石膏和高铝水泥对自流平砂浆性能的影响

The Influence of Gypsum and Alumina Cement on Self-leveling Mortar Performance

水泥基自流平砂浆的收缩开裂是导致自流平砂浆施工失败的主要原因。通过研究硬石膏、二水石膏、半水石膏和不同类型的高铝水泥对自流平砂浆性能的影响,分析石膏和高铝水泥对自流平砂浆抗压强度和限制收缩率的影响,为自流平砂浆石膏和高铝水泥的选择提供技术依据。研究表明,二水石膏和半水石膏对提高自流平砂浆的抗压强度和抑制收缩的作用优于硬石膏;高铝水泥中氧化铝含量对自流平砂浆强度和收缩的影响较大,氧化铝含量最高的CA70对提高自流平砂浆抗压强度和抑制收缩的作用优于CA50-A700和CA50-A900两种高铝水泥。XRD测试结果表明,石膏的掺入能促进胶凝体系中生成更多的钙矾石;相比掺CA50-A700的胶凝体系,掺CA70的胶凝体系中生成了更多的钙矾石。

Shrinkage cracking of cement-based self-leveling mortar is the main cause of failure for its construction. In this paper, through the research of anhydrite, half water gypsum, dihydrate gypsum and different types of alumina cement on the properties of self-leveling mortar, we analyze the influence of gypsum and alumina cement on restrictions shrinkage rate and compressive strength, which provide technical basis for the selection of gypsum and alumina cement. Research shows that the half water gypsum and dihydrate gypsum have the better effect than anhydrite on enhancing strength and inhibit contraction. The content of alumina in alumina cement has great influence on the strength and shrinkage of self-leveling mortar, CA70 with the highest content of alumina is superior to CA50-A700 and CA50-A900 in improving the compressive strength and inhibiting shrinkage of self-leveling mortar. The results of XRD show that the addition of gypsum can promote the formation of more AFt in the cement paste, and compared to the cement paste with CA50-A700, more AFt have been generated in CA70＇s cement paste.