Performance evaluation of SBS modified asphalt mixtures using warm mix technologies

The need for more sustainable methods and techniques in the asphalt paving industry has been increasing and it is important to respond to the needs of society and address issues surrounding its environment and health. In order to better introduce such new and more sustainable methods, it is necessary to combine existing and proven methods with new technology. The main idea of this research was to use the established industry standards of using styrene butadiene styrene (SBS) modified asphalt mixtures and combine it with the relatively new warm mix asphalt (WMA) technology in order to create a more sustainable and eco-friendly asphalt paving process. Two WMA technologies, micro water (Aspha-min) and synthetic wax (Sasobit) based, were used to evaluate their effectiveness in SBS modified asphalt mixtures along with binders. The four major areas of research included the binder analysis (including Superpave binder performance and surface topography); compaction condition study; oxidative aging analysis and mixture performance analysis.;The general findings were that the WMA additives especially improved the binder properties at higher temperatures namely viscosity and rutting and the inclusion of these materials did not adversely affect the engineering properties of the mixtures. Atomic Force Microscopy (AFM) was utilized to obtain the various surface images that showed the strong correlations with especially aging process. The compaction condition study showed that WMA mixtures had better compaction behavior under lower temperatures and gyrations and also the other volumetric results indicated the comparability with the hot mix asphalt (HMA) mixtures. The oxidative aging results showed that the asphalt mixtures aged in the oven had a higher level of aging than the binder by itself aged in the rolling thin film oven (RTFO). Also, the benefit of using WMA technologies (reduced aging) can be accomplished by using lower aging condition.