Study On The Non-gel Encapsulation Process And Its Creep Properties Of Fiber Bragg Grating Sensor

Asphalt concrete pavement is the most common structure form of highway and city road in our country. In recent years, the early damage phenomenon occours in the existed pavement seriously as a surge of traffic and overloading vehicles increase. The early damage can not only lead to and accelerate other forms of damage, but also cause high cost and traffic pressure due to the maintenance and reconstruction. Therefore, it is necessary to monitor internal stress and strain of asphalt concrete pavement structure with appropriate method. Thus providing effective theoretical support for predicting remaining survice life and establishing reasonable maintenance plan.The construction environment of asphalt pavement is more complicated compared to other construction. Traditional method of monitoring can not meet the requirements of pavement structure detection. Fiber bragg grating sensing system has been widely promoted and applicated in the field of pavement structure monitoring because of its unique performance. But it’s hard to ensure reliability of the monitor system because of the failure of sensor encapsulation when comes to the practical applications. So the package structure is one of the key factors to make sure the reliability of monitoring.The analysis of advantages and disadvantages of the common package method shows that deformation consistency between package material and pavement material is key factor to the monitor system; its durability is another one. A new packaging method is designed in this paper. Asphalt mixture is chosen as packaging material in the design in order to improve deformation consistent, there is no macromolecule binder in the encapsulate process to avoid the bad effect on the monitoring, which caused by the macromolecule binder ageing. So as to make sure there is no glue in the encapsulation process of FBG sensor.In this paper, Laboratory experiment has been conducted to carry out the no-gel encapsulation process and testify the feasibility of encapsulation method. Static load and dynamic load has been applied to the sensor to simulate the pavement under various vehicle load. The result shows the encapsulation method is feasible and meaningful.The creep problem of FBG sensor may also influence the effective of monitoring. The creep properties of FBG sensor has been studied by conducting experiment. Effective advice on reducing the bad effect on the monitoring caused by the creep phenomenon has been given at last of the paper.