Multi-objective optimization of biomass filler-based asphalt mix manufacturing using response surface methodology

Asphalt concrete design is an empirical process that often requires time-consuming, expensive laboratory testing. Optimizing mixture design is crucial to guarantee that asphalt concrete fulfills the required properties. This entails making intricate choices regarding the amounts of aggregates, binder, and filler contents to suit several goals. This research repurposes biomass filler [bamboo leaf ash (BLA)] as an alternative to mineral filler [pulverized quarry dust (PQD)] at 0–100 wt%. The mix design proportions, including filler ratio, filler-to-binder ratio, and fine aggregate-to-coarse aggregate ratio, were optimized as independent factors to forecast the fitted responses (rutting resistance and moisture susceptibility) of bamboo leaf ash (BLA)-based asphalt concrete using a full central composite design of the response surface method. Furthermore, the predicted responses were validated using experimental responses. Unlike the fine aggregate-to-coarse aggregate ratio, the results demonstrated that a filler ratio of 35% and a filler-to-binder ratio of 1.0 significantly influence the fitted responses, yielding optimized improvements in rutting resistance and moisture susceptibility with 19–56% and 15%, respectively. The correlations between optimized and experimental variables were strong and accurate, with R-squared values of 96.90% and 94.80% for rutting resistance and moisture susceptibility, respectively. Hence, these response models are advantageous in designing the optimum mix proportions of asphalt concrete incorporating recycled waste materials to achieve the required workability, mechanical, and durability properties.