Characteristics of Recycled Mineral Fillers and Their Effects on the Mechanical Properties of Hot-Mix Asphalt When Used as Limestone Filler Replacements

Abstract

This study was designed to analyze the characteristics of two recycled fillers, hollow concrete block (HCB) powder and brick powder (BP), and to assess their respective impacts on the mechanical properties of hot-mix asphalt (HMA) when used as complete replacements for limestone (LS) filler. The recycled and LS fillers are obtained from construction and demolition wastes and naturally mined for commercial uses, respectively. Filler characteristics were examined using Brunauer–Emmett–Teller, X-ray diffraction, scanning electron microscope, and energy dispersive X-ray spectroscopy. The respective effects of the fillers and the mechanical properties of the HMA mixtures were assessed using Marshall stability, indirect tensile strength, moisture damage by tensile strength ratio, indirect tensile cracking index, and permanent deformation tests. The results demonstrated that HCB powder significantly improved moisture, rutting, and crack resistance in HMA, which are factors critical to extending the life of asphalt concrete. In contrast, using BP resulted in mixed values and negative effects, particularly in terms of moisture resistance and rutting.