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Warm Mix Asphalt Warm Mix Asphalt Evaluation Protocol Evaluation Protocol Brian D. Prowell, P.E. Brian D. Prowell, P.E. Graham C. Hurley Graham C. Hurley

Warm Mix Asphalt Evaluation Protocol -Prowell NEAUPG WMA Evaluation Prot… · Evotherm >10,000 Evotherm * One of two samples did not have striping inflection point in 10,000 cycles

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Page 1: Warm Mix Asphalt Evaluation Protocol -Prowell NEAUPG WMA Evaluation Prot… · Evotherm >10,000 Evotherm * One of two samples did not have striping inflection point in 10,000 cycles

Warm Mix Asphalt Warm Mix Asphalt Evaluation ProtocolEvaluation Protocol

Brian D. Prowell, P.E.Brian D. Prowell, P.E.Graham C. HurleyGraham C. Hurley

Page 2: Warm Mix Asphalt Evaluation Protocol -Prowell NEAUPG WMA Evaluation Prot… · Evotherm >10,000 Evotherm * One of two samples did not have striping inflection point in 10,000 cycles

Why Warm Asphalt?Why Warm Asphalt?•• Reduce production and laydown Reduce production and laydown

temperaturestemperatures•• Reduce emissionsReduce emissions•• Reduce energy costsReduce energy costs•• Reduce aging of binderReduce aging of binder•• Other Benefits:Other Benefits:

–– Cool weather paving (extend season)Cool weather paving (extend season)–– Compaction aid for stiff mixesCompaction aid for stiff mixes–– Reduce bumps from preReduce bumps from pre--existing crack sealantexisting crack sealant

While achieving the same or better density!

Page 3: Warm Mix Asphalt Evaluation Protocol -Prowell NEAUPG WMA Evaluation Prot… · Evotherm >10,000 Evotherm * One of two samples did not have striping inflection point in 10,000 cycles

What is Warm Mix Asphalt?What is Warm Mix Asphalt?

Several process have been developed to Several process have been developed to improve mixture workability allowing lower improve mixture workability allowing lower production and laydown temperaturesproduction and laydown temperatures–– WAM Foam WAM Foam ––KoloKolo VeidekkeVeidekke–– Zeolite Zeolite –– Eurovia/Hubbard ConstructionEurovia/Hubbard Construction–– Sasobit Sasobit –– Sasol International/Sasol AmericasSasol International/Sasol Americas–– Evotherm Evotherm –– MeadWestvacoMeadWestvaco–– Low Energy Asphalt Low Energy Asphalt -- FaircoFairco–– New Products under developmentNew Products under development

Page 4: Warm Mix Asphalt Evaluation Protocol -Prowell NEAUPG WMA Evaluation Prot… · Evotherm >10,000 Evotherm * One of two samples did not have striping inflection point in 10,000 cycles

L.E.AL.E.A’’s sequential mixings sequential mixing

C o a rs e a g g r e g a te s a r e c o a te d

b y a ll th e a s p h a lt

H o t a s p h a lt

D r y , h o t c o a rs e a g g r e g a te s

M o is tu re f ro m f in e a g g re g a te s t r ig g e rs a s p h a lt fo a m in g

F o a m e d a s p h a lt e n c a p s u la te s f in e a g g re g a te s

T h e rm a l e q u ilib r iu m re a c h e dA ll a g g r e g a te s u n ifo rm e ly c o a te d

1 2 0 ° /1 5 0 °C 1 7 0 °C

1 0 0 °C

9 0 °C

P H A S E 1 P H A S E 2

P H A S E 3 P H A S E 4 P H A S E 5

Courtesy of Fairco

Page 5: Warm Mix Asphalt Evaluation Protocol -Prowell NEAUPG WMA Evaluation Prot… · Evotherm >10,000 Evotherm * One of two samples did not have striping inflection point in 10,000 cycles

How does an Agency know How does an Agency know whether a new WMA whether a new WMA

additive/process or any new additive/process or any new asphalt additive will perform?asphalt additive will perform?

