ABSTRACT
The study investigates the effect of pigments as a tinctorial source of colour concrete (colour-crete) with the aim of assessing the dosage level required for an appreciable tinctorial strength for aesthetic purposes. The objective of the study is to produce an alternative to the usual practice of painting of concrete structures after rendering, by now incorporating some percentage of colouring agent into the concrete, when it is plastic. Hence the need to assess the effect(s) of these colouring agents on the strength parameters of the concrete. Two basic locally sourced pigments were used. Their chemical analyses classify them as basically red oxide and carbon black compounds. These pigments were in powdery form and the percentage of the colouring agent added or incorporated was a fractional weight of the cement content in the mix as recommended in BS 1014:1961. The percentage of the pigments incorporated varies from 0% - 6%. Nominal mix ratio of 1:2:4: and 1%:3 were chosen, with water cement ratio of 0.48 and 0.58 respectively. A total number of 192 specimen were produced that is 64 cubes , 64 cylinder and 64 miniature beams. They were tested at 28 days of cast using the destructive techniques. The results obtained shows that with the increase in the percentage of pigment introduced into the concrete, there was negligible reduction in strength compared with the control specimen. And in some cases an increase in strength was observed.