Sustainable optimization of asphalt strength using bamboo leaf ash and sawdust ash fillers

Sustainable reuse of agricultural and biomass waste presents a viable strategy for enhancing asphaltic concrete performance while reducing environmental impact. However, the combined application of Bamboo Leaf Ash (BLA) and Sawdust Ash (SDA) as mineral fillers remains insufficiently investigated. This research examines the effect of blended BLA–SDA fillers on the mechanical and physical properties of asphaltic concrete and determines the optimal mixture through Analysis of Variance (ANOVA). Asphalt cement of 60/70 penetration grade was used, with the conventional filler replaced by BLA–SDA blends from 0 to 100% in 10% increments. The asphalt binder was characterized for penetration (P), softening point (SP), and specific gravity (SG). Total samples of 135 were prepared for the engineered asphalt mixtures while the Marshall Quotient (MQ) was determined to assess strength and stiffness. ANOVA identified the significant parameters and optimal filler composition for maximum performance. F-values and p-values were used to compare the relationship between the asphalt composition and their influence of the performance test. R 2 values were used to determine the fitness of mechanical properties, RMSE were used to assess the model performance, while MAPE were used to analyze the degree of deviation of asphaltic concrete. Similarly, Std. Dev. And C.V. (%) were used to support the reliability of the model. The measured properties of the binder showed a penetration of 70 (0.1 mm), a softening point of 48°C, and a specific gravity of 0.97, while MQ values ranged between 3.7 and 7.1 kN/mm. The discrepancy between predicted and experimental responses was less than 9%, confirming model reliability. Optimization indicated that a blend containing 72.198% SDA and 27.802% BLA, with total ash substitution of 17.22%, achieved the highest desirability of 67.3%. These results confirm that blended BLA–SDA fillers effectively enhance asphaltic concrete strength and promote sustainable, resource-efficient pavement production. • Blended BLA–SDA fillers improved asphaltic concrete’s mechanical strength. • ANOVA identified significant parameters mis influencing asphalt performance. • Optimal composition: 72.198% SDA, 27.802% BLA, 17.22% ash substitution. • Nonlinear models predicted stability, flow, and MQ with high accuracy. • Sustainable fillers reduced environmental impact in asphalt production.