射流压力对混凝土粗骨料分离效率及性质的影响OA北大核心CSTPCD

In order to crush and separate the recycled coarse aggregate(RCA)from the waste concrete(WC),a new method of crushing the concrete and separating the coarse aggregate by using water jet technology was proposed,and the numerical simulation and experimental research on the separation of coarse aggregate from the crushed concrete by water jet were carried out,and the basic properties,2D and 3D morphology,particle shape characteristics and compressive strength of RCA under different jet pressures were explored.The results show that,compared with the mechanical method,the residual adhesion mortar content and needle flake content of water jet RCA are reduced by 53%and 68%,the apparent density is increased by 1.7%,and the porosity and water absorption rate are reduced by 3%and 41%,respectively,which can reach Class I in the national standard.The crushing degree of coarse aggregate by water jet impact is within the acceptable range,and the average particle size of RCA is only about 7%lower than that of natural coarse aggregate.When the RCA is mixed into the recycled aggregate concrete specimen at 30%,40%and 50%respectively,the compressive strength of the waterjet RCA concrete is increased by 5.8%,22.7%and 17.7%respectively compared with the traditional mechanical RCA concrete.This study can provide a theoretical basis for the application of water jet in concrete crushing and reuse.