Self-Healing Concrete Research
10 May 2016
Costain’s Oliver Teall is in the third year of his post-doctoral studies, combining his role as a Civil Engineer with researching one of the most exciting areas of material science and construction technology: self-healing concrete.
Oliver started his PhD at Cardiff University in 2013 working on the Materials 4 Life project, which aims to develop multi-scale, self-healing construction materials, like self-healing concrete.
If the field of construction materials had a ‘holy grail’ then self-healing concrete comes pretty close. Concrete structures degrade for a number of reasons, one of which is their susceptibility to cracking, leading to reinforcement corrosion and spalling, which requires expensive repair schemes. This often means public infrastructure such as roads and rail routes need to be temporarily closed, impacting the general public and incurring significant indirect costs as a result.
Throughout the UK, and indeed the world, organisations spend billions of pounds repairing and maintaining structures. In the UK alone, we spend £50.3 Billion per year on repair and maintenance, roughly equivalent to 35% of our total construction output. A self-healing concrete, which heals its cracks as they develop, could go a long way to solving this.
“Our customers are well aware of how much these problems are costing them, which is why projects like Materials 4 Life are so attractive,” said Oliver.
As part of his PhD, Oliver says he has been exposed to challenges and opportunities which he wouldn’t ordinarily have experienced. As well as the academic qualification, he managed the project from Costain’s perspective, including setting up and constructing the UK’s first self-healing concrete trial structure on the A465 Heads of the Valleys project in South Wales.
The research team, which also included academics from the University of Bath and the University of Cambridge, trialled four separate technologies at the site.
The first technique used shape-shifting materials, known as shape-memory polymers, to repair cracks in concrete. When these materials are heated with a small current, they transform into a shape that the material has ‘memorised’. The researchers believe these materials can be embedded into concrete and used to close cracks.
In the second technique, researchers embedded tiny microcapsules, containing mineral-based healing agents, into the concrete. It is anticipated that once cracks occur, these capsules will release their cargos into the cracks to then heal them. The third technique uses bacteria and nutrients within lightweight aggregates. The bacteria act to help the production of calcium carbonate in the cracks, which the researchers envisage will restrict harmful agents like chlorides from penetrating the concrete.
The final technique involves pumping healing agents through a network of thin channels, known as flow networks, into the concrete to help repair damage.
Before starting his PhD, Oliver never considered post-doctoral study as a career option. While completing a MEng in Civil Engineering at Bristol University, Oliver was accepted onto Costain’s sponsorship scheme, completing two industrial placements during his summer vacations in the infrastructure and energy and process sectors. He graduated in 2012 and worked for Costain as a Graduate Engineer on the M1 Smart Motorways J28-35a scheme for just over a year, before moving to Cardiff to begin his PhD in self-healing concrete.
“When I joined Costain, I never intended to do a PhD or even thought of it as an option. However, when the opportunity was offered to me, I felt it would be a great way to be a part of something completely new and different, while gaining a very valuable qualification and maintaining links with industry,” said Oliver.
A key factor in Oliver’s decision was that, while most PhD students enjoy some limited involvement with industry, on the Materials 4 Life project, Oliver would remain part of Costain and be actively involved with projects throughout his research.
“What immediately caught my eye was that there would be live trials involved, which would give me the opportunity to bring something from a laboratory or concept stage, right up to practical implementation. Getting involved on a practical level suited me much more than a purely academic or lab-based project,” said Oliver.
The final reason was the project had the backing of the construction industry, from contractors and consultants to client organisations and international academic partners.
Indeed, while the PhD has been Oliver’s main focus, he has also been involved in developing relationships with Costain’s customers and supply chain partners, building future research proposals and setting up an Industrial Research Community within Costain.
“We now have ten PhD students across the business. The community will act to promote the work we are doing and identify customer challenges and opportunities which can be addressed through our academic partnerships,” said Oliver.
Undertaking a PhD in a relevant area also benefits Costain and its customers, who look for evidence of technical excellence and Costain’s involvement in highly technical research projects like Materials 4 Life. Not only does it demonstrate that Costain has the in-house technical capability, it also demonstrates the Company’s ability to work with academic partners to develop new solutions.
Bruce Richards, Project Director on the A465 Heads of the Valleys Section 2 Project, said: “A key element needed to deliver successful innovation is to provide opportunities for those innovations to be put into practice. On the A465 project we have given the research team the means to test self-healing concrete in a site environment. It is our responsibility as an organisation to continue to collaborate and share knowledge with our academic and supply chain partners in this way, to together develop the solutions of the future for our customers.”
Oliver added: “Identifying and understanding our customers’ key challenges is a priority for Costain. Forging links with Universities like Cardiff allows us to offer another way to address these challenges, should a solution not already exist within industry. Our University partnerships allow us to propose research projects which address the common issues our customers are facing, combining expert knowledge from academia with our own in-house technical experts to develop solutions.”
For example, the academic team on the Materials 4 Life project are currently developing a proposal for follow-on funding which, if successful, will allow the research project to be taken forward towards target applications and involve many more industry partners.
Looking ahead, Oliver is due to submit his thesis in October and he believes that anyone interested in undertaking post-doctoral education on the job should give it a go.
“If you have a genuine interest in the subject, and are a proactive person who takes advantage of new opportunities I would fully recommend it. A PhD is not for everyone as it requires a lot of self-motivation and commitment, but it can be a great way to advance your knowledge, make high-level contacts within industry and academia and be a part of cutting edge research,” said Oliver.
Oliver’s contribution has been highly praised by Professor Bob Lark from Cardiff University's School of Engineering. He hopes more people from Costain consider undertaking post-doctoral research as part of a career move.
Bob said: "Oliver's involvement in the Materials 4 Life project has ensured that our research has been grounded in the reality associated with its practical implementation. This has enabled wider dissemination of our work and much improved impact, and I am certainly keen to see more Costain employees work with us in this way to further enhance our collaborative partnership with you."
Costain Communications Department