Corrosion-Resistant Fastenings in Road Tunnels - Field Tests

Field tests have been carried out in the Mont Blanc Tunnel to evaluate corrosion-resistant materials usable for fasteners under aggressive conditions. Only the chromium-nickel-molybdenum steels, nickel alloys and titanium proved especially resistant in the long term. The results of field testing over three years, and of laboratory tests, with consideration also given to other marginal conditions, such as material machinability, availability and costs provided the basis for a proposal for the material to be used. The best materials are the chromium-nickel-molybdenum steels containing 6% molybdenum.