Self-healing of asphalt materials–part 2: Enhancement strategies, field applications and sustainability assessment

This article is the second part of a two-part comprehensive review of self-healing asphalt materials (SHAMs). While Part 1 synthesized the fundamental healing mechanisms, influencing factors, and evaluation methods governing intrinsic and extrinsic self-healing phenomena, the present paper focuses on engineered enhancement strategies, large-scale applications, and sustainability-related assessments. The review critically examines the main extrinsic self-healing technologies reported in the literature, including electromagnetic and microwave induction heating, encapsulation systems, and hybrid approaches combining multiple activation mechanisms. In addition, material-based strategies involving polymers, rejuvenators, and conductive additives are discussed in terms of their contributions to healing efficiency, repeatability, and practical feasibility. Particular attention is given to reported laboratory investigations, pilot-scale studies, and field-trial applications, with the aim of bridging the gap between controlled experimental conditions and real pavement performance. Beyond mechanical and healing performance, this review emphasizes the environmental and economic implications through analyses of life-cycle assessment (LCA) and life-cycle cost analysis (LCCA) studies. These aspects are discussed in light of current methodological limitations, data variability, and the lack of harmonized assessment frameworks, which remain critical challenges for large-scale implementation. By integrating technical performance, field readiness, and system-level sustainability considerations, this work complements the theoretical foundations established in Part 1 and provides a structured reference for researchers and practitioners seeking to advance SHAMs toward reliable, scalable, and sustainable pavement engineering solutions.