Corrosion Protection of Reinforcements in Shotcreted Concrete Vessels - 1.

Inspections of silos for sugar beets were conducted. The inspection has also included vessels where heat insulating-coating has been removed from after 10 years of use, and has been replaced by cement plaster for protection of the wire. Heat insulating-gunite in no case met the requirements for sufficient corrosion protection: its adhesion to the concrete wall was insufficient, which had lead to spalling of the coating and, consequently, to open-air weathering of the prestressing wire. Moreover, even gunnite layers of more than 30 mm have been thoroughly carbonized. Due to the carbonatization and local spalling, wires heavily rusted and, in some cases, broke. Some of the silos have been repaired meanwhile - but this was insufficient measure, as seriously corroded wires were left in their position, and wires that had failed totally, were connected without skill.