MKPC水化体系的早龄期变形特性试验研究

Experimental Study on Deformation Characteristics of MKPC Paste at Early Ages

用广口瓶装置测试了MKPC气球样品的体积变形,用千分尺测试了MKPC棱柱体试件的体积变形,研究磷酸钾镁水泥(MKPC)水化体系的早龄期变形规律,同时测试了新拌MKPC浆体的水化温度。结果证实:广口瓶装置测试MKPC气球样品的体积变形有较高的敏感性,其体积变形结果较同龄期MKPC棱柱体试件的线性体积变形高2个数量级。在5 h~48 h水化龄期,MKPC气球样品和棱柱体试体的体积变形率数据存在较好的非线性相关关系。新拌MKPC浆体在水化开始存在1个体积剧烈变化期,水化20 h后体积变形方趋于稳定,MKPC棱柱体试件线性体积变形率测试与计算应以水化24 h的长度作为计算基准更合理。在MKPC中掺适量粉煤灰(FA),其早期水化程度提高,MKPC气球样品的体积膨胀率峰值和残余体积膨胀率值明显高于参考样,且MKPC棱柱体试件的体积收缩为参考样的2/3。

the volume deformation of MKPC balloon sample was measured by wide mouth bottle device,and the volume deformation of MKPC prism specimen was measured by micrometer.The early age deformation law of potassium magnesium phosphate cement(MKPC)hydration system was studied,and the hydration temperature of fresh MKPC paste was measured.The results show that the volume deformation of MKPC balloon samples measured by wide mouth bottle device has high sensitivity,and the volume deformation results are two orders of magnitude higher than the linear volume deformation of MKPC prism specimens of the same age.There is a good nonlinear correlation between the volume deformation rate data of MKPC balloon sample and prism sample at 5-48 h hydration age.The volume deformation of fresh MKPC paste tends to be stable after 20 hours of hydration.It is more reasonable to test and calculate the linear volume deformation rate of MKPC prism specimens based on the length of 24h hydration.The results show that the early hydration degree of MKPC is improved by adding appropriate amount of fly ash(FA).The peak volume expansion rate and residual volume expansion rate of MKPC balloon sample are significantly higher than those of reference sample,and the volume shrinkage of MKPC prism specimen is 2/3 of that of reference sample.