Monitoring the structural capacity of airfield pavement with built-in sensors and modulus back-calculation algorithm

The degree of deterioration in the structural capacity of a pavement is an important indicator of its performance. Conventional falling weight deflectometer, which assesses pavement capacity based on the deflection bowl data under impact loads and is the prevalent method in practice, only characterize the overall bearing capacity of pavement. It does not possess sufficient accuracy in measuring the modulus of pavement structural layer. In this paper, a smart pavement schema was proposed where built-in sensors are incorporated to monitor pavement stress and strain responses under aircraft loads. Theoretical relationship between pavement mechanical responses of a two-layered elastic system subjected to service load is established, which is used for back calculating the modulus of asphalt layer. To demonstrate the concept, sensors are deployed along a taxiway in Beijing Capital International Airport, Beijing, China. The measured mechanical responses by the sensors were incorporated to back-calculate the modulus of asphalt layer, which are then verified through dynamic modulus experiments. The results show that back-calculated modulus by incorporating sensor data is repeatable and can be applied for real-time evaluation of pavement performance without affecting the traffic. Extension of the model and analysis to multi-layered elastic system are discussed.