Influence of cyclic loading on the degradation of mechanical concrete properties

Abstract

At a certain number of cycles the averaged degree of degradation of the Young's modulus and the dynamic elastic modulus were almost on a similar level. The averaged development of Estat and Edyn as well as the determined longitudinal strain resembled towards the abscissa the form of the first two phases of a typical S-shape curve due to fatigue loading. By repetitive measurements the great scatter in the cyclic test-results could be confirmed. The stress-strain relation is particularly suitable for describing material behaviour. The obtained results showed significant changes in the stress-strain curve in terms of the shape, magnitude of the compressive strain and fracture energy. No influence on the compressive strength could be observed. Furthermore it could be shown that the fatigue strain as a material parameter is better suited for describing the degradation process of concrete due to cyclic loading as load parameters like N/Nf. Assumptions referring to the degradation process within material models could be validated.