Mechanical and Durability Properties of HMA Containing PG76-16 and Sustainable Sulfur Waste as Filler

Abstract

In Iraq, sulfur waste (SW) accumulates, posing a costly disposal and gas emission problem. Using SW as a mineral filler is a cost-effective method for reducing the quantity of common filler (calcium carbonate; CaCO3) and hazardous gas emissions. SW was utilized to replace an asphalt binder component in hot asphalt mixes gradually. This study investigates the use of SW as a mineral filler in the construction of sustainable pavements. Three SWAC mixes with PG76-16 asphalt binder were created and compared to the CaCO3-asphalt concrete (AC) mix used as the study's reference. SWAC refers to 4 percent, 5 percent, and 6 percent sulfur-contaminated asphalt concrete, while one AC blend contained a 5 percent CaCO3 concentration (by weight). AC and SWAC mixtures had their Marshall stability, Marshall quotient, tensile strength at 25 and 60°C, tensile strength ratio, and tensile strength modulus at 25 and 60°C determined. SWAC mixtures have decreased tensile strength, tensile stiffness modulus, and tensile strength ratio. When the PG76-16 binder is used, tensile strength ratios remain above the required minimum of 85 percent despite the lower SWAC percentage. In addition, SWAC combinations have greater flow values, indicating a higher rupture strain capacity. All SWAC combinations meet the ASTM standards for 8kN stability, 2-4mm flow, 4 percent air voids, and 14 percent VMA, so long as the correct binder content is maintained. This study found that SW can be used as a mineral filler in pavement applications at a 4–5 percent rate by aggregate weight, similar to the applications studied.