What is Sustainable Construction?

HS2 and the use of Geosynthetic Cementitious Composite Mats, working towards sustainable construction

The theme of sustainability and carbon reduction is currently a huge driver for change across multiple sectors. Here in Britain, the Government has legally committed the UK to reduce its greenhouse gas emissions to net-zero by 2050.

It is estimated that the construction industry accounts for around 45 per cent of the UK’s carbon emissions. As a result, the construction industry must find ways of improving its practices for more sustainable operations. HS2 Ltd is taking significant steps to reduce the impact of their construction work on the environment.

GCCMs (Geosynthetic Cementitious Composite Mats) for the rail sector

The cement industry is one of the two largest producers of CO₂. It is estimated that around 4.1 billion tonnes of cement were produced in 2020, along with a resulting 1.5 billion tonnes of CO₂.

Concrete Canvas Ltd’s Technical Manager, Lee Church says: ‘Concrete has been around for thousands of years. We’re aware that it produces carbon but you can’t just stop using concrete; it’s an essential building material, so we just need to be a bit more selective and creative in how we use it. That’s where GCCMs come in.’

GCCMs are used for erosion control and weed suppression applications across multiple sectors worldwide. One of the largest markets for GCCMs in the UK is the Rail sector. For HS2, GCCMs were specified over ST4 poured concrete to line crest perimeter drainage channels – the material’s biggest use for the rail network in the UK over the last ten years.

Crest drainage is typically required to prevent saturation of embankments and potential slip onto a track below as a result. On Compound 1 the application was required to prevent flooding of the site.

GCCMs have been specified for numerous projects within the HS2 scheme as a temporary solution, replacing ST4 poured concrete with the channels designed to be removed when the compounds are no longer required.

Broadly, use of the environmentally friendly, lower carbon alternative to traditional concrete for HS2 is contributing to reduction of the scheme’s carbon footprint. In simple figures, a lifecycle report from Ricardo Energy and Environment (Ricardo) compared the Global Warming Potential (GWP) of lining a channel in an 8mm Type II GCCM (as specified by ASTM D8364) versus using 150mm of ST4 poured concrete and found that the GCCM has a GWP 45 per cent less than that of the ST4 poured concrete.

More specifically, GCCMs assist in protecting the scheme’s construction environments, as well as reducing waste and carbon emissions through transportation.

Environment

HS2 Ltd are working to deliver Britain’s biggest environmental project through ‘miles of ecological and landscape investments’ in England.

To date, 60 new habitats have been created along the route, including grasslands, ponds and plantings to wildlife. In addition, 350,000 trees have been planted as part of the objective to plant a total of seven million trees and shrubs along the route over the course of the project.

GCCMs are a fantastic, environmentally friendly, lower carbon solution for durable concrete applications, without the mess associated with the installation of poured and sprayed concretes due to rebound or potential environmental damage as a result of the cement content.

Materials and waste

HS2 plans to use the chalk that will be excavated during boring of the Chiltern tunnels to create and plant a new habitat at such a scale – drastically reducing waste associated with the tunnel boring.

Further waste reduction on the site was provided by the unique properties of a GCCM. Lee Church explains: ‘One bulk roll of our CC8™ material is the equivalent of two 6m³ ready-mix concrete trucks. Our material is supplied dry, so, you’re not premixing it then transporting it to site and it’s a lot lighter, quicker and easier to install, and then you just use the available water sources that you have nearby to hydrate the material.’

Why use Type II GCCMs for HS2?

Invented and manufactured with the environment in mind, GCCMs have a low washout rate, low alkaline reserve and phthalate free PVC to minimise environmental impact. Furthermore, the top surface promotes growth of carbon neutralising organisms. The installation process itself is capable of entirely eliminating material waste.

In assisting the journey to carbon neutrality on Britain’s biggest infrastructure project, Concrete Canvas is simultaneously helping to work towards the UK’s aim to achieve net zero greenhouse emissions by 2050 by providing a solution capable of contributing to a more sustainable construction industry.

For further information, get in touch via the contact information below.

Tel: 0345 680 1908

Visit: www.concretecanvas.com