Modeling moisture transport at the surface layer of fatigue-damaged concrete

This study investigates the moisture transport at the surface layer of concrete damaged by uniaxial tensile fatigue loading. In particular, a theoretical model for calculating the surface factor of drying concrete was established and verified with laboratory testing. The effect of mix proportion (e.g. water-to-binder ratio, supplementary cementitious materials) and level of fatigue damage on the moisture desorption at the concrete surface were studied. The results show that the surface factor of drying concrete increases as the environmental temperature or wind speed increases, but seldom changes with the mix proportion and fatigue damage. However, the fatigue loads (up to 30% of the ultimate tensile load) can accelerate the concrete surface water transfer by a factor of 1.05-1.60 times in the initial drying process, mainly due to enlarged surface mass transfer area.