Effect of Salt-Frost Cycles on Mechanical Properties and Uniaxial Compression Stress-Strain Curve of Recycled Coarse Aggregate Concrete

In this study, recycled coarse aggregate concrete (RAC) with incorporation of high-performance water-reducer and air-entraining agent was designed with a water to cement ratio of 0.25. Rapid salt-frost tests were conducted on the RAC specimens, during which mass loss and relative dynamic modulus of elasticity of the RAC specimens after salt-frost cycles (SFC) were obtained. Cubic compressive strength, splitting tensile strength, and uniaxial compression stress-strain curve of the RAC after SFC were also obtained. The loss of mass and relative dynamic modulus of elasticity of the RAC after 250 SFC was 0.5% and 19.31%, respectively; both much lower than the corresponding critical failure values of 5% and 40%, respectively. The cubic compressive strength, splitting tensile strength, peak stress, and modulus of elasticity of the RAC after SFC were found to decrease with the increase in the number of SFC, by 56.9%, 41.3%, 7.9%, and 15.0%, respectively, after 250 SFC. The elastic Poisson ratio and peak strain of the RAC after 0-250 SFC varied slightly around 0.22 and 2,200 mu epsilon, respectively. In addition, the equations for describing the uniaxial compression stress-strain curve of the RAC after 0-250 SFC are presented, which fit well with the experimental results.