Research On The Mechanical Properties And Durability Of The Steel Bridge Coating In Severe Cold Region

The steel is susceptible to corrosion, which highly influences the performance and durability of the steel bridge. Anticorrosion coating protection is commonly used in engineering for steel protection. The winter in severe cold region has special corrosive environments, which poses a serious threat to the properties of the steel bridge anticorrosion.The study designs a series of scientific experiments concerning adhesion force and bending performance of the steel bridge coating in severe cold region. For the bending performance, a quantitative evaluation method in which the fracture area percentage after the bending test is the main evaluation index is proposed. The anticorrosion coating materials are special epoxy zinc-rich primer, micaceous iron oxide intermediate paint and epoxy fluorocarbon paint. Three kinds of coating systems are designed, only primer(D), primer and intermediate paint(Z), primer, intermediate paint and finishing coat(M), respectively. For each coating system there are 3 kinds of thickness, making up a total of 9 kinds.Under the extreme negative temperature, freeze-thaw cycle and dry-wet cycle, the order of the adhesion force for the three kinds of coating system is M>Z>D, while the fracture area percentage Z>D>M. Performance under extreme negative temperature is lower than in the normal temperature. There is no big difference between-43℃ and 25℃. Under the quenching heat cycle, the order of the adhesion and fracture area percentage is M>Z>D. The embrittlement of the finishing coat happens soon under sudden temperature change, losing ductility and resistance to deformation. The coating systems with better bending performance has better coating adhesion. Performance declines with the increase of cycling times. Basically the thicker the composite coating is, the b etter the adhesion is, the worse the bending performance is.