Effect of diethanol-isopropanolamine on the early hydration of C 4 AF and C 4 AF-gypsum systems: a comparative study

Diethanol-isopropanolamine (DEIPA), as an organic complexing agent, has attracted much attention in recent years due to its ability to enhance the early reactivity of C4AF. This study thoroughly investigated the effects of various DEIPA dosages (0.0075 wt%-0.09 wt%) on the hydration of synthesized C4AF (Al/Fe ratio of 1) and C4AF-gypsum (C4AF-G) systems during early hydration. The results indicated that in the pure C4AF system, all dosages of DEIPA contributed to facilitating the hydration of C4AF and promoting the formation of C3(A,F)H6 and poor crystalline OH-AFm phases. After the addition of gypsum, the initial hydration of C4AF was significantly retarded, and the hydrates were transformed into AFt, AFm and amorphous AFm and FH3 phases. The hydration of C4AF was enhanced in the presence of an appropriate dosage of DEIPA (not more than 0.06 wt%). Due to its strong complexation ability toward Fe3+ and Al3+, DEIPA further promoted the formation of amorphous phases.