Effect of warm mixture asphalt (WMA) additives on high failure temperature properties for crumb rubber modified (CRM) binders

This paper investigates the effect of three warm mixture asphalt (WMA) additives on the high temperature rheological properties of both unaged and rolling thin film oven (RTFO) aged crumb rubber modified (CRM) binders. The WMA additives used in this study include Sasobit, RH and Advera. The ambient 40-mesh tire rubber with the concentrations of 10%, 15%, 20%, and 25% by the weight of asphalt binder, respectively, was used in this study. Dynamic shear rheometer (DSR) was employed to measure the complex modulus (G∗) and phase angle (δ) of CRM binders at various testing temperatures. The statistical analysis of variance (ANOVA) was applied to quantify the effects of WMA additives on the CRM binders’ rutting resistance properties. It was found in this study that, the three WMA additives could all improve the CRM binders’ resistance to rutting, and greatly improved high-temperature portion of the performance grade (PG) of CRM binders. It is found that Sasobit had the most remarkable effect on G∗ of both unaged and RTFO-aged CRM binders, RH only had significant effect on G∗ of RTFO-aged binders, Advera’s effect was indistinctive. Furthermore, WMA additives’ effect on δ was not conclusive.

► The WMA additives can improve the CRM binders’ resistance to rutting.
► WMA additives can greatly improve high-temperature PG grade of CRM binders.
► The Sasobit additive has the most significant effect on G∗ of CRM binders.