Special Provisional Specification for Superpave Mixture Design, Standard and RPS Construction of Plant-Mixed HMA or WMA Courses using Crumb Rubber ModifiedAsphalt Binder

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Item ______Superpave Mixture Design, Standard and RPS Construction of Plant-Mixed HMA or WMA Courses using Crumb Rubber Modified Asphalt Binder.

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Item ______Superpave Mixture Design, Standard and RPS Construction of Plant-Mixed HMA or WMA Courses using Crumb Rubber Modified Asphalt Binder.

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IDESCRIPTION – This work is the standard and RPS construction of standard dense graded plant-mixed HMA or WMA

wearing or binder course using Crumb Rubber Modified Asphalt Binder (CRMAB) on a prepared surface using a volumetric mixture design developed with the Superpave Gyratory Compactor (SGC). The use of CRMAB is to be an equivalent replacement for Performance Graded Asphalt Binder (PGAB) graded as PG 76-22.

IIMATERIALS – Section 409.2 with the following additions and modifications.

(a)Bituminous Material. Replace Section 409.2(a) completely with the following:

  1. General. Furnish Crumb-Rubber Modified Asphalt Binder (CRMAB) conforming to the requirements within this specification. Furnish a CRMAB that is a reacted and uniform blend of a base bituminous material and Crumb Rubber Modifier (CRM). Furnish CRMAB that does not exhibit CRM floating on the surface of the CRMAB or agglomerations of CRM particles within the CRMAB. Furnish a CRMAB that is based on a binder design blend profile that includes blend proportions, production temperatures, and reaction times. Furnish a CRMAB that meets the requirements specified within this specification and has demonstrated through laboratory testing that when the CRMAB is mixed with aggregate in an asphalt mixture it provides equivalent rut resistance when compared to the same mixture mixed with PG 76-22. Produce the CRMA binder according to the binder design blend profile and the Producer QC Plan. Produce and furnish CRMA binder meeting the physical requirements of AASHTO M320, except as follows:
  • Solubility Test (AASHTO T 44 or ASTM D 5546). Report test results to the Representative. minimum 88%.
  • AASHTO T 315 performed at a 2 mm gap.
  • Separation Test (ASTM D5976D7173 and D7175). Report test results to the Representative. Test waived if binder is blended on site in tanks that provide continuous agitation.
  • Elastic recovery test (ASTM D6084) to be performed on the residue from the Rolling Thin Film Oven Test at 25 °C and 10 cm elongation with immediate cut of specimen. Do not sieve specimen prior to pouring off sample. Minimum 65%

1.a Base Bituminous Material [PGAB]. Provide and use a base bituminous material from a source listed in Bulletin 15 that is capable of meeting the requirements of Section II(a)1.after modification by the addition of CRM. Provide the grade and source of the base binder in the binder design blend profile and Producer QC Plan. Provide QC testing and certification as specified in Sections 106.03(b) and 702.1(b)1. Provide the Representative a copy of a signed Bill of Lading for bituminous material on the first day of paving and when the batch number changes.

When producing WMA Crumb Rubber Modified Asphalt Binder-Dense Graded (CMRAB-DG) mixes, WMA Technology may be provided or blended with base bituminous material as follows:

1.a.1WMA Technology Additives or Modifiers Blended at the Bituminous Material Supplier Refinery or Terminal. Section 411.2(a)3.except as follows:

Provide certification that the refinery or terminally blended WMA base bituminous material meets the requirements of Section II(a)1.of this specification.

1.a.2WMA Technology Additives or Modifiers Blended at the Bituminous Mixture Producer Plant. ForWMATechnologyadditivesormodifiersblendedwiththebituminousmaterialatthebituminousmixtureproductionplant,prepareaProducer QCPlanor anaddendumto anexistingProducer QCPlan asspecifiedinSection106 andconformingtotheProducerQCPlanrequirementsinSection409.2(e)1.a.Provide QCtestingofthebase bituminousmaterialblendedwiththeWMATechnologyadditiveormodifierandcertifyaccordingtoSection106andSection702thattheblendedbasePGABwiththeWMATechnologyadditiveormodifiermeetstherequirementsoftheSectionII(a)1.afortheindicatedorselectedgradeofPGAB.

