St Aubin's Harbour

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.