Service Field Monitoring And Thermal-Force Coupling Effect On Asphalt Pavement In Alpine Region

In the alpine region,thin air and strong ultraviolet accelerate the aging process of asphalt pavement material.As a result,the adhesion of asphalt is deteriorated.The interaction between solar radiation and external temperature makes the pavement produce large temperature stresses,resulting in fatigue cracking.The outside temperature which is warm-cold alternating makes the roadbed in the freeze-thaw cycle,further exacerbating the asphalt pavement disease.Therefore,how to properly monitor on-site service behavior of pavement structure and material,and research on long-term intelligent monitoring system for asphalt pavement service performance are important to analyze the road damage mechanism,and improve the service level of pavement.Based on highway of the Xining-Lijiang Gonghe to Yushu segment and combined with the geography,climate,environment and pavement structure design of this road to develop intelligent monitoring system for the service performance of the asphalt pavement.The location of road monitoring points was reasonable designed,temperature sensor was buried at the bottom of each structure and horizontal,longitudinal and vertical strain sensor was buried at the bottom of asphalt layer and base layer to realize the service status monitoring of asphalt pavement.Respectively,useing the fiber grating sensor and the resistance-capacitive sensor to achieve the assembly of the original sensor.Self-designed steel sleeve with mesh hole was used to protect the AOSON-AM2302 digital temperature-humidity sensor and capping with silica gel.At the same time,the method using polymer glue to fix the strain gauges.These methods was successfully solving the survived problem when sensor was buried in asphalt pavement.The effects of different encapsulating materials of fiber grating strain sensor on the deformation coordination with asphalt mixture was researched by using asphalt mixture rutting test and cylindrical compression test.Optimization of the sensor that was suitable for the construction site.The reliability of the selected strain sensor was verified.Used the processed sensor to simulate on-site measurement of the road,try to set up a road monitoring points at outdoor to verify the feasibility of long-term asphalt pavement service intelligent monitoring system.According to the test results of the test site at outdoor,the design scheme of the monitoring system is further improved,and then the monitoring points were established in the asphalt pavement highway of the Gonghe to Yushu segment in Maiduo,Qinghai Province.Finally,the finite element software is used to simulate the test surface.The stress state of asphalt pavement was studied under the action of temperature stress and load stress in alpine region.The results show that the fiber grating temperature sensor can accurately test the internal temperature of asphalt pavement structure.The preferred fiber grating strain sensor reliably tests the asphalt pavement strain.The strain gauges treated by a certain technical method can test the asphalt pavement strain.In the low temperature season,the maximum longitudinal temperature tensile stress of the asphalt pavement can reache 0.72 MPa,and the lateral transverse cracks are generated under the coupling of the driving load.The road surface produces a vertical displacement of 5.1mm after 300000 standard axle load.