Influenced of the nature of the aggregate on the cracking mechanisms of normal and high strength concrete

摘要

In this paper the influence of the nature of the aggregate on the cracking behavior of normal and high strength concrete is analyzed. For understanding the effect of aggregate more clearly the mortar used in each of the concretes has also been studied. The aggregate types considered here are crushed granite, crushed quartzite, rounded gravel of different origins (i.e., granite, migmatite, basalt, etc), and smooth quartzite gravel. The experimental part of the study consisted of three-point bend tests performed according to the RILEM TC 50-FMC recommendations. Also, tests on 100_200 cylinders were conducted for obtaining the compressive strength, Young's modulus and splitting-tensile strength. Numerical modeling of the load-deflection response of the beams was performed using the discrete crack approach and a cohesive crack model developed previously. From the numerical analysis, the material fracture parameters, that is, tensile strength and fracture energy have been determined. The study clearly illustrates the influence of the aggregate type on the failure mechanisms of the concrete, and the dependence of this influence on the concrete strength.