In a UK first, the Environment Agency, BAM Nuttall, Arup and Tarmac have successfully trialled the use of two low carbon concrete mixes for works at the Hexham Flood Alleviation Scheme.
The low-carbon concrete has been used across 3 panels, totalling 27 metres of the £6.5 million Hexham flood defences as part of a plan to reduce their carbon footprint, the Environment Agency (EA) has said.
Hexham is a popular tourist destination in Northumberland with visitors able to observe salmon leaping at the masonry arch bridge, dating back to 1793. The Hexham flood alleviation scheme will help to protect up to 90 properties in one of the town's most important commercial areas, providing increased job security by protecting the places people work, keeping businesses open and supporting the wider local economy.
The flood alleviation scheme is almost complete on the south bank at Tyne Mills Industrial Estate and features a new structure installed across the Skinnersburn which would also stop the River Tyne backing up when levels are high. The improvement works to the north bank at Bridge End Industrial estate consist of flood walls and embankment as well as featuring the sections of low carbon concrete at the former Reiver Sports site.
The EA say that more than half of its carbon footprint comes from the construction of flood defences. Using low carbon concrete, such as a new Portland limestone mix, developed by Tarmac, will improve Hexham's resilience to the changing climate while also playing an important part of the organisation's steps towards Net Zero targets.
So far, the trial has presented positive carbon savings compared to a standard concrete mix offering up to 70% reductions of CO2 emissions per cubic metre of concrete delivered to site.
It is hoped that the trials to find new ultra-low-carbon concrete alternatives, will enable future Environment Agency flood defences across the North East to be built more sustainably, with lower embodied carbon. They will also support the delivery of new sustainable concrete products, to the wider construction industry and help to achieve targets outlined in the Net Zero North East England partnership. This collaboration between local government, business, education, the public sector and civil society aims to drive a comprehensive regional approach to tackling the climate emergency.
Leila Huntington, Environment Agency Operations Manager, said:
"The Environment Agency is committed to helping the nation be more resilient to flooding, coastal change, drought and climate change. We all have a role to play in tackling the climate emergency which is why the Environment Agency has committed to reaching Net Zero by 2030. To achieve this we have to adapt, try innovative approaches and ensure that climate and sustainability are at the heart of what we do.
"The trial of low carbon concrete in Hexham is a fantastic example of how we can work with our partners to continue to build flood defences to better protect communities from flooding, whilst also focussing on sustainability, the environment and reducing our carbon emissions."
Ruth Young, area carbon and sustainability lead for BAM, said:
"As the Environment Agency's construction partner in the North East, we are carefully considering how we can limit the environmental impact of the flood defence work we deliver without compromising the strength and resilience of these structures.
"We identified Tarmac's new low-carbon concrete mixes as innovative products, which have the potential to reduce our overall carbon impact across the framework.
"We are working closely with the Environment Agency, Arup and Tarmac, to ensure the materials can be approved for use and look forward to seeing these being used on more civil engineering schemes in the future."
Robert Gossling, head of commercial engineering solutions at Tarmac, said:
"This flood defence project in Hexham highlights the clear sustainability benefits which can be achieved when clients and contractors work in partnership, in this case engaging to help understand the benefits and reduce the concrete carbon footprint of the Environment Agency. The testing comparisons will help build confidence in these new products.
"Against the backdrop of a climate emergency, the use of these mixes marks another important step for the UK concrete and cement industry along its path to net zero. We're committed to demonstrating innovation in low carbon solutions, and we hope that the success of this trial will help accelerate adoption of this and other types of new, sustainable concretes - delivering long-term benefits for the industry."
