The existing bund linings had been severely damaged, which had lead to the attack of and breakdown of the concrete beneath. A new bund lining solution was required to prevent further degradation.
Due to the high concentration hydrochloric acid and sodium hydroxide that could spill into the bunds an extremely chemical resistant bund lining solution was required. We proposed the application of Chemco RB300 glass flake reinforced vinyl ester as a suitable bund lining solution.
Removing the old lining
Following chemical decontamination by the client we initially removed all of the old bund lining using vibration damped breakers and vacuum controlled diamond grinders. Once we had exposed the concrete it became apparent that years of exposure to the aggressive chemicals had caused more degradation to the concrete than was initially apparent.
The damages areas of concrete were broken out and the exposed steel reinforcing prepared to ST3 as per ISO8501:1. The steel reinforcing was treated using Remmers KHB prior to reinstatement using Remmers Betofix RM. This material can be feather edged which was extremely useful given the very restricted working environment that would have made the use of a diamond concrete saw unnecessarily high risk.
A cove detail was installed at the floor wall interface using the same mortar in order to isolate this potential point of movement as per best bund lining practice.
Priming the bunds
The repairs were allowed to hydrate until the moisture content reduced below 6% at which point the bunds were primed using a damp tolerant epoxy primer to ensure excellent adhesion of the new bund lining system. The wet epoxy primer was fully blinded with kiln dried quartz aggregate to form a bonding bridge for the vinyl ester bund lining.
Appling the bund lining
Chemco RB300 was applied in three coats to a nominal bund lining thickness of 1200 microns as per the manufacturers recommendations. This material contains self leafing glass flake which laminate within the coating to provide excellent chemical resistance.
Finally the complete bund linings were tested for pin holing using a DC holiday spark tester. Where aggressive chemicals are found such as these bunds a single pin hole is a point of failure which would allow the aggressive chemicals to again attack the concrete.