Additives Influence on the Properties of Asphalt Binders: A Case Study

Abstract

This study investigated the impact of using modified bitumen binders and additives to enhance the physical characteristics of asphalt mixtures at high, medium, and low temperatures. Both basic and rheological characteristics of the bituminous binders were tested by adding Styrene-Butadiene-Styrene, a type of thermoplastic elastomer, as a chemical additive to asphalt mixtures at various fractions (3.5%, 4%, and 4.5%), and two kinds of modified Bitumen: Kraton styrene block copolymers and Europrene (SOL T 6302). The following methods were used to test the properties of the binders: needle penetration, ductility, softening point, resistance to hardening when exposed to heat and air, Pressure Aging Vessel test dynamic (PAV), Shear Rheometer (DSR), Bending Beam Rheometer (BBR), direct tension test, and storage stability. The results showed that the best properties of the asphalt concentration were observed when using 4% of additives, while the penetration of Bitumen was reduced to 27.2% and 30.3% when adding Kraton and Europrene SOL T6302, respectively. The influence of adding 4.0% additives decreased the bulk specific gravity to 2.395. Laboratory tests showed how the mentioned chemical additives directly affect the properties of the mixture and the binder by increasing their viscosity.