Abstract
Recently, superplasticizers are widely used for producing concrete and improving concrete durability. And in order to reduce environmental loading, set-retarder such as sodium gluconate is attracting attention to control the hydration of cement in the concrete sludge water. In previous paper, we clarified the influence of clay mineral on the fluidity of limestone powder suspension and the adsorption of superplasticizers. In this paper, we investigated the influence of Montmorillonite on the hydration of cement with comb-type superplasticizer or sodium gluconate. We also refered the interaction between the sodium gluconate and clay mineral. The rate of heat liberation of ordinary Portland cement paste was measured by using conduction calorimeter. Using a control stress type rheometer（rotational cylinder viscometer）, the viscosity of ordinary Portland cement paste was measured to estimate the apparent viscosity. And the adsorbed amount of polymer was calculated from the concentrations of the polymer in the initial solution and the liquid phase（after polymer adsorption）. The unadsorbed polymer concentration was measured by Total Organic Carbon Analyzer（TOC）. When the dosage of Montmorillonite increased, the rate of heat liberation of cement with comb-type superplasticizer was changed. However, the rate of heat liberation of cement and the fluidity of cement paste with sodium gluconate were not influenced by addition of Montmorillonite. In the case of comb-type superplasticizers, it is considered that much comb-type superplasticizers adsorbed on Montmorillonite and the amount of adsorbed comb-type superplasticizers on cement relatively decreased. On the other hand, the amount of adsorbed sodium gluconate on Montmorillonite is much lower than comb-type superplasticizers and the amount of adsorbed sodium gluconate on cement did not change.
