Resistencia química del hormigón. XX. Acción del agua de mar: influencia de la adición de escoria a un cemento portland. Estudio por DRX

Abstract

In this work, which is a follow-up of others, the evolution of structural features of enriched fraction (attacked-hydrated cement) is studied by DRX, extracted from one of the mortar prims (1 : 3) of 1 X 1 X 6 cm of the various series of test specimens made with a Portland cement (cement 3) and mixtures cement 3/slag = 85/15, 65/35, 40/60 and 30/70, in weight, immersed in artificial sea water (ASTM D 1141-75) for 56, 90, 180 and 360 days -at this stage- following curing period (24 hours in humidity saturated enclosure and up to 22 days under filtered drinking water). In addition, structural composition was studied by DRX of the new solid phases formed in the preservation-attack media (artificial sea water) where the mortar test pieces were immersed. In the DRX of the various enriched fractions, the peaks of brucite, ettringite and calcite were identified with variable intensity in them all, and those of Friedel salt, plaster and portlandite in part. Intensity of these peaks depends on the mixture used for making the mortar test pieces and on the preservation-attack time. In the DRX of the new solid phases, the peaks of calcite and aragonite were detected with variable intensity, and those of one form prevailed over those of another, depending on system conditions and particularly, on the cement 3/slag mixture used to elaborate the mortar test pieces; the brucite peaks were in addition identified in the diagrams of the solid phases corresponding to media where the mortar test pieces made with cement 3 and the mixture which has 15% slag were immersed.