1.b CRM. Furnish processed CRM from a manufacturer listed in Bulletin 15. Certify, according to Section 106.03(b)3., that the CRM meets the CRM requirements as specified herein. Furnish and use CRM derived from the ambient temperature processing and granulating of recycled tires or derived from the tire retreading process (rubber tire buffings).

Provide the CRM in moisture resistant packaging containers consisting of disposable bags or bulk containers. Provide each packaging container labeled with the manufacturer name, manufacturer’s designation for the CRM, CRM maximum nominal size, mass (weight), and manufacturer’s batch or lot number designation.

Furnish and use CRM meeting the following requirements:

1.b.1 Gradation. Provide CRM that meets the following gradation as determined by sieve analysis according to ASTM D 5644 using 200 mm diameter sized sieves or Florida Department of Transportation, Test Method FM 5-559:

Gradation of CRM

Sieve Size / Percent Passing
600 μm (No. 30) / 98-100
300 μm (No. 50) / 20-100

1.b.2 Contamination, Moisture, and Specific Gravity. Provide and use CRM that is relatively free from fabric, fibers, metal, and other non-rubber materials. The CRM may contain up to 4% by mass (weight) of calcium carbonate or talc to prevent sticking and caking of the CRM particles and to ensure the CRM is free flowing. Determine the total percentage of other contaminants by separating out the other contaminants from the test sample and determining the total mass (weight) of the other contaminants to the nearest 0.1 g (0.004 oz). Provide and use CRM meeting the following requirements:

CRM Requirements

Requirement / Test Method / Criteria
Metal Contaminants / FM 5-559 (Note 1) / 0.01%
Fabric/Fiber Contaminants / (Note 2) / Maximum 0.5%
Other Contaminants / (Note 3) / Maximum 0.25%
Specific Gravity / FM 5-559 (Note 1) / 1.10 to 1.20
Moisture Content / FM 5-559 (Note 1) / Maximum 0.75%
Note 1: Florida Department of Transportation, Test Method.
Note 2: Determine the percentage of fabric/fiber contaminants by separating the fabric/fibers from the CRM particles in a 100 ± 1 g test sample and determining the total mass (weight) of the fabric/fibers to the nearest 0.1 g and calculating percentage by dividing the mass (weight) of fabric/fibers by the mass (weight) of the original sample and multiplying by 100.
Note 3: Determine the percentage of other contaminants by separating the other contaminants from the CRM particles in a 100 ± 1 g test sample and determining the total mass (weight) of the other contaminants to the nearest 0.1 g and calculating percentage by dividing the mass (weight) of other contaminants by the mass (weight) of the original sample and multiplying by 100.

1.c Rut Resistance Equivalency to PG 76-22. Design a CRMAB to provide equivalent rut resistance as compared to a PG 76-22 from an approved manufacturer and source listed in Bulletin 15. Use PG 76-22 that has been tested and certified by the manufacturer to meet the requirements of Standard Specifications for Performance Graded Asphalt Binder, AASHTO M 320, except as revised in Bulletin 25. Determine equivalent rut resistance by conducting laboratory asphalt mixture rut resistance testing. Acceptable laboratory asphalt mixture rut resistance comparison test methods include AASHTO T 324, AASHTO T 340, or AASHTO TP 79, Procedure B, Unconfined.

For the comparison testing, use an asphalt mixture JMF to be used on the project with the only difference being the asphalt binder; one test mixture prepared with CRMAB and one test mixture prepared with PG 76-22. If more than one crumb rubber modified JMF is used on the project, perform comparison testing using only one of the JMFs, but the JMF must be the JMF with the highest design Equivalent Single Axle Load (ESAL) range specified in the project. Prepare, mix and compact the two comparison asphalt mixtures in the exact same manner except for any specifics in mixing and compaction temperatures for the different asphalt binders. For all test methods compact all test specimens for use in the comparison testing to 7 ± 0.5% air voids. Rut resistance equivalency will be determined by comparison of test results between the asphalt mixture JMF using the as-designed CRMAB and the same asphalt mixture JMF using the PG 76-22.

