Meso-mechanical Model Analysis Of Recycled Concrete Based On Random Aggregate

It is generally believed that ordinary concrete is made up of three-phase materials,and recycled concrete contains five-phase materials.The biggest difference between recycled concrete and ordinary concrete is whether old hardened mortar exists or not.Old hardened mortar causes the meso-structure of recycled concrete is more complicated compared to ordinary concrete.For grasping the failure mechanism and mechanical properties of recycled concrete,the dividing phases method is applied in this paper.The failure process and factors of mechanical properties of recycled concrete is studied by the numerical simulation method of random recycled aggregate model,The main research work includes:On the meso level,it is regarded that recycled concrete is a five-phase heterogeneous material,which contains new hardened mortar,old hardened mortar,natural aggregate,new interface transition zone and old interface transition zone.Based on the Monte Carlo method,Algorithms for generating and placing random recycled aggregates in 2D plane and 3D space were compiled by Python language.The interference between ellipsoid regenerated aggregates is judged by a search algorithm.This method optimizes the random generation program of recycled aggregate,and improves the rate of recycled aggregates.Based on the numerical simulation method of the stochastic recycled aggregate model and Concrete Damaged Plasticity,a series of studies on the damage characteristics of the meso-structure of the recycled concrete are carried out,and the whole process of damage generation,development,penetration and final destruction of recycled concrete is analyzed.The research results show that the random recycled aggregate model can well simulate the damage and destruction behavior of recycled concrete,which can reveal the essence of damage and destruction of recycled concrete.Based on the established random recycled aggregate model,a numerical simulation analysis of the influencing factors of the properties of recycled concrete is studied by using the variable parameter method.A large number of numerical simulation experiments were conducted,and the influence of these parameter changes on the mechanical properties of recycled concrete were simulated and analyzed.The research conclusions can provide technical support for the mechanical performance analysis and engineering application of recycled concrete structures,and have certain significance for promoting the development of recycled concrete in China.