Durability of concrete with addition of limestone powder

Abstract

The paper describes the influence of powdered limestone and water-cement (w/c) ratio on the durability of concrete in 5% Na2SO4. Before immersion in sulphate solution the compressive strength, absorbability of concretes and phase composition of pastes were tested. Sulphate durability was assessed by means of a linear deformation of concrete and X-ray diffraction analysis of pastes with and without addition of limestone powder: The results show that a beneficial influence of powdered limestone on concrete durability was observed when w/c <0·60. Above this value, the powdered limestone has almost no essential effect on sulphate resistance. The addition of limestone powder to cement prevents the transformation of ettringite to monosulphate and hemisulphate. Monocarbonate and hemicarbonate were formed instead of those phases.