STRENGTH PROPERTY OF BLENDED CEMENT MADE BY MIXING HIGH EARLY STRENGTH PORTLAND CEMENT AND BLAST FURNACE SLAG CEMENT TYPE B

Abstract

Recently, global warming is a serious problem for environmental protection. In Japan, therefore, reduction of CO₂ emission is an important task in any industries. It is demanded that approach to reduction of CO₂ emission, Especially, in the large scale construction works. It is promoted to use blast furnace slag cement instead of ordinary portland cement because of a little amount of CO₂ emission. However, there is a problem that blast furnace slag cement has lower initial strength than ordinary portland cement. This paper writes down of improvement method about initial strength development for blast furnace slag cement. In this study, we confirmed a strength property of the blended cement which mixed high early strength portland cement and blast furnace slag cement type B as initial strength improvement for blast furnace slag cement. As a result, we confirmed the water cement ratio of the blended cement that has the same compressive strength on 28days as ordinary portland cement. Furthermore, in the case of under 70％ of mixing rates, initial strength development of blend cement which mixed high early strength portland cement and blast furnace slag cement type B is equal to or more than ordinary portland cement. In addition, reduction of CO₂ emission effect was estimate by this test in comparison with ordinary portland cement, too.