Research On Damage Model Of Self-compacting Concrete For CRTS Ⅲ Slab Track And Mortar Damage Model

The mechanical properties of CRTS Ⅲ slab track selfcompacting concrete under high-cycle fatigue load directly affect the overall performance of the slab track.The current research on the fatigue damage mechanical model of self-compacting concrete and mortar is not perfect.Aiming at this problem,In this thesis,the mechanical properties and fatigue tests of self-compacting concrete and mortar are carried out,and the fatigue damage mechanical model of self-compacting concrete and mortar is obtained.The main research contents and results of this thesis are as follows:(1)On the basis of analyzing and comparing the characteristics of various fatigue damage mechanics models,the definition method of the damage variables of self-compacting concrete and mortar in this thesis is determined,and the fatigue damage mechanics model suitable for selfcompacting concrete and mortar is selected.(2)On the basis of obtaining the basic mechanical properties of selfcompacting concrete,a three-dimensional random aggregate model is established in Matlab software by Monte Carlo method;The finite element simulation technology is used to import the concrete compressive constitutive model,the elastic modulus Poisson’s ratio and the elastic modulus matrix obtained from the three-dimensional random aggregate model obtained by the test into Ansys,and perform static test simulation,and use the test data to simulate the numerical simulation.The results are verified.(3)On the basis of obtaining the flexural strength of self-compacting concrete and mortar,the fatigue tests of self-compacting concrete and mortar are carried out,and the fatigue life(N)curves of self-compacting concrete and mortar trabecular specimens under different stress levels(S)are obtained.(4)Based on the fatigue test data of self-compacting concrete and mortar,the parameters in the fatigue damage mechanics model under different stress levels are fitted,and the established fatigue damage mechanics model of self-compacting concrete and mortar is verified.The model shows the "fast-slow-fast" three-stage law of fatigue damage.