Effects of crack width on chloride penetration and performance deterioration of RC columns with sustained eccentric compressive load

摘要

In a marine environment, the mechanical performance of Reinforced Concrete (RC) structures deteriorates mainly due to the coupling action of service load and/or the corrosion of steel bars. Here, the working conditions of RC columns in a marine environment were simulated in the laboratory. The chloride penetration and performance deterioration of RC columns with different widths for the maximum initial crack of 0, 50, 100 and 200 microns, induced by different levels of external sustained eccentric compressive load and environments of chloride corrosion, were simulated by seawater wet-dry cycles. The results showed that the yielding load and ultimate load of the RC column specimens were significantly decreased as the width of the initial cracks increased. Tensile strain and crack width were both parameters contributing to chloride penetration in the tensile area of the RC column specimens. During the seawater wet-dry cycles, the initial cracks on the column specimens changed. The initial cracks tended to vanish due to the self-healing capacity of concrete when the width of the initial crack was smaller than 50 microns. The initial cracks remained relatively constant when the crack widths were between 50 and 100 microns, and the crack widths increased when the initial crack width was larger than 100 microns.