The effects of climate change on highway pavements and how to minimise them: Technical report

Most highway authorities have already experienced the impacts of climate change on their operations in recent years which have caused damage, accelerated deterioration, disruption and increased costs. The accepted climate models for the UK predict that by the 2050’s the UK in general will experience: drier, hotter summers; milder, wetter winters; more extreme rainfall events; and a rise in sea levels. The detailed changes vary across the country. The Department for Transport commissioned TRL to improve the understanding among local highway engineers of the implications of the predicted change in climate parameters, such as rainfall and temperature, for highway pavements and how the impacts might be minimised. This report provides the detailed technical information which is the basis for a DfT guidance document, Maintaining Pavements in a Changing Climate. This technical report describes the impact climate has on the different types of pavement; asphalt, concrete, modular and unbound. The vulnerability of a pavement to climate depends on factors such as pavement type and condition, local geology, traffic flow and proximity to hydrological features. The key climate variables for pavements are temperature, precipitation and soil moisture. The report describes the implications of changes in these variables for the maintenance of the different pavement types. Case studies are used to illustrate the types of impacts climate has had on highways. Recommendations are given on how to adapt to the changing climate and advice is provided for highway engineers on assessing the risk of different climate hazards for their network. The use of adaptive maintenance practices such as permeable pavements and polymer modified binders is encouraged. Other more general actions, such as improving the overall condition of the pavement and providing adequate drainage systems are also encouraged.