Water Sorptivity of Steam Cured Concrete for Railway Precast Elements at Early Ages

Water absorption is closely related to the durability of concrete. To determine the effect of steam curing on water absorption of concrete at early ages, this paper investigated the water absorption of concrete which had different compositions of cementitious materials under three types of technological measures condition (technology A, B and C), and performed water absorption comparisons of various types of concrete by cutting the specimens into three slices: top-level, internal, and bottom. Results indicate that the water absorption of all specimens appears to be gradient distribution from top-level to bottom, and top-level specimens have the highest water absorption. However, in terms of water absorption, there is no significant difference among the other layers. The highest water absorption value is achieved by the top-level of concrete with technology A, which is 42% higher than that of its mid-level. However, the water absorption of top-level, mid-level, and bottom layer of various concretes with technology B and C are all decreased, especially the concretes incorporating admixture A with technology C.The differential value of water absorption between the top-level and mid-level is 3%~18% commonly. By use of suitable technological measures and admixtures, the harm of steam curing on the surface structure of concrete will be alleviated, and the inhomogeneity of the internal concrete can be improved.