For AASHTO T 324, the CRMAB and PG 76-22 rut resistance test results will be considered equivalent if the average rut depth measurements do not show a difference of more than 2.0 mm at either 20,000 cycles or 2.0 mm at the lowest number of cycles where one of the mixtures fails the test if the test automatically shuts off at a maximum rut depth value. Perform the test at a test temperature of 50°C.

For AASHTO T 340, the CRMAB and PG 76-22 rut resistance test results will be considered equivalent if the overall average rut depth measurements do not show a difference of more than 0.5 mm at 8,000 cycles when tested at 50°C.

For AASHTO TP 79, Procedure B, Unconfined, the CRMAB and PG 76-22 rut resistance test results will be considered equivalent if the difference in the average of n=3 specimens (each mixture) is within the multi-laboratory precision estimate + 5 for the Nominal Maximum Aggregate Size (NMAS) of the tested JMF (e.g., the acceptable difference for a 9.5 NMAS mixture is 45+5 = 50). Perform the test at a test temperature of 50°C, a deviatory stress of 600 kPa, and a seating load of 30 kPa.

1.d Terminal Blend CRMAB. If the CRMAB is blended at an asphalt terminal, blend according to the design blend profile and Producer QC Plan. Prepare a QC Plan according to Section 702.1(a). Certify according to Section 702.1(b) and Section 106.03(b) except test the CRMAB as required within this specification. Handle and transport according to Section 702.1(c).

1.e CRMAB Blended at the Asphalt Mixture Production Plant.

1.e.1 CRMAB Blending and Storage Equipment. Provide and use equipment designed for producing CRMAB and capable of blending the base bituminous material and the CRM at the required proportions to produce a reacted and uniform CRMAB. Ensure the equipment includes the following:

  • A batch type or continuous type blending unit that provides accurate proportioning of the base bituminous material and the CRM by either weight or volume and is capable of thoroughly blending the individual CRM particles with the base bituminous material.
  • A blending unit designed and accessible to the Representative that allows the Representative to readily determine the rate of proportioning for the base bituminous material and the CRM during production of the CRMAB and provides a recordation of the base bituminous material and CRM proportions used to produce the CRMAB.

1.e.2 CRMAB Production QC Testing. If the CRMAB is blended at the asphalt mixture production plant, at least 3 weeks before its intended use, provide four 1-quart laboratory blended samples of the CRMAB binder base bituminous material and CRM proposed for use on the project.Include the sources, grades, and proportions of the base bituminous material and CRM in the documentation.

Blend, produce, and test reacted CRMAB according to the Producer QC Plan, at the frequencies identified in the Producer QC Plan, to meet the specified requirements. For QC testing, sample the reacted CRMAB according to PTM No. 1 at the minimum frequencies below and provide a 1-quart split sample each time to the Department for verification testing.

  • One sample per batch (batch blending)
  • Two samples per day (continuous blending)

The Representative may direct the collection of additional random samples of CRMAB in the presence of the Representative for Department verification purposes.

If the CRMAB does not meet the specified requirements make appropriate adjustments in order to correct the blended material, and to correct the blending operation. These corrective actions, within the specified requirements of Section II(a)1., may include increasing the CRM content, lowering the blending temperature, changing the supply of CRM, or increasing the reaction time. Any change in the supply of asphalt or rubber shall include a verification of the design blend profile with the new material. In the event that the corrective actions fail to correct the problem, or the material consistently or frequently fails to meet the specified requirements, suspend all CRMAB production operations and determine the cause of the problem. Provide a written explanation of the problem and a proposed solution to the Department. After the Representative reviews the problem and proposed solution and authorizes CRMAB production to resume, resume production and sample and test the CRMAB for the specified requirements and immediately provide the test results to the Representative. If the viscosity of the CRMAB increases to the extent that plant production or paving operations of the mixture are adversely affected (i.e., density, pattern segregation, flushing, or texture problems occur), suspend CRMAB production and paving operations and determine the cause of the problem. Provide a written explanation of the problem and a proposed solution to the Department. After the Representative reviews the problem and proposed solution and authorizes CRMAB production and paving operations to resume, resume production and sample and test the CRMAB for the specified requirements and immediately provide the test results to the Representative.

