C-S-H及C-S-H脱水相对水泥石结构改性的研究

AN INVESTIGATION OF MODIFIED MICROSTRUCTURE OF HARDENED CEMENT PASTE WITH C-S-H AND DEHYDRATED C-S-H PHASE

以C-S-H及C-S-H脱水相作水泥水化物沉淀中心的品种。从理论上阐明了它们是具有较大介电常数、较小物理化学不均匀系数、高分散度的晶种物质,故具有优先吸附的界面效应及优先沉淀的结晶中心作用,可缓和原始矿物表面的高浓度的屏蔽效应及界面的近程析晶,使水化物分布均匀、结构致密,从而提高水泥石强度。C-S-H及C-S-H脱水相两者中,尤以后者作用更显著。

The effect of C-S-H and dehydrated C-S-H phase used as an 'inoculating seed' of cement hydrate is investigated. Both of them, especially dehydrated C-S-H phase, are able to improve the microstructure of hardened cement paste and enhance the strength of cement. Microcalorimetry, analysis of liquid phase and QXRD are used to study the hydration of C_3S in suspended C_3S solution. Microstructure characteristics of hardened cement paste with addition of C-S-H and dehydrated C-S-H phase are studied by SEM, mercury intrusion porosimetry. The results indicate that both C-S-H and dehydrated C-S-H phase can shorten the 'induce period', accelerate the hydration of C_2S and in- crease the hydration degree of C_3S. The hardened C_3S and hardened cement paste with addition of dehydrated C-S-H phase which consist of fine C-S-H fabric are more dense. This paper reveals that the 'inoculating seed' with large dielectric constant, small inhomogenous coefficient, as well as high specific surface area has the interfacial effect with preferential absorption and nucleation center effect with preferential precipitation. This results in reducing or even elimilating the shielding effect of high ion concentration area around the original minerals of clinker and the early nucleation in the interface. Therefore, the hydrated products are homogenously distributed and the microstructure is densely developed.