Study On The Mechanical And Electrical Properties Of Graphene-reinforced Cement-based Composites

In this paper,in order to study the reinforcing effect of graphene on cement-based materials,the electrical and mechanical properties of graphene reinforced cement matrix composites were simulated by finite element software ANSYS,and the electrical and mechanical tests were carried out.The subject mainly includes the following contents:(1)The electrical test of graphene oxide reinforced cement-based composites was carried out by four-electrode method,and the effect of graphene oxide content on the internal resistance of cement-based materials was studied.Because graphene oxide can enhance the conductivity of composites,and the resistance of the composite was reduced,so the bending and compression tests of graphene oxide reinforced cement matrix composites were carried out by using graphene oxide as modified material for a 7d flexural and compression experiment.The experimental results shows that the bending strength and compression strength of the composites increase with the increase of the content of graphene oxide,which indicates that the addition of graphene oxide can enhance the mechanical properties of cement based composites,and the optimum dosage is 0.03wt%.(2)The graphene-reinforced cement-based composites model was established by using the finite element software ANSYS,and the mechanical properties of the model were studied.The study of mechanical properties includes the compression and tensile properties of composite materials.ANSYS compression calculation shows that the interface contact between graphene reinforced and matrix is good,in which the phenomenon of matrix cracking and contact interface detachment begins to appear from the tip of the reinforcement,and then the damage begins to occur in this area.The tensile calculation by ANSYS shows that first principal stress is much smaller than the stress value under compression stress when the composite is subjected to tensile stress field,which indicates that the composite shows good mechanical properties at this time.(3)Using finite element software ANSYS to form the 3D random model of graphene.Different aspect rations and different shapes of flake graphene-reinforced cement-based composites were set up by APDL program,and the effective resistance of different composites was calculated by the current density of well bonded composites.The results of finite element calculation show that with the increase of graphene volume fraction,it is easier to form conductive network in graphene-reinforced cement-based composites.The lower the effective resistance of graphenereinforced cement-based composites is,the stronger the conductivity is: the aspect ratio has a greater influence on the current density.When the graphene volume content is the same,the current density when the aspect radio is 1:4 is the largest.(4)The elastic modulus of graphene-reinforced cement-based composites with different volume fraction and aspect ratio was predicted by finite element method.The stress,unit strain and volume of all the composites are obtained by using the ETABLE command in the finite element software ANSYS,and the weighted average values of strain and stress are calculated.At the same time,the equivalent effect variation and stress are obtained by the operation function of finite element software.Then the macroscopic modulus of the composite is calculated by using the elastic modulus formula,according to which the effect of graphene aspect radio on the elastic modulus of intelligent concrete prepared by graphene reinforced cement matrix composites is analyzed,and the elastic modulus is predicted.The results show that the elastic modulus of composite materials increases with the increase of graphene content.