Review on Experimental and Analytical Investigation of Advanced Retrofitting Techniques for Fire-Damaged RCC Structures Incorporating Self-Healing Polymers and Fire-Resistant Coating Systems

Abstract

Fire-induced deterioration significantly reduces the strength, durability, and serviceability of reinforced cement concrete (RCC) structures due to irreversible damage to concrete and reinforcing steel. Conventional repair methods often provide only partial restoration and require frequent maintenance. This study presents a comprehensive investigation of advanced retrofitting techniques incorporating self-healing polymers and fire-resistant coating systems for rehabilitating fire-damaged RCC structures. The review covers recent developments in fiber-reinforced polymers (FRP), ultra-high-performance fiber-reinforced concrete (UHPFRC), strain-hardening cementitious composites (SHCC), basalt fiber engineered geopolymer composites (BFEGC), cementitious repair mortars, and intelligent self-healing materials. Experimental evaluation includes compressive strength, flexural behavior, bond performance, crack-healing efficiency, ultrasonic pulse velocity, and residual durability after exposure to 400–900°C. Analytical investigations employ finite element modeling and thermo-mechanical simulations to predict structural performance. The findings demonstrate that advanced retrofitting systems substantially improve post-fire strength, crack resistance, durability, and long-term resilience, offering sustainable solutions for repairing fire-damaged RCC infrastructure.

Introduction

Reinforced Cement Concrete (RCC) structures are essential components of modern infrastructure, including buildings, bridges, tunnels, and industrial facilities. Although concrete is naturally fire-resistant, exposure to high temperatures causes severe deterioration through dehydration, thermal cracking, explosive spalling, and loss of compressive strength. Reinforcing steel also experiences significant reduction in strength and stiffness at elevated temperatures, particularly beyond 500°C. As a result, rehabilitation of fire-damaged structures has become necessary to restore safety, reduce costs, and minimize environmental impacts.

Conventional repair techniques such as concrete jacketing, epoxy injection, steel plate bonding, and shotcrete can restore structural capacity but often face limitations related to durability, corrosion, material compatibility, and performance under repeated thermal exposure. Recent developments in construction materials have introduced advanced repair solutions, including self-healing polymers and fire-resistant protective coatings. Self-healing materials contain healing agents or bacteria that automatically seal cracks, restore continuity, and improve durability. Fire-resistant coatings such as intumescent coatings, ceramic layers, and geopolymer systems provide thermal insulation and reduce heat penetration into structural elements. The integration of these technologies offers a multifunctional rehabilitation approach by improving both structural recovery and fire resistance.

Modern computational tools, including Finite Element Analysis (FEA), Computational Fluid Dynamics (CFD), and machine learning, have improved the prediction of fire-induced structural behavior. These techniques help estimate temperature distribution, crack development, stress changes, and failure mechanisms, reducing dependency on costly full-scale experiments.

The proposed research develops an integrated experimental and analytical framework to evaluate advanced rehabilitation techniques for fire-damaged RCC structures. The study focuses on combining self-healing polymers, fire-resistant coatings, advanced repair materials, and numerical simulations to enhance structural strength, durability, and service life.

Literature Review Summary

Previous studies have investigated various approaches for improving the performance of fire-damaged concrete structures:

• Self-healing concrete technologies have demonstrated the ability to reduce crack propagation, recover mechanical properties, and improve long-term durability after fire exposure.
• Fire-resistant materials, including fiber-reinforced composites, geopolymers, and protective coatings, have shown improved thermal stability and structural protection.
• Numerical modeling techniques have successfully predicted post-fire behavior, including temperature distribution, bond degradation, and structural response.
• Advanced strengthening materials, such as Basalt Fiber Reinforced Polymer (BFRP), strain-hardening cementitious composites (SHCC), Ultra-High Performance Fiber Reinforced Concrete (UHPFRC), and fiber laminates, have improved strength, ductility, crack resistance, and durability of repaired structures.
• Sustainable rehabilitation methods using green materials and composite systems have gained importance due to their environmental benefits and reduced maintenance requirements.
• Damage assessment studies emphasize the importance of combining visual inspection, destructive testing, and non-destructive evaluation methods before selecting suitable repair strategies.

Research has shown that conventional repair methods can restore structural performance, but advanced composite materials and smart repair technologies provide better long-term reliability and resilience.

Key Problem Identified

Fire exposure causes irreversible damage to RCC structures, reducing strength, stiffness, durability, and service life. Existing repair methods often provide temporary restoration and may suffer from durability issues. Therefore, there is a need for innovative rehabilitation systems capable of:

• Automatically repairing cracks,
• Providing thermal protection,
• Restoring structural capacity,
• Improving durability,
• Reducing maintenance requirements.

Proposed Research Approach

The study proposes an integrated rehabilitation framework involving:

1. Fire damage assessment
   • Evaluation of concrete degradation, reinforcement damage, cracking, and residual strength.
2. Advanced repair materials
   • Application of self-healing polymers for autonomous crack repair.
   • Use of fire-resistant coatings for thermal protection.
3. Experimental investigation
   • Testing repaired RCC elements under mechanical and thermal conditions.
4. Numerical analysis
   • Application of FEA, CFD, and machine-learning-based prediction models to analyze structural behavior.

Conclusion

Fire exposure significantly deteriorates the mechanical properties, durability, and serviceability of reinforced cement concrete (RCC) structures through concrete degradation, reinforcement damage, cracking, spalling, and loss of bond strength. The reviewed literature demonstrates that conventional repair methods often provide limited restoration, whereas advanced rehabilitation materials and techniques offer substantial improvements in post-fire structural performance. Fiber-reinforced polymers (FRP), ultra-high-performance fiber-reinforced concrete (UHPFRC), strain-hardening cementitious composites (SHCC), basalt fiber engineered geopolymer composites (BFEGC), bamboo fiber laminates, and self-healing cementitious systems have shown excellent potential for restoring strength, stiffness, ductility, and durability of fire-damaged members. Recent studies also emphasize the importance of comprehensive post-fire damage assessment using both destructive and non-destructive evaluation techniques, supported by numerical modeling and thermo-mechanical simulations. These approaches enable accurate prediction of residual structural capacity and facilitate the selection of appropriate rehabilitation strategies. Furthermore, the integration of intelligent self-healing materials with fire-resistant coatings has emerged as a promising solution for extending service life, reducing maintenance requirements, and enhancing structural resilience. Sustainable repair materials, including geopolymers, natural fiber composites, and eco-friendly cementitious systems, have demonstrated considerable environmental and economic advantages while maintaining satisfactory structural performance. The adoption of advanced retrofitting systems not only improves the safety and reliability of existing infrastructure but also supports sustainable construction practices by minimizing demolition waste and reducing the demand for new construction materials. Overall, the literature indicates that future research should focus on the long-term durability of repaired structures under combined environmental and mechanical loading, optimization of self-healing technologies, development of standardized post-fire assessment procedures, and incorporation of artificial intelligence and digital monitoring techniques for real-time structural health evaluation. These advancements will contribute to the development of resilient, durable, and sustainable rehabilitation strategies for fire-damaged RCC structures and support the formulation of future design guidelines and engineering standards.

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Copyright

Copyright © 2026 Mr. Shailesh Sharad Parankar, Dr. Mohammad Zuhair. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.