Effect of Hydroxyethyl Methyl Cellulose on Cement Paste Hydration

Abstract:

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 (TGDSC) 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 (CSH) coexist in cement paste modified with HEMC, while only ［SiO4］4-tetrahedron monomers exist in the unmodified cement paste.

Key words:cement paste; hydroxyethyl methyl cellulose(HEMC); hydration heat; hydration products; CSH gel polymerization