Retrospective waterproofing of a copper plant, Poland
When extracting copper a waste product exists - a mixture of water and solids. This mud is pumped into large settling tanks so that the solids can settle out. This desposited material is then used as a filling material for the dam so that the water level of the settling tank is steadily increased. The excess water is fed over a tower into a connecting canal of a water course. This canal is located beneath the settling tank. The mud is enriched with chlorides which are not directly aggressive to concrete but could lead to corrosion of the reinforcement.
It was necessary to waterproof the channelling and the tower. The existing waterproofing had been produced from bitumen membranes. Unfortunately gaps had opened up in the membranes. The water could find unimpeded access between the waterproofing and the concrete and thus penetrate it. Corrosion of the reinforcement resulted. As the concrete had not been installed free of cracks, water loaded with contaminants could permeate and therefore damage the entire cross-section.
The internal refurbishment was carried out as follows. The impermeability appeared strongly in a crack in a construction joint in which penetrating water brought contaminants which were deposited along the crack edges and on the surface of the building elements. The cracks were closed by injection with AQUAFIN-P1 and AQUAFIN-P4. Continuous impermeability could not be expected as the injection material could not penetrate into the concrete past the edges of the crack. Soiling on the edges of the crack due to the contamination had blocked the route. Therefore additional internal waterproofing was necessary. This was carried out with AQUAFIN-2K following comprehensive cleaning of the concrete. It was clear that contaminated water would remain in the concrete. This is however stagnant water which aids corrosion less than water that is subjected to constant exchange. Despite 30m of water pressure the restrospective waterproofing measures are still fulfilling their obligations.
AQUAFIN-2K
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