The Microstructure and Chloride Ion Diffusion Characteristics of Cements Containing Metakaolin and Fly Ash

Abstract

Structural failures in concrete buildings are not common. Most of them are a result of poor concrete performance. The durability of concrete is related mainly to the performance properties of the hydrated cement paste and to the environmental conditions. Absorption, permeability and diffusion are the main transport mechanisms by which deleterious substances like chlorides, sulphates and acids penetrate into concrete and cause damage. The strength of concrete is a good indicator of its structural adequacy but not of its durability, therefore designing concrete for durability requires the evaluation of its performance related properties. This study evaluates the effect of pozzolanic additions to normal portland cement by measuring chloride diffusion constant and pore structure characteristics.