The influence of concrete composition on the ratio of strength to elastic modulus as a criterion of crack resistance

Research object. The multivariate regression analysis of the modulus of elasticity and strength of concrete shows dependence on the composition of concrete (C, W/C, aggregate content) and additives (ground blast furnace slag, microsilica, superplasticizer). Portland cement CEM I 42.5 N was used. Results. It was found that with the same types of aggregates, the modulus of elasticity and the strength of concrete depend mainly on the water-cement ratio and cement consumption. In this case, regardless of the composition of concrete and its age, there is a linear correlation between the strength R and the modulus of elasticity E. From the point of view of the crack resistance of concrete, the ratio of strength to the modulus of elasticity R/E is of great importance since it shows the limiting value of elastic deformation before failure. This ratio increases with increasing concrete strength, but the aggregate factor translates all R/E values to a different level of correlation. In this case, it is not the quantity of aggregates that is essential, but their quality. So concrete on expanded clay gravel with the same strength has a lower modulus of elasticity than concrete on dense aggregate.