Experimental analysis of properties of recycled coarse aggregate (RCA) concrete with mineral additives

Nowadays, researches on the usability of recycled aggregate (RA) in concrete is gaining popularity in all over the World due to the preservation of the environment and sustainable development. RA can be obtained after crushing and screening of the construction rubble obtained from demolished structures. The recycled coarse aggregate (RCA) used in this work is obtained from İSTAÇ (The İstanbul Environmental Protection and Waste Processing Corporation) to replace the natural coarse aggregates (NCA) in different proportions. Mineral additives used in this experimental work are silica fume (SF) and ground granulated blast furnace slag (GGBFS) at various ratios. The influence of SF and GGBFS with RCA of hardened concrete, such as compressive strength, tensile splitting strength, density and water absorption of are experimentally investigated. The test results obtained showed that at 100% of the replacement level of RCA, the compressive strength decreases about 24% and the strength reduction is more significant at over 50% RCA content. Increasing the RCA content significantly improves the tensile splitting strength of the concrete according to the compressive strength. The ratios between the tensile splitting strength to the compressive strength are greater in the RCA concretes incorporating GGBFS than the RCA concretes incorporating SF. An inverse relationship between the density and the water absorption ratio is observed in RCA concretes and this relation is more significant in higher amounts of RCA contents.