Binder Rheology and Performance in Warm Mix Asphalt: Interim Report: Fid-Bau Portal

Binder Rheology and Performance in Warm Mix Asphalt: Interim Report

Z. Arega / A. Bhasin

Since the introduction of warm mix asphalt (WMA) in the United States, a variety of different technologies and processes have been developed and used to achieve proper mixing and compaction at reduced temperatures compared to conventional hot mix asphalt. A better understanding of the effect of WMA additives and reduced aging on rheology of asphalt binders is a crucial step towards the successful implementation of WMA. This report presents the preliminary findings from a study conducted to investigate the influence of chemical WMA additives and reduced aging on the viscosity, stiffness, susceptibility to permanent deformation, fracture resistance, and thermal cracking resistance of asphalt binders. Short-term aged WMA binders have reduced stiffness compared to conventional binders due to the reduced mixing temperatures. However, preliminary results indicate that certain WMA additives tend to exacerbate the reduced stiffness of WMA while other WMA additives tend to compensate for this effect. In most cases, long-term aged WMA binders had a similar stiffness but similar or reduced strength compared to conventional binders at intermediate temperatures. Also, the long-term aged WMA binders had similar or slightly reduced resistance to low-temperature cracking compared to conventional binders. In most cases, the use of WMA with recycled asphalt rendered the asphalt binder slightly more susceptible to low-temperature cracking.