Relation entre les propriétés physico-chimiques de l’anode en carbone et sa vitesse de réaction sous CO₂

Abstract:  

Steel bridge elements are exposed to harsh environmental conditions, such as de-icing salts on roadways. These elements need a satisfactory level of protection against corrosion to preserve their long-term structural integrity. A very efficient solution that now popular in Canada is metallization. Metallization is an anticorrosion coating formed by thermal spray of metal, usually zinc, onto the surface to protect. The protection of the steel substrate is ensured by both a physical barrier and a galvanic protection. Designs standards, such as the Canadian Highway Bridge Design Code CAN/CSA S6-14, specify desired conditions for various faying surfaces and associated slip coefficients to be used in slip-critical connections. Currently, these standards do not address faying surface conditions that are metallized. Thus, bridge fabricators are compelled to mask off joint faying surfaces before metallizing, which is very expensive for the industry. Earlier studies investigated the short-duration slip resistance of high strength bolted connections with metallized faying surfaces. Results revealed greater slip resistance than the typical uncoated blast-cleaned Class B faying surface. In this research, creep resistance of slip-critical bolted joints with zinc-metallized faying surfaces is characterized, to ensure that the Class B slip resistance is still valid at long-term. The effect of the relaxation of the clamping force on the slip resistance is also evaluated. Results of this study have shown a satisfactory creep performance. Also, results revealed that the relaxation of the clamping force does not impact significantly the slip resistance of the metallized assemblies. This will likely to influence future code revisions and impact steel bridge fabrication in North America.