Page 6: Warm Mix Asphalt Evaluation Protocol -Prowell NEAUPG WMA Evaluation Prot… · Evotherm >10,000 Evotherm * One of two samples did not have striping inflection point in 10,000 cycles

By using a robust evaluation By using a robust evaluation protocol based on protocol based on performance performance

testingtesting

Page 7: Warm Mix Asphalt Evaluation Protocol -Prowell NEAUPG WMA Evaluation Prot… · Evotherm >10,000 Evotherm * One of two samples did not have striping inflection point in 10,000 cycles

How can a WMA product effect How can a WMA product effect performance?performance?

•• Binder propertiesBinder properties•• Mix designMix design•• Rutting performanceRutting performance•• Cracking potentialCracking potential

–– FatigueFatigue–– Low TemperatureLow Temperature

•• Moisture damageMoisture damage•• Field CompactionField Compaction

Page 8: Warm Mix Asphalt Evaluation Protocol -Prowell NEAUPG WMA Evaluation Prot… · Evotherm >10,000 Evotherm * One of two samples did not have striping inflection point in 10,000 cycles

Specific ConcernsSpecific Concerns

•• Does the WMA improve field compaction Does the WMA improve field compaction (their purpose)?(their purpose)?

•• If the aging of the binder is reduced due to If the aging of the binder is reduced due to lower production temperatures, is rutting lower production temperatures, is rutting more likely?more likely?

•• If WMA improves field compaction, when If WMA improves field compaction, when does that improvement end, e.g. what does that improvement end, e.g. what happens if you dump traffic on the road at happens if you dump traffic on the road at 6:00 AM while it is still hot?6:00 AM while it is still hot?

Page 9: Warm Mix Asphalt Evaluation Protocol -Prowell NEAUPG WMA Evaluation Prot… · Evotherm >10,000 Evotherm * One of two samples did not have striping inflection point in 10,000 cycles

Specific Concerns (Continued)Specific Concerns (Continued)

•• Is moisture damage more likely if the Is moisture damage more likely if the aggregates are not completely dry due aggregates are not completely dry due to lower temperatures?to lower temperatures?

•• Will a wax additive increase the Will a wax additive increase the likelihood for low temperature cracking?likelihood for low temperature cracking?

•• Is mixture stiffness (modulus) reduced Is mixture stiffness (modulus) reduced by decreased aging of the binder?by decreased aging of the binder?

Page 10: Warm Mix Asphalt Evaluation Protocol -Prowell NEAUPG WMA Evaluation Prot… · Evotherm >10,000 Evotherm * One of two samples did not have striping inflection point in 10,000 cycles

NCAT, with the assistance of Dr. NCAT, with the assistance of Dr. Mary StroupMary Stroup--Gardiner from AU, Gardiner from AU,

developed an evaluation protocol developed an evaluation protocol to address these questionsto address these questions

A separate standardized field data A separate standardized field data collection/evaluation protocol has been collection/evaluation protocol has been

developed by the FHWA/NAPA Warm Mix developed by the FHWA/NAPA Warm Mix Asphalt TWGAsphalt TWG

Page 11: Warm Mix Asphalt Evaluation Protocol -Prowell NEAUPG WMA Evaluation Prot… · Evotherm >10,000 Evotherm * One of two samples did not have striping inflection point in 10,000 cycles

Evaluate Potential for Low Evaluate Potential for Low Temperature CrackingTemperature Cracking

•• Low temperature cracking potential is primarily Low temperature cracking potential is primarily related to the binder propertiesrelated to the binder properties

•• Used AASHTO MPUsed AASHTO MP--1A to evaluate low temperature 1A to evaluate low temperature cracking potentialcracking potential

•• Probably overly conservative if product used to Probably overly conservative if product used to reduce production temperaturesreduce production temperatures

•• Lower production temperature Lower production temperature --> reduced aging of > reduced aging of the binder the binder --> reduced stiffness for some period of > reduced stiffness for some period of timetime

•• Superpave IDT test included in field evaluation Superpave IDT test included in field evaluation protocol on reheated materialprotocol on reheated material

Page 12: Warm Mix Asphalt Evaluation Protocol -Prowell NEAUPG WMA Evaluation Prot… · Evotherm >10,000 Evotherm * One of two samples did not have striping inflection point in 10,000 cycles

