Hydration of tricalcium aluminate C(3)A and C(3)A-gypsum mixtures in the presence of surfactants: Adsorption or surface phase formation?

To explain the specific features of the adsorption of polymeric anionic sur factants (superplasticizers) in the C(3)A-water system, the adsorption of p oly(methylenenaphthalene sulfonates) on individual calcium hydroaluminates and hydrosulfoaluminates was studied. The data obtained were compared with the adsorption of these surfactants on a number of hydrolytically stable me tal oxides and hydroxides, as well as an the silicate minerals of clinker. The composition of the products formed during the hydration of C(3)A in the presence of equivalent amounts of surfactants was studied by the methods o f elemental analysis, X-ray diffraction, and DTA. The resultant products ca n be characterized as organomineral phases containing surfactant molecules between the layers of calcium hydroaluminate clusters. All known specific f eatures of surfactant adsorption in the systems containing derivatives of t ricalcium aluminate can be explained based on a similar intercalation mecha nism.