Validation of Self-Healing Concrete and Critical Role Review of Recycled Plastics in Road Design and Construction

Road infrastructure has suffered from several problems of deterioration, cracking, and expensive maintenance. Rigid (concrete) and flexible (asphalt) pavements are susceptible to minor cracks under gradual loading and environmental stress, resulting in costly repairs and reduced service life. This study explores self-healing concrete (SHC) and recycled plastic materials as sustainable alternatives to improve the durability and environmental performance of road pavements. The aim is to evaluate the mechanical properties of both materials, compare the cost analyses, and assess long-term durability. The research employs a mixed-methods approach: it incorporates ANSYS Finite Element Analysis of self-healing concrete to assess mechanical properties and crack-healing capacity, while a systematic secondary-data literature review critically examines the role of recycled plastics in road design & construction. The critical review of recycled plastic’s role largely focuses on using it as a partial binder replacement, examining performance, environmental impacts, and economic feasibility. ANSYS Finite Element Analysis results demonstrated that SHC enhanced strength recovery and crack resistance compared to NC and recycled plastics, especially HDPE and PET, which offer enhanced rutting resistance, reduce binder demand, and provide notable waste diversion benefits. However, potential problems include the limited ability of larger cracks in SHC to be repaired, the environmental risks of microplastic release, and compatibility issues with plastic-modified asphalt. These outcomes promote cost- effective, resilient, and eco-friendly infrastructure solutions aligned with the sustainable development mission. The objective is achieved, and the study validates the research gaps through monitored experiments of SHC and consolidates recent research on recycled plastics relevant to South Africa. The recommendation is that self- healing concrete should not only be used in roads but also in high-risk, high-volume rigid pavement infrastructure such as bridges, highways, and tunnels, where maintenance costs are usually high, so that SHC can minimise them. Integrating SHC and recycled plast