The State-of-the-Art Review on Crack Treatments of Asphalt Pavements: Pertaining Mechanisms, and Elastomer Applicability as Sealant Modifiers

The rapid growth of infrastructure development has led to increased traffic volumes, causing significant distress to asphalt pavements. This degradation compromises road integrity, necessitating effective maintenance strategies to restore structural performance and extend service life. This review examines various preventive and corrective maintenance methods, including crack sealing and filling, seal coating, cold and hot in-place recycling, induction healing, and microcapsule-based self-healing systems, aimed at preventing further cracking in asphalt pavements. The paper primarily focuses on biopolymer modification, particularly rubber-modified crack sealants, as a promising solution to the limitations of traditional crack sealing methods, especially under varying weather conditions and heavy traffic loads. Rubber modifiers have shown improvements in mechanical performance by enhancing adhesion at the asphalt–aggregate interface. Furthermore, crumb rubber, a widely used modifier, helps mitigate aging by absorbing lower molecular weight fractions, preserving sealant functionality, and supporting both short- and long-term performance. However, temperature sensitivity may limit its effectiveness in certain climates. A deeper understanding of the molecular structure and chemical compatibility of natural and synthetic rubbers is crucial for optimizing their use in asphalt sealants. Future studies should prioritize field evaluations of single-component rubber-modified systems to assess their effectiveness under diverse climate and traffic conditions before advancing to multi-component systems.