HEMC对水泥浆早期水化产物形成历程的影响

Influence of HEMC on the Formation Process of Hydration Products in Cement Pastes at Early Ages

为了探讨纤维素醚与水泥浆之间在水化早期的相互作用,通过傅里叶变换红外光谱分析和热分析方法研究了HEMC(羟乙基甲基纤维素醚)对水泥浆前24 h主要水化产物形成历程的影响.结果表明:HEMC延迟了钙矾石、C-S-H凝胶和CH(氢氧化钙)的形成,延缓了水化产物中水分子由吸附态向结晶态的转化;HEMC对不同水化产物的延迟能力不同,对CH的延迟能力最强,对钙矾石和C-S-H的延迟能力较弱.在前24 h中,HEMC没有导致水泥浆生成新的物相.

For studying the interaction between cellulose ethers and cement pastes at early ages,FTIR spectra and thermal analysis were performed to investigate the influence of HEMC(hydroxyethylmethyl cellulose) on the formation process of major hydration products in cement pastes at first 24 h.The results indicate that the HEMC prolongs the formation of ettringite,C-S-H gels and CHCcalcium hydroxide),and retards the transformation of absorbed water to crystal water in hydration products.Moreover,the retardation capacity of HEMC is different for different hydration products,in which the strongest is for CH and weaker is for ettringite and C-S-H gels.No new products are detected in cement pastes modified by HEMC compared to neat cement pastes.