Low embodied carbon concrete mix for the Enterprise Centre

Construction and infrastructure company, Morgan Sindall, has reached a key milestone with the completion of the first major concrete pour at the landmark £11.6 million Enterprise Centre project for the University of East Anglia, UK.

The Enterprise Centre is set to become a leading example of low carbon commercial construction and the project team utilised a specially designed carbon concrete mix for the pour. The concrete pour marks a critical stage in the construction process.

John French, CEO of the Adapt low carbon group at the University of East Anglia, which is managing the project, was on hand to help the site team pour the concrete. He said: “I am thrilled to have been able to contribute to the important process of pouring the specially mixed concrete. It is an integral part of the construction process, especially when aiming for the sustainability credentials that the Enterprise Centre is set to achieve. The project is an important part of the work Adapt is undertaking at The University of East Anglia and our unwavering commitment to supporting low carbon innovation.”

The concrete is a low embodied carbon concrete mix, including 70% GGBS cement replacement together with recycled sand and certified responsibly sourced aggregates. The recycled sand is produced from material excavated from other construction sites and recycled by JT Few at its plant in Great Blakenham near Ipswich. The concrete contains around only 40% of the embodied carbon of normal concrete and is a major component in achieving the low carbon credentials of the project.

Gavin Napper, Area Director at Morgan Sindall, said: “The pour at The Enterprise Centre was a landmark event in this Exemplar Low Carbon Building Project. The concrete is made from a bespoke mix, one of many steps that exemplify the innovation in sustainable construction that everyone involved with the project is aiming to achieve. We are very pleased to be making such solid progress on the project, in conjunction with our project partners.”

“The project team did a great job managing the pour. This is an element of the project that requires real expertise and accuracy. The concrete being poured couldn’t deviate from the specified level by more than five mm either way, so they were dealing with uniquely tight parameters and demonstrated real skill and attention to detail,” added Napper.

This low carbon concrete forms the raft foundation and ground floor of the building which will be simply polished to create the final finish, negating the need for any further finishes, thereby further reducing the embodied carbon of the project. This forms an integral part of the build, drastically reducing carbon emissions and it is very rare for a concrete of this mix to form the finished floor of a building. In total, nearly 1000 m3 of this low carbon concrete was required for the build, 250 m3 for the polished floor comprising one wing of the Enterprise Centre’s E shaped floor plan, with the remaining forming the raft foundation for the whole building.

Lafarge Tarmac provided the specialised concrete mix, via its local JV company, C&H Quickmix, having carried out extensive laboratory trials during the development process.

“This project showcases the flexibility that our innovative concrete solutions and our specialist technical teams can offer to a project, whether it is low carbon specific products or a wider approach to sustainable design,” commented Jeremy Greenwood, Managing Director of Readymix at Lafarge Tarmac. “We developed a product that supported the client’s goals and enhanced the environmental credentials of the building, without compromising on the aesthetics of the finished product. By using GGBS, we were able to reduce embodied carbon, and deliver a solution that offers the opportunity to employ the thermal mass properties of concrete to maximise whole-life performance.”

The Enterprise Centre project is an Exemplar Low Carbon Building, targeting BREEAM (Building Research Establishment Environmental Assessment Method) Outstanding and Passivhaus Certification (the global standard for energy efficient, low-carbon buildings). The mix of the concrete, with its high GGBS content and recycled sand, means that the concrete exceeds the 25% recycled content required by BREEAM.

The centre has been created to achieve a 100-year design life and aspects of the development will be constructed using traditional methods and locally sourced materials. Thetford timber, Norfolk straw and heather will be used, while various elements of the building will be thatched.

The concrete was poured via a concrete pump by Morgan Sindall’s groundworks and civil engineering contractor Tangent Group and was power floated to the close tolerance finish in readiness for grinding and polishing. The development is expected to complete in spring 2015.

Adapted from press release by Louise Fordham

Read the article online at: https://www.worldcement.com/product-news/14072014/embodied_carbon_concrete_mix_for_uea_enterprise_centre_60/