BEHAVIOR OF CONCRETE UNDER FIRE EXPOSURE
European Journal of Materials Science and Engineering, Volume 9, Issue 4, 2024
PDF Full Article, DOI: 10.36868/ejmse.2024.09.04.281, pp. 281-294
Yisihak GEBRE1,*, Habtom GEBREMARIAM1, Abrham G. TAREKEGN1
1 School of Civil and Environmental Engineering, Addis Ababa Institute of Technology, Addis Ababa University, Ethiopia.
* Corresponding author: yisgeb2004@gmail.com
Abstract
Service structures could be built from different materials and concrete is commonly used in construction due to its beneficial mechanical properties, such as its superior compressive strength, long-lasting durability, and ability to resist fire. Structures are anticipated to withstand the various loads they encounter during their operational lifespan, which can typically be determined based on factors such as the type of service, geographical location, and dimensions. These loads can be accurately modeled using advanced software tools that are continuously evolving. However, fire incidents are difficult to predict, making it challenging to foresee their location, timing, and the extent of their impact on structures, resulting reductions in strength and unexpected stress. Therefore, in this study, to examine the performance of concrete of different strength grades and reinforced concrete (RC) beam specimens exposed to fire at different temperatures, an experimental investigation was carried out. During the test, the maximum duration of fire exposure taken is four hours and maximum concrete surface temperature considered is limited to 246°C. For the RC beams, test was conducted under one-point loading with different specimens of 25 mm and 35 mm concrete covers. The results showed that, the strength of RC beam after fire exposure reduces up to 18% and the compression strength of concrete at 246°C of fire exposure temperature with 25 MPa and 30 MPa were observed to drop by 32%, and 48%, respectively as compared to initial strength. Moreover, comparison of experimental results with numerical models were made. The results revealed that the predicted values of the residual compressive strength proposed by Hertz’s model are in good agreement with the experimental values.
Keywords: RC beam, residual strength, fire exposure, temperature.
References:
[1] A.A. Mohamed, M.S. Issa, and A.A. Mahmoud, Behavior of Reinforced Concrete Beams Exposed to Fire,Engineering Research Journal (Shoubra), 47(1), 2021, pp.139-149.
[2] W.C. Jau, K.L. Huang, A study of reinforced concrete corner columns after fire, Cement Concrete Composite 30 (7), 2008, 622–638.
[3] N. Anand, G.P. Arulraj, Effect of grade of concrete on the performance of self compacting concrete beams subjected to elevated temperatures, Fire Technology 50, 2014, pp.1269-1284.
[4] K. Behfarnia, M. Shahbaz, The effect of elevated temperature on the residual tensile strength and physical properties of the alkali-activated slag concrete, Journal of Building Engineering, 20, 2018, pp. 442–454.
[5] N. Anand, A. Godwin, Influence of mineral admixtures on mechanical properties of self-compacting concrete under elevated temperature, Fire Materials 7 (40), 2016, pp. 940–958.
[6] Guide for Determining the Fire Endurance of Concrete Elements, American Concrete Institute Committee 216, ACI 216 R-89, 1994.
[7] O. Arioz, Effects of elevated temperatures on properties of concrete, Fire safety journal, 42, 2007, pp. 516–522.
[8] C.S. Poon, S. Azhar, M. Anson, Y.L. Wong, Strength and durability recovery of fire damaged concrete after post-fire-curing, Cement and Concrete Research 31, 2001, pp. 1307-1318.
[9] D.P. Thanaraj, N. Anand, P. Arulraj, Experimental investigation of mechanical properties and physical characteristics of concrete under standard fire exposure, Journal of Engineering, Design and Technology 17 (5), 2019, pp. 878–903.
[10] A. Varghese, D. J. Samuel, N. Anand, G. P. Arulraj, Studies on behavior of fire affected fiber reinforced concrete, Int. J. Civ. Eng. Technology 9 (10), 2018, pp. 1668–1675.
