Establishment and Application of Stochastic Mesoscopic Concrete Model

Concrete is a kind of complex multiphase composite material, and the spatial distribution of each component of concrete is random, which has an impact on its physical and mechanical properties. This paper presents algorithms for generating two-dimensional (2D) and three-dimensional (3D) arbitrarily graded stochastic concrete aggregate models, graphical format conversion methods, and finite element applications. Aggregate shapes include circular, ellipsoidal, convex polygon, ellipsoidal, and spherical. These models take into account the randomness of appearance, position distribution, and particle size distribution, including the interface transition zone, and the aggregate content can reach a high level. An efficient interference algorithm of ellipsoidal aggregate is proposed, which can reasonably control the thickness of the mortar layer around the aggregate. The corresponding program is compiled by MATLAB to realize the generation of random mesoscopic concrete aggregate geometric model. A graphic format conversion method is provided, which greatly extends the applicability and generality of the random aggregation model. The usefulness of the method in this paper was verified by the mechanical analysis of random aggregate model specimens with different volume fractions and the chloride transport properties of different aggregate shape specimens. In addition, the results of the two cases show that the random aggregate geometry and aggregate content have a great impact on the physical and mechanical properties of concrete, and the randomness of the spatial distribution of aggregates makes the chloride ion transport path and the elastic modulus and Poisson’s ratio of concrete be random. The results of this paper can provide an important research foundation for the study of mesoscopic physical and mechanical properties, gradation theory, and durability of concrete.