Jersey, United Kingdom

A foul pump chamber at the Boat House, a restaurant located in St Aubin’s Harbour, Jersey, required remedial works.

The project involved breaking out the existing base slab of the chamber and casting a new one.

Geomarine, part of the Garenne Construction Group, as well as structural engineers, T&G Limited, were contracted for the project. They turned to Ronez, a supplier of concrete and other materials and Sika to provide a tailor-made solution for the project.

St Abuins harbour concrete project
St Abuins harbour concrete project

Project Requirements

This meant a concrete that would gain adequate strength in a short space of time was required.

As part of an already existing waterproof structure, durability could not be overlooked either when designing a solution for the project.

Although a relatively small-scale project, it posed the uncontrollable challenge of working round the tide, which reinforced the need for a concrete that would gain adequate strength quickly.

Similarly, whilst replacing an existing concrete slab seems simple enough, the narrow yet deep chamber within the tidal zone – that could only be accessed by a specialised team – presented its own complexities.

Additionally, it was important that durability was not compromised and that the new concrete could meet the standards of an already waterproof structure.

Sika Solutions

Designed as a water reducer or plasticiser, Sika ViscoCrete®-4100 (GB) is a liquid admixture based on a unique blend of polycarboxylate polymers technologies.

Particularly suited for use in concretes that require excellent workability retention properties of 4+ hours, the product was specified in this case to hold the initial set for two hours. This provided enough time to situate the concrete without it curing too soon.

SikaRapid®-2 promotes early strength development without negatively influencing final strengths. It was used in this project within grade C40/50 watertight concrete to accelerate the setting time.

"The knowledge and specialist input from Ronez (and their connections with Sika) were invaluable on this project, which despite its small size, was a challenge in design, logistics and installation." Alex Farrow from T&G Limited