This study develops a green, high-performance, cement-based grout by replacing manufactured sand with iron tailings sand (ITS) at ratios of 0–50% to address resource depletion. Fluidity, mechanical strength, and expansion rates were experimentally evaluated to determine engineering feasibility. The results indicate that while ITS inclusion reduces fluidity due to particle morphology, it significantly enhances compressive strength through a physical filling effect. Specifically, the 30% replacement group achieved a peak 28-day compressive strength of 100.4 MPa. Comprehensive analysis identifies 40% as the optimal replacement rate, where the grout strictly satisfies relevant industry specifications regarding fluidity, early strength, and volume stability. This research demonstrates the practical significance of utilizing industrial solid waste to produce high-performance sleeve grout for prefabricated construction.

Unmanned aerial vehicle (UAV) technology is becoming increasingly integrated into the full lifecycle management of expressways, emerging as a vital tool in the intelligent transformation of transportation infrastructure. However, existing research is fragmented, lacking systematic integration and in-depth exploration of common challenges. This paper uses a systematic literature review (SLR) to examine UAV application scenarios, technological advancements and implementation outcomes in expressway planning, design, construction, operation and maintenance. The findings reveal that UAVs have achieved critical applications in all phases, including topographic surveying, progress monitoring, identifying defects, and monitoring the structural health of infrastructure. This has significantly enhanced management efficiency. However, its large-scale deployment along long-distance linear infrastructure in open traffic environments faces systemic barriers, including inefficient data acquisition and processing, hardware limitations in endurance and payload, insufficient algorithm generalization under sparse distress patterns and complex backgrounds, operational uncertainties caused by meteorological and electromagnetic interference, and regulatory constraints related to airspace control and data compliance. Based on these findings, the paper proposes five future research directions: enhancing autonomous perception in complex environments; establishing lightweight, real-time processing frameworks; deeply integrating digital twin platforms; advancing swarm coordination technologies; and developing standardised regulatory systems. This study systematically integrates knowledge in this field, identifies current technical bottlenecks and provides a clear evolutionary path for subsequent research and applications. The study has significant theoretical value and provides practical guidance for advancing the digital and intelligent transformation of highway infrastructure.