The use of impulse and stepped-frequency radar to characterize the hydric behaviour of a porous pavement structure

摘要

This study focusses on examining the behaviour of an innovative asphalt pavement which is created as a solar energy collector, using non-destructive testing involving ground-penetrating radar. The concept of heat exchanger is based on the use of drainage asphalt in the bonding layer through which a heated fluid flows via gravity to de-ice the roadway. In order to develop hydrothermal models for a test site representing such a pavement, the saturated porous layer assumption was required when the water level in each tank (up- and downstream of the structure) was same as the top of the porous layer. Two ground-penetrating radar techniques were tested at this test site: a ground-coupled impulse radar and an air-coupled stepped-frequency radar. The impulse ground-penetrating radar, a high-efficiency non-destructive testing technique which is widely used in civil engineering, provides accurate geometric information, especially for pavement investigation. In the second innovative approach, air-coupled stepped-frequency radar was combined with full-waveform inversion to obtain quantitative information, while retrieving the electromagnetic properties of the successive pavement layers.