Seven road repair methods trialled on Fenland peat soil road

The media were invited on Thursday to see how the trials aim to deliver longer-lasting repairs and better value for taxpayers’ money.

Cllr Alex Beckett, chair of Cambridgeshire's highways and transport committee, Paul Bristow, the mayor of Cambridgeshire and Peterborough, joined representatives from the county council's project team and its project contractor, WinVic, to outline the work so far.

Funded by the Cambridgeshire and Peterborough Combined Authority, the UK’s first trial of its kind is testing seven road-building techniques side by side to find the best solution for roads built on peat.

Cllr Beckett highlighted the significant challenges peat soil roads, like the trial site in Upwell Road, March, cause highways authorities, pointing out that Cambridgeshire has around 1,000 miles of roads affected by peat.

Fenland is home to 93 per cent of those roads, which is why the county council has selected the road in March.

Seven 150-metre sections of road have been dug up, each for a different proposed solution.

One section uses the current repair method as the control: plastic geogrid mesh is laid on the road surface, covered with road plainings and resurfaced with asphalt.

Andy Harmon, framework manager for WinVic, the contractor working with Cambridgeshire County Council on the peat soil affected roads trial project. (Image: Sarah Cliss)

The other construction methods being trialled are:

• Deep Soil Mixing
  A technique that improves the strength and stability of existing peat soils by mixing binding agents directly into the ground beneath the road and verges.
• Incinerator Bottom Ash Aggregate (IBAA)
  A lightweight, durable aggregate used to create a strong foundation layer while reducing overall weight on the underlying peat.
• StrataWeb Grid
  A high-strength cellular confinement system that stabilises road layers and helps distribute traffic loads more effectively.
• Bekaert Steel Wire Mesh
  Steel reinforcement incorporated within the road structure to improve load distribution and provide additional support.

This plastic mesh, known as Geogrid, is currently used in road repairs across Cambridgeshire and the country. (Image: Sarah Cliss)

The trial will help identify which of the methods offers the best solution.

Monitoring of Upwell Road will be carried out over three years using a variety of techniques, from gauges buried beneath the road surface to satellites taking detailed images to show any movement of the road surface, including sinking.

Cllr Beckett said repairing a peat-affected road can cost up to five times more than repairing one built on other soil.

Cambridgeshire Mayor Paul Bristow left on site in Upwell Road, March. (Image: Sarah Cliss)

Not only that, but repairs last half as long as those carried out in other parts of the county.

Cambridgeshire County Council receives no extra funding for the higher cost of repairing and maintaining its peat roads.

Joshua Rutherford, the council’s head of asset management, design and delivery, said it needs £58.3m to maintain the status quo, but the Government provides £31.3m, leaving a £27m shortfall.

James Chapman (left), project manager, with Joe McGilley, design engineer, holding a diagram showing the structure of one of the trials. (Image: Sarah Cliss)

More money has been promised to tackle the repair backlog, but it will arrive over four years, with most coming at the end, leaving the council to find the cash upfront.

It is hoped the trials will provide a better solution to the peat soil-affected roads, but which of the six options will prove the best is up for discussion, with those working on the site pinning their hopes on different methods.

However, there was consensus on just how important the trials are to future maintenance of the county's roads, and satisfying residents fed up with negotiating undulating, pothole-riddled roads around Fenland.

Cllr Alex Beckett, chair of Cambridgeshire's transport and highways committee, pointed out that a pint of peat soil contains the same amount of solids as a pint of milk. (Image: Sarah Cliss)

This plastic mesh, known as Geogrid, is currently used in road repairs across Cambridgeshire and the country. (Image: Sarah Cliss)

The council says peat-affected roads are contributing to an £800m backlog in road repairs across the county.