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

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.