hours at 60C


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Specimen Conditioning (All Specimens)Temperature Equilibration

– 2 hours at 25C (water bath)


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Mechanical TestIndirect Tensile Strength

– 50 mm/min. displacement rate

– Peak Load at Failure


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Test ResultTensile Strength Ratio

– Average Indirect Tensile Strength of Conditioned

Specimens (St,wet) – Average Indirect Tensile Strength of Conditioned

Specimens (St,dry)

TSR =TSR =SSt,wett,wet

SSt,dryt,dry


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Interpreting the ResultsTSR ≥ 0.80

– Acceptable resistance to moisture damage

Some agencies use TSR ≥ 0.70 as criterion

Mix Adjustments for Poor TSR

Liquid anti-stripping additives

Hydrated Lime

Change of aggregate/mix design


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Root-Tunnicliff TestRoot-Tunnicliff Test

Standard Procedure ASTM D4867

Specimen Size

4-inch (100-mm) diameter; 2.5-inch (63-mm) height

6-inch (150-mm) diameter; 3.75-inch (95-mm) height ?



– 7.0 ± 1.0%


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Aging

Loose Mix

– None required

Compacted Specimen

– None required (cool)

Specimen Conditioning (Conditioned Subset)Partial Vacuum Saturation

– Initial saturation of 55-80%


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Specimen Conditioning (continued)

Freeze Cycle

– 15 hours at -18C (OPTIONAL)

Thaw Cycle

– 24 hours at 60C

Specimen Conditioning (All Specimens)Temperature Equilibration

– 2 hours at 25C (water bath)


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Mechanical TestIndirect Tensile Strength

– 50 mm/min. displacement rate

– Peak Load at Failure


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Test ResultTensile Strength Ratio

– Average Indirect Tensile Strength of Conditioned

Specimens (St,wet) – Average Indirect Tensile Strength of Conditioned

Specimens (St,dry)

TSR =TSR =SSt,wett,wet

SSt,dryt,dry


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Interpreting the ResultsTSR ≥ 0.80

– Acceptable resistance to moisture damage

Some agencies use TSR ≥ 0.70 as criterion

Mix Adjustments for Poor TSR

Liquid anti-stripping additivesHydrated Lime

Change of aggregate/mix design


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Environmental Conditioning

System (ECS)

Environmental Conditioning

System (ECS)

Standard ProcedureSHRP-developed (A-003A)

Oregon State University (Terrel et. Al.)

Specimen Size

4-inch (100-mm) diameter; 4-inch (100-mm) height




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ECSECS


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ECSECS


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ECSECS

AgingLoose Mix

– 4 hours at 135C

Compacted Specimen

– None required (cool)


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ECSECS

Specimen Conditioning and TestingInitial Resilient Modulus (uniaxial)

Thawing Cycles (1+)

– 60C

– Repeated loading, Mr

Freeze Cycle – Optional

– Repeated Loading, Mr


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ECSECS

Interpreting the ResultsModulus Ratio

– Multiple conditioning cycles

– Accumulation of moisture damage


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Loaded Wheel TestsLoaded Wheel Tests

Test TemperatureHigh Temperatures (40-60C)

Conducted under water

Loading

Repeated Wheel Passes

– Pressurized rubber hose w/ wheel

– Steel wheel

– Pneumatic wheel


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Asphalt Pavement Analyzer Asphalt Pavement Analyzer


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Hamburg Wheel TrackerHamburg Wheel Tracker


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Hamburg Wheel Tracking TestHamburg Wheel Tracking Test

Rutting SlopeRutting Slope

Stripping SlopeStripping Slope

InflectionInflectionPointPoint

Load CyclesLoad Cycles

R u t D e p t h

R u t D e p t h


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Other TestsOther Tests

ECS Conditioning w/ Mechanical Property Test

00

0.0040.004

0.0080.008

0.0120.0120.0160.016

0.020.02

00 10001000 20002000 30003000 40004000

CyclesCycles

P e r m a n e n t S h e a r

S t r a i n

P e r m a n e n t S h e a r

S t r a i n

ECS ConditionedECS Conditioned

Dry (Unconditioned)Dry (Unconditioned)


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Other TestsOther Tests

Partial Vacuum Saturation w/ MechanicalProperty Tests

Arizona USArizona US--93 Moisture Sensitivity93 Moisture Sensitivity

75%75%

80%80%

85%85%

90%90%

95%95%100%100%

TSRTSR

DesignDesignTSRTSR

FieldFieldG*10HzG*10Hz

20C20C

TestTest

R a t i o

R a t i o

19mm

25mm

G*10HzG*10Hz

40C40C


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Test to Acess the Potencial for Moisture Damage in Asphalt Mixtures