Durability and Rutting Resistance of SBS-Modified Asphalt Mixtures Containing Blowdown as a Sustainable Filler

Abstract

In the pursuit of a sustainable environment, and facing the threat of the continuous growth of solid waste in Iraq, this study investigated the impact of using blowdown, a carbon-sulfur byproduct material of sulfur purification, as a mineral filler on durability and rutting resistance in dense-graded asphalt mixtures using Styrene-Butadiene-Styrene (SBS)-modified asphalt. Three different blowdown rates (4%, 5%, and 6% by weight of aggregate) were used as potential calcium carbonate (CaCO3) replacements. Laboratory tests and parameters, including Marshall stability, indirect tensile strength, tensile strength ratio (durability), and deformation strength, were conducted, and the results were analyzed statistically using Minitab software. The results showed that using 5% blowdown in SBS-modified asphalt mixtures increases the deformation strength, indirect tensile strength at 25 °C, Marshall stability, and Marshall quotient by 51.23%, 0.21%, 14.27%, and 31.44%, respectively, compared to the control mixture that contains CaCO3 filler indicating that using of blowdown as a filler in asphalt mixtures may offer benefits such as enhancing the cracking and rutting resistance of asphalt mixtures while meeting Marshall properties and moisture susceptibility standards and the potential to provide financial advantages and reduce landfill use.