Long-term moisture penetration in concrete exposed to marine tidal conditions

Abstract

The depth of concrete influenced by seawater penetration plays a vital role in many durability processes affecting reinforced concrete structures in the marine tidal zone. In this study, a phenomenological moisture transport model in concrete is developed and is validated with numerous experimental results reported in the literature. The boundary conditions for cyclic wetting–drying in the tidal zone are formulated based on a novel superimposed tide model that more accurately represents real-time tides. The moisture profiles over a large number of wet–dry cycles are evaluated in the tidal zone using the developed models. The long-term moisture penetration characterised by (i) the influential depth of moisture transport (IMDT) and (ii) the cyclic water absorption amount (CWAA) is compared at various locations along the entire tidal zone. Sensitivity analysis was carried out to estimate the influence of material properties and environmental conditions on the IDMTs and CWAAs. The results of the study revealed that the IDMTs and CWAAs predicted by the realistic superimposed tide model are about 3.5 times greater than those predicted by conventional diurnal tide models. This substantial difference justifies the importance of the correct choice of tide model for durability studies in the tidal zone.