Cyclic behavior of full-scale reinforced high-strength recycled aggregate concrete columns

In order to expand the application of high-strength recycled concrete, five full-scale square high-strength recycled concrete columns (600 x 600 mm) were tested under the experimental axial compression ratio (ACR) of 0.54. The seismic behavior of reinforced high-strength recycled aggregate concrete columns under high ACR and the effects of recycled coarse aggregate (RCA) replacement ratio and ACR on the seismic behavior were analyzed. The results showed that the high-strength recycled concrete columns have potential to collapse-resistance capacity subjected to strong earthquakes. Under the similar concrete strengths, the mechanical properties of high-strength recycled aggregate concrete columns and ordinary concrete columns were comparable even under high ACR. As the ACR increased from 0.35 to 0.54, the bearing capacity increased by up to 12.6%, while the ductility decreased by up to 32.8%. The specimens with 100% RCA were more sensitive to ACR than those with 50% RCA. A four-fold restoring force model considering the effects of axial load, reinforcement ratio, shear span, and RCA replacement ratio was established, which was in good agreement with the experimental curves.