Optimising mix design can and should be done. If done well the result will be very encouraging. Preferably a step-by-step statistical approach is adopted to obtain optimum proportioning of concrete mixtures using the data obtained through a statistically planned experimental program. It can be demonstrated that optimization of concrete mixtures can be carried out with different possible options.
The proposed approach consists of five steps, as follows:
(i) specification of the characteristic performance of concrete,
(ii) selection of the levels of key mix design factors,
(iii) experimental work considering trial mixtures using full factorial experiment design for generating data to obtain statistical model for optimization,
(iv) statistical analysis of experimental data and fitting of the strength model, and
(v) optimization of mixture proportions using the fitted strength model.