化学外加剂对粉煤灰混凝土坍落度的影响

The Influence of Chemical Admixtures on Slump of Fly Ash Concrete

就缓凝剂的性能来说,它能减慢水泥的水化速率,从而减慢了混凝土坍落度的损失率。但是对于连续搅拌的混凝土,缓凝剂不但不能减慢坍落度的损失率,反而加速了坍落度的损失。然而据国外资料报道,用粉煤灰来取代部分水泥,即可降低坍落度的损失率。但这要取决于粉煤灰取代水泥的百分率,而且与所用粉煤灰的烧失量有关。本文介绍了国外在这方面的研究成果。

By their very nature, retarding admixtures are supposed to slow the rate of cement hydration, hence slowing the rate of slump loss. But in a continuously mixed concrete, they not only do not slow down the rate of slump loss but, rather, they accelerate it. However, it was found that the use of fly ash as a partial replacement for cement may reduce the rate of slump loss, depending upon the replacement percentage and the loss on ignition of the fly ash used. The investigating results abroad are introduced in this paper.