By Richard Ashton, market development manager Bitumen, TotalEnergies UK
THE impact of increasingly volatile weather conditions is having a noticeable effect on Scottish roads, with figures released in 2022 estimating the total funding required to address potholes and bring the roads up to standard to be in excess of £1.7 billion. Austere budgets and extreme climate variations are putting pressure on ageing roadways not designed to accommodate such fluctuations. While winter brings with it wetter conditions, cold snaps, and a fresh batch of potholes, increasingly hot summer temperatures are softening the bitumen, creating road deformations which undermine its load bearing capacity.
This has resulted in a cycle of degradation and managed decline leading to an ever-increasing number of defects and potholes, a spiralling backlog of works required, and a growing strain on local authority resources – both in time and cost – to manage these issues.
Short-term road work solutions or remedial strategies are not sufficient to fix the problem. Rather, a long-term view of highways asset management is needed in order to futureproof roads and reduce reliance on costly, disruptive, reactionary interventions.
Early issues detection: The stitch in time that saves nine potholes
Potholes are symptomatic of larger roadway issues tied to longer term wear, tear and fatigue. If left unchecked, small issues like cracks and micro-fractures can quickly escalate into much larger problems. Indeed, the occurrence of frequent or concentrated potholes often points to a failure to address the underlying or preceding roadway conditions that led to potholes occurring.
By identifying and addressing issues early on, road maintenance teams can prevent potholes from forming in the first place. While early issues monitoring and detection is an always-on strategy, tackling microcracks over the summer season is recommended to stymie their eventual development into potholes over the winter months.
Technological advances such as computerised highway asset management systems allow local councils to regularly monitor, assess and triage road conditions, using data and sensors to detect issues well ahead of time.
Roadway resilience: material and maintenance strategies
Roadway resilience refers to a road network’s ability to withstand and recover from adverse weather conditions, heavy traffic, and other stressors, making it less likely to develop potholes and other issues.
Achieving this is far easier said than done, requiring a holistic interplay of management and material strategies across every stage of a roadway’s lifespan.
Surface treatments: Surface treatments, such as Emulsis from TotalEnergies, are designed to prevent water ingress, delay surface deterioration, restore skid resistance, and seal early surface cracking. This is particularly helpful when managing roadways in wetter conditions, as it can substantially reduce the development of potholes which develop when water freezes inside a microcrack over winter.
Bitumen material selection: Roads are most prone to heat damage in their early years, and cold damage in their later years as bitumen oxidises – and becomes more brittle – as it ages. To counter the effects of extreme weather, bitumen with a softening point of 80+ offers greater resistance to deformation and allows a much larger safety margin in case of extreme heat.
Transport for Scotland addressed extreme weather requirements through the introduction of TS2010, an asphalt surfacing specification comprised of Stone Mastic Asphalt mixtures based on German best practice. Bitumen-polymer mix Styrelf Extreme 100 from TotalEnergies was designed to comply with this specification. More broadly, bitumen-polymer mixes which feature cross linked long chain polymers are well-suited to Scottish roadways as they delay the oxidative ageing process while reducing the roads vulnerability to heat at the outset and cracking long-term, markedly reducing the need for intervention or resurfacing compared to pure bitumen products.
Sustainability through durability
Climate-proofing roadways and taking a long-term view of roadway maintenance work hand-in-hand, underpinned by a sustainable approach that prioritizes durability in order to reduce the long-term maintenance burden.
This means developing a whole lifespan strategy for highway asset management that can accommodate weather extremes and increased weight and wear, while implementing proactive maintenance programs in order to extend the life of the Scottish road networks. One barrier to this approach is increased costs. While investing in quality materials that can withstand weather conditions may cost more upfront, a 2019 Rutgers study found it can save 10-30% in the long run by reducing the need for frequent repairs and maintenance.
By stepping back from remedial efforts to incorporate a long-term view of roadway maintenance, local councils can reduce their cumulative maintenance load over time, freeing up resources and budgets for longer-term highway projects. This approach is more environmentally friendly and economically sustainable in the long run, while also reducing disruption and risk for road users.
