Experimental Study on the Influence of Elevated Temperature on the Mechanical Properties of Concrete Using Crumb Rubber as Partial Replacement of Fine Aggregate and Corrugated Round Steel Fibers

Abstract

The global scientific research circle and government agencies face a number of serious environmental challenges, one of which is the recycling of “End of Life Tires” (ELT). An estimation of one billion tires is expected to end their useful life annually, of which only roughly 50% are recycled at the moment, with the remainder ending up in landfills. Consequently, to solve this gap in the ELT\'s utilization rate, it is imperative to enhance the current application and furthermore create new applications for recycled tire materials. One of such areas that is currently being investigated is the introduction of waste tire into concrete as partial replacement of natural aggregates in concrete production. This experimental study investigated the influence of elevated temperatures on the mechanical properties of M25 grade concrete, specifically its compressive strength, split tensile strength, and flexural strength. The study focused on the effect of incorporating crumb rubber as a partial replacement of fine aggregate at varying percentages 5%, 10%, 15%, and 20% along with a constant 2% of corrugated round steel fibers. After a standard 28 days water curing period, concrete specimens were subjected to a range of elevated temperatures 2000C, 4000C, 6000C, and 8000C, to simulate fire-like conditions. The results of the study revealed a significant and consistent reduction in all three mechanical properties as the exposure temperature increased, which is a common characteristic of concrete under thermal stress. However, the performance varied notably among the different mixes. For compressive and flexural strength, the concrete mix with 10% crumb rubber (CR) demonstrated superior performance, consistently retaining the highest residual strengths at higher temperatures compared to all other mixes. This finding suggests that a 10% replacement level strikes an optimal balance, where the crumb rubber helps to relieve internal thermal stresses through its melting and decomposition, while the steel fibers provide crucial internal reinforcement to prevent catastrophic failure. In contrast, the split tensile strength tests showed a different trend. The mix with 5% crumb rubber exhibited the best performance at all temperatures. This indicates that while the steel fibers effectively bridged cracks and enhanced tensile properties, higher percentages of crumb rubber led to a greater number of weak bonds within the concrete matrix, which negatively impacted its tensile strength. The study concludes that the strategic incorporation of crumb rubber and steel fibers can enhance the thermal performance of concrete, but the optimal percentage of crumb rubber is dependent on the specific mechanical property being optimized. The findings also led to recommendations for preventive measures against fire damage in concrete, such as the use of fire-resistant mixes, application of protective coatings, and ensuring adequate concrete cover over reinforcement.

Introduction

Concrete is widely used in infrastructure due to its availability, moldability, durability, and thermal resistance. Despite its fire-resistant properties, concrete structures can suffer damage when exposed to fire, mainly due to changes in their mechanical, physical, and chemical properties. Fire risk remains a top concern in India and globally, causing significant economic losses and fatalities. Fire damage often results from electrical faults, gas leaks, and fireworks, with Maharashtra being particularly affected.

The U.S. sees a fire incident every 24 seconds, mostly in residential buildings, causing billions in damages. While most fire-damaged reinforced concrete (RCC) structures retain some strength and can be repaired, only a small fraction require demolition. Evaluating residual strength through destructive and non-destructive tests is essential before retrofitting.

Materials discussed:

• Crumb Rubber: Recycled rubber granules from tires, used as partial replacement of fine aggregates in concrete, offering environmental benefits and improved mechanical and acoustic properties.

• Corrugated Round Steel Fibers: Steel fibers added to concrete to improve strength, durability, and crack resistance.

Study Aim:
To investigate how elevated temperatures affect the mechanical properties (compressive, tensile, flexural strength) of concrete containing crumb rubber and steel fibers, addressing the environmental issue of granite waste disposal and expanding knowledge on crumb rubber concrete’s fire performance.

Methodology:
The study involves experimental testing of concrete mixes with varying crumb rubber percentages (5%, 10%, 15%, 20%) and 2% steel fibers, cured for 28 days, then exposed to temperatures up to 800°C. The mechanical properties after heating are tested and analyzed.