Sasobit Binder TestsSasobit Binder Tests

Test PG58-28 Base

PG64-22

Control

PG64-22 Sasobit®

PG70-22 Sasoflex

PG76-22

PG76-22 Sasoflex

Modifier None None 2.5% Sasobit® 4% Sasoflex None 4% Sasoflex

Test Temp., °C 58 64 64 70 76 76

Original DSR, G*/sin δ, kPa 1.015 1.815 1.790 2.689 1.290 1.461

RTFO DSR, G*/sin δ, kPa 2.781 3.868 3.950 4.548 3.096 2.682

Test Temp., °C 19 25 25 28 31 31

PAV DSR. G*sinδ, kPa 4138 3554 2906 2448 1059 2635

Test Temp., °C -18 -12 -12 -12 -12 -12

BBR Creep Stiffness (S), MPa

248 208 164 153 165 251

BBR m-value 0.316 0.317 0.306 0.328 0.315 0.292

Page 13: Warm Mix Asphalt Evaluation Protocol -Prowell NEAUPG WMA Evaluation Prot… · Evotherm >10,000 Evotherm * One of two samples did not have striping inflection point in 10,000 cycles

Evaluate Effect on Mix DesignEvaluate Effect on Mix Design

•• Chose a virgin mix design with a granite Chose a virgin mix design with a granite aggregate used by a contractor supplying one aggregate used by a contractor supplying one of the additivesof the additives–– Original mix design was Ndesign = 125Original mix design was Ndesign = 125–– Coarse gradedCoarse graded

•• Replicated mix design with limestone Replicated mix design with limestone aggregateaggregate

•• Aged and compacted samples at 190, 230, Aged and compacted samples at 190, 230, 265 and 300265 and 300°°F, samples mixed 35F, samples mixed 35°°F higher F higher temperaturetemperature

Page 14: Warm Mix Asphalt Evaluation Protocol -Prowell NEAUPG WMA Evaluation Prot… · Evotherm >10,000 Evotherm * One of two samples did not have striping inflection point in 10,000 cycles

Limestone - SGC

0.0

1.0

2.0

3.0

4.0

5.0

6.0

190 230 265 300Compaction Temperature, F

Air

Void

s, %

PG 58-28 Aspha-min PG 58-28 Control PG 64-22 Aspha-min PG 64-22 Control

Samples mixed 35F above compaction temperature

Page 15: Warm Mix Asphalt Evaluation Protocol -Prowell NEAUPG WMA Evaluation Prot… · Evotherm >10,000 Evotherm * One of two samples did not have striping inflection point in 10,000 cycles

Limestone

0

1

2

3

4

5

6

13.5 14 14.5 15 15.5 16VMA, %

Air

Voi

ds, %

Control Zeolite Sasobit Evotherm

190F

Page 16: Warm Mix Asphalt Evaluation Protocol -Prowell NEAUPG WMA Evaluation Prot… · Evotherm >10,000 Evotherm * One of two samples did not have striping inflection point in 10,000 cycles

Measuring Field Measuring Field CompactabilityCompactability

•• Not SGC Not SGC –– Constant shear deviceConstant shear device•• Constant stress device better simulates a Constant stress device better simulates a

roller in the fieldroller in the field–– Rolling wheel compactorRolling wheel compactor–– PTI vibratory compactorPTI vibratory compactor

•• NCAT used vibratory compactor since we did NCAT used vibratory compactor since we did not have a rolling wheelnot have a rolling wheel

•• Used vibratory compactor to produce Used vibratory compactor to produce performance specimens since density effects performance specimens since density effects performanceperformance

Page 17: Warm Mix Asphalt Evaluation Protocol -Prowell NEAUPG WMA Evaluation Prot… · Evotherm >10,000 Evotherm * One of two samples did not have striping inflection point in 10,000 cycles

ModulusModulus•• Stiffness of HMA input for MStiffness of HMA input for M--E pavement E pavement

designdesign•• Dynamic modulusDynamic modulus

–– Recommended for field evaluation protocolRecommended for field evaluation protocol–– Preparing samples in field without reheating can Preparing samples in field without reheating can

be hit or missbe hit or miss•• Resilient modulusResilient modulus

–– DiametralDiametral test used in test used in NCATNCAT’’ss laboratory laboratory evaluationsevaluations

