Warm-Mix Asphalt Laboratory Permanent Deformation Performance in State of Pennsylvania: CaseStudy

Permanent deformation has been recognized as one of the primary distresses in asphalt pavements especially in hot climates. A Warm-Mix Asphalt (WMA) mixture is composed of air voids, asphalt binder, aggregates, and a WMA technology. The permanent deformation performance of WMA mixtures is attributed to mixture properties as well as the amount of plant aging that occurs during production. This paper presents the laboratory permanent deformation resistance potential of WMA mixtures used in the State of Pennsylvania. Four plant produced WMA mixtures with identical volumetric properties and different WMA technologies (i.e., Advera®, Sasobit®, LEA, and Gencor) were included in the study. The stiffness and deformation resistance behavior of these WMA additives as well as performance grade verification were also evaluated. The Mobile Asphalt Testing Laboratory (MATL) prepared a mix design replication of plant produced HMA control mix. Performance tests, namely the flow number and Hamburg tests were performed to evaluate the permanent deformation resistance potential of the asphalt mixtures. Ranking of the asphalt mixtures was provided based on the rutting resistance derived from these tests. In general, the MATL mix design replicate and plat produced HMA mixtures measured better permanent deformation resistance test results followed by WMA/Sasobit® mixture. Compared to the HMA control mixtures, the WMA mixtures were found to be susceptibility to rutting due to less aging during production particularly at lower testing temperatures. In conclusion, the findings from this study can assist State DOTs and agencies to evaluate pavement structures and design rut resistance WMA mixtures.