Abstract：By using scanning electron microscopy, X-ray diffraction, mercury intrusion and other testing methods, the mineral composition and surface characteristics of three admixtures (limestone powder, fly ash, and ground granulated blast furnace slag) commonly used in hydraulic concrete were studied, and the hydration mechanism of binary and ternary cementitious material systems was studied. The results showed that the surface of limestone powder particles was rough, which could promote the early hydration of cement, weakly participate in the reaction and generate hydrated carbon calcium aluminates, but it had no volcanic ash activity. The limestone powder has a greater impact on the pores in the range of 20~100 nm in cement stone. As the content of limestone powder increases, the pores in this range increase and the pore structure of hardened paste gets worse. Fly ash contains a large number of spherical particles, the surface of the particles is dense and smooth, and it contains a large number of vitreous bodies. The pozzolanic effect of fly ash can optimize the pore structure of slurry by combining fly ash with limestone powder
2024, Vol. 0 
