CEMEX UK complete longest slipform pour in Europe
Company supplies 11,000 cubic metres of concrete for continuous 29-day pour on Lee Tunnel project
THE longest continual slipform pour in the UK, and possibly in Europe, has been carried out by CEMEX UK on one of the five shafts for Thames Water’s Lee Tunnel project in Beckton, Greater London.
Engineers from contractors MVB, a joint-venture partnership between Morgan Sindall, VINCI Construction Grands Projets and Bachy Soletanche, spent 29 days continuously pouring concrete into the slipform shutter of the shaft on behalf of client Thames Water.
Three cranes were used to deliver the concrete to three skips to pour into the 80m deep shaft, demanding a total of 11,000 cubic metres of concrete. The concrete was batched on-site and placed at a rate of 100–150mm (shutter rise) per hour.
A bespoke C50/60 concrete was designed using a number of admixture blends to control setting times, including Isoflex superplasticiser and MR 800D retarder. The concrete also contained 500 tonnes of steel fibres as reinforcement.
‘This was a tremendous achievement with nine concrete mixes of different levels of retardation supplied on a regular and continuous basis to form an integral part of this vital structure,’ said Chris Leese, vice-president, Readymix and Mortars.
‘The materials have been developed using the latest technology and challenge our expertise, to ensure that we can meet the structural requirements of the tunnel. Such developments are key to helping to build a greater Britain.’
The Lee Tunnel is first of two tunnels which will capture an average of 39 million tonnes of London’s sewage and, by itself, prevent more than 16 million tonnes of sewage mixed with rainwater overflowing into the river Lee each year.
