Chloride diffusion investigation under different magnitudes of hydrostatic pressure for pre-cracked concrete

Abstract

The service life of the reinforced concrete structure in the marine environment can be impaired significantly due to chloride-induced corrosion. However, how the chloride diffusion in pre-cracked concrete structures is affected by the hydrostatic pressure is poorly understood. This study experimentally examined the effect of hydrostatic pressure on the chloride diffusion in pre-cracked concrete. Cracks with five different widths, i.e., 20 μm, 40 μm, 60 μm, 80 μm, and 100 μm, were manually created each using a splitting tensile apparatus. The chloride diffusion in the concrete with a certain crack was then studied under four different hydrostatic pressures of 0 MPa, 0.1 MPa, 0.3 MPa, and 0.5 MPa. Experimental results show that the chloride diffusion in concrete with a crack greatly relies on both the hydrostatic pressure and the crack width. The chloride concentration increases as the hydrostatic pressure grows, particularly for the wider cracks with width ranging from 60 μm to 100 μm. Unexpectedly, the hydrostatic pressure has a negligible effect on the chloride distribution in the concrete with a crack width no larger than 40 μm. Thus, the critical crack width is between 40 and 60 μm. Both the chloride diffusion coefficient and the chloride concentration of concrete at a certain depth increased gradually as the hydrostatic pressure increased, the latter of which exhibited a linear relationship with the hydrostatic pressure The experimental findings enrich our understanding of the behavior of pre-cracked concrete when exposed to chloride-induced corrosion at different depths of marine environments.