Solution proposed by authors of this paper is to change the type of coarse aggregate into the aggregate of higher quality in order to achieve better strength for a given concrete with a speciÞ c quantitative composition. Concrete classiÞ ed in 3 groups was subjected to test: ordinary concrete of w/c = 0,70 and w/c = 0,58, and also high strength concrete of w/c = 0,28. In each group concrete was made using four
different types of coarse aggregate. Comparing test results of strength properties it should be stressed that there is a signiÞ cant effect of coarse aggregate on the values obtained, as conÞ rmed by a statistical analysis. One can look for “concrete strength” in other sources than those consisting in a unit increase of cement content, through as shown, an appropriate choice of the type of coarse aggregate.