For each batch or continuous production lot of CRMAB, provide the Representative with the following CRMAB documentation:

  • The source, grade, amount, and temperature of the base bituminous material before the addition of CRM.
  • The source, gradation, and amount of CRM and the CRM content expressed as a percent by weight of the total CRMAB.
  • Dates and times of the CRM additions and resultant QC test results.
  • A record of the temperature, with date and time reference, for each batch or continuous production lot. Begin recordingfrom the time the CRM is added to the base bituminous material and continue until the batch or continuous production lot is used to produce asphalt mixture. Record temperatures at specific time intervals or at critical CRMAB production points to monitor the CRMAB production.

Provide a Certificate of Analysis (COA) for each batch or for each continuous production lot of CRMAB produced stating that it meets the physical requirements of AASHTO M 320, as noted in Section II(a)1., based on the QC tests of the CRMAB.

  1. Virgin Mix, Mix Containing 5% to 15% RAP, or Mix Containing 5% Recycled Asphalt Shingles (RAS). Furnish CRMAB as specified in Section II(a)1. Provide the Representative with a copy of a signed Bill of Lading for CRMAB on the first day of paving when the batch number changes when providing terminal blended CRMAB. Provide the Representative with a copy of the COA on the first day of paving and when the batch number changes when providing CRMAB blended at the asphalt mixture production plant.
  2. Mix Containing More than 15% RAP or Mix Containing Both 5% RAS and 5% or More RAP. The LTS will evaluate the asphalt cement in the RAP and, if applicable, the RAS source material. The LTS will determine the class (grade) of asphalt binder that the Contractor is required to use as the base bituminous material in the CRMAB.

Furnish CRMAB as specified in Section II.(a)1. Provide the Representative with a copy of a signed Bill of Lading for CRMAB on the first day of paving when the batch number changes when providing terminal blended CRMAB. Provide the Representative with a copy of the COA on the first day of paving and when the batch number changes when providing CRMAB blended at the asphalt mixture production plant.

(b)Aggregate.Section 409.2(b)

(c)ReclaimedMaterials.Section 409.2(c)

(d) Filler.Section 409.2(d)

(e)MixtureComposition for Standard and RPS Construction.Section 409.2(e) with the following modifications and additions:

  1. Virgin Material Mixtures Section 409.2(e) and add the following:

After compacting SGC specimens containing CRMAB, hold the specimen in the SGC with a sufficiently loaded top plate until the specimen cools a sufficient length of time to prevent swelling of the specimen that would affect the volumetric analysis of the compacted specimens.

If WMA Technology is used, Section 411.2(e) shall apply and the special SGC specimen handling above shall also apply.

Increase the minimum Voids in Mineral Aggregate (VMA) requirement in Table B of Section 409.2 by 1% for each mix type.

(f)Mixture Acceptance Section 409.2(f)

(g) WMA Technology Requirements. Section 411.2(g),(h),(i) and (j)

IIICONSTRUCTION–

(a)Preplacement Requirements.

1.PavingOperationQCPlan.Section409.3(a)1.and add the following:

When pavingwith WMA CRMAB-DGmixtures, prepare andsubmitadditionalinformationspecifically relatedtoall aspectsofthefieldcontrolofWMACRMAB-DGmixturepavingoperationstotheRepresentativeaspartofthepavingoperationQCPlan.EnsurethepavingoperationQCplanincludestherecommendationsanddirectionfromtheWMATechnologyTechnicalRepresentative.Describetheconstruction equipment andmethods necessarytocontrol the WMA CRMAB-DG paving operationsincludingtesting,delivery,placement,compaction,andprotectionoftheWMA CRMAB-DGpavementcoursesforalloperationsincludinghandwork.

