Comparative analysis of cold in-place recycling for roadway maintenance and rehabilitation from the perspectives of technical-cost-environmental nexus

Cold-in-place recycling (CIR) is a sustainable road pavement maintenance technology for its on-site operation and complete reuse of reclaimed asphalt pavement. However, its sustainable performance has not been thoroughly investigated. This study aims to systematically assess and compare CIR against three alternative maintenance technologies from technical, cost and environmental perspectives, specially taking into account different numbers of repaired layers. The technical improvement in full-depth loading resistance is evaluated using a newly developed multi-sequenced repeated load (MSRL) test. Environmental impacts are assessed through life cycle assessment (LCA), while cost analysis is conducted using life cycle cost analysis (LCCA), with consistent system boundary applied. Additionally, a nexus analysis is performed using a modified Boston Consulting Group (BCG) matrix to comprehensively examine the sustainable performance of different treatments and further explore the synergies and trade-offs among various assessment aspects. The multi-dimensional sustainable assessment results reveal the influence factors in each perspective. Final BCG matrix shows that CIR can achieve the comparable technical performance to the conventional maintenance treatment, while reducing GHG emissions by 60.8% and cost by 45.8%. The methodology and findings of this study are expected to provide helpful insights for decision-makers in reducing negative impacts and promoting integrated management for sustainability.