The effect of recycled concrete aggregate and steel slag on the dynamic properties of asphalt mixtures

A high percentage of asphalt mixtures (in terms of weight and volume) are composed of aggregates; thus, new aggregates are needed to build and maintain roads. The use of waste material as aggregates in the pavement industry can prevent the accumulation of waste material and environmental pollution and can reduce primary production costs. Thus, the objective of the present study was to determine the mechanical properties of asphalt mixtures with waste concrete and steel slag aggregates. Six different asphalt mixtures containing three types of aggregate (dacite, recycled concrete and steel slag) were used to prepare Marshall specimens and to determine the optimal asphalt binder content. The mechanical characteristics of the mixtures were evaluated by Marshall stability, indirect tensile resilient modulus, dynamic creep and indirect tensile fatigue tests. The results indicated that the optimal mixture contained steel slag coarse aggregates and recycled concrete fine aggregates.

► The optimal mixture contained SS as coarse aggregates and RCA as fine aggregates.
► The mechanical properties of mixture containing RCA as course aggregate was poor.
► Permanent deformation in the optimal mixture was 40% less than the control sample.
► Resilient modulus in the optimal mixture was 2.35 times greater than control sample.
► The fatigue life of the optimal mixture was greater than control sample.