In-situ corrosion protection of metal sections in the sewers of London.
Constructed back in the 19th century, the steelwork in the main chambers of the trunk sewer in East London suffer from advanced corrosion in the permanently damp and acidic atmosphere.
The owner, Thames Water Utilities, sought innovative solutions to arrest the deterioration, and trials were conducted to assess the benefits of Flexcrete’s advanced cementitious coatings for the protection of metal.
Ultimately the favoured product was Cemprotec E942, an epoxy and polymer modified coating with excellent adhesion directly to steel even when there is some residual surface dampness present. To demonstrate the versatility of the E942, varying levels of preparation were used, including needle gunning to bright metal and hand wire brushing to remove the bulk of the oxidation. The product was applied by brush in two 1mm coats with the second coat placed as soon as the first was stable. The areas were then left for eight months before examination revealed that passivation had occurred, preventing further corrosion.
Thames Water Utilities, London