Damage and Destruction Research of Recycled Concrete with Waste Brick Based on Modified Random Aggregate Model

Mesoscopic numerical simulation is the key method to study the properties of materials. In this paper, recycled concrete is considered as a heterogeneous composite of mortar, brickbat aggregate, recycled aggregate from abandoned concrete and interface in meso-level. The coarse aggregate was simplified as irregular convex polygon, and packed randomly with the application of the theory of gradation, the coarse aggregate such as the waste brick and abandoned concrete were parameterized based on the mix ration, a modified two-dimensional finite element model of random aggregate was proposed and uniaxial compression process was simulated. The results concluded that: (1)with the displacement loading, the lateral deformation in specimen is large and the internal deformation is small, as the percentage of replacement of waste brick aggregate increases, the deformation increases as well. (2)With the same strain control rate, the beginning of the breaking process for recycled concrete containing brick comes early, cracks are produced through waste brick, however, the growth of cracks and the beginning of the breaking process in recycled concrete without bricks is produced through the interfacial transition zone. (3)Before the yield damage of specimen, the results of the computations show a good agreement to the experimental data, after reaching the critical strain at which rapid and continuous crack propagation starts, there is some deviation between simulated results and experimental results which indicates that the failure criteria of material is unreasonable and needs to be further improved. © 2019, The Editorial Board of Journal of Basic Science and Engineering. All right reserved.