(b)WeatherLimitations.DonotplaceCRMAB-DGpavingmixturesfromOctober1toMarch31inDistricts1-0,2-0(exceptJuniataandMifflinCounties),3-0, 4-0, 5-0(Monroe andCarbon Counties only),9-0(Cambria andSomerset Counties only),and10-0;andfromOctober16toMarch31inDistricts2-0(JuniataandMifflinCountiesonly),5-0(exceptMonroeandCarbonCounties),6-0,8-0,9-0(exceptCambriaandSomersetCounties),11-0and12-0.Noexceptionstopavingweatherlimitationswillbeallowed,unlessawrittenrequestissubmittedwithsupportingreasonstotheRepresentativeandtherequestisapprovedinwritingbytheDistrictExecutive.DonotplaceCRMAB-DGpavingmixtureswhensurfacesarewetorwhenthe air or surface temperature is55For lower. If workishaltedbecause of weather conditions, the RepresentativemayallowtheContractortoplacelimitedquantitiesofmixturethatareenroutetotheproject.

(c)BituminousMixingPlant.Section409.3(c) and when using WMA Technology, Section 411.3(c)

(d)Hauling Equipment.Section 409.3(d) except as follows:

Provideinsulationonallsidesofthetruckbody,adouble-walledtruckbody,oraheatedtruckbodywhentheairtemperatureisbelow55F.

(e)BituminousPavers.Section409.3(e)1

(f)Rollers.Usesteel-wheel,orvibratoryrollersasspecifiedinSection108.05(c)3.Operaterollersaccordingtomanufacturer'srecommendations.Usevibratoryrollerswithseparatecontrolsforvibrationandpropulsion.Use an appropriate additive to prevent roller pick up of the HMA or WMA.

(g)Demonstration.Before proceedingwith the actualwork,demonstratetothe Representative thatthe proposedCRMA-DGmixturecanbeproduced,placed, andcompactedtomeettherequirementsofthisspecification. Placeaminimumof100tonsforeachtrialdemonstration. The 100 tons of demonstration pavement may be placed within or outside of project limits. Simulatethehaulingtimeforthedemonstration.ObtainandtestthreeloosemixturesamplesattheplantforCRMAB bindercontent andgradationandthreepavementcoresfromthedemonstrationpavementfordensity.TestonesetofvolumetricspecimensforAirVoidsatNdesign(Va)andtestforonemaximumspecificgravityofthemixturevalue.Iftestresultsdonotmeetspecificationlimitsforbothsingleandmultiplesampletolerancesforanyparameter,performanotherdemonstration. Remove and replace any trial demonstration pavement placed within the project limits that does not meet specificationlimits

Thisworkisincidentaltothewearing/binder course.Ifvibratoryrollingisproposed,demonstratetothesatisfactionoftheInspector-in-Chargethatnobreakingofaggregateorflushingofasphaltbinderresultsfromthevibration.

(h)PreparationofExistingSurface.Section409.3(g)

(i)SpreadingandFinishing

  1. General Requirements.

1.aPlacing.Unlessotherwiseallowed,deliver,place,andcompactCRMAB-DGpavingmixturesduringdaylighthours.Ensurethemixturedoesnotcontainlumpsofcoldmaterial.The air and pavement surface temperature shall be a minimum of 55F. When the air and pavement surface temperatures range between 55F and 64F, the laydown temperature shall be between 290F and 325F. For temperatures greater than 64F, the laydown temperature shall be between 280F and 325F.

Use a MaterialTransferVehicle (MTV) as specifiedinSection108.05(c)5duringplacementofCRMAB-DGmixtures. HavetheMTV performadditionalmixingoftheCRMAB-DGmixtureandthendepositthemixtureintothepaveratauniformtemperatureandconsistency.

1.bSpreadingandFinishing.Section409.3(h)1.bandasfollows:

PlanandscheduleoperationstominimizehandworkofCRMAB-DGmixtures.Donotallowthefinishedpavementsurfacetoflush.Flushingiscontinuousorrepeatedareasofexcessiveasphaltonthepavementsurface.Areasthataredeterminedtobeflushed willbeconsidereddefectivework.