[en] Diethanol-isopropanolamine (DEIPA) is a tertiary alkanolamine used in the formulation of cement grinding-aid additives and concrete early-strength agents. In this research, isothermal calorimetry was used to study the hydration kinetics of Portland cement with DEIPA. A combination of X-ray powder diffraction (XRPD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC)–thermogravimetric (TG) analysis and micro-Raman spectroscopy was used to investigate the phase development in the process of hydration. Mercury intrusion porosimetry was used to study the pore size distribution and porosity. The results indicate that DEIPA promotes the formation of ettringite (AFt) and enhances the second hydration rate of the aluminate and ferrite phases, the transformation of AFt into monosulfoaluminate (AFm) and the formation of microcrystalline portlandite (CH) at early stages. At later stages, DEIPA accelerates the hydration of alite and reduces the pore size and porosity

[en] Alite-ye'elimite clinker is a high cementing clinker prepared by introducing calcium sulfoaluminate, a non-silicate mineral, into the cement clinker. The mineral composition and mechanics of tricalcium silicate-rich sulfur aluminate prepared at 1300 °C are reported. The effects of copper slag and phosphorus slag on the phase composition, heat release and compressive strength were investigated. The phase composition was analysed by X-ray powder diffraction. The results show that the copper slag and phosphorus slag can lower the burn temperature of the clinker and promote the coexistence of C₃S and C₄A₃$\overline{S}$. The quality of clinker produced at 1300 °C is satisfactory. The compressive strength of mortar curing at 28 d is higher than that of P·II 52.5.

[en] Alite-ye'elimite cement is an alternative cement that combines desirable characteristics of calcium sulfoaluminate cements and Portland cement in that it shows improved strength development at early age while retaining high portlandite contents. The key problem in the clinkering process is to produce the alite-ye'elimite phase assemblage so that both phases can co-exist. In this study, a new synthesis method is proposed to achieve the coexistence of alite and ye'elimite consisting of a secondary heat treatment step at 1250 °C after regular Portland clinker firing at 1450 °C. Quantitative X-ray powder diffraction and electron microscopy were used to analyze the phase composition of clinker before and after the secondary heat treatment. The results show that ye'elimite develops during secondary heat treatment of calcium sulphate enriched clinker by reaction of C₃A and sulphate phases. Additional ferrite is formed as result of rejection of Fe originally in solid solution with C₃A during ye'elimite formation