Lift shafts successfully sealed

Citi-Con helped Trencon Construction to devise an innovative solution to stop water seepage into the lift shafts at the new purpose designed Netcare Alberton Hospital in Johannesburg, Gauteng.

The eight lift shafts are in an area with a very shallow water table. Water would, therefore, seep from the bottom of the lift pits and opposite sides, flooding the shafts at a rapid rate. As fast as the water was pumped out of the shafts, they would fill up again.

Citi-Con first washed the walls of the shaft with a high-pressure water spray. We then closed all the areas from where water was leaking with cementitious plugs. Next, a 45° fillet was installed in the lift pits to seal the wall to floor joint. This was followed by the treatment of the walls and lift pits with post-initial set applied colloidal silica (P3) technology.

P3 penetrates at least 38mm within the pore structures of the concrete. It then reacts with available Calcium Hydroxide providing a longer Calcium Silicate Hydrate (C-S-H) chain. Once this reaction has taken place, SCP fills the capillaries as opposed to blocking them.

SCP was suggested because it is ideally suited for use on existing concrete. In this case, the concrete was nine months old.