| The temperature and humidity change of concrete pavement in actual service will produce corresponding temperature and humidity response in pavement,which is related to the actual service life of concrete pavement.In addition,due to the alternation of day and night in the service environment(seasonal change)and the change of temperature and humidity,the corresponding temperature-humidity stress is formed in the concrete.The joint influence of heavy load of vehicles and temperature-humidity stress makes the concrete produce certain deformation and even cracking.Therefore,it is of profound guiding significance to study the internal temperature-humidity deformation behavior of concrete and comprehensively consider the influence of concrete on the deformation behavior of concrete pavement under the joint action of vehicle wheel load.Focusing on the deformation behavior of pavement concrete under periodic wet-heat-wheel load coupling,the research work and results of this topic are as follows:(1)Concrete shrinkage deformation test was carried out under the condition of periodic change of ambient temperature and humidity.The monitoring work of temperature and humidity distribution in each position of concrete is carried out simultaneously,and then the internal humidity strain of concrete is obtained through theoretical analysis and calculation.The relationship between the equivalent humidity content and humidity strain in concrete and the equivalent humidity stress-strain model in concrete are established.The results show that the relationship between equivalent moisture content and humidity strain can be expressed by a quadratic curve,and the sensitivity of humidity strain to equivalent moisture content increases with the temperature-humidity cycle.The internal equivalent humidity stress-strain model of concrete is similar to the ascending section of uniaxial stress-strain model of common concrete.(2)The device that can simulate the wheel reciprocating motion is designed to simulate the wheel load effect in the actual service of the track panel.The device can effectively simulate the wheel reciprocating motion in the process of the constant change of the space of the temperature-humidity alternating box and the temperaturehumidity environment.Thus,cyclic wheel load can be provided to track panel in the process of temperature-humidity cyclical cycle.(3)The strain monitoring work of concrete channel panel is carried out under the combined action of periodic temperature-humidity and wheel load.The results show that the deformation of the inner plate corner position of concrete channel panel under the action of periodic temperature,humidity and wheel load is as follows: the strain at the corner of the slab is greater than that at the edge of the slab than that at the center of the slab,and the wheel load has a great influence on the temperature-humidity deformation behavior of concrete.Based on the concrete equivalent humidity stressstrain model,a calculation method for humidity warping deformation of concrete pavement is proposed.(4)The response values of internal temperature and humidity of concrete pavement panel under this environment were synchronously monitored by the strain monitoring of the lower pavement panel in the periodic cycle of ambient temperature and humidity.The monitoring results showed that the temperature and humidity changes of each position inside concrete pavement panel also showed periodicity under the action of periodic temperature-humidity,and the response law was as follows: The difference of temperature and humidity in concrete pavement surface increases with the depth of measuring points and the distance from the boundary.(5)By comparing the concrete under scanning electron microscopy in the internal microstructure under different test conditions,it’s found that the periodic temperature and humidity inside the concrete under the function and wheel load in a certain degree of microfracture,wheel load fatigue effect further aggravate the deterioration of concrete,crack width is more wide,and the microstructure of concrete deterioration reasons are analyzed.It is believed to be the result of mutual influence and joint action of many factors. |
