Filling capacity analysis of self-compacting concrete in rock-filled concrete based on DEM

Abstract

Rock-filled concrete (RFC) is a construction technique of preparing mass concrete that is based on self-compacting concrete (SCC). The filling status of SCC in a rockfill will directly affect the construction quality of RFC. To evaluate the filling property of SCC in a rockfill, experimental tests are first investigated, and then a 3D numerical model based on the discrete element method (DEM) is proposed. The SCC is assembled from the granular elements that are enveloped by the virtual mortar with a certain thickness. The mortar layer thickness and the micro parameters of the granular elements are calibrated by the excess paste theory and the slump flow test results. The pouring process of the calibrated SCC in a rockfill is simplified as L-type flow. In the comparison of the results of the DEM simulations and the experimental test results, the influences of the yield stress of SCC and the voids of the rockfill on the filling capacity are analyzed. The filling effect increases with the decrease in the yield stress of the SCC and the increase in the void ratio of the rockfill. Meanwhile, the fluidity of the SCC should be increased as much as possible without segregation, and the void ratio of the rockfill should be expanded when conditions permit. The comparison shows that the results of the proposed DEM model are in great agreement with the results of the experimental tests.