Seismic changes in conditions are hitting roads hard, which makes developing materials to combat climate change more important than ever, says FM Conway’s David Smith
Climate change is taking its toll on the UK’s infrastructure.
As global temperatures rise, weather patterns are becoming more erratic and extreme events such as flash flooding can rapidly destroy the fragile composition of our roads. At the same time, the long-term effects of drier, warmer summers and wetter, colder winters are placing the fabric of our network under strain.
These trends pose serious challenges, but this is a good time to initiate change. Highways England’s Road Investment Strategy provides an opportunity for renewal in a way that designs in durability.
At the same time, the effects of climate change highlight the increasingly urgent need to address challenges on many local networks, requiring more central government funding that goes beyond surface-level repairs to address much-needed replacement of the whole road.
The further good news is that we are developing a better body of information on how roads are responding to climate change, with initiatives such as the European Open Road programme looking at how the composition, age, condition and underlying geology of highways affect their resistance.
“The next critical step to creating resilient networks is now to develop materials which manage the effects of climate change”
Developing this understanding is essential if we are to find solutions. The next critical step in creating resilient networks is to develop materials that manage the effects of climate change.
This relies on three things: a better understanding of the properties of the materials we use on the road; accurately designing materials to meet the challenge; and a data-driven approach to manufacture and construction that enables us to monitor performance through the whole lifecycle.
Predicting performance from lab to lane
On the journey from the laboratory to the pavement, asphalt undergoes a series of stresses – from heating in the plant to transfer to the road – which can affect its properties and ultimately how it performs.
To address the effects of climate change, we need to be able to predict how materials perform in a live environment. Working with the University of Nottingham and the University of New Hampshire, we have developed a testing regime that goes a long way to meeting this challenge by simulating real-life pressures in a way that allows us to design out unwanted behaviours.
Doing so gives us accurate data on the properties of the materials we are laying and creates an environment where we can really start to understand the materials we are working with.
Designing in resilience
Having guaranteed that the material on the road is the same as the one we’re testing in the lab, we can then design in behaviours we want. Broadly speaking, we need materials which offer greater flexibility to cope with a range of conditions.
“We need materials which offer greater flexibility to cope with a range of conditions”
The use of polymer modified bitumen (PMB) in asphalt mixes is one solution and the reason that FM Conway has invested in its own PMB manufacturing plant over the past 12 months. Chemical additions to bitumen enable us to build in elasticity to manage the effects of heating and cooling of the road pavement.
Critically, this can be applied to the surface course, but also holds huge potential when applied to whole-road renewal, which will become increasingly essential if we are to establish a more resilient network.
Adopting a data-driven approach
Having designed in new characteristics, we then need to track how that material is used, creating a data trail from the laboratory to the pavement that informs how we maintain the network to maximise its performance.
The use of tools such as intelligent pavers means we can record how as well as what we are laying. By capturing this information, in the long term we can create the specifications to combat climate change on an increasingly precise level. For example, this could include adjusting mixes in one part of the UK to deal with increasing rainfall or more frequent snowfall, compared with other areas that are expected to suffer from summer heatwaves.
Adopting these new approaches will also help to create cost efficiencies now and in the future. By knowing more about the composition of our roads, we can make them more resilient but also more easily laid, maintained and even recycled into new materials – helping to maximise precious resources.
Predictions over the extent and pace of global warming and its effects are the subject of continued debate. It is clear, however, that we need a more intelligent, data-driven approach to design a resilient road network.
Achieving this relies on a greater understanding of the challenges we face as well as the materials and methods we use to meet them.
David Smith is development director at FM Conway