–– Testing variability can mask differencesTesting variability can mask differences

Page 18: Warm Mix Asphalt Evaluation Protocol -Prowell NEAUPG WMA Evaluation Prot… · Evotherm >10,000 Evotherm * One of two samples did not have striping inflection point in 10,000 cycles

Test Samples for SPT TestsTest Samples for SPT Tests

150 mm tall by 100 mm diameter, cored from SGC

Page 19: Warm Mix Asphalt Evaluation Protocol -Prowell NEAUPG WMA Evaluation Prot… · Evotherm >10,000 Evotherm * One of two samples did not have striping inflection point in 10,000 cycles

Agg

C or W

Temp

Binder

64-2

258

-28

WC 300

265

230

190

400000

320000

240000

400000

320000

240000

400000

320000

240000

AggGraniteLMS

Binder58-2864-22

C or WCW

Interaction Plot for Resilient Modulus

Page 20: Warm Mix Asphalt Evaluation Protocol -Prowell NEAUPG WMA Evaluation Prot… · Evotherm >10,000 Evotherm * One of two samples did not have striping inflection point in 10,000 cycles

Rutting SusceptibilityRutting Susceptibility

•• Simple Performance TestSimple Performance Test–– Repeated load permanent deformationRepeated load permanent deformation–– Field protocol recommends testing at Field protocol recommends testing at

climatic high temperature climatic high temperature -- 66°°, e.g. 64 , e.g. 64 –– 6 = 6 = 5858°°C and 600 C and 600 kPakPa

•• Torture TestTorture Test–– Asphalt Pavement Analyzer at climatic high Asphalt Pavement Analyzer at climatic high

temperaturetemperature–– Hamburg TestHamburg Test

Page 21: Warm Mix Asphalt Evaluation Protocol -Prowell NEAUPG WMA Evaluation Prot… · Evotherm >10,000 Evotherm * One of two samples did not have striping inflection point in 10,000 cycles

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

16.00

18.00

20.00

Control Zeolite Sasobit Evotherm

Rut

Dep

th, m

m

300F 265F 230F 190F

APA Rut Depth for PG 64APA Rut Depth for PG 64--22 22 -- GraniteGranite

Page 22: Warm Mix Asphalt Evaluation Protocol -Prowell NEAUPG WMA Evaluation Prot… · Evotherm >10,000 Evotherm * One of two samples did not have striping inflection point in 10,000 cycles

Air Voids Resilient Modulus APA Rutting 265 230 265 230 265 230

None = (0.8895)

= (0.1161)

= (0.9695)

= (0.9969)

= (0.3071)

< (0.0002)

Zeolite = (0.2250)

> (0.0122)

= (0.9968)

= (0.9391)

< (0.0025)

< (0.0420)

Sasobit > (0.0006)

> (0.0059)

= (1.0000)

= (0.8911)

= (0.9926)

= (0.9752)

Evotherm > (0.0000)

> (0.0001)

= (0.9801)

= (0.9987)

= (0.9833)

< (0.0087)

Comparison of Additives to Comparison of Additives to Hot Mix Produced at 300FHot Mix Produced at 300F

Page 23: Warm Mix Asphalt Evaluation Protocol -Prowell NEAUPG WMA Evaluation Prot… · Evotherm >10,000 Evotherm * One of two samples did not have striping inflection point in 10,000 cycles

Strength GainStrength Gain•• WMA materials improve compactionWMA materials improve compaction•• What happens, if anything, if you open What happens, if anything, if you open

roadway to traffic while WMA is still hot?roadway to traffic while WMA is still hot?•• Basically looking at a change in binder Basically looking at a change in binder

properties with timeproperties with time•• For example, true emulsion mixes will For example, true emulsion mixes will ““curecure””

to a higher strengthto a higher strength•• Indirect tensile strength sensitive to binder Indirect tensile strength sensitive to binder

stiffnessstiffness

Page 24: Warm Mix Asphalt Evaluation Protocol -Prowell NEAUPG WMA Evaluation Prot… · Evotherm >10,000 Evotherm * One of two samples did not have striping inflection point in 10,000 cycles

