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.
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.
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