THE MECHANISM OF STARCH MALEATE HALF ESTER(SMHE) AS WATER-REDUCER FOR CEMENTITIOUS COMPOSITES

摘要

In this paper, the properties of cement paste added starch maleate half ester (SMHE) were investigated. The adsorption amount was measured with Chemical Oxygen Demand (COD) technique, and the adsorption of SMHE on cement particles conforms to Langmuir's adsorption isotherm. The fluidity, thickness of adsorption layer on cement particles as well as ζpotential of cement particles in the presence of SMHE were studied. The results indicate that SMHE is a water-reducer which can improve the fluidity of paste. The dispersion mechanism of SMHE comes from the synergism of steric hindrance repulsion and electrostatic force, and the former plays an important role for the improvement of fluidity.