Measurement Of Temperature And Stress Field Of Asphalt Pavement By Fiber Bragg Grating Sensor

In recent years,with the rapid development of transportation,the highway has been built on a large scale in China.Asphalt pavement,as one of the main structural forms of the expressway,carries vital important transportation tasks.However,serious damage has occurred on asphalt pavement surface of highway at the same time,which has affected the traffic safety,shortened the road use life and caused the economic resources wasted.The emergence of asphalt pavement damage not only related with the vehicle load,but also the environmental factors.The asphalt mixture for building asphalt pavement is a kind of temperature sensitive material which is affected by the change of external temperature.It is necessary to use advanced testing methods to monitor the temperature and stress field of asphalt pavement.However,Most of the existing pavement detection methods have many problems,such as destructive,lag and limitation,which cannot accurately,dynamically and universally collect the internal information of the pavement.The maturity and development of fiber Bragg grating sensing technology provides a new way for monitoring the internal strain state and temperature information of the asphalt pavement structure.In this paper,the self-encapsulated fiber Bragg grating sensor is embedded in the asphalt pavement,to monitor the temperature information and strain state of the internal structure of pavement.First of all,the fiber Bragg grating is encapsulated and protected.The strain sensor encapsulated by geogrid and the temperature sensor protected by steer tube.The calibration results show that the sensitivity of the two kinds of sensors is close to the sensitivity of the bare grating,and the sensors can meet the precision requirements of the road monitoring.The packaged fiber Bragg grating sensors are embedded in the structural layers of different depths of the asphalt pavement in the experimental area.The temperature information and stress-strain states of each structure layer are collected and recorded in summer and winter.According to the temperature data,the change of the temperature of the asphalt layer with different depths can be described and the change law and trend of temperature field and the correlation of the change of each depth temperature field can be analyzed.According to the strain data of each structural layer,the influence of temperature change on the stress and strain state of asphalt pavement can be analyzed.By adding the vehicle load at the time of high temperature and low temperature,the response of the asphalt pavement under the coupling of temperature and vehicle load can be analyzed according to the strain data measured in the vehicle test.In this paper,the ABAQUS finite element software is used to establish the model to simulate the internal temperature and stress-strain state of the asphalt pavement under the same conditions.Compared with the measured results,it can verify the feasibility of the fiber Bragg grating sensor used in road engineering monitoring and the effectiveness of the field measured data.