Research And Application Of Epoxy Quick Repair Material Based Bridge Expansion Joint

Bridge expansion joint device structure is important and susceptible to damage components,once the damage occurs,not only affects driving safety,but also endanger the bridge structure,so it is particularly important for its repair.Traditional repair materials are mostly cement-based repair materials,which have disadvantages such as poor deformability,low early strength and high cost.Studies have shown that HEC has the advantages of high early strength,small shrinkage deformation,strong adhesion,good water resistance,large ultimate strain,and rapid solidification.Therefore,it has important practical significance to apply it to the repair of bridge expansion joints.In this paper,NPEL128(E51)epoxy resin produced by Ningbo Tianyi Steel Bridge Pavement Engineering Co,Ltd.was used as the cementing material.Through indoor tests and corresponding data analysis,a high-performance epoxy Resin concrete(HEC)suitable for repairing bridge expansion joints was obtained,the main research content and conclusions are as follows:(1)Determined the control parameters of the optimal mix ratio of HEC.With reference to the mix design method of asphalt mixture SMA-13,in the case of the optimal gradation of aggregate(the gradation curve is as close as possible to the median curve required by the specification),the 1d compressive strength is used as the control index to explore the difference The impact of rubber-stone ratio and coagulant content on the mechanical properties of HEC,wherein the rubber-stone ratio is the ratio of the mass of the cementitious material to the total mass of each grade of aggregate.The results show that when the rubber-to-stone ratio is 8%,the compressive strength reaches the maximum,and the ultimate failure strain energy reaches more than 31000με;when the amount of coagulant is 1%,the 1d strength can be increased by 22.6%,if continue to increase the coagulation accelerator Although the dosage and strength have been further improved,the initial setting time will be shortened to less than 30 minutes,so 1% of the coagulant dosage is selected.(2)The establishment of a model interfacial adhesion of HEC.Through indoor tests,the repair materials and existing concrete specimens are studied as a whole,small components are prepared,and split tensile tests are used to test the repair components with different roughness,different old concrete strength and different interface treatment methods.The results show that within a certain range,as the sand filling depth increases,the bond strength between the new and old concrete also increases,but when the sand filling depth at the interface exceeds 17 mm,its value does not change much;With the increase of concrete strength,the bonding strength also increases;when the interface is coated with epoxy resin interface agent,the bonding strength is lower than that of the specimen without interface agent.Based on the above test results,the interface bonding model of HEC was established.(3)The fatigue life equation of HEC and the repaired structure is obtained,.With the aid of the fatigue testing machine,the stress control mode is used to obtain the fatigue life of the specimen under different stress levels;based on the stress-strain curve obtained from the fatigue test,the integral function in the ORIGIN software is used to obtain the consumption of each specimen when it fails The total energy consumption of the test data;the test data is fitted and analyzed,and it is found that the single logarithmic fatigue life equation is used to fit the fatigue test data of HEC and repaired components.There is a good linear relationship,and the correlation coefficients can reach 0.99 and 0.95 respectively.Above;and the fatigue life and cumulative energy consumption of the two have a good linear relationship on the double logarithmic axis,and the correlation coefficient can reach more than 0.98.Therefore,the fatigue life equation established based on the test data can better predict the fatigue life of the two.At the same time,compared with cement concrete,under the condition of high stress level,the fatigue performance of repaired components is lower than that of cement concrete due to the existence of weak areas,and the comprehensive fatigue performance of HEC is better than that of cement concrete.(4)Verifies the safety of opening to traffic one day after the bridge expansion joint is repaired.Through indoor experiments,the constitutive relationship between the new and old concrete and between the HEC and the expansion joint was obtained;the bridge expansion joint model after the repair was established using ABAQUS,and the bonding of HEC was simulated with the help of spring elements.The moving load simulation is realized through the DLOAD subroutine.Finally,the simulation results are compared with the test results.It is found that when the car passes through the bridge expansion joint 1d after the repair is completed,the new and old concrete,HEC and the expansion joint are between the new and old concrete and HEC and the expansion joint.The resulting bond stresses are all less than the maximum stress value of the repaired component when bond failure occurs.Therefore,it is safe to open the bridge for traffic 1day after the repair of the bridge expansion joint is completed.(5)The construction technology of HEC has been formulated.Based on the preparation method of HEC,the influence of roughness and interface treatment methods on the bonding performance of HEC and the maintenance method of HEC,combined with traditional bridge expansion joint repair technical solutions,the construction technology of HEC repairing bridge expansion joints has been formulated,which can be used for actual projects.