Mechanical performance of sustainable asphalt mixtures manufactured with copper slag and high percentages of reclaimed asphalt pavement

Abstract

The use of reclaimed asphalt pavement (RAP) in the construction of hot mix asphalt (HMA) pavements is a widely used alternative in the development of sustainable road infrastructure. For this reason, the use of higher RAP contents continues to be a topic of interest. This study evaluated the performance of semi-dense asphalt mixtures incorporating 50% to 70% RAP and 7.5% and 15% copper slag (CS) as partial replacement of aggregate, to determine the influence of CS on the effective increase of RAP in the design of sustainable asphalt mixtures. The mixtures were evaluated using macrotexture, fatigue strengths, water sensitivity, and the Hamburg wheel tracking test. The results show that the use of RAP improves the permanent deformation resistance (RD) and fatigue life of the mixtures, while the mean texture depth (MTD) and indirect tensile strength ratio (ITSR) decrease. The incorporation of CS in the mixtures with RAP improved MTD and ITSR compared to the mixtures including only RAP and allowed higher RAP contents in fatigue and Hamburg wheel tests without showing a negative influence.