Influencia de la adición del BaCO3 sobre la hidratación del cemento portland

Abstract

[EN]The effect of incorporation of BaCO^ in portland cement hydration has been studied. From this study it is inferred that presence of BaCO^ in cements makes them require a higher quantity of mixing water. However, mechanical resistances do not seem negatively affected, for a formation ofcarboaluminates by chemical reaction between the barium carbonate and the Cy4 of the clinker appears. The BaCO^ reveals a retardant effect on the setting time, in presence of gypsum as much as in its absence. The BaCO^ with gypsum reacts as BaSO^, a salt of a very high stability. The formation of this barium salt inhibits the formation of ettringite in pastes. Finally, the presence of BaCOj in cements ensures that no expansive process will occur in sulphatic means either external or internal, for carbonate is going to react with these sulphates and form BaSO^, preventing thus the formation of expansive ettringite.