[11] A.M. Lafta, H.K. Sultan, A.J. Abdulkareem, and A.A. Hassan, Effect of the heat from fire on the strength of the concrete. In AIP Conference Proceedings, 2806 (1), 2023, pp 1-6.
[12] V. Kodur and W. Khaliq, Effect of temperature on thermal properties of different types of high strength concrete, Journal of Materials in Civil Engineering, 23(6), 2011, pp. 793-801.
[13] M. Mohammad, S. A. Saif Ali, A. A. Ali, Mathematical Models for Prediction of Some Mechanical Properties of Concrete Exposed to Burning, University of Babylon Repository, 2011.
[14] J. Shen, and Q. Xu, Effect of elevated temperatures on compressive strength of concrete, Construction and Building Materials, 229, 2019, p.116846.
[15] E. Ünlüoglu, I.B. Topçu, B. Yalaman, Concrete cover effect on reinforced concrete bars exposed to high temperatures, Construction and Building Materials, 21 (6), 2007, pp. 1155-1160.
[16] L.O. Onundi, M.B. Oumarou, and A.M. Alkali, Effects of fire on the strength of reinforced concrete structural members, American Journal of Civil Engineering and Architecture, 7(1), 2019, pp.1-12.
[17] R.K. Aboud, h.K. Awad, and S.D. Mohammed, Effect of Fire Exposure on the Properties of Self-Compacting Concrete reinforced by Glass Fibers, Engineering, Technology & Applied Science Research, 14(2), 2024, pp.13369-13375.
[18] I.B. Topçu, B. Is¸Ikdag, The effect of cover thickness on rebars exposed to elevated
temperatures, Construction and Building Materials, 22 (10), 2008, pp. 2053-2058.
[19] D.P. Thanaraj, N. Anand, P Arulraj, K Al-Jabri, Investigation on structural and thermal performance of reinforced concrete beams exposed to standard fire, Journal of Building Engineering, 32, 2020, p.101764.
[20] D.K. Sudarshan, and A.K. Vyas, Impact of fire on mechanical properties of concrete containing marble waste, Journal of King Saud University-Engineering Sciences, 31(1), 2019, pp.42-51.
[21] K. D. Hertz, Concrete strength for fire safety design, Magazine of Concrete Research, 57 (8), 2005, pp. 445–453.
[22] EN 1992-1-2: Eurocode 2: Design of Concrete Structures-Part 1-2: General Rules-Structural Fire Design, Brussels, Belgium, 2004.
[23] ASTM C 136-06: Standard Test Method for Sieve Analysis of Fine and Coarse
Aggregates, ASTM International, 2014.
[24] EN 12390-4:2019, Testing hardened concrete – Part 4: Compressive strength of
test specimens, 2019.
[25] C. Rao, R. Kumar, A study on behaviour of normal strength concrete and high strength concrete subjected to elevated temperatures, International Journal of Civil and Environmental Engineering, 9 (3), 2015, pp. 283-287.
[26] B. Toumi, M. Resheidat, Z. Guemmadi, Coupled effect of high temperature and heating time on the residual strength of normal and high-strength concretes, Jordan Journal of Civil Engineering, 3(4), 2009, pp. 322-330.
[27] K. K. Poloju, R.K Manchiryal, C. Rahul, Strength Studies on Different Grades of Concrete Considering Fire Exposure, American Journal of Civil Engineering, 6(1), 2018, pp. 16-23.
[28] D Larissa, A. L Kirchhof, P Luiz Carlos, F Silva, Assessment of Concrete Residual Strength at High Temperatures using Ultrasonic Pulse Velocity, The e-journal of non-destructive testing 20(7), 2015, pp. 1-9.
[29] G.A. Khoury, Effect of fire on concrete and concrete structures, Progress in Structural Engineering and Materials, 2(4), 2000, pp.429-447.
[30] D. N. Bilow, and M. E. Kamara, Fire and concrete structures, In Structures Congress: Crossing Borders, 2008, pp. 1-10.
