2019 Volume 73 Issue 1 Pages 111-117
In cold region such as Hokkaido, when placing concrete in winter, it is necessary to carry out appropriate curing. However, blast furnace slag cement concrete requires longer curing than ordinary Portland cement concrete. Therefore, in order to increase the use of blast furnace cement for concrete production, it is necessary to improve initial strength development. The purpose of this study is to clarify the influence of hardening accelerator on the reaction of blast furnace slag powder. In this study, we focused on hardened blast furnace slag and calcium hydroxide to clarify the influence of accelerators. As a result, it was clarified that the initial strength enhancement of the sample mixed with nitrite-type accelerator was high. Moreover, it confirmed that the nitrite type-AFm was produced as a hydrate in sample with nitrite-type accelerator. Also, it was shown from the results of phase equilibrium model calculation that the volume of the hydrate did not change significantly.
