Britain’s road network is its most valuable infrastructure asset by a considerable margin, believed to be worth around £344bn.
It consists of more than 187,000 miles of strategic and local roads, and much of its inherent value resides in the billions of tonnes of asphalt that makes up the surface of our highways.
Conservative estimates suggest at least two billion tonnes of the asphalt in situ in Britain’s road network could be recovered and reused. Doing so would limit our reliance on finite primary resources, reduce the carbon footprint of our roads, and significantly cut the cost of building new roads or maintaining existing ones – yet only a fraction of this tonnage is currently being recycled.
Against the backdrop of funding shortages, councils are always seeking ways to reduce highways expenditure while also improving their carbon footprint. So why haven’t they tapped into this huge resource of valuable and recyclable material?
The problem is not a lack of desire, but a lack of data about what our roads are actually made of. The material composition of our roads differs on a street-by-street basis, with the volume and quality of asphalt, along with the amount of filler and binder used, varying depending on factors such as the road’s usage and location.
A certain mix of aggregates and bitumen will only be suitable for a certain type of road. So, if recycled materials are being used, you need to know their exact composition before you can put them to use elsewhere – and in many cases, this data simply does not exist.
Establishing the material composition of a road is a simple process. It involves taking core samples of the road – a process known quite logically as ‘coring’ – then carrying out a basic analysis to determine its composition. Coring is undertaken by highways contractors on a day-to-day basis, but the information they glean is rarely logged in a central database. This means it is difficult for councils to plan how these materials can be effectively reused.
By integrating the process of coring and testing into the programme of road maintenance, local authorities could quickly build up a bank of data about the quality, quantity, value and best future use of recovered asphalt. This can then be matched with upcoming projects to ensure the material is deployed in the most effective way.
Some councils are alive to this issue and have engaged with infrastructure services company FM Conway to help gather this data, then use it to set out a robust recycling plan for their road network. Many, however, are not taking such steps.
Where more significant costs can be incurred is in the storage of recovered road materials, which must be held until work on a suitable maintenance project starts. Large volumes of road materials need to be recovered to achieve appropriate economies of scale to make it cost-efficient. Storage can therefore become costly, but this must be weighed against the significant financial and environmental costs of procuring primary aggregates for construction or maintenance projects.
With robust information about the materials in the road network and their material value, local authorities can undertake a thorough cost-benefit analysis and take a decision on the most cost-effective approach. This is something that cannot be done without that vital data.
There needs to be communication and collaboration between council departments if the use of recovered road materials – and the data collection that facilitates recycling – is to be incorporated into day-to-day operations.
Opportunities to achieve efficiencies are all too often missed because of a lack of communication. For example, if a road is being closed to replace highways signage, there is no reason that coring could not be undertaken at the same time to collect data about that stretch of road. Not only would this minimise disruption to the public and allow data collection to be done at minimal cost, but it would also allow departments to share knowledge more easily.
At FM Conway, whenever we are carrying out maintenance works, we request that the council informs other departments about the project so that they can make best use of the road closure. If this was done as a matter of course, there is no doubt it would yield shared efficiencies both for us and for councils.
If we are going to tap into the huge value locked in our roads, this way of working needs to become the status quo for local authority highways departments. Road composition analysis needs to be widespread, whether done as part of a dedicated coring programme or as a process during routine maintenance works.
Departments must collaborate to ensure that all possible efficiencies are exploited, and councils need to have a highways contractor on board who is able to interpret the data and guide them through the process of turning it into a robust asset management plan.
It will require innovation and commitment from local authorities and their industry partners to make this happen. But as pressure grows to cut costs, reduce carbon emissions and embrace the circular economy, the huge benefits that road recycling could bring can no longer be ignored.
David Smith is development director at FM Conway