Where Geophysics Meets Asphalt - Monitoring Roads Using Fibre Optics

Fibre optic sensing technologies, and in particular Fibre Bragg Gratings (FBGs), are enabling high precision and detailed mapping of strain in various structures by direct integration into the material layers. Here, embedding fibre optic sensor lines in asphalt has been demonstrated to detect miniscule changes in lateral strain due to vertical deformations of road construction layers, in response to the loads in real-time traffic conditions. The spatial and temporal resolution of the system allows for very detailed mapping of the deformations due to vehicle loads, including the extraction of the viscoelastic properties of the pavement and the rigidity characteristics of the underlayers. By continuous and/or periodic monitoring of the dynamic asphalt behaviour in response to controlled loads, the long-term changes in the near-surface properties due to material aging because of weather conditions or traffic loads can be extracted. Such detailed analysis can enable monitoring of large-scale assets, literally paving the way for a new approach to asset management of roads.