Towards greener highway infrastructure: evaluating the embodied carbon and cost efficiency of rigid pavement designs

The construction sector, a major contributor to global greenhouse gas emissions, is facing increasing scrutiny to reduce environmental impacts. Rigid pavements, which are commonly used in highways, airport runways and aprons, industrial ground slabs, and other infrastructure, offer the opportunity to mitigate embodied carbon through optimised design practices. Effective strategies to reduce embodied carbon and construction costs are essential for sustainable infrastructure development. This study aims to evaluate the impact of concrete grade and subgrade CBR values on the embodied carbon, design thickness, and cost of rigid pavements. By analysing different concrete grades and CBR values, this study seeks to identify the most efficient design options that balance environmental performance and economic feasibility. The research employed a comprehensive methodology, including data collection, pavement design, embodied carbon analysis, and cost analysis. The analysis reveals that higher concrete grades result in increased embodied carbon due to higher cement content, although they only marginally impact overall costs. In contrast, variations in CBR values significantly affect both the pavement thickness and associated costs. Higher CBR values lead to a reduced pavement thickness, lower embodied carbon, and decreased construction costs. Lean mix concrete consistently offers a more cost-effective and environmentally friendly option than cement-treated bases. This study provides valuable insights for designing rigid pavements with reduced environmental impact and cost, emphasising the need for careful consideration of the concrete grade and CBR values in achieving sustainable infrastructure solutions.