Resistencia química del hormigón. XXI. Influencia de la adición de escoria a un cemento portland de alta resistencia inicial. Estudio de la concentración iónica del sistema cemento 1/escoria-agua potable filtrada

Abstract

In the present work, a continuation of others, there is studied the variation of the pH, and likewise the concentration of the ions Ca (II) and SO₄ (II) of the means (filtered potable water) in which there have been submerged the test tube series of mortar (1:3) made with an industrial Portland cement of high initial resistance (cement 1 <> P-550-ARI) and with the cement mixtures 1/slag = 85/15 - 65/35 - 40/60 and 30/70, in weight, submerged during the curing period (21 days) and later during 56-90-180 and 360 days (conservation periods), in this stage. There is likewise studied the chemical composition of the new solid phases formed in said means. The structural composition of said solid phases (calcite) was determined by DRX, and account of this was given in (2). In the different cases studied it was demonstrated that an increase of the content of Ca (II) is produced in the dissolution and in the solid phases mentioned, and likewise of the value of the pH, which depends on the mixture utilized to manufacture the different test tube series and on the time of conservation. The Ca (II) found in the dissolution (filtered potable water) is less than 0,1 X 10^-2 mols (in the majority of cases it is less than 0,07 X 10^-2 mols) while in the new solid phase it is greater (normally, greater than 0,3 X 10^-2 mols). On the contrary, the ion SO₄ (II) has not been detected in the solid phases mentioned, being found in small quantities in the different liquid phases (filtered potable water); less than 0,08 X 10^-2 mols in the majority of the cases.