Numerical Simulation Of Mechanical Properties Of Nano Metakaolin Concrete Based On CT Scante

In order to study the effect of internal composition materials on the mechanical properties of concrete,the mechanical properties of metakaolin cement mortar were obtained by mechanical tests,the distributions of cement,aggregate and pores in nano metakaolin concrete were obtained by method of CT scanning.Then,a two-dimensional mesoscopic numerical model of nano metakaolin concrete was established,the numerical model is used to study the failure characteristics of concrete with or without considering the interface transition zone.Finally,exploring the method to establish three-dimensional mesoscopic numerical model of nano metakaolin concrete were explored by using the Mimic.The research work of the paper is listed as follow:(1)The mechanical parameters and model of nano metakaolin mortar were determined.Through compressive and flexural tests,the influence of nano metakaolin on strength of mortar were studied.The two-dimensional mesoscopic numerical model was established.The numerical results and the test results about compressive strength and flexural Strength were compared,and the availability of the model was verified.(2)A two-dimensional mesoscopic model of nano metakaolin concrete was establishment under meso-scale.Using the principle of gray segmentation,the gray value of CT scanning about the concrete was counted.Determine the Boundary partition value and distribution of aggregate,mortar and pores,established two-dimensional mesoscopic numerical model of nano metakaolin concrete under meso-scale.during uniaxial compressive and uniaxial tensile processes,the influence of aggregate area ratio,geometric nonlinearity and other parameters on the destruction characteristics of concrete were discussed.(3)A two-dimensional mesoscopic model of nano metakaolin concrete considering interface transition zone was established under meso-scale.Based on the two-dimensional mesoscopic model of nano metakaolin concrete obtained,the "pixel expansion" method was used to establish the numerical model containing the interface transition zone.Based on this model,the influence of the interface transition zone width and elasticity modulus on mechanical behaviors were discussed under macro-scale.(4)A three-dimensional mesoscopic model of nano metakaolin concrete was established.Two methods in the Mimics module were exploring,which are meshing-assigning material and assigning material-meshing-assembling model.Then a three-dimensional mesoscopic model of nano metakaolin concrete was established,and deformation law of metakaolin concrete during uniaxial compression were researched.