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Material gains: the road ahead for recycled asphalt

Our infrastructure has huge embedded value – to the economy, to society and to the way we live our lives every day. 

It’s difficult to overestimate and even harder to quantify. But in some instances, our failure to grasp the true value of our assets is entirely preventable.

In practice, our road network is a huge untapped resource of valuable materials, which are continually removed and replaced in the course of highways maintenance works. 

A major benefit of asphalt is that it can be 100 per cent recycled as asphalt, with the aggregate and binder fully re-used.

Potential in the billions

The UK has a mature road network and as a rough estimate there could 2bn tonnes of asphalt which could be recycled – all as part of the continual process of repairing the network.

“Over the last decade our industry has undoubtedly taken important strides to normalise road recycling. But our approach is often too sporadic”

There are environmental and economic benefits. Not only does recycling cut the carbon footprint of our roads, but it also reduces our reliance on finite primary aggregates and bitumen – the binder which remains subject to considerable price volatility.

Over the last decade our industry has undoubtedly taken important strides to normalise road recycling. But our approach is often too sporadic.

We need to get to the point where public sector clients and their term maintenance contractors work in partnership to develop an annual plan for road recycling.

This should set out on a street-by-street basis the volume and quality of asphalt that will be recycled and where it will be stored before it can be re-used.

Scratching the surface

Developing this approach will require greater analysis of the composition of existing roads by using coring techniques.

The aim should be to determine the quality, quantity, value and best future use of asphalt planings, match these with forthcoming projects and realise the full value of managing roads as a proper resource – and as a material asset.

“Recycling targets and plans have been crucial to success in other sectors, and we should be ambitious in asking: why not infrastructure, too?”

We need to be armed with this information because not all road planings are the same. They differ in quality and value because they have different original properties – some have high polished stone value aggregates, others are made of limestone or hardstone. 

Understanding this composition in advance is crucial and underpins any attempt to fully plan the use of recycled content. 

As with any new process, there needs to be a thorough cost-benefit analysis, and the value of the materials should be considered against the costs of segregating the planings and transporting them to a discrete store before they can be re-used on the network.

The road ahead

In our future maintenance of roads we must plan the systematic reworking of asphalt to both reduce the need for finite aggregates, cut embodied carbon and also extend the life of the asset as far as possible.

This calls for better planning by contractors and councils and a greater understanding of the quality and composition of planings that can be recycled on a street-by-street basis.

Many councils already have high targets for the re-use of materials. An annual plan for road recycling would allow them to better benchmark targets and set out the actual scope to cut carbon and recycle highways materials.

It’s been crucial to success in other sectors, and we should be ambitious in asking: why not infrastructure, too?

David Smith is development director at FM Conway

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