Abstract
The mechanical behavior of concrete under biaxial loading condition (especially biaxial compression) is one of the most important indexes to evaluate the quality of concrete. To study the mechanical behavior of concrete under biaxial compression at mesoscale, we adopted our recently developed 3D numerical model based on Voronoi tessellation and cohesive elements. A constitutive model considering the friction effect is used in the model to characterize the fracture behavior of all potential fracture surfaces inside the concrete. A series of numerical experiments with different biaxial compression stress ratios were carried out. It was found that with the increase of the biaxial compression ratio, the proportion of energy increment caused by friction stress increases. The effect of inner friction coefficient on the biaxial relative strength was also investigated, and this kind of study is hard to be carried out through laboratory experiments. The results show that the inner friction coefficient has a great influence on the biaxial relative strength of concrete, and there is a positive correlation between these two parameters. Based on the above rules, a conservative biaxial relative compression strength envelope is obtained by setting the inner friction coefficient as zero.
Highlights
In the design of concrete structures, the biaxial strength and fracture behavior are very important.To reveal the mechanism of the concrete biaxial fracture, researchers have carried out a series of experiments [1,2,3,4,5,6,7], including biaxial compression experiments, biaxial tension experiments, and biaxial mixed tension compression experiments
We mainly study the fracture behavior of the concrete under biaxial compression
We build up a 3D meso model of concrete based on the Voronoi tessellation and
Summary
In the design of concrete structures, the biaxial strength and fracture behavior are very important. To reveal the mechanism of the concrete biaxial fracture, researchers have carried out a series of experiments [1,2,3,4,5,6,7], including biaxial compression experiments, biaxial tension experiments, and biaxial mixed tension compression experiments In those studies, the researchers adopted the relative strength to reflect the strengthening effect (or weakening effect) of the complex loading condition. Based on our previous research works about the numerical model with cohesive element [43,44], in this paper, we adopt the Voronoi tessellation and zero thickness cohesive element to generate concrete mesostructure, and a modified constitutive model considering the inner friction effect is adopted. The effect of inner friction coefficient on the biaxial relative strength is studied
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