Laboratory Performance of Asphalt Mixtures Containing Recycled Asphalt Shingles

Abstract

The use of recycled asphalt shingles (RAS) as a partial replacement for petroleum-based virgin asphalt binder has received considerable attention in recent years. The objective of this study was to conduct a comprehensive laboratory evaluation of asphalt mixtures containing RAS, including stone mastic asphalt. Mixes were designed to meet Superpave® design criteria. A suite of laboratory tests was conducted to capture the mechanistic behavior of the mixtures against major distresses. Laboratory testing evaluated rutting performance, moisture resistance, and fracture resistance of laboratory produced mixtures by using the Hamburg loaded wheel-tracking test, semicircular bending test, and thermal stress restrained specimen tensile strength test. Results of the experimental program indicated that the draft revision of AASHTO PP 53, Standard Practice for Design Considerations When Using Reclaimed Asphalt Shingles (RAS) in New Hot-Mix Asphalt, overestimated the shingle asphalt binder availability factor. In addition, asphalt mixtures containing 5% RAS performed as well as the control asphalt mixture containing no RAS at high, intermediate, and low temperatures. Furthermore, the inclusion of RAS showed an improvement in rutting performance by resulting in a lower rut depth as compared with the control mixture containing no RAS.