蒸养混凝土的毛细吸水特性研究

采用ISAT(initial surface absorption test)方法,试验研究了蒸养混凝土的毛细吸水特性,调查了胶凝材料组成、养护条件以及蒸养工艺对蒸养混凝土毛细吸附系数的影响,并探索了相应影响机制及降低蒸养混凝土毛细吸水性的技术途径.结果表明:相对于标养条件,蒸养混凝土由表及里不同位置呈现更大的毛细吸水梯度;混凝土暴露表层的蒸养效应是导致其毛细吸水梯度增大的主要原因;采用粉煤灰、矿渣及硅灰复掺技术、对蒸养后的混凝土进行后续水养以及在蒸养过程中对暴露表层进行保湿覆盖处理均能减少蒸养混凝土的毛细吸附系数,降低蒸养混凝土由表及里的毛细吸水梯度.

Water Sorptivity of Steam Curing Concrete

Initial surface absorption test(ISAT) method was employed to investigate the water sorptivity of steam curing concrete as well as the effects of binder types, curing condition and steam curing technology on capillary absorption coefficient of concretes. The corresponding mechanisms and technical measurements reducing capillary absorption role of steam curing concrete were studied. Results indicate that, compared with standard curing concretes, a much higher water absorption gradient from exposure surface to interior of steam curing concretes is observed, which results from the bad effects of elevated temperature on the top surface directly exposed to steam during steam curing period. The capillary absorption coefficient of steam curing concrete and the corresponding gradient of capillary absorption from exposure surface to interior both can be decreased by incorporating a compound of fly ash and slag or silica fume, using such technical measurements as subsequent water curing and/or water retaining coverage.