Making roads climate resilient and sustainable in low and middle income countries
In the wake of the United Nations Conference of the Parties on Climate Change (COP26), attention was again focused on how best to accelerate action towards the goals of the Paris Agreement and the United Nations Framework Convention on Climate Change. It is widely recognized that climate change poses a critical threat to future development, especially 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 series of extreme weather events, for example:
- Rising sea levels are expected to cause storm surges in coastal areas (as seen in Dhaka, Bangladesh)
- The heat waves are expected to be more severe (as seen through Ethiopia)
- Precipitation is estimated to increase in intensity (as seen worldwide).
The increased frequency and intensity of these extreme weather events can have a devastating impact on human life and physical infrastructure. The impact on road transport systems can be particularly severe, leading to delays, disruptions, damage and potentially breakdowns.
- Exposure to flooding shortens the life expectancy of highways and roads. Water stress can cause damage, requiring more frequent maintenance, repairs and rebuilding. Road infrastructure in coastal areas is particularly sensitive to more frequent and permanent flooding due to sea level rise and storm surges.
- Higher temperatures can cause pavements to soften and expand. This can create ruts and potholes, especially in high traffic areas. Heat waves can also limit construction activities, especially in areas with high humidity.
- Heavy rains can cause flooding, which could disrupt traffic, delay construction activities, and weaken or wash away soil and culverts that support roads.
The focus on how pavement innovation can support the adaptation and development of sustainable, climate-resilient roads has received increasing attention from transport professionals and academic research. The University of Birmingham is leading a consortium of researchers to explore how new paving approaches can be tested and redeployed in low- and middle-income countries (LMICs).
The Climate-resilient sustainable road paving project is driven by the recognition that certain types of resilient pavements can experience fatigue damage due to overloading, poor construction, inadequate drainage and the impact of more extreme weather conditions. Such damage can lead to fatigue cracks and ruts leading to the formation of potholes and unacceptable levels of road roughness requiring increased costs for maintenance and road use.
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 centers, but also essential for stimulating and supporting industrial development and the economy. In rural areas, especially those in low-income countries, roads are an integral part of economic and agricultural livelihoods. They facilitate access to health care, education, credit, political participation, etc. The impact of extreme events is therefore a costly danger for roads in terms of degradation, necessary maintenance, potential reduction in lifespan and associated societal impacts.
To enable transport infrastructure to adapt to climate change and minimize the impact of extreme weather events, it is important to understand how roads are planned and managed and to identify weaknesses and strengths in the face of 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 indicator of future risks. As most transport infrastructure is expected to last for decades, it is important to understand how the future climate might affect investments in the years to come.
A key partner of the CRISPS project, Universiti Putra Malaysia (UPM) has developed an innovative fiber mastic asphalt (FMA) technology to combat the impact of climate change on Malaysia’s roads. Research conducted at UPM on the use of oil palm cellulose fiber has shown that the inclusion of palm fiber in asphalt improves the quality of flexible road surfaces through micro-reinforcement. An evaluation of in-service roads built using FMA showed increased strength, less fatigue cracks, rutting and lower levels of road roughness and, as a result, costs of using the roadways. lower roads, compared to those built from conventional asphalt. As a result, the lifespan of FMA-based pavements is up to 10 years longer than those constructed from conventional materials.
Failure to take into account the impact of climate change in the future design, maintenance and operation of roads could lead to accelerated deterioration of roads and higher costs for road users. The University of Birmingham-led CRISPS project will support the development of innovative approaches that test and validate alternative road paving technologies such as Modified Epoxy Seals (MECS) and Modified Epoxy Surfaces (MEAS) alongside FMA and deploy them in LMIC environments. The project aims to support the adoption of adaptation measures that could be crucial for the protection of current and future investments in road infrastructure and the economic, social and other functions they perform.