Sustainable Recycling of Sulfur Waste Through Utilization in Asphalt Paving Applications

The vast quantity of sulfur waste (SW) materials accumulating in Iraq is creating costly disposal and gas emission problem. Application of SW as an asphalt binder performance extender is an economical solution to decrease virgin binder usage, as well as toxic gas emission. The present study investigates the potential use of SW as a partial substitution for sustainable pavement construction. Asphalt cement binder was partially substituted with different percentages of SW (10%, 20%, and 30% by weight). The resultant binders were subjected to penetration, ductility, softening point, absolute viscosity, elastic modulus, durability, and cracking index tests. Furthermore, a total of three sulfur waste-asphalt concrete (SWAC) mixtures and one asphalt concrete (AC) reference mixture were designed for the study. Three SWAC mixtures were designed with 10%, 20%, and 30% SW content, respectively. Mechanical and durability tests including Marshall stability, Marshall quotient, static indirect tensile strength at 25 and 60 & DEG;C, tensile strength ratio, and flexural strength at 0 and 15 & DEG;C were conducted on AC and SWAC mixtures. Results indicate that 10% SW-substituted binder show lower softening point and durability and keep the ductility value at a minimum range of ASTM specification of 100(+) cm and temperature susceptibility in the preferable range. The SWAC mixtures show lower Marshall stability and moisture susceptibility. The values of stability and tensile strength ratio are still greater than the minimum values of ASTM specification limit up to 20% SW. Although flexural strain values of 10% SWAC mixtures is lower than those of control mixtures, these strain values considered to be acceptable. Overall, 10% of SW by weight of asphalt can be recycled and used as sustainable materials for paving applications to that found in this study.