SOME NOTES ON SIZE EFFECT AND INFLUENCE OF AGGREGATE ROUGHNESS

摘要

Several theoretical and experimental studies exist on the size effect of concrete structures. Many works have appeared based on fictitious models of rupture; the ones developed by Z. Bazant are mentioned here. Within this context, a lot of studies verify several mechanisms of rupture of concrete structures under the influence of the size effect in different concrete slab specimens, as for instance the one originated from the shear and the rupture of the steel-concrete bond using the pull out test. Although the strength to compression of concrete is not as noticeable as the shear, some studies demonstrate that the strength of concrete decreases as the size of the laboratory specimen increases. The results of the tests on the size effect, once it is attributed to that effect represent several causes, such as: wall effect; relationship between dimensions of concrete laboratory specimens, aggregate concrete structures and others. This paper presents a critical analysis of the influence of size and aggregate surface in the size effect study since, up to the moment, several authors have disregarded its importance.