Study On The Bonding Properties Of The Interface Between Polymer Materials And Concrete

With the development of the country’s urbanization,the construction of underground pipe network systems is also developing rapidly.With the expansion of the underground pipeline network and the passage of time of operation,many engineering accidents have occurred in the underground pipeline network system across the country,posing a serious threat to the people’s life and property safety,the most prominent of which is the defect of buried pipelines.The resulting engineering accident.In recent years,the polymer grouting repair technology proposed by Chinese civil engineering expert Academician Wang Fuming has a very good application effect in the treatment of buried pipelines.The bearing capacity of the polymer-pipe composite structure after the polymer grouting repair depends on the bonding interface between the two.However,at present,there is not enough understanding of the mechanical properties of the polymer-concrete bonding interface.As for the lack of theoretical support for stability analysis of composite structures.Therefore,this paper focuses on the interface bonding properties of high-polymer materials and concrete,and the contents and results are as follows:(1)Designed the direct shear test method and device for the interface between polymer and concrete,set 6 kinds of polymer density conditions,3 kinds of concrete strength conditions,6 kinds of normal pressure conditions,2 kinds of interface humidity conditions,and then made The test piece is subjected to a direct shear test.The results show that the failure morphology of the bond interface between polymer and concrete is greatly affected by polymer density,normal pressure,and interface moisture;the interface bond-slip curve is significantly different under the action of non-directional pressure;The bond strength has obvious correlation with high density and concrete strength.(2)The DIC test is used to analyze the whole process of interfacial shear failure;the scanning electron microscope test is used to observe the microstructure of the interface.The results show that the presence of interfacial moisture hinders the adhesion of polymer and concrete,thereby reducing the interface bond strength.(3)Based on the Mohr-Coulomb strength theory,the shear strength criterion of the bonding interface between polymer and concrete is established.Based on the characteristic analysis of the data obtained from the direct shear test,the bilinear model under the action of the non-directional pressure,the linear-exponential model under the action of the normal pressure,and the Popovics model were respectively proposed,and compared with the test data.Fitting,it is found that the bilinear model can not be used to fit the pressure,and the linear-exponential model is better for the normal pressure.(4)Based on the cohesive force model,a direct shear test simulation model of the polymer-concrete interface was established,and the numerical simulation was carried out for the conditions that the pressure could not be applied,and the change process of the interface shear stress was obtained.Comparing the interface bond strength,shear modulus,slippage and other parameters and bond-slip curve data obtained through numerical simulation with the measured data,the results show that the bilinear model cannot be fitted under pressure Better,the linear-exponential model fits better under normal pressure.