Chloride induced corrosion is a main cause for damages on concrete structures and thus
responsible for a large share of the cost for the rehabilitation of concrete structures. On bridge decks covered with asphalt the concrete surface can not be inspected visually or with common potential techniques. As a result the planning of the repair of bridge decks is usually based on a small number of probes and the experience of the engineers involved. Therefore, a non-destructive method for the localisation of zones with increased chloride contents on bridge decks is desirable.
Ground-Penetrating-Radar (GPR) is a non-destructive inspection method that can be applied on large objects such as bridge decks. Today, it is mainly used for structural problems such the concrete cover of rebar or the localisation of tendons. There, asphalt pavement does not cause significant problems. Several authors have suggested GPR as a method for the localization of damages and zones with increased chloride contents and a number of pilot studies has been carried out. However, no final conclusion has been reached on the applicability of this approach.