A Costain highways site in south Wales is being lined up as practical laboratory to check the properties of new, “self-healing” concrete that it is hoped will save customers time and money.
The contractor has started construction of a trial structure on the “Heads of the Valleys” highways improvement project, giving it an opportunity to monitor the performance of the material in a real site-based environment.
Self-healing concrete uses a combination of shaped memory polymers, micro-capsules and bacteria. If the concrete is damaged, these “added ingredients” help restrict the growth of cracks and repair minor cracks as they appear. Through these mechanisms, the long-term durability of concrete structures can be increased.
Costain civil engineer Oliver Teall said: “We’ll be building a full-scale wall structure with a number of concrete panels. Into each panel we will incorporate different combinations of self-healing techniques. These will be loaded to artificially damage them, and then monitored to see how they react and recover over time.
“We plan to start testing at the end of September, running for a minimum of six months. From this trial we should gain an insight into the feasibility of constructing a full-scale structure with these techniques and their early-stage effects on structural properties.
“We’ll be looking at the effect of the healing techniques on areas such as stiffness, permeability and the mechanical damage recovery of the trial panels.”
Costain is the lead industrial sponsor for the Materials for Life research project led by Cardiff University, which has brought together researchers at Cardiff, Bath and Cambridge Universities. The aim of the programme is to develop smart materials with increased durability and lifespan.
Teall is currently on secondment to Cardiff University where he is completing a PhD as part of the project. His role includes the coordination of the site tests of the material and developing the shape memory polymer system.
He added that the benefits of the self-healing concrete would be felt by Costain’s customers. “It will extend the life of key assets, optimising performance and reducing disruption of maintenance activity due to its self-healing nature. This is a new generation of advanced material at the leading edge of technology, so we expect spin-offs and other successes along the way that we’re not expecting.”
Costain also won a category award in the Celebration of Technology and Innovation (CETI) awards in California last year, for its role in helping develop the self-healing concrete.
