Construct - Issue 50

“...it could unlock huge potential in how we tackle challenges like getting to net zero”

The trial covered six patches, two that were resurfaced with traditional mix as a control, two with 50% RAP and two others with 50% RAP and bio-rejuvenator for robust comparison.

The next and potentially biggest hurdle is implementing the results of this trial into business as usual. Andy continues, “Regulatory constraints are rightly tight for Britain’s strategic road network – safety has to come first. But if we can find a way to make it easier to innovate under controlled circumstances then it could unlock huge potential in how we tackle challenges like getting to net zero. “One option might be to explore year-long departures from specifications as a first step, rather than the piecemeal model we have at the moment. It would save time and resources on negotiating higher recycled material quantities on a project-by-project basis. At the same time, it would give the client control to review the departures after a year and modify them as necessary.”

“RAP in material mixes is nothing new. The question now is what’s needed to push the RAP content even higher and make it work harder. Could bio - rejuvenators give more protection to our roads and make them more resilient to use and weather extremes? The trials with National Highways will give us the answers – what worked, what must be tweaked and by how much,” says Andy Weymouth, framework delivery manager at FM Conway. Rigorous testing is currently underway at the University of Nottingham, using accelerated wear simulations in the laboratory in addition to visual monitoring of the patches. Early indications are promising service life extension by 20 to 30%. A good result has the potential to reduce both long-term repair costs and carbon, on top of minimising closures for maintenance.

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