Carried out on behalf of the Borough of Poole, the project involved the maintenance of a 480 m2 area of sheet piles situated in an inter-tidal stormwater culvert in the Poole suburb of Creekmoor and located within a coastal preservation site. The steel piling was showing extensive signs of corrosion, including severe rust staining, due to continued exposure to salt spray and cyclical tidal immersion.
As the sheet piles are frequently submerged and are subject to tidal fluctuations, one of the concerns was seeking a remedial solution that could withstand early immersion during the refurbishment works. It was also important that the chosen repair and protection products could demonstrate excellent adhesion to the steel substrate in this constantly wet environment. The project was managed by Balfour Beatty and Flexcrete materials were applied by Coastal Preservation Services.
Due to the presence of corrosion byproducts, marine growth and other contaminants, it was important that thorough surface preparation was carried out and the sheet piling was cleaned by UHP blasting to a sound, contamination-free surface. Flexcrete Cemprotec Clutch Filler was then applied with a pointing gun to flush fill the clutches and this was followed by a 2 mm application of Flexcrete Cemprotec E942 using airless spray techniques. Both products are rapidly applied, as Cemprotec Clutch Filler only needs to stabilise before application of Cemprotec E942 and on marine sheet piling a 2 mm application of E942 can be built up as a single coat to enable completion in just one shift.
Cemprotec E942 is a waterborne, two component, cement and epoxy modified polymer coating that is fast curing and withstands early immersion within just two hours of application, offering exceptional resistance to wash-out. Used as a stand-alone anti-corrosion coating, it requires far less surface preparation than alternative products as it achieves bond when just surface rusting has been removed. The water-based nature of Cemprotec E942 is a critical consideration for projects such as this, as unlike solvent-based products, it does not pose any threat to marine life and can be safely applied.
The dense matrix of Cemprotec E942 offers low permeability to water, even at 10 bar positive and negative pressure, and very high diffusion resistance to the ingress of chloride ions, oxygen and acidic gasses. It is also CE marked in accordance with the demands of BS EN 1504.
Adapted from press release by Katherine Guenioui
Read the article online at: https://www.worldcement.com/product-news/31102014/flexcrete-provides-corrosion-protection-for-poole-harbour-769/