Mechanical Resistance of Hot-Mix Asphalt Using Phosphorite as Filler

Phosphorites (PF) have small particle sizes and interesting chemical compositions to be used as filler in asphalt mixtures. The present study assessed the performance that a hot-mix asphalt (HMA) displays when the natural filler (NF) is completely replaced by PF. X-ray diffractometry (XRD), X-ray fluorescence (XRF), and scanning electron microscope (SEM) tests were carried out on NF and PF particles. Asphalt mastic was manufactured using a weight ratio of filler (NF and PF) to asphalt binder of 11.2. Penetration, softening point, viscosity, and linear amplitude sweep test were performed on the asphalt mastic. The following tests were carried out on mixes manufactured with NF (control) and PF (HMA-PF): Marshall, indirect tensile strength, Cantabro, resilient modulus, permanent deformation, and fatigue under stress-controlled mode. Additionally, moisture damage resistance was assessed through the tensile strength ratio (TSR) parameter. The HMA-PF mix displayed a better performance in all the evaluated properties, without increasing the optimum asphalt binder content. PF as fillers could be an interesting alternative in the manufacture of HMA mixtures subjected to high temperature climates.