Strength Gain ExperimentStrength Gain ExperimentZeolite Strength Gain

0

20

40

60

80

100

120

140

2 Hours 4 Hours 2 Hours +1 Day

2 Hours +3 Days

2 Hours +5 Days

Tens

ile S

tren

gth,

psi

WarmControl

Page 25: Warm Mix Asphalt Evaluation Protocol -Prowell NEAUPG WMA Evaluation Prot… · Evotherm >10,000 Evotherm * One of two samples did not have striping inflection point in 10,000 cycles

Moisture SusceptibilityMoisture Susceptibility

•• Laboratory moisture susceptibility tests Laboratory moisture susceptibility tests typically performed on oven dry aggregatestypically performed on oven dry aggregates

•• Lower production temperatures used in WMA Lower production temperatures used in WMA may result in incomplete drying of aggregatesmay result in incomplete drying of aggregates

•• Need to simulate field conditions in laboratoryNeed to simulate field conditions in laboratory•• For field trials,For field trials, samples prepared in the samples prepared in the

field without reheatingfield without reheating

Page 26: Warm Mix Asphalt Evaluation Protocol -Prowell NEAUPG WMA Evaluation Prot… · Evotherm >10,000 Evotherm * One of two samples did not have striping inflection point in 10,000 cycles

Simulating a Drum PlantSimulating a Drum Plant

Page 27: Warm Mix Asphalt Evaluation Protocol -Prowell NEAUPG WMA Evaluation Prot… · Evotherm >10,000 Evotherm * One of two samples did not have striping inflection point in 10,000 cycles

Failure ModesFailure Modes

Adhesive Cohesive

Page 28: Warm Mix Asphalt Evaluation Protocol -Prowell NEAUPG WMA Evaluation Prot… · Evotherm >10,000 Evotherm * One of two samples did not have striping inflection point in 10,000 cycles

Granite TSRGranite TSR

AdditiveAdditiveDry Dry

AggregateAggregate300F300F

SSD+ in SSD+ in Bucket Bucket Mixer at Mixer at

250F250F

Bucket Bucket Mixer WithMixer WithAntiAnti--StripStrip

AntiAnti--Strip Strip AgentAgent

HMAHMA 0.970.97 1.161.16 0.860.86

0.870.87

0.94*0.94*

NANA

0.75% LOF 0.75% LOF 65006500

ZeoliteZeolite 0.810.81 0.670.67 1.5% Lime1.5% Lime

SasobitSasobit 0.68 (250F)0.68 (250F) 0.710.71 0.4% 0.4% MagnabondMagnabond

EvothermEvotherm NANA 0.960.96

* Dry Strength 17.5 psi, wet strength 16.5 psi

Page 29: Warm Mix Asphalt Evaluation Protocol -Prowell NEAUPG WMA Evaluation Prot… · Evotherm >10,000 Evotherm * One of two samples did not have striping inflection point in 10,000 cycles

PG 64-22 Granite

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

18.0

20.0

0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000 10,000

Cycle

Ham

burg

Rut

Dep

th, m

m

Control Sasobit

Test Terminated

Stripping Inflection Point

Page 30: Warm Mix Asphalt Evaluation Protocol -Prowell NEAUPG WMA Evaluation Prot… · Evotherm >10,000 Evotherm * One of two samples did not have striping inflection point in 10,000 cycles

Granite Hamburg Stripping Granite Hamburg Stripping Inflection PointInflection Point

AdditiveAdditiveSSD+ in SSD+ in

Bucket Mixer Bucket Mixer at 250Fat 250F

Bucket Mixer Bucket Mixer WithWith

AntiAnti--StripStrip

AntiAnti--Strip Strip AgentAgent

HMAHMA 6500*6500* NANA

8500*8500*

>10,000>10,000

NANA

0.75% LOF 0.75% LOF 65006500

ZeoliteZeolite 39753975 1.5% Lime1.5% Lime

SasobitSasobit 34503450 0.4% 0.4% MagnabondMagnabond

EvothermEvotherm >10,000>10,000 EvothermEvotherm

* One of two samples did not have striping inflection point in 10,000 cycles

Page 31: Warm Mix Asphalt Evaluation Protocol -Prowell NEAUPG WMA Evaluation Prot… · Evotherm >10,000 Evotherm * One of two samples did not have striping inflection point in 10,000 cycles

Thoughts on Moisture Thoughts on Moisture SusceptibilitySusceptibility

•• Many do not Many do not ““trusttrust”” TSR testTSR test•• Hamburg is severe alternativeHamburg is severe alternative•• If mixtures pass Hamburg, they should If mixtures pass Hamburg, they should

perform in the fieldperform in the field•• Environmental conditioning system and Environmental conditioning system and

SPT for future?SPT for future?

