Influence of limestone on the hydration of calcium sulfoaluminate cements
Calcium sulfoaluminate (CSA) cements can be blended with mineral additions like limestone powder in order to optimize properties and costs.This study investigates the effect of limestone on the hydration of a commercial CSA clinker blended with anhydrite.Cement formulations with M=2.1, 1.1 and 0 (M=molar ratio of anhydrite to yeelimite) were blended with high and intermediate amounts of limestone powder.Pastes without limestone served as reference systems.The hydration was followed by isothermal calorime try, X-ray diffraction and thermogravimetric analyses.Additionally, the experimental data were compared with the phase assemblage predicted by thermodynamic modeling using the geochemical speciation code GEMS-PSI.Calorimetric results indicate that limestone accelerates the hydration kinetics.It is sug gested that this can arise from additional nucleation sites provided by limestone.In addition to such a physical effect, systems with limestone form hemi-and monocarbonate instead of monosulfate, which cause an indirect stabilization of ettringite.In formulations with higher M-value, the effect of limestone needs to be taken into account together with that of an hydrite, to obtain high compressive strength.
CSA Limestone Thermodynamic Modeling Mineralogy Compressive strength
Martin.Lukas H.J. Winnefeld.Frank Müller.Christian J. Lothenbach.Barbara
Empa-Laboratory Concrete and Construction Chemistry,8600 Diibendorf ,Switzerland Saint Gobain Weber,8404 Winterthur,Switzerland
国际会议
武汉
英文
229-245
2013-10-23（万方平台首次上网日期，不代表论文的发表时间）