Evaluation of the feasibility of treated waste glass as aggregate in asphalt mixture

In this study, waste glass was utilised as an aggregate substitution. Hydrofluoric acid (HF) was applied as an etching agent to roughen waste glass’ surface. Five mix designs incorporating untreated and acid-treated waste glass were fabricated to facilitate the study. Laboratory measurements, namely Marshall stability test, indirect tensile stiffness modulus test, moisture susceptibility test, and dynamic creep test, were performed to analyse the performance of asphalt mixture containing glass aggregate. The results showed that roughening glass aggregate’s surface texture by acid treatment significantly enhances the mechanical properties of asphalt mixture, namely resilient modulus, tensile strength, and creep resistance of the asphalt mixture. Utilising treated glass increased resilient modulus by 250 MPa, improved tensile strength ratio values by five percentage points, and enhanced creep resistance by 1.5 times. Herein, HF acid was deemed feasible for use as glass etching agent. As spent HF acid is an industrial waste, utilising waste HF as an acid-treatment agent can give value-add not only for treating glass aggregate but also to the reuse of spent HF acid itself.