Formation of ettringite in two varieties of ternary systems
The formation of ettringite and the expansion associated with it were studied on paste made from Portland cement, two Al-besring compounds such as calcium aluminate cement and calcium sulphoaluminate cement, and calcium sulfate with different resctivities (anhydrite, α-hemihydrate and gypsum).The hydration process and formation of ettringite in the binders with different con tent of calcium sulfate was investigated by free expansion testing, isothermal conduction calorimetry, X-ray diffraction (XRD) and environmental scanning e lectronic microscope (ESEM).Results showed that the reactivity and amount of the calcium sulfate determined the balance between the hydration products of ettringite and monosulfate, and also the early hydration kinetics including the formation content, size and location of ettringite.It was also found that all the ternary systems with higher addition of calcium sulfate expand significantly.When a higher content of α-hemihydrate was added, besides ettringite much secondary gypsum also forms in voids between cement granules, which exerted adverse effects on the properties of ternary systems.However, the formation content of ettringite appeared to have no connection with the expansion value.
Ettringite Calcium aluminate cement Calcium sulphoaluminate cement Calcium sulfate Hydration Expansion
Linglin Xu Peiming Wang Guofang Zhang
School of Materials Science and Engineering,Tongji University Key Laboratory of Advanced Civil Engineering Materials,Ministry of Education,Shanghai 201804,China
国际会议
武汉
英文
9-16
2013-10-23（万方平台首次上网日期，不代表论文的发表时间）