Research on cement hydration and hardening with different alkanolamines

In this work, six types of alkanolamines (i.e., TEA, TIPA, DEIPA, EDIPA, THEED and THPED) were added into Portland cement as chemical additives, and their effects on physical properties and hydration of Portland cement as well as mechanism were investigated. The results show that all the alkanolamines expect TEA can effectively improve the degree of cement hydration. TEA delays the hydration of alite because the formation of the TEA-Ca2+ complex inhibits the growth of CH. TIPA accelerates the hydration of C4AF at late stage, but reduce the early strength due to its air-entraining effect. The lower dosages of DEIPA and EDIPA have the advantages of TEA and TIPA, which increase not only the early strength but also the late strength. They promote both the hydration of the aluminum and ferrite phase as well as catalyze the conversion of AFt to AFm, which lead to the optimization of pore size distribution. The effects of THEED and THPED on hydration of Portland cement are similar though their molecular structure are different which improve the late strength and have larger suitable dosage range.