Abstract
Superplasticizers are used for producing self-compacting concrete and high strength concrete, and improving concrete durability. Many research papers have reported on the influence of certain ions such as SO42－ on the dispersion-adsorption of comb-type superplasticizers. This study discusses the influence of inorganic electrolytes（CO32－, PO43－ and SO42－）on the fluidity of CaCO3 - H2O suspension and the adsorption of superplasticizers.
The viscosity of the suspension was measured to estimate the apparent viscosity at a shear stress of 200Pa. 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 a larger amount of functional groups was introduced onto the main chain, the influence of inorganic electrolytes on the fluidity of CaCO3 suspension with phosphate ion was decreased. And calcium ion may possibly cause shrinking of the polymer chains. Comb-type polymers containing graft chains with some extent of chain length are effective for preventing the fluidity decrease when calcium ion concentration is high.
