Improving the properties of reclaimed asphalt pavement for roadway base applications.

Final report; Oct. 2009-Aug. 2012.PDFTech ReportFL/DOT/BDK81 97702Contract Number BDK81 977-02PavingAsphalt pavementsPavement performancePortland cement concretePortland cementWaste productsRecycled materialsFloridaFlorida Institute of Technology. Civil Engineering Dept.Cosentino, Paul J.Kalajian, Edward H.Bleakley, Albert M.Diouf, Babacar S.Krajcik, Ryan E.Misilo, Thaddeus J.Petersen, Andrew J.Sajjadi, Amir M.Florida Institute of Technology. Civil Engineering Dept.Florida. Dept. of TransportationNTL-HIGHWAY/ROAD TRANSPORTATION-MaterialsNTL-HIGHWAY/ROAD TRANSPORTATION-Construction and MaintenanceNTL-HIGHWAY/ROAD TRANSPORTATION-Pavement Management and PerformanceUS Transportation CollectionThe objective of this study was to improve Reclaimed Asphalt Pavement\ue2\u20ac\u2122s (RAP) strength in base courseapplications while reducing creep to an acceptable level using compaction techniques, fractionating,blending with high quality base course aggregate, and/or by chemical stabilization with asphalt emulsion,Portland cement, or lime. RAP/limerock blends with and without chemical stabilization were compacted bymodified Proctor, Marshall, or gyratory methods, cured, and tested for strength and creep. Strength testsincluded limerock bearing ratio (LBR), unconfined compression, Marshall compression, and indirect tensiletests. Strength specimens were tested dry and soaked to evaluate retained strength. Seven-day onedimensionalcreep testing was performed. Gyratory compaction produced higher densities than modifiedProctor or Marshall compaction. At the same density, gyratory compaction improved RAP\ue2\u20ac\u2122s strength by afactor of two to three over modified Proctor but had less effect on creep. Modified Proctor moisture-densityplots followed an S-shape without a clear optimum; modified Proctor may not be the best method to predictRAP compaction behavior. Fractionating RAP did not improve strength or creep unless RAP was remixed tomatch a maximum density curve. Fractionating did not produce acceptable LBRs or creep. RAP blendedwith limerock, cemented coquina, or reclaimed concrete aggregates showed improved LBR and creepperformance. RAP/aggregate blends have the potential to be used as Florida base course. As the amount ofaggregate blended with RAP increased, LBR increased and creep decreased. Creep behavior of blends with75% aggregate was similar to 100% aggregate. Unstabilized blends with 50% aggregate did not produceLBR values over 100. Blends of 50% RAP/50% limerock stabilized with 1% of either asphalt emulsion orcement attained soaked LBRs over 100 and acceptable creep. Blends of RAP with 75% limerock attainedsoaked LBRs close to 100 and low creep without any chemical stabilizer. Adding RAP to limerock blendsgenerally increased the soaked retained strength and improved permeability compared to 100% limerock