Mechanical properties and uni-axial compression stress-strain relation of recycled coarse aggregate concrete subjected to salt-frost cycles

An experimental research was performed on the mass loss, relative dynamic modulus of elasticity (RDME), cubic compressive strength (f(cu)), splitting tensile strength (f(t)) and stress-strain relationship for recycled aggregate concrete (RAC) after exposure to salt-frost cycles (SFC). The tests were carried out on two RACs with water to cement ratios of 0.45 and 0.35. Experimental results show that the number of SFC has a significant effect on the properties of RAC. With the increase in the number of SFC, the mass loss decreased first then increased while the RDME, f(cu) and f(t) decreased continuously at an increasing rate. The descending branch of the stress-strain curves of the RACs was found to become steeper with the increase in the number of SFC, showing that the RACs became more brittle after salt-frost cycles. Meanwhile, the peak stress and elastic modulus of the RACs decreased and the peak strain increased at an increasing rate with the increase in the number of SFC. Equations for the complete stress-strain curves of the RACs after SFC were developed, which were in good agreement with experimental stress-strain curves. (C) 2018 Elsevier Ltd. All rights reserved.