Case Study – London Underground

Substrate Details

2 Concrete Catch Pits approx size 1200x600x1500mm.
The pits are located Approx 100m from the platform station, they are positioned on either side of the track. One is on the north bound side and the second on the south bound

LUL induction certificate was required by all engineers before any work could be carried out including pre inspection. The work could only be carried out between the hours of 1am and 5am and pending any other engineering works. 

Preparation

Suck out all the water and waste in the sump using gully sucker followed by power wash.
Cracks and holes were repaired using a high build epoxy resin mastic which was applied by hand using a trowel
The concrete surface was then washed using a diluted (max 10%) Sodium Hypochlorite (bleach)
This is applied using a hand held sprayer with Viton seals. Used to remove and kill off any algae or bacterial growth.
Power wash again.  Gully suck water from the wash down.  A diluted Hydrochloride Acid wash (max 10%) using hand held sprayer with Viton seals. This was required to etch the concrete surface to give maximum adhesion and also to remove any surface salts on the concrete structure.
Power wash again.

 Spraying

Epoxy spray applied  with one coat at 6mm.  Once the resin cured the acro props were reinstalled. 

concrete-catch-pits-before

Before

 

concrete-catch-pits-after

After

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