Findings:

• Concrete strength declines with increasing temperature.

• Significant changes occur after 300°C, with major structural weakening above 600°C.

• Crumb rubber concrete exhibits varying performance based on rubber content.

Fire Resistance of Concrete:
Concrete offers many fire safety benefits: it doesn’t burn or melt, produces no toxic smoke, prevents fire spread, maintains structural integrity, and can be repaired post-fire. Case studies like the Windsor Tower fire highlight concrete’s ability to prevent collapse compared to steel structures.

Preventive Measures:

• Use of fire-resistant concrete mixes (mineral admixtures, low-heat cement).

• Protective coatings (intumescent paints, lightweight mortar).

• Adequate concrete cover over reinforcement.

• Building design considerations (compartmentation, fire safety systems).

• Regular maintenance and risk assessment.

These measures improve concrete’s fire resilience, protecting lives and assets.

Conclusion

The following summarizes the conclusions of the study. 1) The effect of elevated temperatures on the compressive strength of M25 concrete reinforced with 2% corrugated steel fibers and incorporating 5%, 10%, 15%, and 20% crumb rubber with elevated temperatures shows significant decrease in compressive strength for all mixes as the temperature rises. However, the concrete mix with 10% crumb rubber demonstrated the best performance, retaining the highest residual strength at 6000C (8.48 N/mm2) and 8000C (3.22 N/mm2). This indicates that the 10% crumb rubber, combined with the steel fibers, provided an optimal balance for mitigating thermal stress and maintaining structural integrity at high temperatures. In contrast, higher crumb rubber percentages (15% and 20%) resulted in lower strengths, likely due to excessive void formation. In summary, the use of 10% crumb rubber and 2% steel fibers is an effective strategy for enhancing the thermal performance and residual strength of M25 grade concrete. 2) The split tensile strength of concrete containing crumb rubber and steel fibers with elevated temperatures has drastically reduced. The data shows that the mix with 5% crumb rubber retained the highest split tensile strength at all temperatures, outperforming the mixes with higher crumb rubber percentages. Specifically, while the 5% crumb rubber mix started at 4.47 N/mm2 at 2000C, it still maintained a strength of 0.50 N/mm2 even at 8000C. In contrast, the mixes with 10%, 15%, and 20% crumb rubber showed progressively lower tensile strengths. This indicates that increasing the crumb rubber content has a negative effect on tensile strength, despite the reinforcing action of the steel fibers. In summary, the optimal balance for maintaining split tensile strength at elevated temperatures is achieved with a lower crumb rubber percentage of 5%. 3) This study found that elevated temperatures significantly reduce the flexural strength of concrete containing crumb rubber and steel fibers. The data shows that the mix with 10% crumb rubber retained the highest strength across all temperatures, with a strength of 3.58 N/mm2 at 8000C. This indicates that the 10% crumb rubber, combined with the steel fibers, provided an optimal balance for mitigating thermal stress. Conversely, mixes with higher crumb rubber content (15% and 20%) showed much lower strengths, suggesting that an excessive amount of crumb rubber introduced too many weak points into the concrete. In summary, the strategic use of 10% crumb rubber and 2% corrugated steel fibers is an effective approach to enhancing the flexural strength and overall performance of concrete under thermal stress. 4) The concrete can be prevented by enhancing concrete\'s fire resistance using fire-resistant concrete mixes, applying protective coatings which heat-resistant coating like in tumescent paint can create a protective layer that swells and expands upon exposure to fire or lightweight mortar, and ensuring adequate concrete cover over reinforcement, insulating the concrete and concrete surfaces with board systems made from fire-resistant materials can also be effective.

