Concrete: grey and coloured

Abstract

The addition of pigment to concrete concerns a number of issues that have to be understood and tackled effectively. The compatibility, durability and stability of a pigment are primary factors classifying its adequacy. Various forms of pigments, qualities and compositions conceive dissimilar effects on concrete and methods of application. Incorrect choice of materials, mix proportions, formwork and curing will result in a low quality coloured concrete. In this study chemical analysis of different pigments was performed to investigate the elements present so as to check the adequacy of the pigment for its application. Probable changes in standard consistency and setting times where tested so as to discover any alterations pigments induce on the cement paste. The effects on concrete where investigated through compressive strength tests and testing of mix properties as well, which where finally compared to ordinary grey concrete. Dispersion of colour in concrete is also an issue, and this was also explored by casting slabs with different pigments, aggregates and additives and examined for cohesiveness in colour by increasing the contrast to enhance the identification of variations. Cores were also cut to study the through dispersion of pigment in concrete.