THE PROBLEM
The concrete storage tank was exhibiting significant evidence of Sulfate attack as a result of the action of hydrogen sulphide. The Digestate store had not previously had a tank lining applied as it was not expected that hydrogen sulphide would be present.
SOLUTION
Initially we removed all of the existing scale and eroded concrete by method of abrasive blasting, leaving a non-friable surface to which we could apply the new tank lining.
Following blasting areas of cracking were exposed within the concrete. Following consultation with the clients engineers, an additional reinforced coat was applied to these cracks using a woven multi directional reinforcement tape embedded in Remmers Epoxy Universal.
For this tank lining Remmers Epoxy Universal was the chosen specification. This crack bridging epoxy has extensive case histories within the anaerobic digestion market, spanning over 20 years.
Due to the porosity of the concrete and initial penetrating coat was applied by method of brush and roller, helping to work the epoxy tank lining into the pores and fissures. A second coat was then applied with the addition of a thixotropic agent by rubberized trowels. This two stage approach proved highly effective at filling the highly porous surface.
As part of our standard quality assurance the integrity of the lining was checked using a DC holiday spark tester, as per best tank lining practice. This is essential to achieve a defect free tank lining.
Where pin holes were found they were marked, prior to touching in using the same material applied by brush.
