Análise da variação da resistência à compressão axial do concreto com a direção da aplicação de carregamento e com as condições de contorno

Abstract

It is known that the properties presented by concrete are originate from its internal microstructure, therefore the knowledge of the same is essential for the improvement and innovation of the civil construction. In this context it is important to emphasize that there are microregions that represent the weakest link of the set, corresponding to areas that during the element request initiate the cracking process of the material, located between the cement paste and the aggregates, called transition zones. The present study verifies how representative these regions are in relation to the axial compressive strength of concrete test specimen, due to the direction of application on the loading of concrete launching, since the provisions of these microregions are related to the direction of launch and which according to the loading direction these zones can become even more fragile. The work also analyzes how the specimens behave in relation to cracking and resistance when modified the boundary conditions in the execution of the tests. At the end of experimental procedures a numerical analysis was carried out using the Lattice Discrete Element Method (LDEM) and the Finite Element Method (FEM) applied in commercial software Abaqus / Explicit. For the development of the work cubic specimens of dimensions of 10 cm from three concrete traces were produce in the case of 30 MPa, 50 MPa and 65 MPa. When the parallel loading to the concrete launch was applie, higher average strengths were obtainad than when the load was applied perpendicular to the launch. Regarding the boundary conditions, it was verified that when the specimens are with their faces restricted, there is a significant increase of resistance due to the confinement of triaxial tensions generated, this behavior could also be verified in the numerical simulations.