civl 598 asphalt paving materials asphalt rubber

CIVL 598 Asphalt Paving Materials CIVL 598 Asphalt Paving Materials

Asphalt Rubber Asphalt Rubber

This LectureThis Lecture

Module 1: Introduction of ARModule 1: Introduction of AR

Module 2: Structural Design of RACModule 2: Structural Design of RAC

Module 3: AR MaterialModule 3: AR Material

Module 4: ConstructionModule 4: Construction

Module 5: Inspection GuideModule 5: Inspection Guide

5.0 Inspection 5.0 Inspection GuideGuide

Operation, Production, and Operation, Production, and Trouble ShootingTrouble Shooting

AC Plant OperationsAC Plant Operations

Plant operations during RAC mix Plant operations during RAC mix production are essentially the same as production are essentially the same as for standard AC mix production. CT 109 for standard AC mix production. CT 109 requirements apply.requirements apply.

DifferencesDifferences Production and monitoring of the asphalt Production and monitoring of the asphalt

rubber binder for wet process mixes.rubber binder for wet process mixes. Plant mixing temperatures of 300-325Plant mixing temperatures of 300-325ºF ºF

may be slightly higher than usual.may be slightly higher than usual.

AR Binder ProductionAR Binder Production

Required DocumentationRequired Documentation AR Binder Design Profile, includingAR Binder Design Profile, including

Component identification and proportionsComponent identification and proportions CRM gradationsCRM gradations AR test results showing compliance with AR test results showing compliance with

specificationsspecifications Certificates of Compliance for Certificates of Compliance for

componentscomponents Asphalt CementAsphalt Cement Asphalt Modifier (Extender Oil)Asphalt Modifier (Extender Oil) Scrap Tire CRMScrap Tire CRM High Natural CRMHigh Natural CRM

Asphalt Rubber Blend Design Example Design Asphalt Rubber Blend Design Example Design ProfileProfile

Minutes of ReactionMinutes of Reaction Spec. Limits @ Spec. Limits @ 45 minutes45 minutes

(Caltrans (Caltrans 12/2005)12/2005)

TESTTEST 4545 9090 240240 360360 1,441,4400

Viscosity, cP Viscosity, cP Haake@ 190Haake@ 190ººCC 240240

0028028000

28028000

28028000

21002100 1500 - 40001500 - 4000

Resilience@ Resilience@ 2525ººC (% C (% Rebound)Rebound)(ASTM D 5329)(ASTM D 5329)

2727 ---- 3333 ---- 2323 18 Minimum18 Minimum

R & B R & B Softening Pt., Softening Pt., ººC (C (ASTM D36)ASTM D36)

59.059.0 59.559.5 59.559.5 60.060.0 58.558.552 – 7452 – 74

(125-165(125-165ºF)ºF)

Cone Pen @ Cone Pen @ 2525ººCC(ASTM D217)(ASTM D217)

3939 ---- 4646 ---- 5050 25 – 7025 – 70


Inspection itemsInspection items Batch sheets or production logs for Batch sheets or production logs for

AR binder that show the amounts AR binder that show the amounts (typically by mass) of the (typically by mass) of the components used. Check proportions components used. Check proportions of: of: Asphalt CementAsphalt Cement Extender oilExtender oil Scrap tire CRMScrap tire CRM High natural CRMHigh natural CRM


The AR binder production logs or The AR binder production logs or viscosity testing logs should indicate viscosity testing logs should indicate when the CRM was added. when the CRM was added.

Before adding AR binder to the aggregate:Before adding AR binder to the aggregate: Verify minimum AR interaction time of 45 Verify minimum AR interaction time of 45

minutes has elapsedminutes has elapsed Verify AR binder viscosity meets or Verify AR binder viscosity meets or

exceeds the minimum 1500 cPs exceeds the minimum 1500 cPs requirement at 375requirement at 375ºFºF

Continue to monitor viscosity hourly Continue to monitor viscosity hourly during RAC mix productionduring RAC mix production


Follow sampling and testing frequency Follow sampling and testing frequency requirements listed in the project special requirements listed in the project special provisions for AR binder and individual provisions for AR binder and individual components. components. Typically, at least one one-gallon sample should Typically, at least one one-gallon sample should

be obtained from each batch of binder produced. be obtained from each batch of binder produced. Of these, some samples would be randomly Of these, some samples would be randomly

selected and tested for specification compliance.selected and tested for specification compliance.

Take additional samples if any changes or Take additional samples if any changes or discrepancies are observed in any of the discrepancies are observed in any of the materials.materials.


