Climate Resilience and Energy Harvesting of Thermo-Active Roads

The climate is changing rapidly, altering the long-term environmental loading parameters of roads. Increased frequency and severity of extreme weather events cause serious road damage and transport disruption, including melting roads in heatwaves and potholes due to freeze–thaw cycles, with highway repair and maintenance costing England alone £1.4 billion in 2021/2022. The recently established UK projects SaFEGround, Digital Roads, and an RAEng Research Fellowship will synergise ideas and methods to develop low-carbon and resilient roads. In particular, the RAEng Research Fellowship involves deploying an innovative shallow geothermal energy system (SGES) for subgrade heat storage/extraction and pavement temperature regulation. Such research is at the forefront of Transport and Energy Geotechnics. Very little research has been conducted on the pavement-pipe-subgrade SGES and factors affecting their performances, especially in the field of civil engineering (e.g. thermal properties enhancement of subgrade materials, pavement/pipe/subgrade interaction, complex thermo-mechanical behaviour under extreme climates). This paper provides an overview of the systematic research approach that fully characterises thermally improved road materials via physical modelling, finite element numerical analysis, field trials and LCA, with some preliminary results analysed. The proposed thermo-active road technology would be applicable to a wide range of transport projects in many regions to reduce climate-related road maintenance costs and carbon emissions.