National Highways concrete roads programmed questioned

The National Highways Concrete Roads programme sets out to deliver new road surfaces that will last for the next 40 years. However, the replacement of concrete road pavements with asphalt questions the achievement of that objective.

Concrete roads make up almost 400 miles (4%) of England’s motorway and major A-road network. They were mainly built in the 1960s and 1970s. The first part of the National Highways Concrete Roads programme will see £400 million invested between 2020 to 2025 to ‘rebuild and revitalise’ concrete roads that have performed well for approaching 60 years despite traffic volumes and loads being significantly higher than those originally designed and constructed for.

Rather than ‘rebuild and revitalise’ two projects so far carried out under the programme have ‘removed and replaced’ sections of the concrete road with asphalt. It is questionable whether the new road surfaces laid on the A11 and A14 will provide the required 40 years performance, particularly when traffic forecasts are increasing.

On the A11 8km of dual carriageway between Spooner Row and Tuttles Interchange at Wymondham in Norfolk and on the A14 between Haughley and Tothill in Suffolk concrete pavements were removed and recycled as the foundation layer which was finished with a thicker asphalt road surface. Some 90,000t of quarried aggregate was required for the A14 scheme alone and requires imported bitumen as the binder. UK produced cement is available in many low-carbon forms without any performance reduction.

Although designed for a 40 year performance life, the reality may prove rather more short-term. The asphalt will most likely require resurfacing after 12 years with major maintenance required by year 20 and further resurfacing by year 30. A concrete road surface, however, would not have required such major interventions and across the world concrete pavements are the norm under heavy traffic loading as they fully recognise the whole life benefits.

“The replacement of concrete road surface with asphalt has raised eyebrows. Particularly when you consider that over a 40-year life span concrete offers far better whole-life CO2 and cost solutions as it will not need resurfacing or major maintenance,” explained Joe Quirke, chairman of Britpave – the infrastructure industry association.

He continued: “Furthermore, concrete is far more future-proofed. It is more resilient to the predicted impacts of climate change as it does not melt and rut during high summer temperatures and is more resistant to flood damage and the potential for potholes cause by winter freeze/thaw cycles.”

In addition, concrete pavements built using new CO2 reduced cements can provide unmatched environmental benefits such an the reflective albedo that reduces the need for streetlighting, a stiffer road surface that has been proven to reduce fuel consumption by up to 6% and the ability to produce a robust, long-lasting cover for wireless coils that can inductively charge vehicles as they drive over without the worry of the coil becoming dislodged due to premature road surface deterioration.

“Given the wide range of long-term performance and minimum maintenance benefits of concrete roads, it is surprising that the National Highways programme has replaced them with a road surface that doesn’t offer the whole life benefits,” said Quirke.