硅灰、偏高岭土对矿渣-粉煤灰微珠胶凝材料性能的影响

Influence of silica fume and metakaolin on properties of slag⁃fly ash microbead cementitious materials

首先通过改变粉煤灰微珠掺量,确定满足快速修补要求的矿渣-粉煤灰微珠胶凝材料基体的最佳配比,再调节偏高岭土、硅灰掺量,研究其对复合胶凝材料凝结时间、力学性能和水化机理的影响。研究发现,偏高岭土对凝结时间的改变较硅灰更敏感。通过化学结合水测试,分析了不同硅灰和偏高岭土掺量对矿渣-粉煤灰微珠胶凝材料水化反应程度影响的原因。力学实验结果表明:矿渣-粉煤灰微珠胶凝基体复合掺加5%硅灰(质量分数)+15%偏高岭土(质量分数),试块2 h抗压强度为11.5 MPa、28 d抗压强度达到75.2 MPa,且呈现缓慢递增的趋势。

Firstly,the optimum ratio of slag⁃fly ash microbead cementitious material matrix meeting the requirements of rapid repair was determined by changing the content of fly ash microbead,and then the content of metakaolin and silica fume was adjusted to study its influence on the setting time,mechanical properties and hydration mechanism of composite cementitious materials.It was found that metakaolin was more sensitive to the change of setting time than silica fume.The in⁃fluence of different silica fume and metakaolin content on the hydration reaction degree of slag⁃fly ash microbead cementi⁃tious material was analyzed by chemical bound water test.The mechanical test results showed that the compressive strength of the test block was 11.5 MPa in 2 h and 75.2 MPa in 28 days with the composite of slag⁃fly ash microbead cementitious matrix and 5%silica fume(mass fraction)+15%metakaolin(mass fraction).