As long as interaction time and As long as interaction time and viscosity meet or exceed viscosity meet or exceed minimum requirements, the AR minimum requirements, the AR binder may be added to the binder may be added to the aggregate, even if viscosity aggregate, even if viscosity differs from values shown in the differs from values shown in the design profile. design profile.

The design profile serves as a guide, not as a The design profile serves as a guide, not as a specification. If viscosity during production specification. If viscosity during production differs from design profile by 400 cPs or more differs from design profile by 400 cPs or more for corresponding interaction interval, obtain a for corresponding interaction interval, obtain a binder sample for compliance testing. binder sample for compliance testing.


If viscosity falls below the minimum limit If viscosity falls below the minimum limit of 1500 cPs, the AR binder cannot be used of 1500 cPs, the AR binder cannot be used to make RAC.to make RAC.

To restore viscosity, the AR binder producer may To restore viscosity, the AR binder producer may add up to 10% more CRM (using the design ratios add up to 10% more CRM (using the design ratios of scrap tire and high natural CRM) by total of scrap tire and high natural CRM) by total binder mass. binder mass.

The amount of CRM added shall be documented.The amount of CRM added shall be documented. An additional 45 minute interaction period is An additional 45 minute interaction period is

required after CRM addition. required after CRM addition. Viscosity of the “adjusted” AR binder must Viscosity of the “adjusted” AR binder must

comply with viscosity specifications in order to comply with viscosity specifications in order to proceed with RAC mix production.proceed with RAC mix production.

RAC Mix ProductionRAC Mix Production

Required DocumentationRequired Documentation RAC Mix Design including:RAC Mix Design including:

Individual and combined aggregate gradationsIndividual and combined aggregate gradations Results of individual and combined aggregate Results of individual and combined aggregate

quality testsquality tests Aggregate source(s) and blend proportionsAggregate source(s) and blend proportions Theoretical maximum specific gravity/densityTheoretical maximum specific gravity/density Design AR binder contentDesign AR binder content Design air voids contentDesign air voids content Design VMADesign VMA Hveem StabilityHveem Stability


Verify AC plant complies with CT 109 requirements.Verify AC plant complies with CT 109 requirements. Check aggregate bins.Check aggregate bins. Sample aggregate cold feed or hot bins as Sample aggregate cold feed or hot bins as

appropriate and verify gradation. Test Sand appropriate and verify gradation. Test Sand Equivalent as required.Equivalent as required.

Verify RAC mixing and discharge temperatures.Verify RAC mixing and discharge temperatures. Visually inspect the RAC mix in the haul truck before Visually inspect the RAC mix in the haul truck before

it leaves the plant.it leaves the plant. Sample and test RAC mix according to the project Sample and test RAC mix according to the project

special provisions. Tests include gradation, AR special provisions. Tests include gradation, AR binder content, maximum theoretical specific binder content, maximum theoretical specific gravity, lab-compacted air voids, and Hveem gravity, lab-compacted air voids, and Hveem stability.stability.


Verify that haul trucks are tarped.Verify that haul trucks are tarped. Maintain inspector's log of pertinent Maintain inspector's log of pertinent

information, including but not limited information, including but not limited to: to: List of samples obtainedList of samples obtained Plant test results (aggregates and mix) Plant test results (aggregates and mix) Quantities of AR binder and RAC mixQuantities of AR binder and RAC mix Binder production temperatures and Binder production temperatures and

viscosity measurements, etc.viscosity measurements, etc. Other required informationOther required information


May use Caltrans Form CEM-May use Caltrans Form CEM-3501, AC Production/Placement 3501, AC Production/Placement Checklist modified for RACChecklist modified for RAC

Inspection at Paving SiteInspection at Paving Site

Before Overlay Placement:Before Overlay Placement: Verify surface preparation is completeVerify surface preparation is complete

Cracks treated or sealed?Cracks treated or sealed? Damaged areas repaired?Damaged areas repaired? Milling properly completed (if applicable)?Milling properly completed (if applicable)? Surface clean and swept?Surface clean and swept? Tack coat properly applied?Tack coat properly applied?

Verify ambient and pavement Verify ambient and pavement temperatures are at least 55temperatures are at least 55ºF and risingºF and rising


EquipmentEquipment Verify that paver and rollers meet size Verify that paver and rollers meet size

requirements, are in good working condition, requirements, are in good working condition, and qualified operators are on-siteand qualified operators are on-site

Verify sufficient steel-tired rollers are Verify sufficient steel-tired rollers are available for breakdown and intermediate available for breakdown and intermediate compaction. compaction.

