The application of non-destructive methods in the diagnostics of the approach pavement at the bridges

Abstract

The article presents the possibility of using non-destructive methods of road pavement diagnostics as an alternative to traditional means to assess the reasons for premature cracks adjacent to bridge objects. Two scanning methods were used: laser scanning to measure geometric surface deformation and ground penetrating radar (GPR) inspection to assess the road pavement condition. With the use of a laser scanner, an effective tool for road deformation assessment several approach pavement surfaces next to the bridges were scanned. As the result, a point cloud was obtained including spatial information about the pavement deformation. The data accuracy was about 3 mm, the deformations were presented in the form of deviation maps between the reference surface and the actual surface. Moreover characteristic pavement surface cross-sections were presented. The in situ measurements of the GPR method were performed and analysed in order to detect non-homogeneity in the density of structural layers of the pavement. Due to the analysis of the permittivity of individual layers, it was possible to detect non-homogeneity areas. The performed GPR measurements were verified by standard invasive tests carried out by drilling boreholes and taking cores from the pavement and testing the compaction and air voids content in asphalt layers. As a result of the measurements made by both methods significant differences in layer compacting factor values were diagnosed. The factor was much smaller in the area directly next to the bridgehead and much larger in the zone located a few meters away. The research showed the occurrence of both design and erection errors as well as those related to the maintenance of engineering structures.