Portal de Periódicos da CAPES

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

1999; Spanish National Research Council; Volume: 49; Issue: 254 Linguagem: Inglês

10.3989/mc.1999.v49.i254.449

1988-3226

Gabriel Dumitru, T. Vázquez, F. Puertas, María Teresa Blanco‐Varela,

Concrete Corrosion and Durability

The effect of incorporation of BaCO 3 in portland cement hydration has been studied. From this study it is inferred that presence of BaCO 3 in cements makes them require a higher quantity of mixing water. However, mechanical resistances do not seem negatively affected, for a formation of carboaluminates by chemical reaction between the barium carbonate and the C 3 A of the clinker appears. The BaCO 3 reveals a retardant effect on the setting time, in presence of gypsum as much as in its absence. The BaCO 3 with gypsum reacts as BaSO 4 , a salt of a very high stability. The formation of this barium salt inhibits the formation of ettringite in pastes. Finally, the presence of BaCO 3 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 4 , preventing thus the formation of expansive ettringite.