Sustainability and resilience in pavement infrastructure: a unified assessment framework

The American Society of Civil Engineers ranks the existing pavement infrastructure in the USA at a sub-par 'D' grade. Population growth, fast-paced industrialisation and infrastructure ageing put significant strain on the road and highway network. To enhance the sustainability of existing and upcoming pavement infrastructure, researchers have developed numerous models and tools for quantifying the resource consumption, environmental impact and socioeconomic consequences of these systems. However, these models do not incorporate the robustness of construction nor consider the performance and reliability of such infrastructure. Cognisant of the need to balance the sustainability and resilience elements of transportation infrastructure, this research introduces a quantitative framework for their combined assessment. As part of this multi-criteria analysis, the individual metrics (impact categories) of sustainability and resilience are identified and a quality index, I-Q, is introduced to evaluate the combined degree of sustainability and resilience of a pavement project in north Texas, USA. The pavement was constructed on sulfate-rich expansive clays, and the subgrade was stabilised with materials such as lime and fly ash. The framework provides a powerful decision-making tool to engineers, owners, state and federal agencies and other stakeholders for the selection of appropriate pavement design or construction alternatives while balancing both the sustainability and resilience aspects.