Page 32: Warm Mix Asphalt Evaluation Protocol -Prowell NEAUPG WMA Evaluation Prot… · Evotherm >10,000 Evotherm * One of two samples did not have striping inflection point in 10,000 cycles

Field SectionsField Sections

Numerous U.S. sections to dateNumerous U.S. sections to dateWorld wide in denseWorld wide in dense--grade, SMA and OGFCgrade, SMA and OGFC

Page 33: Warm Mix Asphalt Evaluation Protocol -Prowell NEAUPG WMA Evaluation Prot… · Evotherm >10,000 Evotherm * One of two samples did not have striping inflection point in 10,000 cycles

Seeing is Believing!Seeing is Believing!Orlando, FL Orlando, FL -- 20042004

Hot Mix 314 F Aspha-min Mix 254 F

138.1 pcf 138.5 pcf

Page 34: Warm Mix Asphalt Evaluation Protocol -Prowell NEAUPG WMA Evaluation Prot… · Evotherm >10,000 Evotherm * One of two samples did not have striping inflection point in 10,000 cycles

MD SMA Sasobit Trial MD SMA Sasobit Trial Capital Beltway Capital Beltway -- 20052005

Page 35: Warm Mix Asphalt Evaluation Protocol -Prowell NEAUPG WMA Evaluation Prot… · Evotherm >10,000 Evotherm * One of two samples did not have striping inflection point in 10,000 cycles

OGFC with Sasobit OGFC with Sasobit Beijing, China Beijing, China -- 20052005

•Breakdown - 95°C (203°F)

•Finish - 75°C (167°F)Courtesy of Don Watson

Page 36: Warm Mix Asphalt Evaluation Protocol -Prowell NEAUPG WMA Evaluation Prot… · Evotherm >10,000 Evotherm * One of two samples did not have striping inflection point in 10,000 cycles

1

2

3

4

5

6

7

8

Wearing Control Wearing PG 67-22Evotherm

Wearing PG 67-22Evotherm with 3% Latex

AP

A R

ut D

epth

, mm

NCAT Test Track NCAT Test Track -- APAAPA

Page 37: Warm Mix Asphalt Evaluation Protocol -Prowell NEAUPG WMA Evaluation Prot… · Evotherm >10,000 Evotherm * One of two samples did not have striping inflection point in 10,000 cycles

The Lab/Field DisconnectThe Lab/Field Disconnect

Page 38: Warm Mix Asphalt Evaluation Protocol -Prowell NEAUPG WMA Evaluation Prot… · Evotherm >10,000 Evotherm * One of two samples did not have striping inflection point in 10,000 cycles

Evotherm Field Rut Depths - NCAT Test Track

0.00

0.20

0.40

0.60

0.80

1.00

1.20

1.40

1.60

1.80

PG 67-22 Control Evotherm PG 67-22 Evotherm PG 67-22 w/ 3%Latex

Rut

Dep

th, m

m

Rut Depths after 500,000 ESALs

Page 39: Warm Mix Asphalt Evaluation Protocol -Prowell NEAUPG WMA Evaluation Prot… · Evotherm >10,000 Evotherm * One of two samples did not have striping inflection point in 10,000 cycles

Elements for Field TrialsElements for Field Trials•• Samples of raw materialsSamples of raw materials•• Mix DesignMix Design

–– Aggregate propertiesAggregate properties•• TrafficTraffic•• Volumetric propertiesVolumetric properties

–– Without reheating (contractor)Without reheating (contractor)–– Reheated (agency)Reheated (agency)

•• Performance testsPerformance tests–– Rutting Rutting –– APA and SPTAPA and SPT–– E*E*–– TSR and/or HamburgTSR and/or Hamburg–– Fatigue (should be better)Fatigue (should be better)–– Low Temperature IDTLow Temperature IDT

