Influential depth of moisture transport in concrete subject to drying–wetting cycles

An analytical approach is used to investigate the influential depth over which moisture transport occurs within initially saturated concrete subjected to drying–wetting cycles. During drying the moisture transport is modelled as an evaporation–diffusion process with instantaneous evaporation at the moving gas–liquid interface, while the wetting of dried concrete surface zone is described by capillary absorption. Based on the water loss and intake balance during drying and wetting, an equilibrium drying–wetting time ratio is identified. By this ratio, the drying–wetting cycles are classified as drying-dominated, wetting-dominated and equilibrium ones. The corresponding moisture influential depths are expressed explicitly in terms of environmental factors and material transport properties. With the available concrete sorptivity data, the equilibrium time ratio and influential depth are calculated and discussed in depth.