Numerical Simulation of Aggregate Shapes of Three-Dimensional Concrete and Its Applications

The plane extension method was used to model aggregate shapes of three-dimensional (3D) concrete. In this method, the convexity condition requires that the volume formed by all the extension points and border planes be positive. A test method is adopted that involved summing the aggregate volumes to judge the intersection and overlap of aggregates. In the 3D random aggregate simulation (3D-RAS) structure, the shape, size, and spatial distribution of the aggregate particles resemble real concrete in the statistical sense, and fundamental aggregate diameters within the same gradation are assumed to follow random Gaussian distributions. The fracture process test of a three-point notched beam considering the effects of inhomogeneous material was used to validate the proposed aggregate model. Numerical illustrations show that aggregate shapes play an important role in the failure process of beams. Parameter studies also show that, although the homogeneity index has only a small influence on the elastic modulus, it plays an important role in the nonlinear softening behavior. The aggregate distribution has a little influence on the overall mechanical response of the concrete composite. The interfacial transition zone (ITZ) thickness has a great effect on the ultimate load of the concrete. An optimal aggregate volume fraction should exist for the concrete composites.

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