Sustainable Pavement Solutions: A Study of the Performance of Permeable Asphalt Mixtures Incorporating Steel Slag and Recycled Concrete Aggregate

This study addresses the limitations of current research on the clogging mechanism of asphalt mixtures, which are constrained by costly and complex testing equipment. We introduce a novel method to assess the permeability and clogging conditions of asphalt mixtures, focusing on the use of basic oxygen furnace steel slag aggregate (SSA) and recycled concrete aggregate (RCA) in the production of permeable asphalt mixtures (SSA-RCA-PAMs). A series of experiments was conducted to evaluate the volume expansion, water stability, low-temperature performance, high-temperature performance, and permeability of permeable asphalt mixtures (PAMs). The results indicate that the volume expansion of SSA-RCA-PAM increases with the SSA replacement ratio but remains below 1%, satisfying industry standards. SSA-RCA-PAM demonstrated performance superior to that of conventional PAM, particularly the blend with a 25% RCA–75% SSA ratio, which exhibited a 6.97% freeze–thaw splitting strength ratio increase. The permeability coefficients of both conventional PAM and SSA-RCA-PAM decreased with increasing number of test cycles, following a quadratic parabolic trend. Clogging analysis confirmed that higher SSA replacement ratios corresponded to better permeability and smaller clogging areas in SSA-RCA-PAM. This research provides innovative solutions for sustainable road construction, enhancing the resource utilization of waste steel slag and recycled concrete aggregates.