A Case Study on Reinforcing Asphalt Pavement Using Sensing Geogrid Based on Fiber Bragg Grating

When traditional geogrids are used to mitigate reflective cracks in asphalt pavement, it is difficult to monitor the internal state of the pavement and the strain of the geogrid in real time. This study proposes a sensing geogrid based on warp-knitting technology, where fiber Bragg grating (FBG) sensors are embedded into the geogrid through the weaving process, enabling it to possess both reinforcement and strain-sensing functions. The sensing geogrid was calibrated through laboratory tensile tests, and field monitoring was conducted to obtain optical signal variation data at various stages during asphalt pavement paving, as well as the deformation of the geogrid at different measurement points in each stage. The results indicate that the weaving process did not damage the FBG sensors, and the sensing geogrid exhibited good optical signal performance and normal signal acquisition during the production and transportation stages. The strain of the FBG sensors and the geogrid showed a linear correlation, with a correlation coefficient of 845 με/nm, demonstrating good deformation compatibility between them. Field monitoring confirmed that the sensing geogrid has good construction adaptability and can perceive fluctuations in optical signals and deformation of the geogrid during the construction process. Specifically, significant deformation of the geogrid occurred during the construction of the asphalt-treated base (ATB-25) and bottom layers, accompanied by substantial fluctuations in optical signals due to construction machinery. In contrast, signal fluctuations were smaller during the construction of the middle and surface layers, with the influence depth of construction machinery being approximately 22 cm. Compared to ordinary road sections, the deflection basin curve of the reinforced section was gentler, and the maximum deflection was reduced by approximately 41%. This study confirms the feasibility of the sensing geogrid and provides a valuable reference for its application in road engineering.