Experimental investigation of pavement behavior after embankment widening using a fiber optic sensor network

In order to investigate the actual health condition of asphalt concrete pavements on widened road embankments, a full-scale model test study was conducted. A fiber Bragg grating–based sensor network was developed to monitor the strain distributions within the pavement structure, which was subjected to differential settlements. An improved packaging and installation method of the quasi-distributed sensor system was utilized, which not only ensured a high sensor survival rate but also achieved accurate measurement of axial strains in longitudinal and transverse directions. Based on the monitoring results, the strain characteristics of the pavement structure under different settlements were analyzed in detail. It is found that in general, the top layer of the asphalt pavement structure was subject to tension stress due to the differential settlement of the embankment. Plastic deformation of the pavement was observed when the differential settlement increased to 22 cm. The base layer of the pavement had the most significant response in comparison with the top and middle layers. The geogrid reinforcement in the embankment had a positive effect to alleviate the tension stress in the pavement. This experimental study also indicates the capability of fiber optic sensor networks to monitor the performance of pavements with a high degree of accuracy.