Building Resilient Roads for a Changing Climate

Many researchers have demonstrated the evidence of a changing climate. It’s also been shown that climate change will have negative impacts on agriculture, health, water and food supply to name a few sectors. This presentation is based on a study conducted at the CSIR on the effects of climate change on roads, with particular focus on the effects of rising temperatures on bituminous binders used for building asphalt roads in South Africa.

The study is important because it presents a practical solution to making South African roads more adaptable to the inevitable impacts of a changing climate. The interdisciplinary study incorporated climate model projections with algorithms used for road material selection to quantify the effects of climate change on bituminous binder selection.

Rising temperatures as a result of climate change were investigated by incorporating climate model projections and geographical information systems into current road material selection practices. Current design methods incorporate performance-graded (PG) specifications which were introduced in 2019 by the Road Pavement Forum and now form part of a South African National Standard. The investigation on adapting asphalt pavements for climate change intends to guide best practise on how to incorporate climate change effects into current specifications for bituminous binder selection.

The temperature of a road surface is dependent on the climate in the area and plays an important role in determining the stiffness of the asphalt layer. Most climate models predict an increasing rate in the rise of average air temperatures in the near future. As the average air temperatures increases, it is expected that the frequency and duration of extreme temperatures will also rise. This will have a direct impact on asphalt pavement performance by increasing the potential for permanent deformation of pavements and the rate of age hardening of asphalt binders. Interpolated maps of minimum and maximum pavement temperatures were generated using climate model data for two 20-year periods, up to the years 2040 and 2060. The same model was used to generate two historic 20-year periods, going back to 2000 and 1980. The maps produced from the study can eventually be used to identify adaptation measures which may include modifying current design and maintenance practices.

The overall objective is to assist engineers and urban planners build roads that can withstand evolving demands in order to build climate resilient infrastructure that can inform adaptation policies for industry.

About the Presenter

Refiloe is research civil engineer in the Pavement Design and Construction Research Group within the Smart Mobility Cluster and Transport Infrastructure Engineering Impact Area at the CSIR. Her research interest and application is concerned with sustainable development in the field of transport infrastructure, in particular adaptation and resilience of South African roads against the impacts of climate change. Her work is aimed towards providing cost-effective and sustainable solutions to road design and construction. Refiloe graduated from the University of the Witwatersrand in 2011 with her undergraduate degree in civil engineering. She joined the Council of Scientific and Industrial Research (CSIR) in 2014 as a candidate researcher where her research work has focussed on the use of industrial by-products as an alternative road and rail construction material. Her recent work has focussed on incorporating climate change strategies into transport infrastructure design and adaptation.