An investigation on mechanical and physical properties of recycled aggregate concrete (RAC) with and without silica fume

Abstract

Experimental studies for determining the mechanical and the physical properties of the recycled aggregate concrete (RAC) with and without silica fume (SF) is inspired by the Urban Renewal Law which regulates circumstance of existing structures in Turkey. According to this law, the structures which have been built lacking quality engineering, built without considering urban planning, and are risk prone (i.e. susceptible to earthquakes), will be demolished and rebuilt using recent Turkish Standards. Implementing this law is expected to increase the quantity of waste concrete. Minimizing waste disposal through structural and non-structural areas without a harmful effect on nature has a vital importance in Turkey. In this study, demolished-building-rubble is used as recycled aggregate (RA) with and without SF in concrete mixtures. Twelve concrete mixtures in three groups are produced, and the mechanical properties of the concrete specimens such as compressive strength, tensile splitting strength and elasticity modulus, and physical properties of the concrete specimens such as density and water absorption ratio are determined. The proportion 30% of RA in concrete mixtures is proposed as the optimum ratio. Low regression coefficient of RAC with SF is observed in the short-term. It is found that 5% SF content in the RAC is more convenient to improve the low properties of RAC (i.e. compressive strength).