Analysis of relative humidity change in low water-cement ratio concrete

Relative humidity movement of different internal location in an ordinary coarse aggregate concrete and two pre-wet ceramsite concretes with 0.3 water-to-cement ratio were experimentally investigated. The internal RH-change of concretes with one-dimensional moisture transported was measured, in different RH curing environment. The results indicates that: when the cumulative curing time was a definite value, the internal RH decreased more slowly with the time of moist curing deferred. All location values of internal RH of concrete with pre-wet ceramsite were higher than those values of ordinary aggregate concrete, and the internal RH of concrete was higher with the moisture content of ceramsite increased. In the drying environment, with the increased of moisture difference between concrete internal and environment, the RH decrease rate of internal concrete was fast, where the rang from naked surface to the 5cm location deep, when the rang exceed deep 10cm, influence of environment RH on the internal RH was very slight; internal RH of ceramist concrete decreased slowly than ordinary concrete at the same condition.