In part two of our feature on the building materials of the future Professional Builder looks at the potential of graphene in the construction industry.
It is 200 times stronger than steel but – at just one atom thick – one of the thinnest materials known to science. Add to that excellent heat and electrical conductivity and it’s no wonder that graphene has been greeted as a wonder material. Today, a number of companies are eager to exploit these properties in building materials, with a recent partnership between specialists at the University of Manchester and a contractor promising to advance its use in concrete.
“The Graphene Engineering Innovation Centre (GEIC) is dedicated to translating research from the academic world into practical real-world products,” explains GEIC Application Manager, Dr Craig Dawson. “An indication of how serious the prospects for the materials are taken is in the levels of investment involved, with the nation’s two major institutions for the advancement of the material, the National Graphene Institute, and the GEIC sharing a budget of over £120 million.”
The Centre also runs a European Regional Development Fund project called Bridging the Gap, through which contractors and manufacturers can access the latest thinking on graphene. Through that initiative, and with the help of an Innovate UK award, Nationwide Engineering and the GEIC were able to score one of graphene’s most recent successes in the construction sector with Concretene, an additive product that has given Craig’s team the opportunity to determine if the material can really achieve what academic papers claim.
The project has seen graphene-enhanced Concretene used for the floor of a new gym in Amesbury, Wiltshire. The additional properties gained by engineering graphene into the concrete meant that the builders were able to eliminate the need for steel reinforcement in the floor slab, saving on both the price of the steel itself but also the associated labour in laying it. Due to the small amount of graphene needed to provide those performance gains – approximately 0.01 per cent by volume of concrete laid – Nationwide Engineering claim Concretene can deliver savings of 10 – 20 per cent, depending on project size.
Moreover, construction firms need no additional equipment or training to use the product. Craig Continues: “The goal was to be as non-disruptive as possible at the point of use, so that site workers would not have to change their processes in any way. As a consequence, the graphene was introduced at a batching plant as an admixture to the ready mixed concrete and then poured and worked in the normal way.”
The benefits do not end with graphene’s green credentials either. Whilst the volume of concrete at the Amesbury job was reduced by 25 per cent, there is already evidence of increases in flexibility, as well as tensile and compression strength, whilst researchers are equally anticipating improvements in durability. Sensors installed in the floor will provide further data and allow the team to monitor its performance over the long term.
The Nationwide Engineering experience is now just one of many avenues for graphene in construction, with pre-cast and concrete shuttering another possible application, particularly in relation to the gains that could be made in the speed of de-moulding. Any structural usage will, of course, demand significant accreditation, but it is again an active area of research and development. Concretene is, for instance, currently undergoing BBA and CE accreditation through the BRE for use with internationally recognised structural and civil engineering design codes.
Today, graphene can be bought commercially in relatively large quantities, with some of the largest makers in capable of producing 100s of tonnes in powder form per annum, although the quality of the finished product does vary. There are two broad methods for its manufacture – either ‘exfoliated’ from graphite or where carbon is extracted from a gas and then deposited as graphene as a substrate, with the former being considerably more cost effective. At the same time a separate method of producing graphene from waste materials – such as from the plastics industry – is beginning to become a viable option, which is clearly good news from the point of view of the circular economy.
Furthermore, because graphene exhibits impressive strength gains, it is hoped it could be put to use with recycled materials, in order to reduce the amount of primary material that is used in the manufacture of building products, and the Graphene Engineering Innovation Centre is already working with a producer of recycled aggregate on that basis. The longer term goal is for graphene to facilitate a reduction in the cement content of the likes of bricks and mortar – as well as the industry’s consumption of concrete, which is one of the world’s most carbon hungry commodities.
“On the back of the one Nationwide Engineering pour, we’ve had huge interest from around the world,” concludes Craig. “We’ll be looking to partner with them in a patent of the process, and we know that it can be scaled upwards to become commercially viable. For construction graphene’s sustainability wins clearly have appeal, and that’s across a whole range of applications. One of our partners is National Highways, for example, and graphene could well have a role to play in improvements to the longevity of everything from road surfaces, to street furniture and road markings. We have a trial of graphene-enhanced asphalt due to take place in the autumn on the A1 near Alnick, Northumberland. At the same time, given that graphene is supplied as a powder, there’s no reason why it couldn’t be introduced to products like bagged cement in the future – it is that range of applications that makes it such an exciting area of research.”
To watch a video that explains the graphene process and Nationwide Engineering’s pour in Amesbury, visit https://www.youtube.com/watch?v=2yogj3ns3XU