Polycarboxylate comb-like copolymer (PCE) is a kind of polyelectrolyte, which is easily affected by the ions in cement suspensions. In this work, the effects of sulfate ion on the surface charge, adsorption and dispersion in cement system with PCE as dispersant were investigated in detail. The addition of sulfate ion apparently decreased the positive charge on the surface of cement particles. The sulfate ion reduced the adsorption and dispersibility of PCE in cement suspensions, which was due to the competition between sulfate ions and PCE in the adsorption behaviour on the surface of cement particles.
YoshiokaK., SakaiE., DaimonM., and KitaharaA.Role of Steric Hindrance in the Performance of Superplasticizers for Concrete. J. Am. Ceram. Soc., 80 (1997) 2667–2671.
2.
YamadaK., HaneharaS., and HonmaK.Effect of the chemical structure on the properties of polycarboxylate type superplasticizers, Cement Concrete Res., 30 (2000) 197–207.
3.
YoshiokaK., TazawaE., KawaiK., and EnohataT.Adsorption characteristics of superplasticizers on cement component minerals, Cement Concrete Res., 32 (2002) 1507–1513.
4.
RanQ.P., and SomasundaranP., MiaoC.W., LiuJ.P., WuS.S., ShenJ.Adsorption Mechanism of Comb Polymer Dispersants at the Cement/Water Interface, J. Disper. Sci. Technol., 31 (2010) 790–798.
5.
PlankJ., VladD., BrandlA., and ChatziagorastouP.Colloidal chemistry examination of the steric effect of polycarboxylate superplasticizers. Cement Int., 3 (2005) 101–110.
6.
UchikawaH., HaneharaS., and SawakiD.The role of steric repulsive force in the dispersion of cement particles in fresh paste prepared with organic admixture. Cement Concrete Res., 27 (1997) 37–50.
7.
RanQ.P., SomasundaranP., MiaoC.W., LiuJ.P., WuS.S., and ShenJ.Effect of the length of the side chains of comb-like copolymer dispersants on dispersion and rheological properties of concentrated cement suspensions, J. Colloid Interf. Sci., 336 (2009) 624–633.
8.
SolisF., and CruzM.O.Collapse of flexible polyelectrolytes in multivalent salt solutions. J. Chem. Phys., 112(4) (2000) 2030–2035.
9.
VeigaK.K., and GastaldiniA.L.G.Sulfate attack on a white Portland cement with activated slag. Constr. Build. Mater., 34 (2012) 494–503.
10.
YamadaK., OgamaS., and HaneharaS.Controlling of the adsorption and dispersing force of polycarboxylate-type superplasticizer by sulfate ion concentration in aqueous phase. Cem. Concr. Res., 31 (2001) 375–383.
11.
DivetL., and RandriambololonaR.Delayed ettringite formation: the effect of temperature and basicity on the interaction of sulphate and C-S-H phase. Cem. Concr. Res., 28(3) (1998) 357–363.
