High and intermediate temperature performance of warm asphalt rubber containing conventional warm mix additives and novel chemical surfactant

Abstract

Warm mix asphalt (WMA) technology is widely used to address the workability concerns of rubberized asphalt paving materials. In this study, a novel chemical surfactant – alube– is proposed for the production of warm asphalt rubber (WAR) binders. To assess its suitability, the high and intermediate temperature performances of the resultant alube-WAR binder (AWAR) was compared with those of two conventionally produced WAR binders, namely sasobit-WAR binder (SWAR) and rediset-WAR binder (RWAR). An economic evaluation of the WAR binders was also done in order to assess their cost-competitiveness. For the high-temperature performance study, the high-temperature viscosity, viscosity-temperature susceptibility (VTS), rutting resistance, and stress sensitivity were investigated, while for the intermediate-temperature performance, the fatigue resistance factor was evaluated. Different findings were obtained from the performance and cost investigation. Alube was found to successfully lower the high temperature viscosity of AR binder but not as effective as the two conventional WMA additives. The VTS property of AR binder was only improved by the organic WMA additive (sasobit), while the chemical additives (rediset and alube) showed negative effects. In terms of rutting resistance, AWAR was superior to RWAR and AR, but was outperformed by SWAR. Also, SWAR was the least susceptible to stress changes, while AWAR and RWAR showed comparable performance. Based on the G*sin δ test, the fatigue resistance of the AR binder improved after the incorporation of the chemical additives and deteriorated after sasobit was added, and the performance ranking was determined as RWAR > AWAR > AR > SWAR. Overall, only SWAR had a better high-temperature performance than AWAR, whereas for intermediate temperature performance, only RWAR was better. Furthermore, economic analysis showed that AWAR is the most cost effective of the three WAR binders. The findings of this study indicate that alube has the potential of being utilized as a WMA additive for AR binders and can be utilized in wide range of road projects due to its cost-effectiveness.