无碱液体速凝剂对掺不同石膏的水泥性能影响

Effect of Alkali-Free Liquid Accelerator on Properties of Cement Adding Different Gypsum

研究无碱液体速凝剂对不同石膏种类及掺量水泥性能的影响。凝结时间、抗压强度试验结果表明,随着水泥中石膏含量增加,水泥净浆凝结时间减少,砂浆1 d抗压强度略有增加;相同掺量下,掺二水石膏的水泥净浆凝结时间最短,掺半水石膏凝结时间最长,掺无水石膏的水泥胶砂1 d抗压强度最高,掺半水石膏抗压强度最低。水化温度、X射线衍射(XRD)、热重分析(TG)表明,不同水泥掺无碱液体速凝剂水化过程温升、水化生成钙矾石和氢氧化钙数量,以及水化程度不同,导致水泥浆体力学性能不同,是导致无碱液体速凝剂与不同水泥适应性的原因之一。

The effect of alkali-free liquid accelerators on the cement properties of different types and contents of gypsum was studied.The results of setting time and compressive strength showed that with the increase of gypsum content in cement,the setting time of cement paste shortened and the 1 d compressive strength of mortar increased slightly.Under the same dosage of gypsum,the setting time of cement paste with dihydrate gypsum is the shortest,while that with hemihydrate gypsum is the longest.The 1 d compressive strength of cement mortar with anhydrite gypsum is the highest,while that with hemihydrate gypsum is the lowest.The analyses of hydration temperature,XRD and TG show that the temperature rise,the amount of ettringite and calcium hydroxide generated during hydration and the hydration degree of different cement with alkali-free liquid accelerator lead to different physical properties of cement paste,which is one of the reasons for the adaptability of alkali-free liquid accelerator to different cements.