建設材料特集 高ビーライトセメントおよび高ビーライト系混合セメントを用いたコンクリートの諸特性

Abstract

Recently in Japan, the demand for low heat cement to prevent thermal cracks is growing higher because of scaling up of concrete structures. Usually, moderate heat portland cement and binary or ternary blended cement in which ground blast-furnace slag and fly ash were admixed have been used as low heat cement. However, such blended cements have several problems. For examples, the heat of hydration of moderate heat cement is not sufficiently low. The quality of blended cement is not stable and it is very difficult to control and stabilize its quality because of incorporating industrial by-products, and the rate of carbonation is quite fast. Therefore, belite-rich cement is expected much as low heat cement which is more durable and effective to prevent thermal cracks.In this study, the effect of the content of belite in cement on the property of concrete was investigated by using four kinds of belite cements in order to make the characteristics of belite-rich cement clear. The relations between the replacement ratio of blast-furnace slag and adiabatic temperature rise or strength were also investigated using belite-rich cement containing about 60% of C2S, under the condition that the replacement ratio of fly ash was kept 30% constant.