Breakdown rollers must have vibratory Breakdown rollers must have vibratory capabilitycapability

Delivery method: Do not use windrows if Delivery method: Do not use windrows if ambient temperature is marginally cold.ambient temperature is marginally cold.


Caltrans requirements for RAC-G, Caltrans requirements for RAC-G, ambient temperature <65ambient temperature <65ºFºF::

RAC-G spread temperature 290-325RAC-G spread temperature 290-325ºFºF Minimum temperature for breakdown Minimum temperature for breakdown

rolling is 280rolling is 280ºFºF VVibratory mode is required for RAC-G ibratory mode is required for RAC-G

breakdownbreakdown Complete breakdown before RAC mat Complete breakdown before RAC mat

temperature drops below 260temperature drops below 260ºFºF


Less stringent for Less stringent for ambient ambient temperature temperature ≥ ≥ 6565ºFºF

Other jurisdictions recommend Other jurisdictions recommend minimum 290ºF for breakdown rolling minimum 290ºF for breakdown rolling or completion thereofor completion thereof

Compaction requirements will be Compaction requirements will be implemented for RAC-G mixes in the implemented for RAC-G mixes in the future, with acceptance based on future, with acceptance based on corescores


Caltrans placement temperature requirements for Caltrans placement temperature requirements for RAC-O and RAC-O-HB ambient temperature <65RAC-O and RAC-O-HB ambient temperature <65ºF ºF are the sare the same as for RAC-G. ame as for RAC-G.

Other jurisdictions do not recommend placing Other jurisdictions do not recommend placing RAC-O at temperatures <65RAC-O at temperatures <65ºF.ºF.

For open-graded RAC mixes, use static mode for For open-graded RAC mixes, use static mode for breakdown compaction. breakdown compaction. Do not use vibratory Do not use vibratory mode. mode. Percent compaction is not a requirement for Percent compaction is not a requirement for open-graded mixes.open-graded mixes.


During RAC placement:During RAC placement: Collect load tickets and track tonnage Collect load tickets and track tonnage

placedplaced Measure placement thickness and Measure placement thickness and

calculate yield calculate yield Observe coordination between RAC Observe coordination between RAC

delivery and placement – record if trucks delivery and placement – record if trucks or paver are waitingor paver are waiting

Note any rejected loads of RACNote any rejected loads of RAC Observe delivery operations - are good Observe delivery operations - are good

practices being used?practices being used?


Record if windrows are used.Record if windrows are used. Monitor RAC temperatures at spread and during Monitor RAC temperatures at spread and during

breakdown and intermediate compaction.breakdown and intermediate compaction. Observe paver operations – note discrepancies Observe paver operations – note discrepancies

from good practice that might impact quality of from good practice that might impact quality of joints or ride (smoothness).joints or ride (smoothness).

Joints at proper locations?Joints at proper locations? Observe raking, luting, handwork. Broadcasting Observe raking, luting, handwork. Broadcasting

of excess mix or over-raking will damage the of excess mix or over-raking will damage the appearance of the finished pavement.appearance of the finished pavement.


Observe compaction operations – note Observe compaction operations – note discrepancies from good practice that discrepancies from good practice that might impact in-place densitymight impact in-place density Breakdown roller(s) following immediately Breakdown roller(s) following immediately

behind paver?behind paver? Breakdown roller(s) using vibratory mode?Breakdown roller(s) using vibratory mode? Sufficient breakdown rollers operating to Sufficient breakdown rollers operating to

keep up with paver? keep up with paver? Intermediate static roller(s) keeping up?Intermediate static roller(s) keeping up? Finish rollers effective?Finish rollers effective?


Rules of Thumb for RAC-G compaction:Rules of Thumb for RAC-G compaction:

Need to get 95% of minimum Need to get 95% of minimum required density with breakdown required density with breakdown coverages to achieve adequate coverages to achieve adequate compaction.compaction.

Mix temperature is critical for Mix temperature is critical for adequate compaction of RAC-G adequate compaction of RAC-G materialsmaterials

After PavingAfter Paving

Check the appearance of the finished Check the appearance of the finished surface for roller marks, scuffs, gouges, or surface for roller marks, scuffs, gouges, or other irregularitiesother irregularities

Check smoothness as required in project Check smoothness as required in project special provisionsspecial provisions

Visually evaluate quality of paving joints Visually evaluate quality of paving joints and identify any areas that may need to be and identify any areas that may need to be sealed.sealed.

