Concrete has been around since the Romans, but predicting its behaviour is still difficult. On a construction site much depends on ‘curing’: poured concrete hardening and becoming strong enough for further building phases to go ahead. Curing times depend on the type and amount of cement used in concrete as a binding agent, and the weather at the construction site.

Accurately predicting when concrete will hit critical strength is valuable in construction projects: getting it wrong means costly delays. Uncertainty over curing times also has environmental costs: cement production is a major contributor to climate change, and construction companies sometimes use more cement in concrete than necessary to ensure it will hit critical strength when needed.

Traditionally, testing concrete strength has been laborious, involving manual monitoring, lab tests on crushed samples and waiting. But now the CORE project (Concrete curing prediction and schedule Optimisation for Resource Efficiency) – supported by UK Research and Innovation (UKRI) through the Industrial Strategy Challenge Fund’s Transforming Construction Challenge – is working to give construction companies real-time information on concrete strength. This will enable them to accurately predict, several days in advance, when concrete will be strong enough, and help them communicate this information to site teams through project plans and schedules that are automatically updated.

CORE has developed a prototype system, combining sensors with innovative software, to make predictions based on historic curing times, local weather conditions and precise measurements from particular concrete pours.

Sam Ellenby is product lead at project partner Converge, a company that makes sensors for measuring concrete strength. For him, the strength of CORE lies in its testing of the prototype on live construction projects, through the involvement of construction specialists BAM Nuttall:

“BAM is an innovative contractor, working at a scale where you can see a difference. The proof is when you visit their site teams using the new system. They see the benefit every day and are excited about it.”

According to Sam, the project has already transformed Converge: “As a start-up company it’s made us a more exciting proposition for investors.” An additional £3 million in venture capital funding has followed the UKRI grant, and Converge are looking to expand their team by 50% as a result.

For construction crews on the ground, meanwhile, the prototype system is also proving its worth. As BAM Nuttall’s head of innovation, Colin Evison, explains, it is being used in the redevelopment of London City Airport, where several site days have already been saved: “On a project this size, saving just one day makes a big difference – and more than offsets the costs of our system.”

The new system is estimated to save four to six hours per concrete pour, totalling some 60-100,000 hours on a typical construction project.

Partners

This project partners with Converge