London 2012 Olympics Press Centre

 Sustainable recycled concrete mixes used for PT slabs & concrete frame

An exciting and unusual project, Walsh provided engineering services on a vital part of the Olympic Park to deliver the press centre which was used by journalists from around the world.

Walsh provided the detailed design for the post-tensioned (PT) slabs and pre-cast columns on this Allies and Morrison designed project.

Concrete mixes using up to 50% ‘Stent’ secondary aggregate, a by-product of the china clay industry, were used in the concrete frame to satisfy the high quota for recycled materials set by the Olympic Delivery Authority.

GGBS cement replacement, which at the time was not commonly used in post-tensioned slabs due to the adverse impact it has on early age strength, was included in the concrete mix to further enhance the sustainability credentials.

Existing test data and previous experience were used to justify a cement replacement level of 15%.

Walsh worked closely with PT contractors to develop and test concrete mixes that will use much higher proportions of cement replacement in the future.