Based On The Vehicle Bridge Coupling Vibration Of Cast-in-situ Concrete Durability Study

Widespread attention may be paid to the durability of reinforce concrete structures all over the world.The fundamental direction of concrete technology development is to adhere to the strategy of sustainable development,on the basis of harmonious coexistence with the earth resources and environment,to improve the durability of concrete structures to the maximum extent and to increase its service life.In the course of maintenance and reinforcement and the concrete structure under construction of the bridge,which are exist to vehicle-bridge coupling vibration,which affects the durability of concrete structure.Therefore,It is of great practical significance to explore the coupling vibration of vehicle and bridge caused by driving load on the durability of concrete structures on the bridge.Aiming at the problem that the vehicle-bridge coupling vibration affects the durability of the bridge,this paper studies the influence extent of the vehicle-bridge coupling vibration on the durability of cast-in-place concrete by using the method of simulating the vehicle-bridge coupling action in the laboratory.First of all,through the consult the literature and the actual investigation,Finding that the bridge vibration frequency in the range of 0.33Hz-10Hz,others,the range of dynamic deflection is between 0.12mm～10mm;and then selecting the pavement of bridge as the representatives of cement concrete to optimization design and validation;then using orthogonal test design.With the vibration frequency,vibration amplitude,begin vibration time and time is applied to the concrete as the four principal factors,three factors were selected in the indoor simulation of vehicle-bridge coupling vibration of cast-in-place concrete,testing the durability.In this study,chloride ion permeation tests,concrete iron accelerated corrosion tests,water permeation tests,frost resistance tests and sulfate corrosion resistance tests were carried out in the laboratory.Studying that the effects of vehicle-bridge coupling vibration on the durability of concrete.The study found that the main factors of different vibration effects on the chloride migration coefficient method is begin vibration time,the second is the frequency,amplitude and applied to vibration time with minimal impact;different vibration scheme to weight loss rate of concrete iron,the depth of water percolation,the loss rate of compressive strength and the ratio of corrosion resistance,main factors is begin vibration time,followed by vibration application time,frequency and amplitude of the smallest.The transfer coefficient of chloride ion of 28d and 56d of concrete subjected to the coupling vibration of vehicle and bridge increased by 37%and 63%respectively compared with that of normal formed concrete.The weight loss rate of the concrete subjected to the coupling vibration of vehicle and bridge increased by 0.39%compared with that of the normal formed concrete reinforcement,and the seepage height increased by 64%.By vehicle-bridge coupling vibration of concrete after freezing 50 times,100 times and 150 times,which concrete compressive strength than the normal concerte compressive strength loss rate increased by 0.07%,0.07%and 0.07%respectively;By vehicle-bridge coupling vibration of concrete after sulfate dry-wet circulation 30,60,and 90,corrosion resistant coefficient of compressive strength than the normal shape of corrosion resistant coefficient of concrete compressive strength increased respectively 5%,1%,and reduced 10%;The coupling vibration of car and bridge reduces the durability of concrete.Finally,through the analysis of microscope,studying the vibration effects of different schemes on the pore structure of concrete.The test results show that the different vibration scheme to concrete of the middle layer structure of the hole diameter is mainly distributed in 0.1 um-1um and 4 um～25 um,which the aperture of effects the structure of upper layers and lower layers are mainly distributed in 0.01 u m～lu m and 2.5u m～25 um.Different vibration scheme to the pore of concrete structure influence factors is begin vibration time,between before and at the beginning of the concrete initial setting,the influence of vibration is largely on the pore structure.