Performance of Rock Pins Galvanized Layers Assessed with Non-Destructive Method

Pins are installed in rock mass to prevent rocks and debris from falling on infrastructure and workers. During the transportation and installation process, the galvanized protective layer of the pins can suffer several types of damage that reduces their service-life against corrosion. In this context, laboratory tests were carried out in order to evaluate the performance of the galvanizing layer under different aggressive conditions. Accelerated corrosion tests were applied to three configurations; two with pins embedded in sand and one with pin grouted in concrete. For each configuration, three states of damage were compared: undamaged galvanized pin (NDGP), damaged galvanized pin (DGP), and non-galvanized pin (NGP). The assessment of the pin condition was performed using non-destructive techniques (pulse echo, acoustic emission and current corrosion measurements). The results provided insightful information about the limits of the galvanization depending on the initial damage state and the surrounding environment. The main result showed that the zinc layer offers the highest protection even if damaged, however, the inverse was observed when leaching rates from sand was possible.