Research On The Workability Of Flowing Self-compacting Concrete Considering Random Shape Of Coarse Aggregate

Simulating the rheological behavior of self-compacting concrete based on discrete element method,study on the interaction mechanism of its internal structure from the microscopic view,and it is beneficial to improve the workability of self-compacting concrete in essence.It usually uses spherical particles with uniform size or size distributing evenly in a certain range for simulation in traditional discrete element method.While in fact,the shape and size of coarse aggregate have important influence on the workability of self-compacting concrete.In order to comprehensively and accurately simulate the workability of flowing self-compacting concrete,this paper uses coarse aggregate units which are close to the real state?both shape and size?.Use a fast and effective method to establish the model of random shape polyhedron,and Clump command in PFC,a discrete element software,to transform the existing polyhedron model into the corresponding shape discrete element to simulate real shape coarse aggregate,and the size and number of coarse aggregate units are also in accordance with the real gradation to make the coarse aggregate unit in the numerical model close to real state.For more convincing calculation result,simulate slump test respectively in random shape coarse aggregate units with real gradation and spherical units,and compare the expansion degree and T₅₀₀ of the two with the measured values.The results show that the former is closer to the test and thus verify the feasibility and correctness of random shape particles with real gradation as coarse aggregate.At last,simulate L-box test in the same way to assess the passing ability of self-compacting concrete,and the results are good agreement with the test.This research as an exploratory work to develop the simulation method of rheological behavior of self-compacting concrete further,it approaches the coarse aggregate unit in DEM to real state in both shape and gradation,and verify the feasibility and correctness.And it provides a new valuable idea to study on the property of the flowing self-compacting concrete.