Strategies for the use of sustainable materials in road construction: a qualitative delphi study

Abstract

The construction industry is increasingly prioritising sustainability, driven by the urgent need to minimise environmental impacts and improve resource efficiency. In line with that, sustainable materials in road construction offer significant potential to reduce carbon footprints, enhance durability, and support circular economy principles. However, despite growing interest, there remains a limited understanding of effective strategies to integrate these materials specifically for improving road durability and overall construction performance. Thus, this study aims to investigate strategies for the use of sustainable materials in road construction. Using a qualitative Delphi method involving two rounds of semi-structured interviews, the research identified 11 commonly used sustainable materials, alongside 23 targeted strategies to enhance road durability and an additional 23 strategies to improve overall road construction practices through sustainable approaches. Notably, these strategies were classified material-wise, providing customised and actionable guidance for each sustainable material. 17 and 11 experts participated in the two Delphi rounds, selected through purposive sampling. The study offers a comprehensive, practical roadmap that bridges theoretical knowledge with real-world application. Key recommendations emphasise fostering collaboration across stakeholders, rigorous technical validation, and the incorporation of lifecycle assessments to promote sustainable material adoption in road construction. This distinguishes the study, making it uniquely valuable for stakeholders seeking effective pathways to advance sustainable road infrastructure.