Evaluation of fracture behavior of stone mastic asphalt (SMA) containing recycled materials under different loading modes at low temperatures

Abstract

Using natural materials (including aggregates and bitumen) in the asphalt paving industry causes significant and irreparable damage to the environment annually. Utilizing waste materials in producing asphalt pavements can be a suitable solution to reduce such damages. Therefore, this paper studied the impacts of recycled crumb rubber (CR), recycled PVC particles, and reclaimed asphalt pavement (RAP) in different percentages on the performance of stone mastic asphalt (SMA) mixture against low-temperature cracking. PVC and CR additives were added to asphalt mix in two wet and dry methods. Thermal cracks are important and common failures of asphaltic pavements, and considerable financial budgets are allocated annually in different countries to deal with these damages. In this investigation, the fracture toughness of 16 various asphalt mixes at three distinct temperatures (temperatures of zero, −10, and −20° C) and under three diverse loading modes (including the mixed-mode I/ II, the pure mode II, and the pure mode I), were investigated by Semi-circular bending (SCB) fracture test. In addition to laboratory reports and mechanical studies, life cycle assessment (LCA) was utilized in this research to estimate and compare the influence of these asphalt mixes on the environment. The outcomes of mechanical tests and environmental analysis demonstrated that the usage of waste materials in this study has significantly enhanced the fracture strength of the SMA mix against low-temperature cracks and reduced its negative environmental effects. Therefore, the mixture containing RAP and 20% recycled PVC had the most satisfactory performance both in terms of environmental and fracture performance.