Corrosion rate of reinforced concrete incorporating recycled concrete aggregates

One of the main strategies to reduce environmental impact of the concrete industry is to recycle/reuse waste materials. However, one of the unknown aspects of recycled aggregate concretes is their durability in harsh environments. This study presents research work on the mechanical and durability properties of concrete incorporating recycled aggregate. Recycled aggregate was made by crushing the demolished concrete from a building site in Erbil. Six types of concrete mixtures were tested: concrete made entirely with natural aggregate as control concrete, and five types of concrete made with natural fine and recycled coarse aggregate (20%, 40%, 60%, 80%, and 100% replacement of coarse recycled aggregate). Superplasticizer was used to reduce water/cement ratio. Two tests were performed, including compressive strengths test and electrical resistivity test under chloride-contaminated environments, which indirectly measures corrosion rate of concrete. The results show that electrical resistivity decreases with increasing incorporation level of RCA. Regarding corrosion tests, the ER of 100%RCA concrete was about 57% of the corresponding ER of the control specimen. However, 49% reduction for control specimen and a 42.29% reduction for 100% RCA concrete under natural chloride attack. In addition, the chloride attack does not affect the compressive strength of recycled aggregate concrete