SCC mix design: Penttala design method • It is based on statistical analysis of a large number of concrete tests in which the most important variables were derived by linear regression and, thereafter, the model was generated by non-linear regression so that the best correlation was achieved • It was noticed that in addition to water-cement ratio and the dosage of superplasticizer the properties of the sub-mm (# < 0.125 mm) dry ingredients (especially the gradation curve) had the largest effect on the properties of selfcompacting concretes