Effect of New Alkanolamines on Cement Hydration and Hardening

Diethanolisopropanolamine (DEIPA), ethyldiisopropylamine (EDIPA), N,N,N',N'-tetrakis-(2-hydroxyethyl)-ethylenediamine (THEED) and N,N,N',N'-tetrakis-(2-hydroxypropyl)-ethylenediamin (THEED) were developed as chemical additives in cement pastes. The effect of alkanolamines on the cement hydration process and hardening properties as well as air contents was investigated. The results indicate that DEIPA and EDIPA can significantly improve the strength of cement mortar at various ages (by 4.4% and 10.4% at 56 d, respectively) and promote the degree of cement hydration. The transformation from AFt to AFm is accelerated by DEIPA and EDIPA, effectively optimizing the pore size distribution for a lower porosity. THEED and THPED can promote the cement hydration and increase the late strength, but adverse to the early strength of mortar due to their air-entraining performance. In addition, the addition range of THEED and THPED is wider than that of DEIPA and EDIPA.