Fatigue performance evaluation of bottom ash-modified asphalt concretes using various aggregate types

The road network is the most important infrastructure for the country's economic development. Asphalt concrete (AC) pavement is a common type of pavement surface used in both developing and developed countries. In this study, bottom ash (BA), a by-product from coal-fired power plants, was used to improve the performance of AC in combination with various aggregates in Thailand. The aggregates used with the BA were comprised of limestone (L), granite (G), and basalt (B) aggregates. The asphalt cement penetration grade 60/70 (AC 60/70) was used for this research. The influence of BA replacement ratio (0%, 10%, 15%, 20%, and 25% by total weight of fine aggregate) on the Marshall properties and indirect tensile strength (ITS), as well as mechanistic performance (indirect tensile resilient modulus (IT M_r), indirect tensile fatigue life (ITFL), rut depth, and skid resistance), was evaluated. The B-AC exhibited the best Marshall properties, ITS and performance due to its highest optimum asphalt cement. The BA replacement ratio could improve the Marshall properties, ITS and performance of BA-AC for all studied aggregates due to the reaction between BA molecular and asphalt cement up to the best value at the optimum BA replacement ratio (OPT-BA), which was 15, 20, and 5% BA for BA-AC containing B, G, and L aggregates, respectively. The IT M_r was found to be directly related to ITS in a linear function. The IT M_r controls not only the ITFL (tensile failure) but also the rut depth resistance (compression failure). Based on the critical analysis of this research output, a stepwise procedure to determine the optimum BA replacement ratio and the mechanistic parameters of BA-AC is suggested to determine the thickness of pavement surface at a reasonable cost.