Determination of Mixing and Compaction Temperatures for the Rubberized Asphalt Binders Based on Shear Rate Dependent Viscosity

Abstract

Despite the numerous advantages of using modified asphalt binders, there are a number of challenges associated with their use. One of these challenges is related with specifying the temperatures at which modified asphalt binders should be mixed and compacted. The Equiviscous method aims to calculate the Mixing and Compaction Temperatures (MCTs) of the unmodified binder. Nevertheless, the implementation of this method for modified asphalt binder results in very high MCTs, which may not be appropriate during the asphalt mixes construction. This paper investigates two alternative methods for the modified binder with Crumb Rubber (CR), referred to as the High Shear Rate (HSR) viscosity and Zero Shear Viscosity (ZSV) methods. Besides, the MCTs obtained from these methods are compared to the ones obtained using the Equiviscous method. For this purpose, one type of asphalt binder modified with three percent of CR has been used. The results have shown that the application of the ZSV method has resulted in more reasonable MCTs for the rubberized binder, which have been from 30 to 50 °C lower than the ones obtained using the Equiviscous method.