Researchers Discuss Need to Make Roads Climate Resilient and Sustainable in Low and Middle Income Countries

“The impact on road transportation systems can be particularly stark, leading to delay, disruption, damage and potentially failure.”

• Dr Michael Burrow, Department of Civil Engineering
• Professor Nicole Metje, Department of Civil Engineering
• Dr Mehran Eskandari Torbaghan, Department of Civil Engineering
• Dr Gurmel Ghataora, Department of Civil Engineering
• Dr William Avis, International Development Department

In the wake of the United Nations Climate Change Conference of the Parties (COP26), attention has once again focused on how best to accelerate action towards the goals of the Paris Agreement and the UN Framework Convention on Climate Change. It is widely accepted that Climate Change poses a critical threat to future development, particularly in areas where poverty is widespread and infrastructure is either underdeveloped or vulnerable to extreme weather events. The body of scientific evidence indicates that climate change will increase the frequency and intensity of a range of extreme weather events, for example:

• Sea level rise is predicted to result in storm surges in coastal areas (as seen in Dhaka, Bangladesh);
• Heat waves are forecast be more severe (as seen across Ethiopia); and
• Precipitation is estimated to increase in intensity (as seen globally).

The increased frequency and intensity of these extreme weather events can have a devastating impact on both human life and physical infrastructure. The impact on road transportation systems can be particularly stark, leading to delay, disruption, damage and potentially failure.

• Exposure to flooding events shortens the life expectancy of highways and roads. The stress of water may cause damage, requiring more frequent maintenance, repairs and rebuilding. Road infrastructure in coastal areas is particularly sensitive to more frequent and permanent flooding from sea level rise and storm surges.
• Higher temperatures can cause pavements to soften and expand. This can create rutting and potholes, particularly in high-traffic areas. Heat waves can also limit construction activities, particularly in areas with high humidity.
• Heavy rains may result in flooding, which could disrupt traffic, delay construction activities, and weaken or wash out the soil and culverts that support roads.

A focus on how innovation in pavement surfacing can support adaptation and the development of climate resilient sustainable roads has received growing attention from transportation professionals and academic research. The University of Birmingham is leading a consortium of researchers to explore how new approaches to road surfacing can be tested and redeployed in low and middle income (LMIC) settings.

The Climate Resilient Sustainable Road Pavement Surfacings Project is driven by a recognition that certain types of flexible road pavement can suffer fatigue damage due to overloading, poor construction, inadequate drainage and the impact of more extreme weather. Such damage can result in fatigue cracking and rutting leading to the formation of potholes and unacceptable levels of road roughness necessitating increased maintenance and road use costs.

This damage to infrastructure can also have a significant impact on the functioning of communities, cities and regions. Road networks are not only essential for the interconnection and movement of goods between major urban and regional centres but also critical to stimulating and sustaining industrial development and the economy. In rural areas, particularly those in low-income countries, roads are integral to economic and agricultural livelihoods. They facilitate access to healthcare, education, credit, political participation, and more. The impact of extreme events thus pose a costly hazard to roads in terms of degradation, necessary maintenance, potential decrease in lifespan and associated societal impacts.

To enable transportation infrastructure to adapt to climate change and minimise the impact of extreme weather events, it is important to understand how roads are planned and managed and to identify weaknesses and strengths in dealing with climate change. Transportation systems have historically been designed and planned in response to past climate records. However, due to climate change, historical climate is no longer a reliable predictor of future risk. As most transportation infrastructure is expected to last for decades, it is important to understand how future climate might affect investments in the coming years.

A key partner in the CRISPS project, the Universiti Putra Malaysia (UPM) have developed an innovative Fibre Mastic Asphalt (FMA) technology to address the impact of climate change on Malaysia’s roads. Research at UPM on the use of cellulose oil palm fibre showed that the inclusion of palm fibre in asphalt enhanced the quality of flexible road pavement through micro reinforcement. An assessment of in-service roads constructed using FMA has shown an increase in strength, less fatigue cracking, rutting and lower levels of road roughness and consequential lower road use costs, compared to those constructed from conventional asphalt. As a result, the lifespan of the FMA based road pavements are up to 10 years greater than those constructed from conventional materials.

Failure to take account of impact of climate change in future road design, maintenance and operation, could cause accelerated road deterioration and higher road user costs. The University of Birmingham led CRISPS project will support the development of innovative approaches that test and validate alternative road surfacing technologies such as Modified Epoxy Chip Seals (MECS) and Modified Epoxy Asphalt Surfaces (MEAS) alongside FMA and deploy this in LMIC settings. The project aims to support the adoption of adaptation measures that could be crucial to the protection of current and future road infrastructure investments and the economic, social, and other functions they serve.