Project: Margate Sewage Treatment Works
Product: SHOTCRETE 513
Client: Southern Water
Contractor: Corroless Eastern
Specialist Sub-Contractor: GSSL
Margate Sewage treatment works sits nestled in the cliffs more like a bond villains lair than a waste water treatment plant. Unfortunately, there was a dark force lurking within in the form of severe degradation of the concrete within the inlet chamber and Archimedes screw chambers. This was identified for repair along with replacement of the Archimedes screws as part of a major resilience project by Southern Water.
Prior to Corroless Eastern tendering for the works, a concrete condition survey had been conducted which had identified the extent of sulphate contamination of the concrete. This identified to which depths existing concrete had to be removed to in order for the remaining concretes sulphate content to be acceptable.
A particular challenge of this project was that the inlet chamber would remain live throughout this element of the works, so to prevent debris entering the treatment process, screening was installed on the lowest level of the scaffold to catch aggregates released from the hyrdo-demolition works.
Ultra High-Pressure water jetting units were used to remove the defective concrete to the prescribed depths. The effectiveness of this was verified by the taking of and laboratory analysis of dust samples for sulphate content.
Once the degraded concrete had been removed, they were able to identify steel reinforcement that had been corroded to such an extent that replacement was required.
Natural Cement’s SHOTCRETE 513 was the specified product for carrying out the concrete repair works within the inlet chamber and Archimedes screw chambers.
SHOTCRETE 513 is an environmentally friendly, dry-spray concrete with rapid strength gain. The product is suitable for dry-spray applications where a quick turnaround is necessary as it starts to set after 4 minutes & totally set in 10. It’s suitable for installation up to any thickness from a minimum of 10mm. It has high chemical resistance properties and can be used in cold & wet conditions. The product is also DWI Reg.31 approved for potable water applications.
The SHOTCRETE 513 was applied by specialist sprayed concrete subcontractor GSSL with climatic monitoring undertaken throughout to ensure the correct installation conditions. Post application, the curing and strength of the concrete repair materials was monitored using rebound hammers and by the taking of and laboratory analysis of core samples from spray outs. Once sufficiently cured, a final Epoxy modified cementitious coating was applied in two coats.
The project at Margate was conducted in three separate mobilisations over three years, including one within the Covid 19 pandemic. Well done to all involved for a successful project completed in an extremely challenging environment.
Date added: 12/12/2023