Study On Constitutive Relationship Of New Epoxy Resin Concrete Under Uniaxial Compression

The new epoxy resin concrete(NERC)is a composite material formed by mixing,moulding and curing with epoxy resin as the main material,adding appropriate amount of hardener and thinner as adhesive and sand as aggregate.The material has the advantages of high strength,toughness and durability compared to ordinary concrete.At present,there are few studies on the material properties of NERC and the constitutive relationship are still unclear.In this paper,further research is carried out on the basis of the NERC mix proportion given in the previous research of the subject group in the following aspects.Firstly,the NERC preparation technology has been optimised.To address the problems of high work intensity and low preparation efficiency in the original NERC preparation technology,this paper uses methods such as the introduction of electromechanical equipment to solve the problems of the original technology.Secondly,the material properties of NERC were determined through experimental studies: This paper obtains the cubic compressive strength,axial compressive strength and splitting tensile strength of NERC at the ages of 7,14 and28 days,respectively,through compression tests on NERC test pieces,and analyses their failure modes;A comparative analysis of the trends in strength at these three different ages determined the optimum curing period for NERC to be 14 days;The proportional relationships between axial compressive strength,splitting tensile strength and cubic compressive strength were obtained as 0.81 and 0.11 respectively;The modulus of elasticity of NERC was determined to be 9000 MPa with the Poisson’s ratio of 0.32 at the optimum curing period.Finally,by combining experimental studies with theoretical calculations,a equation for the constitutive relationship of NERC under uniaxial compression was proposed: In this paper,stress-strain full curve of NERC under uniaxial compression was obtained by using an electro-hydraulic servo pressure tester to apply the load in a combination of load control and displacement control;The theoretical equations for the constitutive relationship of NERC under uniaxial compression were derived by rigorous mathematical derivation based on the classical curve characteristics of concrete,existing curve equations and the characteristics of the uniaxial compressive stress-strain test curve of NERC;The theoretical equation curves were compared with the experimental curves to determine the values of the rising and falling segments of the NERC uniaxial compressive stress-strain curve under the present mix ratio;The variation of the NERC Poisson’s ratio during the loading process was analysed.This paper gives the material properties of NERC such as compressive strength,tensile strength,modulus of elasticity and Poisson’s ratio through experimental research,puts forward the equation of the constitutive relationship of NERC under uniaxial compression,initially clarifies the physical and mechanical properties of NERC,lays a theoretical foundation for the next experimental research and finite element simulation analysis of the group,and also provides a reference for the promotion and application of practical engineering.