The Slimes Tank is located on the head of Boulby Potash mine. Water and potash are pumped into it and solids and liquids separated. Chlorides had penetrated the reinforcing steel and caused delamination to the concrete to approximately 60% of the tank. St Astier was required to provide “holding” solution until re-construction.
To remove all chloride attacked concrete clean and prime reinforcing steel and overspray the full area with a Silane water repellent.
Using a mobile tower scaffold to access the defective areas, hammer testing was carried out to determine the extent that the concrete had delaminated. All areas of loose concrete were then removed by hand and disposed of via an on-site skip.
The areas were then prepared by grit blasting to achieve a bright metal finish to the steel reinforcement. These reinforcing bars were given a single unbroken coat of Nitoprime Zincrich primer in accordance with the manufacturer’s recommendations. The external elevation was then pressure cleaned to remove all salts and two coats of Nitocote SN502 penetrating silane-siloxane was applied using a low pressure spray.