Conduct an Advanced Numerical Simulation Investigation on the Rutting Performance of Coal Liquefaction Residue Asphalt Mixture

Zhe Wang^1*Zhen Wang¹Chuan Sha¹Shuangfeng Guo²Pengfei Li³Wenhua Zheng⁴Hongbo Cao¹Xiaowei Shan¹Guoqing Cao⁵Jie JI⁴

• ¹Beijing Municipal Road & Bridge Building Material Group Co. Ltd., beijing, China
• ²College of Transportation Engineering, Nanjing Tech University, nanjing, China
• ³Jianke Public Facility Operation Management Co., Ltd., beijing, China
• ⁴Beijing University of Civil Engineering and Architecture, Beijing, China
• ⁵Qingdao NO1 Municipal Engineering Co., Ltd., Qingdao, China

Coal liquefaction residue is a byproduct of coal-to-liquid technology, known to adversely affect the ecological environment and human health. This study investigates the influence of coal liquefaction residue on the rutting resistance of asphalt mixtures. The residue was used to replace fine aggregate on a volumetric basis, and a rutting model was developed using the discrete element method in PFC2D to analyze mixture behavior under various temperatures and loads. The research focuses on the effect of zero to four point seven five millimeter coal liquefaction residue particles on macroscopic rutting behavior by examining the displacement of fine particles and the distribution of force chains. Results indicate that rutting development in mixtures containing coal liquefaction residue follows a power-function growth pattern, divided into three stages. Particles within the mixture demonstrate strong self-organization adaptability, reducing the likelihood of stress concentration at rut initiation. During rutting evolution, particles sized zero point six to two point three six millimeters contribute significantly to deformation, while smaller particles (one point one eight to two point three six millimeters) are more susceptible to passive displacement due to compression and collision with larger particles (two point three six to four point seven five millimeters). However, in asphalt mortar with higher adhesive strength, the smaller zero point six to one point one eight millimeter particles are more extensively coated by larger particles, resulting in reduced displacement compared to the one point one eight to two point three six millimeter fraction. Numerical simulations confirm that replacing the one point one eight to two point three six millimeter and two point three six to four point seven five millimeter particles with indirect coal liquefaction residue single particle sizes, and the zero point six to one point one eight millimeter and one point one eight to two point three six millimeter particles with direct coal liquefaction residue single particle sizes, are rational approaches. Direct coal liquefaction residue significantly enhances the high-temperature performance of asphalt mixtures compared to indirect coal liquefaction residue, consistent with the outcomes of macroscopic rutting tests.