Simulation of Preparation Process of Manufactured Sand Based on Discrete Element Method and Its Grading Influence on Pore Structure Distribution of Concrete
摘要
In order to clarify the preparation process parameters of manufactured sand, optimize its quality, and analyze the effect of its grading on the microstructure of concrete, the three-dimensional models of jaw crusher, vibrating screen and conveyor belt were established by using SolidWorks 2016 software. Rocky DEM4.5 software was used to simulate the initial crushing, screening, and transportation stages of the manufactured sand preparation process, with Linear Spring Dashpot as the normal contact model and Coulomb as the tangential contact model; furthermore, the key process parameters were defined. The manufactured sand grading model was then proposed, thereby, the influence of the grading of manufactured sand on the distribution of pore structure in concrete and the interfacial transition zone (ITZ) was studied. The experimetal results show that the particle size of granite, after being crushed in the jaw crusher, is primarily concentrated between 80 and 130 mm, with a crushing energy consumption typically below 100 000 J. However, certain instances of granite exhibit higher energy consumption due to undergoing multiple crushings within the chamber. At the same time, the granite causes significant wear on the jaw crusher plate. Furthermore, the tilt angle of the vibrating screen should be adjusted to between 10 and 15 degrees, while the layout angle of the conveyor belt needs to be set at 16 degrees. The proposed manufactured sand grading model is feasible, and the pore diameter distribution inside concrete increases with an increase in the fineness modulus of manufactured sand.