There are a variety of tools that can help prolong the life of roads – and cut their whole-life carbon footprints. This was the message to emerge from a Local Council Roads Innovation Group (LCRIG) webinar, Walking the walk on climate change, held on 11 February 2024.
As one of the webinar attendees commented in the Q&A session, it seems a tall order for councils to invest in preventative treatments when they are struggling to find the cash to repair deteriorating roads. However, as webinar chair and highways maintenance consultant Mike Harper pointed out, it looks like local authorities who want to access all the available road maintenance funding from central Government will have to show willing in this respect.
At the end of last year, the Department for Transport confirmed that an extra £500m would be allocated to road maintenance in England in 2025-26, bringing the total pot to £1.6bn. However, there was a caveat: 25% of that additional funding would be held back until local authorities could show that they are collecting the right data and delivering proactive maintenance before potholes start to form.
The LCRIG webinar started with a presentation by sustainability consultant Emma Pye. She outlined the reasons behind net zero policies, spoke about how climate change was causing roads to deteriorate more quickly and highlighted the benefits of using PAS 2080 principles when planning projects.
PAS 2080 sets out how carbon emissions should be measured, recorded and reduced. It’s an approach Thermal Road Repairs fully supports, which is why we worked to achieve PAS 2080 accreditation for our carbon management system – for Scope 1, 2 and 3 emissions - back in February 2024.
Howard Robinson, chair of ASI Solutions, talked about asphalt preservation, explaining that it ideally should be applied to an asphalt surface around two years before it is expected to show signs of visible surface defects. After that, the treatment should be reapplied at five-year intervals up to three times.
For surfaces that are already showing signs of deterioration, surface dressing would be a better choice, Robinson advised. Such roads may require shallow potholes and other defects to be fixed first. We would suggest using a low carbon method such as Thermal Road Repairs’ technology - which creates permanent repairs and cuts carbon emissions by 85% compared to traditional methods.
Steve Williams, director of contractor Henry Williams spoke about some of the specialist treatments it deploys, pointing out that asphalt preservation can be applied to footways, as well as carriageways. Referring to Road Surface Treatments Association (RSTA) guidance on the carbon footprints of maintenance treatments, he highlighted the carbon savings that can be gained from using this measure rather than an asphalt overlay. Pye, who produced the RSTA guidance noted that this was due to be updated in April this year.
Williams also spoke about targeted surface treatment, a technique that is used in mainland Europe. This involves applying surface treatment only to areas that are likely to deteriorate at a faster rate than the general road surface, for instance around ironwork, at centre line joints or utility reinstatements.
For roads that are in worse condition, and which aren’t too highly trafficked, local authorities could consider shallow depth recycling or retread, suggested Williams. This involves planing the road surface, leaving the material where it is, and then alternatively harrowing and spraying it with emulsion to create a binder or base course in situ – although this is not suitable for all roads, he said.
Williams also provided some ballpark figures on what the various treatments might cost. Asphalt preservation could cost between £3 and £4 per square metre; surface dressing between £5 and £7 per square metre and carriageway retread £15 to £20 per square metre plus the cost of any surfacing.
There’s no silver budget when it comes to highways maintenance and management. But, as this webinar demonstrated, there are a range of tools that can make sense in terms of both carbon and cost reduction.
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