Laboratory studies to investigate the properties of CIR mixes containing steel slag as a substitute for virgin aggregates

► This paper evaluates effects of steel slag on mechanical properties of CIR mixtures. ► Anionic emulsion is more compatible for production of CIR mixtures containing slag. ► Use of anionic emulsion improves CIR resistance to permanent deformation. ► Steel slag enhances resistance to permanent deformation of CIR mixtures. This paper aims to evaluate the effectiveness of steel slag as a substitute for virgin aggregates on mechanical properties of cold mix recycling asphalt pavement. For this purpose, gradation requirements of two types of Reclaimed Asphalt Pavement (RAP) materials in Cold In Place Recycling (CIR) mixes were modified. Mixtures’ gradation requirements were satisfied by adding 20% and 10% of two types of new aggregates in accordance with Asphalt Institute CIR grading requirements. The results showed that the use of steel slag can enhance Marshall stability, resilient modulus, tensile strength, resistance to moisture damage and resistance to permanent deformation of CIR mixes. Use of anionic bitumen emulsion is recommended in preparing mixtures, because of its compatibility with them.