Study On The Mechanical Properties Of Interfacial Transition Zonebased On The Mesoscopic Model Of Concrete Random Aggregate

Concrete is consisted of aggregate,mortar and interfacial transition zone in microscopic level,which is heterogeneous and multiphase composite materials are widely used in practical engineering.The interface transition zone,aggregate and mortar play a key role in the mechanical properties of concrete.So the physical and mechanical parameters of interface transition zone,aggregate and mortar are absolutely necessary for concrete in microscopic level.The physical and mechanical parameters of aggregate and mortar can be tested,but interfacial transition zone is very slight,that is difficult to make the test pieces and load,so it is very difficult to measure.In recent years,numerical simulation becomes a way to study on concrete in microscopic along with the development of computer technology.In this paper,the numerical simulation method is used to study the mechanical properties of the interface transition zone,and the following research results are obtained.(1)The paper is based on Monte Carlo random sampling principle;the real mix proportion of concrete is calculated for aggregate content,the distribution of random convex aggregates is improved,the random aggregates are put on from big to small,that is can ensure aggregate gradation of concrete.The boundary of the interface transition zone is extracted with AUTOCAD software;the microscopic models of two-dimensional convex polygon random aggregate are established in microscopic level.(2)The mechanical properties of the interface transition zone is studied by uniaxial compression with ABAQUS.The results showed that compression strength of interface transition zone decreases with the increase of the maximum aggregate size,but the elastic modulus of interface transition zone has little change.(3)The results showed that the strength grade of concrete has significant effect on compression strength and elastic modulus of interfacial transition zone.The compression strength and elastic modulus of interface transition zone are found to increase with strength grade of concrete.The relationship between the compression strength of concrete and the compression strength of interface transition zone is obtained,the relationship between the elastic modulus of concrete and the elastic modulus of interface transition zone is obtained by fitting the formula.For the future,we can continue to study the strength of the interface transition zone and the elastic modulus of the interface transition zone.