Laboratory Study on Warm-Mix Asphalt Additives

Although several WMA projects have been explored in the United States, Europe, and some countries in Asia, there is a need for the research to evaluate the applicability of WMA in Thailand. In this study, the fundamental properties of asphalt binders modified with one of the commonly used additives (Sasobit®) were evaluated. The properties include the viscosity, rheological properties, rutting, and fatigue resistance. In addition, the compactability of mixtures was also investigated to determine whether the mixes can reach the desired density at lower temperatures. It was found that the Sasobit® modification can improve the workability and the fundamental properties of asphalt binders as shown in better rutting and fatigue resistance, and also higher in complex shear modulus. The measurement of the compactability shows that less energy required to compact the Sasobit®-modified asphalt mixes to desired density even at 20C-40C below compaction temperature. The mixtures modified with Sasobit® have greater resistance to densification under traffic, or higher potential to resist permanent deformation. However, there is no effect of Sasobit® on the resistance of asphalt mixtures to moisture damage, but the reduction of mixing and compaction temperatures can cause detrimental effect on the moisture sensitivity.