Experimental Research Of The Asphalt Pavement Dynamic Loading Test And Analysis Based On Optical Fiber Bragg Grating Technology

Based on fiber grating sensor technology and combined with the characteristics of structure andconstruction of asphalt concrete pavement, a kind of optical fiber Bragg grating sensor used formonitoring the strain of asphalt concrete structure is designed with tire rubber as encapsulation materials.Through the static and dynamic loading tests, the feasibility of using the sensors to monitor the law of theasphalt concrete structure’s internal strain is verified.The mechanical properties of tire rubber are tested under the condition of normal and hightemperature, the result shows that: the performance of packaging material is relatively stable underdifferent temperature conditions, the limit tensile strength is47⁵1MPa，the compressive ultimatestrength is87⁹5MPa and the elasticity coefficient is129¹37MPa. The dimension of strain sensor is100mm×10mm×10mm. The encapsulation process is confirmed, and strain sensor is obtained throughencapsulating the fiber Bragg grating.According to the structure of the sensor, the sensor calibration system is designed to calibrate thesensor. The strain sensitivity coefficient reaches5.5768pm/με which increased5.1times compared to thebare fiber Bragg grating （1.1pm/με）, which indicates that the encapsulation method has strain sensitivityenhancing effect. The temperature sensitivity coefficients reaches0.0084/℃which decreased by26.3%compared to the fiber Bragg grating （11.2pm/℃）, which indicates that the encapsulation method hastemperature desensitization effect.Embedding the sensor in the rut sample which is made by SMA-13to implement static test showsthat the correlation between load and the strain is ε=0.044F-0.778. The theoretical relationship betweenloads and strain obtained by using ANSYS to simulate static loading test is that εANSYS=0.048F-0.1326.The contiguous value between the test and theory result indicates that the internal strain of the asphaltconcrete structure can be reflected better by using the sensor.Dynamic loading tests include rutting test, shot impact test and aircraft landing gear drop test. Thewave crest changing trend along with time obtained in the rutting test is that:y=6×10^-5t³-0.0725t²+30.792t3339.2. Since there are uncontrollable factors in the shot impacttest process, the wavelength changes can not reflect the change trend of the strain. The wave crestchanging trend along with time obtained in the aircraft landing gear drop test is thaty=1×10^-10t³-5×10^-6t²+0.0657t19.337. The static and dynamic loading tests show that: the optical fiber grating sensors can well reflect thecharacteristics of strain of asphalt concrete in static and dynamic loading tests, the output signal is stable.The sensor is not destructed when the rut sample is molded and dynamic loading test is implemented,which indicates high survival rates. The sensor can be used to monitor the strain of asphalt concretestructure.