In 2017, five innovative gravity based wind turbine foundations were constructed at a dry dock in Newcastle upon Tyne and installed offshore at Blythe Wind Farm using a ‘float and submerge’ method. Each foundation required substantial steel reinforcement to withstand the pressure of the water, which in turn required anti-corrosive protection to resist the harsh marine environment.
Flexcrete Ltd, now a part of AkzoNobel, supplied each of the five foundations with corrosion protection. A relatively thin layer of concrete protection can protect steel from corrosion by maintaining an alkaline environment and preventing the ingress of chloride ions, but a lack of sufficient cover was identified, and Cementitious Coating 851 (now Intercrete 4841, part of the International range of protective coatings) was chosen as the solution.
A 2mm coating of the product provides the equivalent of 100m of concrete cover, allowing specified design life to be achieved by reinstating cover through a thin layer of protective cementitious coating. This represented an ideal alternative to drastic and costly solutions such as demolishing or recasting sections that failed to meet required specifications. A thin protective layer is also preferred to dense concrete layers, which can create challenges in terms of weight and congested space.
The Blythe Offshore Wind Farm is expected to produce enough low-carbon electricity to power approximately 34,000 UK households and save around 57,600 tonnes of CO2 emissions a year. By using gravity based foundations, pilings were not required, circumventing a costly and labor-intensive process which can be disruptive to the local ecosystem.
This high capacity was achieved by installing the turbines further from the coast in deeper water, which in turn was enabled through durable construction and the advanced concrete protection of Cementitious Coating 851/Intercrete 4841. Interzone 954 was also applied to the steel, providing it with long-term corrosion resistance. The application was successful, and the applicators went on to use the same system to coat a service reservoir in nearby Fenham.
Location of Project: Newcastle, United Kingdom
Products/System Used: Intercrete 4841, Interzone 954
Project Size: approx. 1,577m2
Project Owner: BAM Offshore Wind