Effect of Salt-Frost Cycles and Impact Loads on Residual Axial Capacity of Reinforced Concrete Column

This paper presents the results of experimental and analytical studies of the performance of reinforced concrete (RC) columns subjected to the salt-frost cycles (SFC), the impact, and their combined action under axial compression loading, respectively. Three groups of RC columns, with each RC column equipped with six cubic specimens, were constructed. Rapid SFC tests aiming at exploring the damage appearance of one group of RC columns and the relative dynamic modulus of elasticity (RDME), the mass loss (vm), as well as the cubic compressive strength loss (Delta f(cu)) of the specimens after SFC were carried out. The drop-hammer impact loading tests were performed to investigate the damage appearance and the dynamic responses of the other group of axially loaded RC columns. The failure modes, load-midspan vertical displacement, and axial capacity of the remaining group of RC columns subjected to the combined action of SFC and impact under axial compression loading were also investigated. Based on the analytical study, the models to calculate the residual axial capacity of RC columns subjected to the SFC, the impact, and their combined action are proposed, respectively.