References

[1] Alamri, M., & Khawaji, M., “Utilizing Edge-Oxidized Graphene Oxide to Enhance Cement Mortar’s Properties Containing Crumb Rubber: Toward Achieving Sustainable Materials”, Polymers, Volume 16, Issue 14, 2082, July 2024. https://doi.org/10.3390/polym16142082 [2] A. A. Che Ani, M.Y. Mohammed Al-Fasih, I.S. Ibrahim, N.N. Sarbini, K.H. Padil, “Influence of Waste Crumb Rubber as a Partial Replacement for Fine Aggregates on Concrete Properties”, Lecture Notes in Civil Engineering, Volume 385, pp. 383–395, January 2024. https://doi.org/10.1007/978-981-99-6018-7_28. [3] Bakhtiari Ghaleh, M., Asadi, P. & Eftekhar, M. R., “Enhancing Mechanical Performance of Waste Tire Concrete With Surface Double Pre-Coating by Resin and Micro-Silica”, Journal of Building Engineering, Volume 50, June 2022. [4] Zrar, Y. J., & Younis, K. H., “Review Mechanical and Durability Properties of Self-Compacted Concrete Incorporating Waste Crumb Rubber as Sand Replacement: A Review”, Sustainability, Volume 14, Issue 18, 11301, September 2022. https://doi.org/10.3390/su141811301 [5] Alsif, A., Albidah, A., Abadel, A., Abbas, H., & Al-Salloum, Y., “Development of Metakaolin-Based Geopolymer Rubberized Concrete: Fresh and Hardened Properties”, Archives of Civil and Mechanical Engineering, Volume 22, Issue 1, Article No. 144, June 2022. [6] Mhaya, A. M., Baharom, S., & Huseien, G. F., “Improved Strength Performance of Rubberized Concrete: Role of Ground Blast Furnace Slag and Waste Glass Bottle Nanoparticles Amalgamation”, Construction and Building Materials, Volume 342, Part B, 128073, August 2022. https://doi.org/10.1016/j.conbuildmat.2022.128073 [7] Murali, M., Mohammed, B. S., Abdulkadir, I., Liew, M. S., & Alaloul, W. S., “Utilization of Crumb Rubber and High-Volume Fly Ash in Concrete for Environmental Sustainability: RSM-Based Modeling and Optimization”, Materials, Volume 14, Issue 12, 3222, April 2021. https://doi.org/10.3390/ma14123222. [8] Adamu, M., Mohammed, B. S., & Liew, M. S., “Mechanical Properties and Performance of High Volume Fly Ash Roller Compacted Concrete Containing Crumb Rubber and Nano Silica”, Construction and Building Materials, Volume 171, pp. 521-538, May 2018. https://doi.org/10.1016/j.conbuildmat.2018.03.138 [9] Thomas, B. S., Gupta, R. C., & Panicker, V. J., “Recycling of Waste Tire Rubber as Aggregate in Concrete: Durability-Related Performance”, Journal of Cleaner Production, Volume 112, Issue 1, pp. 504-513, January 2016. https://doi.org/10.1016/j.jclepro.2015.08.046 [10] Gupta, T., Chaudhary, S., & Sharma, R. K., “Mechanical and Durability Properties of Waste Rubber Fiber Concrete With and Without Silica Fume”, Journal of Cleaner Production, Volume 112, Part 1, pp. 702-711, January 2016. https://doi.org/10.1016/j.jclepro.2015.07.081 [11] Moustafa, A., & ElGawady, M. A., “Mechanical Properties of High Strength Concrete with Scrap Tire Rubber”, Construction and Building Materials, Volume 93, pp. 249-256, September 2015. https://doi.org/10.1016/j.conbuildmat.2015.05.115 [12] Thomas, B. S., & Gupta, R. C., “Long Term Behaviour of Cement Concrete Containing Discarded Tire Rubber”, Journal of Cleaner Production, Volume 102, pp. 78-87, September 2015. https://doi.org/10.1016/j.jclepro.2015.04.072 [13] S. Thomas, R.C. Gupta, V.J. Panicker, “Experimental and Modelling Studies on High Strength Concrete Containing Waste Tire Rubber”, Sustainable Cities Society, Volume 19, pp. 68–73, December 2015. [14] S. Thomas, R. C. Gupta, P. Mehra and Sanjeev Kumar, “Performance of High Strength Rubberized Concrete in Aggressive Environment”, Construction and Building Materials, Volume 83, pp. 320-326, May 2015. https://doi.org/10.1016/j.conbuildmat.2015.03.012 [15] Ning Li, Guangcheng Long, Cong Ma, Qiang Fu, Xiaohui Zeng, Kunlin Ma, Youjun Xie, Bote Luo, “Properties of Self-Compacting Concrete (Scc) with Recycled Tire Rubber Aggregate: A Comprehensive Study”, Journal of Cleaner Production, Volume 236, 117707, November 2019. [16] Gupta, T., Chaudhary, S., & Sharma, R. K., “Assessment of Mechanical and Durability Properties of Concrete Containing Waste Rubber Tire as Fine Aggregate”, Construction and Building Materials, Volume 73, pp. 562-574, December 2014. https://doi.org/10.1016/j.conbuildmat.2014.09.102 [17] Mohammad Abedi, Terje Kanstad, Stefan Jacobsen, Guomin Ji, “Shrinkage Properties of Steel Fiber Reinforced Concrete- A Review”, Applications in Engineering Science, Volume 23, 100244, 2025. https://doi.org/10.1016/j.apples.2025.100244 [18] Amr Ghoniem, Louay Aboul Nour, “Experimental Investigation into the Properties of Crumb Rubberized Concrete Incorporating Corrugated Round Steel Fibers”, Archives of Civil and Mechanical Engineering, 24:100, 2024. https://doi.org/10.1007/s43452-024-00883-z [19] Vadim Soloviev and Evgenii Matiushin, “The Effects of Corrugated Steel Fiber on the Properties of Ultra-High Performance Concrete of Different Strength Levels”, Buildings, 13, 2591, 2023. https://doi.org/10.3390/buildings13102591 [20] Ahmed A. El-Abbasy, “Tensile, Flexural, Impact Strength, and Fracture Properties of Ultra-High-Performance Fiber-Reinforced Concrete – A Comprehensive Review”, Construction and Building Materials, Volume 408, 133621, 8 December 2023. https://doi.org/10.1016/j.conbuildmat.2023.133621 [21] Jinlin Ran, Tingchun Li, Dianhao Chen, Liming Shang, Weiteng Li, Qingwen Zhu, “Mechanical Properties of Concrete Reinforced with Corrugated Steel Fiber under Uniaxial Compression and Tension”, Structures, Volume 34, Pages 1890-1902, December 2021. https://doi.org/10.1016/j.istruc.2021.08.135 [22] Ingrid Lande Larsen, Rein Terje Thorstensen, “The Influence of Steel Fibres on Compressive and Tensile Strength of Ultra High Performance Concrete: A Review”, Construction and Building Materials, 256, 119459, 2020. https://doi.org/10.1016/j.conbuildmat.2020.119459 [23] Amjad Khabaz, “Performance Evaluation of Corrugated Steel Fiber in Cementitious Matrix”, Construction and Building Materials, Volume 128, pp. 373-383, 15 December 2016. https://doi.org/10.1016/j.conbuildmat.2016.10.094 [24] Peng Zhang, Zhe Feng, Jinjun Guo, Yuanxun Zheng and Peng Yuan, “Mechanical Behavior and Microscopic Damage Mechanism of Hybrid Fiber-Reinforced Geopolymer Concrete at Elevated Temperature”, Ceramics International, Volume 50, Issue 24, Part B, Pages 53851-53866, 15 December 2024. https://doi.org/10.1016/j.ceramint.2024.10.238 [25] Jiongfeng Liang, Liuhaoxiang Wang, Wanjie Zou, Wei Li, “Compressive behavior of Partially