Effects of copper slag and recycled concrete aggregate on the properties of CIR mixes with bitumen emulsion, rice husk ash, Portland cement and fly ash

Abstract

Construction and maintenance of roads require a large volume of aggregates for use in base, sub-base and surface layers. At the same time, the expansion of asphalt roadways results in the production of a large amount of asphalt road waste, known as reclaimed asphalt pavement (RAP). This paper aims to investigate the feasibility of the use of copper slag and recycled concrete aggregate (RCA) as substitutes for virgin aggregates in modifying the gradation of cold recycled mixes made with RAP material. In addition, the effects of three types of additives including Portland cement, fly ash, and rice husk ash on the properties of recycled mixtures were investigated. Marshall, Indirect tensile strength, resilient modulus, moisture susceptibility, and dynamic creep tests were conducted to evaluate the mechanical properties of the mixes. Toxicity characteristic leaching procedure was used to assess the environmental impacts of copper slag. The use of copper slag had better results than limestone and RCA probably due to better interlocking and superior physical and mechanical properties. With regard to the effects of additives, Portland cement was found to be the most effective additive. The difference between fly ash and rice husk ash was found to be statistically insignificant.