Study on fire resistance and mechanical properties of modified recycled waste oyster powder in asphalt binder

Abstract

In this study, an eco‐friendly approach is presented for the innovative use of waste oyster shell (OS) powder modified with zinc stannate, aliphatic alcohols, and silane coupling agents blended with styrene‐butadiene‐styrene (SBS) modified asphalt to make a flame‐retardant binder (modified oyster shell [MOS]/styrene‐butadiene‐styrene [SBS]/MA), which is rendered flame retardant and smoke suppressive. Compared with the original SBS/MA, MOS/SBS/MA with a 2% addition rate showed a 35.44% increase in ultimate oxygen index, a 30.62% reduction in peak exotherm, a 10.87% reduction in smoke density, and a 75% reduction in volatile organic compound (VOC) emissions. It also has excellent mechanical properties, with increases in composite modulus, elastic modulus, and storage modulus of 68.58%, 97.29%, and 59.59%, respectively, at 46°C. The thermal stability of MOS/SBS/MA is also improved, with a decomposition temperature 26°C higher than that of SBS/MA. Pavement performance tests show that the water‐soaked Marshall's split strength has increased by 3.87% and the coefficient of rutting by 3.51%. Increased by 3.51%, this method effectively utilizes the waste OS, improves the fire‐retardant properties of asphalt while retaining the mechanical properties of the modified asphalt binder, and provides a model for developing sustainable fire‐retardant asphalt in coastal areas.