Influence of Mineral Admixtures on Early-Age Autogenous Shrinkage of High-performance Concrete

摘要

The influence rules of the mineral admixtures containing fly ash, ground slag and silica fume on the early-age autogenous shrinkage of high-performance concrete have been discussed in this paper. According to the research results, fly ash mixture can substantially decrease the early-age autogenous shrinkage of high-performance concrete, while the silica fume will increase the autogenous shrinkage. Meanwhile the influence of ground slag on autogenous shrinkage is related to its fineness and admixture amount. Generally, it is believed that when the fineness of the fly ash is higher than 4000cm~2/g, the autogenous shrinkage will increase with the increasing admixture amount. The double admixture or 'multi-admixture' of fly ash or ground slag is better for reducing the early-age autogenous shrinkage of concrete than the 'single-admixture'. The early-age autogenous shrinkage of concrete occurs in distinctive linear dependence with the three types of mineral admixtures.