Discrete element analysis of the rheological characteristics of self-compacting concrete with irregularly shaped aggregate

Concrete is a heterogeneous, multiphase, composite material, and the size and shape of the coarse aggregate used have an important influence on the rheological properties of the concrete. The aggregate is usually simulated with spherical particles in the discrete element method (DEM). However, the shape of real aggregates is uncontrolled and polytropic. Therefore, spherical particles hardly reflect the actual situation. To comprehensively analyze the rheological characteristics of self-compacting concrete (SCC), experimental and simulated tests of slump-flow and L-box tests of different performative SCC are investigated. An efficient and fast random polyhedron particle generation method is proposed to simulate the real shape of the coarse aggregate, which is close to the actual state. The slump-flow and L-box tests of SCC are simulated by using the established discrete element model and the irregular generating particle method. The slump-flow test shows that the generation method could effectively simulate the flow state of concrete, and the L-box test evaluates the passing ability of SCC. The rheological characteristics of the yield stress τ0 and plastic viscosity η are verified as Bingham model parameters, and the numerical results are perfectly consistent with the experimental results.