Simulating passing ability of self-compacting concrete in the J-ring test using cohesive particle liquid bridge model

As a two-phase material composed of liquid slurry and solid particles, the local blocking phenomenon may occur in the pouring process of fresh self-compacting concrete (SCC) and thus affects the workability of fresh mixture. In this paper, three-dimensional discrete element method (DEM) is used to simulate the passing ability of SCC. First, 3D laser scanning technology and Clump method are combined to accurately characterize real geometry of coarse aggregate, and then an improved cohesive particle liquid bridge model (CPLBM) considering the nonlinear moisture force between particles is proposed to simulate the interaction of moist particles. The comparison with laboratory test results verified that the constructed DEM model can better reflect fluidity and anti-segregation of SCC. Based on this, the ability of SCC mixes to pass through gaps in reinforcing bars and related influencing factors are studied by simulating J-ring test, and the blocking process of SCC is analyzed on meso-level through particle displacement detection method. The simulation results indicate that constructed discrete element model can well simulate the gap passage process of SCC. The effect on the passing rate of aggregates with larger particle size is more significant. The aggregate passing rate is related not only to the ratio of the bar spacing to the maximum aggregate size, but also to the difference between the two.