Effects of simulated environmental conditions on the internal relative humidity and relative moisture content distribution of exposed concrete

Simultaneous measurement of the relative moisture content (RM) within concrete by the electrode method and the relative humidity (RH) within concrete using humidity sensors was conducted to elucidate the effects of cyclic daily changes in the environmental conditions (temperature and RH) and rainfall on the internal RH and RM distribution within exposed concrete. The effects of the presence of cracking in concrete were also experimentally investigated in comparison with uncracked concrete. As a result, the changes of the internal RH and RM distribution within concrete due to external temperature/RH changes were found to occur only in the surface region of concrete, while moisture was found to decrease extremely slowly deeper inward. As for the effect of cracking on the RM distribution within concrete, a larger crack width tended to lead to a slightly higher drying rate. In regard to the effect of rainfall, the duration of rainfall and whether or not the concrete is directly exposed to rainwater were found to be more important than the amount of rainfall.