纤维素醚-膨胀珍珠岩耦合作用下水泥浆体早期水化规律

Early stage hydration law of cement pastes under the coupling effect of cellulose ether and expanded perlite

利用水化放热速率、XRD、FT-IR、DTG和Ca(OH)2含量测试手段,研究了羟丙基甲基纤维素醚和膨胀珍珠岩两种保水因子单掺和耦合作用条件下水泥浆体的早期水化规律及二者的作用机理。结果表明羟丙基甲基纤维素醚能够显著降低水泥浆体早期水化放热速率峰值,且能延缓诱导期和加速期出现的时间,对水泥浆体中后期水化没有明显的延缓效应。膨胀珍珠岩可以降低早期水化放热速率峰值,效果较羟丙基甲基纤维素醚差,但对水泥水化无延缓效应。当二者耦合作用时,具有显著的叠加效应。水化12h时,羟丙基甲基纤维素醚和膨胀珍珠岩能够显著降低水泥浆体中Ca(OH)2含量,较空白样分别降低了43.6%和9.1%。水化1和3d时,水泥浆体中Ca(OH)2含量随二者掺加而降低的趋势变缓。

Early hydration law of cement pastes modified with hydroxypropyl methyl cellulose ether and expanded perlite and their mechanism in cement pastes were studied by hydration exothermic rate, XRD, FT-IR, DTG and Ca（OH）2 content. The results show that hydroxypropyl methyl cellulose ether can significantly reduce the peak of hydration exothermic rate of cement paste in early stage. Hydration induction period and acceleration period of cement pastes were delayed. It had little retarding influence on middle and late period hydration of cement paste. The peak hydration exothermic rate of cement pastes modified with expanded perlite was decreased. The effect was worse than the hydroxypropyl methyl cellulose. Expanded perlite had no retarding effects on cement hydration. It had obvious coupling effect under combined action of hydroxypropyl methyl cellulose ether and expanded perlite. Hydroxypropyl methyl cellulose ether and expanded perlite can significantly reduce the content of Ca（OH）2 after 12h hydration. The content of Ca（OH）2 in cement pastes respectively decreased by 43.6% and 9.1% than blank samples. After 24 and 72h hydration, the trendy of decreasing of Ca （OH）2 content in cement paste became very slow with both hydroxypropyl methyl cellulose ether and expanded perlite mixing.