Global building product manufacturer, Sika, is providing a long-term concrete repair and Total Corrosion Management (TCM) solution to strengthen the roof of the world’s oldest operating aquarium and help return it to its full, Victorian glory for generations to come. Sikacem®-133 Gunite was selected as the high-performance, cement-based repair mortar to replenish the ageing, deteriorating concrete soffits which form part of the roof at Brighton’s historic SeaLife Centre. With repair work being undertaken in the vicinity of marine tanks, the project required intense management and coordination between the main contractors, Barwin, and structural engineers, Gyoury Self Partnership, to ensure repairs were carried out successfully without harm to the marine life.
Structural surveys showed a 1,200m2 area of the 174-year-old, Grade II-listed SeaLife Centre’s soffits had been subjected to prolonged chloride contamination, increasing the risk of concrete delaminating from the roof. With the problem intensifying due to cracks forming to the limestone banding of the roof’s connecting columns, main contractors, Barwin, required a quality, large volume concrete repair solution to bolster the failing soffits and prevent further damage. Sikacem®-133 Gunite was more than up to the challenge. As part of the repair work which has been carried out in multiple phases since 2011, contractors, Barwin, removed the contaminated soffits which were reinstated with Sikacem®-133 Gunite, a fibre reinforced polymer-modified one component micro repair concrete. The Sikacem®-Gunite 133 was dry spray-applied and hand-finished with a trowel to provide a smooth finish ready for a decorative protective coating.
To manage the steel corrosion within the structure, products from Sika’s TCM portfolio were utilised. Sika® FerroGard®-903+,a surface applied multi-functional liquid corrosion inhibitor was used. Once applied to a concrete surface the liquid migrates to the reinforcement through the concrete and forms a protective layer which suppresses any existing corrosion activity or prevents any further activity. In addition where chlorides were high, Sika® Galvashield® galvanic, sacrificial anodes were installed to prevent the formation of new corrosion sites (incipient anodes) adjacent to the refurbished concrete. This simple, innovative anode system involves a small, circular shaped cementitious shell encasing a zinc core which is quickly and easily fastened to exposed steel reinforcement. Once installed, the anode’s zinc core corrodes sacrificially to the surrounding rebar therefore protecting the rebar.