By Tom Austin-Morgan

Climate change is a clear and increasing factor affecting the transport network. From extremes of temperatures in the summer and winter, to increasing rainfall and storms, road surfaces are central to enhancing resilience. 

“Developments need to focus on the durability, safety and sustainability of roadways under the varying conditions that we're experiencing,” says Benn Teasdale, General Manager at civil engineering company, Colas.

“In warm weather asphalt can melt and in cold weather it can become brittle,” he explains. “These extremes of temperature cause ruts and potholes which can be exacerbated by freezing water.”

To combat this, he says, researchers are looking at heat resistant materials which use modified bitumen or even rubber crumb to help maintain structural integrity even in prolonged heatwaves. There are also early trials of frost-resistant surface materials underway, including mixtures that incorporate polymers and other additives to enhance the resilience to the freeze-thaw cycle.

Unfortunately, these new materials come with a cost and because the UK’s extreme weather events are not as prolonged as elsewhere in the world, Teasdale says there is a degree of resistance to spending money on products that aren’t required all year round. However, the Colas group is conducting research elsewhere in the world which could feed into work here in the future.

Predictions and projections

Climate projections are another area of focus, where the ‘climate risk’ is assessed, which includes predicting the likelihood of increased rainfall, higher temperatures, and other extreme weather events.

“This will help design the infrastructure to withstand those future conditions,” Teasdale says. “Some of this doesn’t necessarily sit with the contractors or material developers. The designers, local authorities, National Highways, they need to be looking at these projected scenarios. There are tools out there: climate models, regional projects, and risk assessments that can guide long-term decision making.”

He admits that the industry itself needs to adapt as a lot of processes are conducted in the same way they were as much as 40 years ago. He calls for design standards to be adapted and modified to accommodate these new and future scenarios.

Advanced technologies, specifically AI, have become a trend across industries and Teasdale says it’s no different in the area of monitoring road conditions.

“We’re still at the early stages,” he explains. “Cameras on survey vehicles are now linked to an AI app to monitor road surfaces for levels of deterioration. We’re starting to trial AI on site surveys as well where we survey via a tablet and the AI builds a risk assessment and condition of the road. 

“It helps us to develop what we need to deliver in terms of what preventative treatment could be used, how the materials could be recycled in-situ to save cost and have less impact on the environment.”

However, there is one aspect he describes as “absolutely key” to any road surface maintenance programme; it’s relatively simple and already exists on most roads.

“In terms of heavy rainfall, the first thing that needs to be looked at by highway asset managers is drainage systems,” Teasdale concludes. “Are they being regularly cleaned and maintained? Have they got a robust programme in place? Are they jetting? Are the run-offs clear? On rural roads, are they clearing ditches?

“Maintenance of drainage systems is key and the quickest win when it comes to keeping road surfaces in good condition.”

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Image: poor road conditions in the UK; credit: Shutterstock.