<p>The sustainability of transportation infrastructure, particularly road construction, has emerged as a pressing global concern due to its substantial environmental and public health impacts. This study conducts a macro-level life cycle assessment (LCA) of solid waste-based pavements utilizing steel slag and reclaimed asphalt pavement, with a specific focus on evaluating the environmental, economic, and health advantages of these alternative materials. A comprehensive LCA model was developed, integrating critical factors such as carbon emissions, PM_2.5 reductions, and life-cycle costs. The analysis encompasses all stages of the pavement life cycle, including raw material extraction, construction, usage, and end-of-life disposal, while also incorporating the dynamic effects of pavement deterioration and vehicle fuel consumption. In this study, a more refined life cycle benefit analysis was performed by accounting for slag production capacity and road mileage across different provinces in China, providing a more detailed regional assessment. The results demonstrate that implementing solid waste-based pavements across the mainland of China could reduce CO₂e emissions by 45.65% (10291 million tons), PM_2.5 emissions by 33.91% (64.33 million tons), and costs by 13.74% (218.81 billion CNY) over a 30-year period, while preventing approximately 4990 premature deaths attributable to PM_2.5 exposure. When monetizing these health benefits and climate impacts, the study projects a total net economic benefit of 316.30 billion CNY over 30 years. This research offers a scalable framework for assessing the multidimensional benefits of solid waste-based pavements, providing crucial insights for policymakers, engineers, and industry stakeholders committed to promoting sustainable and cost-effective infrastructure solutions.</p>