Identify core locations for compaction Identify core locations for compaction acceptanceacceptance

TroubleshootingTroubleshooting

If any type of RAC mix problem If any type of RAC mix problem is suspected, obtain samples is suspected, obtain samples immediately and test for immediately and test for compliance with project special compliance with project special provisions.provisions.

Log full description of problem Log full description of problem and related activities and report and related activities and report to the RE.to the RE.


Possible Problems to Watch For:Possible Problems to Watch For: Segregation: Particle size segregation may be Segregation: Particle size segregation may be

difficult to ID in coarse graded RAC-G difficult to ID in coarse graded RAC-G mixtures. May appear segregated even if not, mixtures. May appear segregated even if not, due to small percentage of fines included.due to small percentage of fines included. When in doubt, sampleWhen in doubt, sample ID affected truckloads and corresponding ID affected truckloads and corresponding

placement areas for infoplacement areas for info Size segregation is often accompanied by Size segregation is often accompanied by

temperature segregationtemperature segregation


Temperature segregation may be identified Temperature segregation may be identified using a heat gun or infrared camerausing a heat gun or infrared camera To measure actual mix temperature without To measure actual mix temperature without

surface effects, use a 6-inch long probesurface effects, use a 6-inch long probe Indicates hot and cold spots in the mix that Indicates hot and cold spots in the mix that

can cause differences in compactioncan cause differences in compaction Can see areas in haul trucks and pavers where Can see areas in haul trucks and pavers where

mix is not circulating and has cooledmix is not circulating and has cooled Shows when material from paver wings is Shows when material from paver wings is

dumped into the hopper and where it comes out dumped into the hopper and where it comes out behind the screedbehind the screed


SmokeSmoke Blue smoke means that the mix is too Blue smoke means that the mix is too

hot and plant operating temperature hot and plant operating temperature needs to be adjustedneeds to be adjusted

White smoke is steam - too much White smoke is steam - too much moisture in the mix. May make mix moisture in the mix. May make mix tender and interfere with compaction. tender and interfere with compaction. Aggregate needs to be dried longer Aggregate needs to be dried longer before mixing with the AR binder. before mixing with the AR binder.


Stiff appearance: Too cool or possibly Stiff appearance: Too cool or possibly somewhat low AR binder content. Check somewhat low AR binder content. Check temperature and get a mix sample for temperature and get a mix sample for further testing if needed.further testing if needed.

Dull, flat appearance: Low AR binder Dull, flat appearance: Low AR binder content and/or excessive fines. content and/or excessive fines. Localized areas may indicate Localized areas may indicate insufficient mixing or segregation. Get insufficient mixing or segregation. Get sample and test for gradation and AR sample and test for gradation and AR binder content.binder content.


Slumped and shiny appearance typically Slumped and shiny appearance typically indicates high AR binder content. indicates high AR binder content. RAC-O and especially RAC-O-HB may look this way RAC-O and especially RAC-O-HB may look this way

and still meet specificationsand still meet specifications Old descriptive term is “wormy” – mix seems to Old descriptive term is “wormy” – mix seems to

almost crawl while watchedalmost crawl while watched Some complying RAC-G mixes may also be wormySome complying RAC-G mixes may also be wormy Visually check for binder drain down in the haul Visually check for binder drain down in the haul

truck bed, sample and test for AR binder content truck bed, sample and test for AR binder content and gradationand gradation

Summary of Module 5Summary of Module 5

Changes in the plant inspector’s duties due to Changes in the plant inspector’s duties due to RAC production are limited to:RAC production are limited to: Monitoring AR binder production and viscosity Monitoring AR binder production and viscosity

resultsresults Sampling AR binder and individual component Sampling AR binder and individual component

materials for verification and acceptancematerials for verification and acceptance Changes to field inspector’s duties are very minor, Changes to field inspector’s duties are very minor,

primarily related to monitoring RAC temperature primarily related to monitoring RAC temperature and compaction operations:and compaction operations: Use modified CT production/placement report formUse modified CT production/placement report form Compaction acceptance for RAC-G will be based on Compaction acceptance for RAC-G will be based on

cores at locations designated by Caltranscores at locations designated by Caltrans

The BeginningThe BeginningKeeping roads good with asphalt paving materialsKeeping roads good with asphalt paving materials

The BeginningThe BeginningKeeping roads good with asphalt paving materialsKeeping roads good with asphalt paving materials

http://www.cp2info.org/centerhttp://www.cp2info.org/center

Questions Questions ??

civl 598 asphalt paving materials asphalt rubber

Documents

ar binder viscosity

ar binder production

ar binder producer

batch of binder

binder sample

asphalt rubber binder

ar material module

introduction of ar module