Performance Characteristics of Thin Lift Overlay Mixtures Containing High RAP Content, RAS, and Warm Mix Asphalt Technology

摘要

The purpose of this study was to design and evaluate the performance of thin lift mixtures incorporating ahigh Reclaimed Asphalt Pavement (RAP) content, Recycled Asphalt Shingles (RAS), and a Warm MixAsphalt (WMA) technology both individually and collectively. A Superpave 9.5 mm mixture wasdesigned with new materials and designated as the control mixture. The same control mixture wasdeveloped with 40% RAP, with 5% RAS, and with 35% RAP and 5% RAS. Each of the mixture designswas then repeated at a lower mixing and compaction temperature using a wax-based WMA technology.The effect of the RAP and/or RAS on the stiffness of each mixture was measured using thedynamic modulus. The performance of each mixture was determined by measuring reflective crackingresistance using the Overlay Tester, low temperature cracking resistance using the Asphalt ConcreteCracking Device, and moisture susceptibility using the Hamburg Wheel Tracking Device. Additionally,binder was extracted from each mixture and the Performance Grade determined.The mixtures incorporating high RAP content and/or RAS exhibited higher stiffness which wasconfirmed with the extracted binder grading results. The use of RAP and/or RAS reduced the reflectivecracking resistance but did not negatively impact the low temperature cracking resistance of the mixtures.Moisture susceptibility test results indicated that the addition of RAP and/or RAS improved the mixturesresistance to moisture failure. Results indicated that the addition of WMA technology to the mixturesprovided similar or improved performance in the majority of the mixture tests.