After years of service, the cementitious substrate of a sulphuric acid containment at a pulp and paper plant was acidified. This happened as a result of an acid base reaction due to ground moisture, which occurred beneath previous repairs and caused repeated failure.
The client turned to our partners at Corrocoat US to provide a solution and requested that the restoration work be planned around normal operations.
The containment was first blasted with 40k psi equipment, incorporating a salt remover to expose all areas weakened by acidification and also remove soluble sulphur salts. This was followed by grinding and cutting to allow for proper forming and placement of Epoxy Polymer Concrete. The bottom of the tank was mechanically prepared with power tools and treated to remove soluble sulphur compounds. Prior to priming the cementitious surfaces were treated to return to alkalinity and ensure integrity of the concrete.
The curbs and surface were restored to their original dimensions using Corrocoat Epoxy Polymer concrete in conjunction with normal forming. Once the concrete was cured and the form removed, all transitions from grade to vertical were laminated, including from the tank pedestal onto the tank walls to protect the underside of the tank floor from releases.
Upon hardening the fibreglass was hand sanded and solvent cleaned prior to applying Plasmet AR3 in 3 successive coats to provide a film of 40-48 mils. Plasmet AR3 was selected as it is equally resistant to caustics and acids and is approved by FDEP for mineral acid containment applications.