Holding back the tide with Tarmac AS one of the largest flood defence constructions in the UK, main contractor Balfour Beatty brought Tarmac on board to deliver the concrete material for the £86 million project on the Flyde coast. Anchorsholme’s inadequate sea wall needed to be replaced between Cleveleys and Little Bispham because it was prone to flooding, caused road disruptions and posed a health and safety risk.
The team were tasked with constructing a new concrete wall; higher and with deep steps built into it to disperse the assault of breaking waves. Combined with an elevated promenade, the new approach would reduce flooding. Pre-cast units, each weighing around 14 tonnes form the backbone of the defensive wall and part of Tarmac’s job was to find a blend of concrete to secure these in place.
Digging started each day after the tide went out and the team had to work quickly to pour the concrete before it came back in. “We had a really small window for when we could pour so we covered the joints of the concrete with a layer of sand to try and protect them from the waves. Each day’s work seemed to be a real battle against the clock,” says Russell Marsden, Tarmac’s external account manager.
Another challenge came in finding a quality aggregate that would stand the test of time. Abrasion tests, carried out by Balfour Beatty and Manchester University, identified aggregate from a quarry in Ireland as the most suitable for the job but “getting the aggregate from Ireland to Lancashire proved to be a pretty sizeable logistical challenge,” continues Marsden. Technicians at Tarmac’s Yorkshire laboratory developed a bespoke blend of Toproc using the specified aggregate, creating a high performance concrete that gains strength quickly and is especially dense and durable. “After just four days of lab testing the new mix was achieving strengths of over 61N and was ready to go for a site trial,” explains Marsden.
Marsden and the team are now supplying concrete for the redevelopment of the raised promenade. n Concrete Quality testing Unlike most building materials, concrete’s unique properties means the older it gets the stronger it becomes. However, before it can be used on largescale projects, it must undergo a number of tests in accordance with BS EN 12350-2:2009. “This will involve passing a number of quality assurance trials before it is used in any form of construction,” explains Nick Oliver, operations manager at ESG. “In the initial stages, the workability of wet mix concrete should be tested to ensure it can meet the demands of the project. “These assessments can be carried out via a number of methods including slump, flow and slump flow tests, where a heap of the material is poured onto a flow table and measured in terms of how far it spreads. Once the level of workability is known, adjustments can then be made to the mix.”
If fibres are added to concrete, the wet mix may need to undergo further tests to ensure a uniform level of distribution, explains Oliver. In projects where waterproof concrete is used, cubes undergo permeability tests and once complete “the samples are split open and examined for liquid penetration and permeation,” he says.
Concrete’s compressive strength also has to be measured to ensure it can handle project pressures, while other testing methods include measuring its density, elasticity, flexural strength and shrinkage. “As the compressive strength of concrete changes as it cures, these tests are carried out after 24 hours and then periodically thereafter and finally at 28 days for compliance.”
With BS EN 12390-2:2009 stipulating the maximum water temperature for curing concrete test specimens should be 22°C, ESG – a provider of testing, inspection and compliance services – has invested £100,000 installing data logging temperature alarm systems in its Uxbridge concrete laboratory and has constructed an enclosed area to house curing tanks in a permanent temperature controlled environment throughout the laboratory testing period. “This means that we can confidently guarantee the curing temperature compliance to 20°C ± 2°C,” says Oliver.
SIKA PROVIDES GRAND SOLUTION IN BRIGHTON
The Grand Hotel in Brighton is ready to welcome guests to its iconic seafront accommodation whatever the weather thanks to a roof overlay system applied with Sika Liquid Plastics’ Decothane Omega 15 solution. Opened in 1864, the hotel made global headlines following the IRA bombing of the Conservative party conference in 1984 and underwent a major refurbishment and the addition of a spa in 2013.
The latest roofing project is the third to be delivered at the hotel by contractor, Allweather Roofing & Construction, part of the Allweather Group, and forms part of a wider refurbishment scheme by main contractor, J. Davies Building Limited. The 130m2 roof area of existing asphalt roof had been leaking in several areas and Allweather Roofing recommended the Decothane Omega 15 cold liquid-applied system as the ideal solution for overlaying the roof, taking into account the exposed seafront location. For more information, visit www.sika.com
HOPE TRANSFORMS BAGGED CEMENT MARKET FOLLOWING LAUNCH OF NEW PRODUCTS
Having firmly established themselves in the bulk cement market, Hope has officially unveiled its new high performing bagged products, which, for the first time, are all available in the company’s own packaging. Available immediately, the eagerly anticipated launch includes 12 key products, and is designed to freshen up the sector and create real value for stockists.
Underpinned by a customer centric approach and strong brand heritage, Hope’s customer’s can expect to benefit from advanced packaging technology and unparalleled delivery service, which aims to provide a consistent lead time commitment of 1-3 days.
Hope will also be launching a sector-leading incentive scheme for builders’ merchants and professional builders, bringing a new approach to the market driving traffic into their stockists and helping to grow their businesses” For further info visit www.hopecement.com, follow @Hope_InABag or call 0845 5201 840