Sustainable Masonry Retrofitting and Upgrading Techniques: A Review

Highlights: What are the main findings? Sustainable Retrofitting Techniques: This review paper critically examines various fiber retrofitting and upgrading techniques: (1) mechanical, (2) thermal, and (3) integrated (structural and thermal). TRM vs. FRP Systems: Textile reinforced mortar (TRM) systems offer superior performance compared with fiber reinforced polymer (FRP) systems in masonry retrofitting, due to better material compatibility, breathability, fire resistance, and lower environmental impact. Integrated Retrofitting: Combining structural and thermal retrofitting techniques, such as in the case of natural fiber TRM (NFTRM), enhances the load-bearing capacity of masonry walls while improving their insulation properties, addressing both seismic resilience and energy efficiency. Notably, standards/guidelines are absent for NFTRM system applications. Challenges and Future Research: Further research is needed into fiber treatments, hybrid reinforcement strategies, and the durability and moisture absorption problems. What are the implications of the main findings? Sustainability: The innovative application/use of natural fiber-based building materials can support global sustainability goals. Notably, it can help in reducing dependence on synthetic materials and minimize the carbon footprint. Cost-Effectiveness: Integrated (structural and thermal) retrofitting approaches, such as the use of NFTRM, aim to lower long-term maintenance costs and extend the lifespan of buildings. Seismic Resilience and Energy Efficiency: Improved structural and thermal performance (separately or via integrated retrofitting approaches) of retrofitted masonry walls addresses vulnerabilities in unreinforced masonry (URM) structures, an essential factor for buildings in earthquake-prone areas and for reducing overall energy consumption. This study presents a comprehensive review of various advanced methodologies that have been used to enhance the structural and thermal performance of masonry walls through innovative and sustainable retrofitting/upgrading techniques. Focusing on three primary approaches—mechanical/structural retrofitting, thermal retrofitting, and integrated (structural and thermal) retrofitting, this paper critically examines various masonry-strengthening strategies. Retrofitting techniques are categorized by material use and objectives. Fiber-based solutions include insulation materials, fiber composite mortar for strength, FRP for high-strength reinforcement, and TRM for durability. According to the relevant objectives, retrofitting can enhance structural stability (FRP, TRM), improve thermal insulation, or combine both for integrated performance. Particular emphasis is placed on the effectiveness of TRM systems, with a comparative analysis of man-made (glass, steel textile) and natural fiber-based TRM solutions. Regarding integrating natural fibers into TRM systems, this study highlights their potential as eco-friendly alternatives that reduce environmental impact while maintaining or improving structural integrity. Furthermore, it highlights and examines techniques for testing masonry walls. In this context, this review highlights the applicability of natural fiber as a sustainable building material in various retrofitting/upgrading solutions.