ASPHALT CONCRETE–WEARING COURSE (AC-WC) PERFORMANCE USING GOLD-MINING SAND WASTE AS FINE AGGREGATE IN SUSTAINABLE PAVEMENTS

Abstract

This study evaluates the mechanical and volumetric performance of Asphalt Concrete–Wearing Course (AC-WC) mixtures incorporating Gold-Mining Residual Sand Waste (GMRSW) as a sustainable substitute for natural fine aggregate. Four mix designs were prepared with GMRSW substitution levels of 0%, 25%, 50%, and 75% by weight of fine aggregate. The Marshall mix design method was used to determine the optimal performance in terms of Marshall stability, flow, Marshall Quotient (MQ), and volumetric properties. The results showed that the 75% GMRSW mixture achieved the highest Marshall stability (1202.87 kg) and Marshall Quotient (498.33 kg/mm), significantly outperforming the control mixture (989.83 kg and 369.69 kg/mm, respectively). These improvements are attributed to the angular texture and rough surface of GMRSW particles, which enhanced particle interlocking and load-bearing capacity. However, the 25% GMRSW mixture exceeded the allowable limit for Voids in Mix (VIM) at 5.57%, slightly above the Indonesian highway specification threshold of 5%. All other mixtures met the required specifications for AC-WC, indicating that GMRSW is a viable and effective fine aggregate replacement up to 75% substitution. Despite the improvements in stability, the increased angularity also made compaction more difficult, highlighting a trade-off that should be optimized in future applications. This research supports the beneficial reuse of GMRSW in tropical pavement engineering, contributing to environmental sustainability by reducing the reliance on natural aggregates. Further investigations are recommended to evaluate fatigue resistance, moisture susceptibility, and long-term field performance of GMRSW-modified asphalt mixtures.