羟乙基甲基纤维素对水泥水化的影响

Effect of Hydroxyethyl Methyl Cellulose on Cement Paste Hydration

利用等温量热法、核磁共振谱(NMR)分析、X射线衍射相分析以及热重差示扫描量热(TG-DSC)分析等方法,研究了羟乙基甲基纤维素及其掺量对水泥浆体水化放热、水化产物以及水化进程的影响.研究表明,羟乙基甲基纤维素能够延缓水泥早期水化,降低早期水化放热速率和水化放热量,但其对水泥中后期水化则没有明显的延缓作用;羟乙基甲基纤维素与水泥水化产物之间发生了相互作用,使得水泥浆体水化产物C-S-H凝胶中的硅氧四面体由一聚合态向一聚合态和二聚合态共存转变.

The hydration degree and the phase compositions of cement pastes were studied by using isothermal calorimetry, Nuclear magnetic resonance （ NMR ） spectroscopy, thermogravimetry-differential scanning calorimetry （TGDSC） and X-ray diffraction （XRD）. Results show that hydroxyethyl methyl cellulose（HEMC） retards the early-age hydration of cement paste, decreases the early-age hydration rate and hydration heat of cement paste, but hardly retards the hydration of cement paste after the deceleratory period. Interactions between HEMC and cement hydration products take place. [SiO4]4- tetrahedron monomers and dimers of calcium silicate hydrate （C-S-H） coexist in cement paste modified with HEMC, while only [SiO4]4- tetrahedron monomers exist in the unmodified cement paste.