Study on the influence of FCC waste catalysts on the interaction ability between asphalt and fillers

Fluid catalytic cracking (FCC) waste catalysts produced by petroleum cracking contain many harmful substances, such as heavy metals, and improper treatment can lead to environmental pollution. To solve this problem, this study investigated four types of FCC (LM, SH, A, SL) waste catalyst as a substitute filler for limestone mineral powder and examined their interactions with asphalt and fillers. The X-ray fluorescence (XRF), scanning electron microscope and specific surface area tests were conducted to compare the performance of FCC waste catalyst and fillers. Meanwhile, the effects of FCC waste catalyst on asphalt mastic composed of limestone mineral powder and asphalt were evaluated using surface energy, interaction parameters, and FTIR. Results show that there is little difference in the main components of the four waste FCC catalysts and limestone mineral powder. However, the surface roughness and specific surface area of the FCC catalysts are significantly greater than those of limestone. Moreover, the addition of FCC waste catalyst can improve the adhesion of asphalt with fillers and aggregates, and significantly enhance the interaction capabilities between the filler and the base asphalt, especially for SH. FTIR analysis confirms that the aforementioned improvements are achieved through physical interactions. This study reveals the effects of different FCC waste catalysts on asphalt mortar, and provides a theoretical basis for promoting the practical application of FCC waste catalysts in road engineering.