Experimental Assessment and Multicriteria Optimization of Asphalt Mixtures Modified with Biochar

Abstract

Agricultural wastes have recently gained considerable attention as sustainable modifiers in asphalt modification due to their functional performance and environmental benefits. Biochar produced from agricultural biomass, in particular, has shown significant potential in order to improve performance and sustainability of asphalt and asphalt mixtures. However, limited studies have investigated the use of biochar obtained from spent tea and its optimum ratio in asphalt and asphalt mixtures. Therefore, this study experimentally investigated properties of asphalt mixtures modified with biochar derived from pyrolysis of spent tea waste. Physical and chemical properties of asphalt modified with biochar at ratios of 0.5%, 1%, 2%, 3%, and 4% were investigated. Physical properties of modified asphalt indicate that 50/70 asphalt and biochar are compatible. According to chemical test results, it was observed that biochar filled voids in asphalt components. It was also determined that there was a physical interaction between biochar and 50/70 asphalt. Indirect tensile strength, tensile strength ratio, and rutting performance of asphalt mixtures prepared with asphalt-modified biochar were determined. It has been observed that rutting resistance of modified asphalt mixtures at high temperatures increases. Further, the optimum ratio of asphalt modified with biochar was investigated by taking into account the analytical hierarchy process and complex proportional assessment, which is a multicriteria decision-making method. This study has determined use of biochar obtained from spent tea as an asphalt modifier.