Abstract
It is expected that the amount of fly ash（FA）emitted from coal fired power plant is increased. It is important to utilize effectively FA as blended material. But FA blended cement has the problems which are decrease of early age strength and resistance to neutralization. It is thought that the problems are resolved by using the cement including more alite（C3S）and free lime（f.CaO）than those of ordinary Portland cement（N）. This paper discusses the hydration reaction of blended high-alite cement containing FA or blast furnace slag（BFS）as blended material.
The blended cement replaced with FA or BFS by 20％ showed as great heat liberation as N. And the porosity of 3 or 7days cured blended cement were lower than N or same. It is expected that the early age strength of the blended cements are comparable to that of N. The amount of Ca（OH）2（CH）in the hydrated blended cements were close to that of N. And the amount of CH was increased by increase of f.CaO. It is expected that the resistance to neutralization is improved by increasing the amount of C3S and f.CaO in the base cement. Increase of f.CaO accelerated early hydration of BFS and tended to accelerate hydration of FA.
