The Measurement Of Asphalt Pavement Structure Stress-Strain Field Using FBG Sensor

Asphalt concrete with its unique performance has become one of the main forms of China’s highway and high-grade roads pavement constitute. With the increasing traffic load, pavement structure produced a lot of early disease, this needs to analyse the early damage mechanism of asphalt pavement and the law of development, and to research the asphalt road surface structure. The current pavement structure behavior research mainly relys on detecting road surface and incising pavement structure, this kind of method is time-consuming, arduous, making damage for the pavement structure continuity, and unable to carry on the long-term dynamic monitoring of the pavement structure. With the mature of optical fiber grating sensing technology, it is possible to monitor internal mechanics of the asphalt pavement structure and environmental index.In this paper a designed fiber Bragg grating sensors had been used to realize the dynamic monitoring for the internal strain of asphalt pavement structure. Results of analysis can provide certain reference basis for the design of asphalt pavement structure.by using the good performance of geogrid and soil deformation coordination,optical fiber Bragg grating strain sensors were made for monitoring a pavement structure strain. The sensor is calibrated through the indoor test, and the results show that the sensitivity of the sensor is1.04pm/μεand close to the bare grating sensitivity, which meets the accuracy requirement of the asphalt pavement monitoring. The sensors were embedded in the test site located in Dalian bay ShuGang highway; the embeding process gone with the road construction progress.After project completion, the test section would be monitored.The test procedure take different speed, the data got from the optical fiber is used to analyse the mechanical response of different asphalt pavement structure under the action of moving load, combined with ABAQUS finite element software, the theoretical value is simulated, which then were compared with the test field data analysis results. Results show the measured data and finite element simulation of linear has a good correlation coefficient.The results show that the performance of optical fiber grating sensor is well, which meets the needs of the asphalt pavement structure monitoring, at the same time it also provides certain material selection reference basis for pavement structure monitoring using optical fiber grating sensor. The data and analysis results measured by fiber Bragg grating sensors, has a certain reference value for the asphalt pavement structure design.