Research on discrete element simulation of slump test for fresh self-compacting concrete

Abstract

A numerical computational modelling of slump tests for fresh self-compacting concrete (SCC) was developed in this investigation based discrete element method (DEM). The coarse aggregates in DEM model were characterized by using spherical shapes and 3D irregular geometries obtained by scanning real aggregates, respectively. By comparing the results of the slump simulation tests corresponding to the two geometric models, it was found that the average error of the latter was smaller, about 2.9%. The results of quantitative analysis of the rotational kinetic energy for both found that the motion of the real coarse aggregate model was more consistent with the actual situation. The effect of coarse aggregate gradation characteristics on the flow properties of fresh SCC was investigated based on the real coarse aggregate model. The results indicated that the increase in the content of large-size coarse aggregate or its replacement of small-size coarse aggregate both resulted in the deterioration of the flow properties of fresh SCC. During the lifting of the bucket at the beginning of the slump test, different velocity distribution patterns existed before and after the complete separation of the bucket from the concrete. The maximum flow velocity, about 0.8 m/s, occurred when the bucket was not completely separated from the SCC and was distributed in the top part of the inner bucket.