Encased Recycled Aggregate Concrete Columns after Exposure to Elevated Temperature”, Journal of Constructional Steel Research, Volume 221, 108889, October 2024. https://doi.org/10.1016/j.jcsr.2024.108889 [26] Shan Gao, Jieqi Li, Tomoya Nishiwaki, Yao Ding, Jing-xuan Wang, “Structural Implementation of Recycled Lump Prepared from Waste Concrete after Elevated Temperatures: Mechanical and Environmental Performances”, Structures, Volume 67, 106970, September 2024. https://doi.org/10.1016/j.istruc.2024.106970 [27] Kore Sudarshan D. and A. K. Vyas, “Impact of Fire on Mechanical Properties of Concrete Containing Marble Waste”, Science Direct: Journal of King Saud University – Engineering Sciences, Volume 31, pp. 42-51, 2019. [28] Rahul. M. Phuke and Mr. Jayesh G. Barke, “Review Paper on Impact of Fire on Concrete and Concrete Structure”, International Journal of Interdisciplinary Innovative Research & Development (IJIIRD), ISSN: 2456-236X, Volume 02, Issue 01, pp. 73-77, 2017. [29] Yakudima Akibu Ghali, Ruban Sugumar and Hassan Abba Musa, “Impact of Fire on Steel Reinforcement in Reinforced Concrete Structures”, International Journal of Scientific and Research Publications, Volume 5, Issue 10, October 2015. [30] K. Ghazi Wakili, E. Hugi, L. Karvonen, P. Schnewlin and F. Winnefeld, “Thermal behaviour of Autoclaved Aerated Concrete Exposed to Fire”, Elsevier, Cement & Concrete Composites 62, pp. 52-58, 2015. [31] Awoyera, P. O, Akinwumi, I. I., Ede, A. N. and Olofinnade, M. O, “Forensic Investigation of Fire-affected Reinforced Concrete Buildings”, IOSR Journal of Mechanical and Civil Engineering (IOSR-JMCE), Volume 11, Issue 4, Version IV, pp. 17-23, July-August 2014. [32] Jinhua Sun, Longhua Hu, and Ying Zhang, “A Review on Research of Fire Dynamics in High-Rise Buildings”, Science Direct: Theoretical & Applied Mechanics Letters 3,042001, 2013. [33] Chrysanthos Maraveas, Konstantinos Miamis and Apostolos A. Vrakas, “Fiber-Reinforced Polymer-Strengthened/Reinforced Concrete Structures Exposed to Fire: A Review”, Scientific Paper, Structural Engineering International, pp. 500-513, June 2012. [34] Lars Boström, Robert Jansson, “Self-Compacting Concrete Exposed to Fire”, SP Technical Research Institute of Sweden, 2008. [35] David N. Bilow, “Fire and Concrete Structures”, American Society of Civil Engineers (ASCE), Crossing Borders, Structures 2008: Crossing Borders, 2008. [36] Guillermo Rein, Xun Zhang, Paul Williams, Ben Hume, Alex Heise, Allan Jowsey, Barbara Lane, and Jose L. Torero, “Multi-Storey Fire Analysis For High-Rise Buildings”, 11th Interflam 2007, London, pp. 605-616, 2007. [37] Ian A. Fletcher, Stephen Welch, José L. Torero, Richard O. Carvel and Asif Usmani, “The Behaviour of Concrete Structures in Fire”, Journal of Thermal Science, January 2007. [38] Min Li, Chun Xiang Qian, and Wei Sun, “Mechanical Properties of High-strength Concrete after Fire”, Cement and Concrete Research, Volume 34, pp. 1001-1005, 2004. [39] Chi Sun Poon, Salman Azhar, Mike Anson, Yuk Lung Wong, “Effect of Post-Fire Curing on Fire Damaged Concrete”, Cement and Concrete Research, September 2001.

Copyright

Copyright © 2025 Jadhav Amol Shivaji, Mrs. Ansari Fatima Uz Zehra. 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.