Experimental analysis of properties of recycled coarse aggregate (RCA) concrete with mineral additives Ö. Çakır ⇑ Yıldız Technical University, Department of Civil Engineering, 34220 Istanbul, Turkey highlights  At 100% RCA content, the concrete strength decreases about 24%.  Tensile splitting strength/compressive strength of RCA concretes are 7.7–11.4%.  Inverse relation between density–water absorption at higher RCA content observed. article info Article history: Received 20 March 2014 Received in revised form 9 May 2014 Accepted 18 June 2014 Available online 12 July 2014 Keywords: Recycled coarse aggregate concrete Silica fume Ground granulated blast furnace slag Mechanical properties Physical properties Regression analysis abstract 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 _ ISTAÇ (The _ Istanbul 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. Ó 2014 Elsevier Ltd. All rights reserved. 1. Introduction Concrete is the most common and useful material in the construction industry and has contributed to the advancement of civilizations throughout last century. However, construction activ- ities demand a significant amount of natural materials in order to produce cement and aggregate. Procurement of these natural materials significantly modifies the natural sources and creates major environmental problems [1]. Furthermore, sustainable waste management is another major issue faced by countries all over the world. In order to minimize the environmental impact and energy consistency of concrete used for construction facilities, reuse of construction and demolition (C&D) wastes can be a beneficial way which leads sustainable engineering approaches to concrete mix design [2]. As many developing countries all over the world, Turkey has also been generating a huge amount of C&D waste which generates serious environmental problems to deal with. Due to the Urban Renewal Law, it is estimated that demolition and maintenance of the structures at the end of their design span result 4–5 million ton/year of C&D waste [3]. In March 2006, the Istanbul Metropoli- tan Municipality and the Istanbul Environmental Management in Industry and Trade Inc. ( _ ISTAÇ) prepared a plan, called Construc- tion and Demolition Waste Management Plan. According to the plan, it was decided that import centers would be established at each municipality to collect local wastes [4]. On the other hand, the cement industry, in particular, already uses by-products from the production of silicium (silica fume) and steel (blast furnace slag). As recycling and reuse are http://dx.doi.org/10.1016/j.conbuildmat.2014.06.032 0950-0618/Ó 2014 Elsevier Ltd. All rights reserved. ⇑ Tel.: +90 2123835242; fax: +90 2123835133. E-mail address: cozgur@yildiz.edu.tr Construction and Building Materials 68 (2014) 17–25 Contents lists available at ScienceDirect Construction and Building Materials journal homepage: www.elsevier.com/locate/conbuildmat