Tensile Strength, Deformation Strength, and Semi-circular Bending Properties of Carbon–Sulfur as a Sustainable Filler in Asphalt Mixes

This research investigated the effect of utilizing a carbon–sulfur by-product material of sulfur purification, as a filler replacement in dense-graded asphalt mixtures using 40/50 asphalt in various carbon–sulfur rates. Carbon–sulfur filler was evaluated as a replacement for the commonly used industrial filler, calcium carbonate (CaCO₃), aiming to find a cost-effective solution to Iraq’s growing solid waste problem and declining landfill capacities, such as carbon–sulfur. Various laboratory tests and parameters, including the Marshall stability and flow, indirect tensile strength, moisture susceptibility, deformation strength, and semi-circular bending test, were conducted on each mixture group. The results suggested that concentrations of 5% and 6% carbon–sulfur provided several benefits. These included enhanced resistance to cracking and rutting, as well as compliance with Marshall properties and moisture susceptibility. Consequently, these findings indicate that the use of carbon–sulfur as a filler could potentially lead to significant cost savings and a reduction in landfill use.