•• InIn--place densityplace density–– Bond strengthBond strength–– Change in density with timeChange in density with time

Page 40: Warm Mix Asphalt Evaluation Protocol -Prowell NEAUPG WMA Evaluation Prot… · Evotherm >10,000 Evotherm * One of two samples did not have striping inflection point in 10,000 cycles

Missouri NMissouri Ndesigndesign VTMVTM

0

1

2

3

4

5

6

7

300 250 250 250 225 225 250 250 225 225

Compaction Temperature F

SG

C A

ir V

oids

, %

Compacted Hot Reheated

Control Sasobit Evotherm

Average of six samples

Page 41: Warm Mix Asphalt Evaluation Protocol -Prowell NEAUPG WMA Evaluation Prot… · Evotherm >10,000 Evotherm * One of two samples did not have striping inflection point in 10,000 cycles

Missouri APA Rut DepthMissouri APA Rut Depth

0

1

2

3

4

5

6

7

300 250 250 250 225 225 250 250 225 225

Compaction Temperature F

APA

Rut

Dep

th, m

m

Compacted Hot Reheated

Control Sasobit Evotherm

Average of six samples

Burner Fuel?

Page 42: Warm Mix Asphalt Evaluation Protocol -Prowell NEAUPG WMA Evaluation Prot… · Evotherm >10,000 Evotherm * One of two samples did not have striping inflection point in 10,000 cycles

Missouri TSRMissouri TSR

Average of six samples

0.00

0.20

0.40

0.60

0.80

1.00

1.20

300 250 250 250 225 225 250 250 225 225

Compaction Temperature F

TSR

Compacted Hot Reheated

Control Sasobit Evotherm

NA

Page 43: Warm Mix Asphalt Evaluation Protocol -Prowell NEAUPG WMA Evaluation Prot… · Evotherm >10,000 Evotherm * One of two samples did not have striping inflection point in 10,000 cycles

Things We Need to Go ForwardThings We Need to Go Forward

•• Larger trials Larger trials –– Ongoing!Ongoing!•• A robust product evaluation protocol A robust product evaluation protocol –– Draft Draft

Developed!Developed!•• Better understanding of effect on rutting and Better understanding of effect on rutting and

moisture damage moisture damage –– Lab vs. FieldLab vs. Field•• Procedures for mix design and QC/QA (Do Procedures for mix design and QC/QA (Do

they need to be different?)they need to be different?)•• A way for Agencies to specifyA way for Agencies to specify

–– Temperature reduction?Temperature reduction?–– Binder grade?Binder grade?

Page 44: Warm Mix Asphalt Evaluation Protocol -Prowell NEAUPG WMA Evaluation Prot… · Evotherm >10,000 Evotherm * One of two samples did not have striping inflection point in 10,000 cycles

The Bottom LineThe Bottom Line

What ever we add to HMA or however What ever we add to HMA or however we decide to make HMA differently, we we decide to make HMA differently, we need a means to evaluate the change need a means to evaluate the change to ensure that it will give us equal or to ensure that it will give us equal or

better performancebetter performance

Page 45: Warm Mix Asphalt Evaluation Protocol -Prowell NEAUPG WMA Evaluation Prot… · Evotherm >10,000 Evotherm * One of two samples did not have striping inflection point in 10,000 cycles

Performance Tests: WhatPerformance Tests: What’’s s Needed (Circa 2004)Needed (Circa 2004)

•• Accurate and precise performance tests Accurate and precise performance tests we are confident inwe are confident in

•• Timely resultsTimely results•• User friendlyUser friendly•• Relationship between the test results Relationship between the test results

and field performanceand field performance•• Relationship between reduced field Relationship between reduced field

performance and costperformance and cost

Page 46: Warm Mix Asphalt Evaluation Protocol -Prowell NEAUPG WMA Evaluation Prot… · Evotherm >10,000 Evotherm * One of two samples did not have striping inflection point in 10,000 cycles

For More Information:www.ncat.usNCAT 05-04 Aspha-minNCAT 05-06 SasobitNCAT 06-02 Evotherm