Fresh, Mechanical, and Durability Characteristics of Self-Consolidating Concrete Incorporating Recycled Asphalt Pavements

Abstract

This paper investigates the fresh, mechanical, and durability characteristics of self-consolidating concrete incorporating recycled asphalt pavements (SCCRAP). A total of 12 concrete mixtures were prepared and tested. Mixtures were divided into three different groups, with constant water to cementitious materials ratio of 0.37, based on the recycled asphalt pavement (RAP) content: 0, 25, and 50% coarse aggregate replaced by RAP. All mixtures were prepared to achieve a target slump flow equal to or higher than 500 mm (24 in.). The control mixture for each group was prepared with 100 percent portland cement, whereas all other mixtures were designed to have up to 70 percent of the portland cement replaced by a combination of supplementary cementitious materials (SCMs), such as class C fly ash and granulated blast furnace slag. The properties of fresh concrete investigated in this study included flowability, deformability, filling capacity, and resistance to segregation. In addition, the compressive strength at 3, 14, and 28 days; the tensile strength; and the unrestrained shrinkage up to 80 days were investigated. Using up to 70 percent slag as partial replacement of cement in concrete mixtures developed a 28-day compressive strength less than that of the control mixture by 26 and 49% for RAP content of 25 and 50%, respectively. Increasing the RAP content from 0 to 25 and 50% caused the split tensile strength of all mixtures to decrease significantly. Based on the results obtained in this study, it is not recommended to replace the coarse aggregate in self-consolidating concrete with more than 25 percent RAP.