Properties of recycled PVC aggregate concrete under different curing conditions

This paper presents the properties of concrete prepared by replacing 20%, 30%, 40% and 50% of natural sand with recycled PVC (RPVC) aggregate under different curing conditions. Six different curing regimes were applied including continuous water curing, continuous open air curing, continuous laboratory curing and in the remaining three regimes, concrete specimens were exposed to initial water curing periods of 3, 7 and 14 days. The effects of each curing techniques on the compressive strength, splitting tensile strength, elastic modulus, initial and final absorption were determined. Results showed that irrespective of the curing condition, RPVC incorporation generally reduces the mechanical properties of concrete measured in terms of compressive strength, splitting tensile strength and modulus of elasticity. However, curing condition affects the strength of both normal and RPVC aggregate concrete, the RPVC aggregate concrete is more sensitive to air storage curing. Moreover, CEB-FIP model code is found to provide an adequate prediction of splitting tensile strength of RPVC aggregate concrete at different curing conditions. A low absorption can be achieved for RPVC aggregate concrete exposed to different curing conditions classified as "good" concrete quality. In general, continuous water curing is the most suitable curing condition for concrete; however, initial water curing for 14 and 7 days decrease the strength of RPVC concrete only up to 7.3% and 9.8%, respectively. (C) 2016 Elsevier Ltd. All rights reserved.