Development of an In Situ Measurement Device for Airfield Pavement Interface Characterization

Regular pavement condition evaluation is the key to ensuring a good asset management of in-service pavements, because it allows anticipating and optimizing maintenance or rehabilitation works. In particular, interface bonding conditions between asphalt concrete layers are of major concern because in most cases, structural problems come from interface defects, and furthermore, they have a huge impact on the pavement current mechanical behavior and its remaining service life. Usual structural nondestructive testing devices do not allow assessing this parameter on their own. This is the reason why there is a need for an in situ measurement system. The French Civil Aviation Technical Center (STAC) launched an ambitious research and development program with the objective of developing a proof-of-concept for such a device and associated data analysis methodology, which enables characterization of the interface response for several mechanical solicitations, including rolling-wheel passage or heavy weight deflectometer dynamic impulse load, with a two-fold purpose: a better understanding for research purposes of the interface's mechanical behavior and its evolution during the life of the pavement and to have at their disposal an operational tool to evaluate the interface bonding condition of in-service pavements. This paper presents the measurement device developed by the STAC. It is inspired by the ovalization system invented in the 1970s by the Laboratoires des Ponts et Chaussees, which consists of measuring the diameter variation of a core-hole in three horizontal directions (longitudinal, transverse, and 45 degrees) during the passage of a rolling-wheel. The first part of the paper focuses on the device development process that led to the final prototype. The second part is dedicated to the 3-D finite element modeling developed for data analysis. The results from a field survey, performed on the STAC's test facility, are finally presented and compared with numerical simulations.