Resistencia química del hormigón XXV. Influencia de la adición de escoria a un cemento Portland. Estudio de la concentración iónica del sistema cemento 3/escoria-agua potable filtrada

Abstract

This work, which follows on others, study the variation of the pH, and likewise the concentrations of the ions Ca (II) and SO₄ (II) of the filtered potable water in which there were submerged the test specimens of mortar (1:3) made with a Portland cement (cement 3 < > P-450) and with the mixtures cement 3/slag = 85/15 - 65/35 - 40/60 and 30/70 of weight, submerged for a curing period (21 days) and later during 56 - 90 - 180 and 360 days (conservation periods), in this stage. It also study the chemical composition of the new solid phases formed in the said means. The structural composition of the solid phases (calcite) was determined by DRX; an account of this was given in (2). In the different studied cases it has been demonstrated that an increase of the content of Ca (II) in the solution and in the new solid phases and of the value of the pH is produced, which depends on the mixture used to manufacture the different test specimen series and on the time of conservation. The content of Ca (II) in the solution is less than 0,1 X 10^-2 moles, in most of the cases, while in the new solid phases is greater, reaching 4,31 X 10^-2 moles. On the contrary the ion SO₄ (II) has not been in the solid phases mentioned, being found in little quantities in the different liquid phases (filtered potable water); the greater contents correspond to the means of the mixture that have the greater mounts of slag (60 and 70 % of weight).