高炉水砕スラグ-セッコウ系硬化体の微構造
1978 年 1978 巻 155 号 p. 154-159
詳細
1978 年 1978 巻 155 号 p. 154-159
The hardened cement pastes prepared from blast furnace slag powder, gypsum and slaked lime were examined with SEM observation, measurement of pore-size distribution, X-ray analysis and test of compressive strength after 36-week aging in water.
The results obtained are as follows :
1) The microstructures in hardened slag-gypsum cement pastes were controlled by the quantity of slaked lime mixed.
2) Independent of the mixing ratio of slag and gypsum, the hardened pastes mixed with more than 20% of the slaked lime had porous structures containing needlelike ettringite, gel substances and unreactive materials, being cracked because of expansion.
3) The hardened paste mixed with 0.5% of slaked lime had a compact structure consisting of strips of ettringite cemented with gel materials and a large quantity of gel pores, which were suitable for the development of compressive strength.
4) The mechanism for formation of microstructures in hardened slag-gypsum cements mixed with slaked lime was explained on the basis of the phase-equilibrium diagrams of the systems of CaO-Al2O3-CaSO4-H2O.
