American Journal of Civil Engineering and Architecture
ISSN (Print): 2328-398X ISSN (Online): 2328-3998 Website: Editor-in-chief: Mohammad Arif Kamal
Open Access
Journal Browser
American Journal of Civil Engineering and Architecture. 2019, 7(1), 1-12
DOI: 10.12691/ajcea-7-1-1
Open AccessArticle

Effects of Fire on the Strength of Reinforced Concrete Structural Members

Lateef O. Onundi1, , M. Ben Oumarou2 and Abba M. Alkali1

1Department of Civil and Water Resources Engineering, University of Maiduguri, Nigeria

2Department of Mechanical Engineering, University of Maiduguri, Borno State, Nigeria

Pub. Date: January 19, 2019

Cite this paper:
Lateef O. Onundi, M. Ben Oumarou and Abba M. Alkali. Effects of Fire on the Strength of Reinforced Concrete Structural Members. American Journal of Civil Engineering and Architecture. 2019; 7(1):1-12. doi: 10.12691/ajcea-7-1-1


This multidisciplinary research focuses on the effect of fire on structures due to the Boko Haram insurgency in Maiduguri, Northern Nigeria. It is aimed at giving a further contribution to understand the effect of fire with respect to the local aggregates, quenching methods and proposing an assessment methodology based on a suitable analytical procedure applied to reinforced concrete subjected to sustained fire. Cement, river sand, Bama gravel and water in standard proportion in accordance to BS1881 Part 101 were mixed to produce beams, slabs and cubes of different sizes and cured for 28 days. The samples were burnt in a designed fire simulation furnace using sugarcane bagasse as fuel with varying air velocities for 2 hours. Cooling of samples was carried out using water splashing, CO2 powder fire extinguisher and air cooling methods before the compressive strength tests using a Seidner Compressive Testing Machine and Non-destructive test with Rebound Hammer. The scanning electron microscopy tests were carried out using a Phenom ProX scanning electron microscope for imaging and analysis to physically examine and determine the elemental micro structural redistribution and influence on the tested samples. As the temperature within the experimental set-up reaches 900°C, the temperature around the vicinity of slab, beam or cube reached an average of 500°C. The results of the investigations show that different cooling methods induce varying levels of deteriorating and significant effects on the final internal micro-structures as well as physical, mechanical and thermal characteristics of concrete. Results from the destructive and non-destructive tests show that losses of strength vary from a minimum of 37.73% to a maximum of 86.67 % in the samples investigated. The local aggregates used namely the river sand and the Bama gravel surely influenced the medium grade reinforced concrete behaviour when subjected to fire.

reinforced concrete fire structural members Bama gravel quenching method spalling strength loss

Creative CommonsThis work is licensed under a Creative Commons Attribution 4.0 International License. To view a copy of this license, visit


Figure of 13


[1]  Wikipedia. List of Wildfires; Available online at:, accessed on: December 29, 2018 at 15:07 PM.
[2]  Melvin S. A. Performance of Concrete Structures Exposed to Fire; hlnthNattonal SAMPE (Society for the Advancement of Material and Process Engineering) Technical Conference, Atlanta, Georgia, “Materials and Processes-In-Service Performance”, Vol. 9, October 4-6, 1977.
[3]  Wikipedia. Grenfell Tower fire; Available online at:, accessed on: December 29, 2018 at 15:07 PM.
[4]  Leonard M.K., Mang’uriu G.N. and Paul M. Effects on Flexural Strength of Reinforced Concrete Beam Subjected to Fire; Civil and Environmental Research; ISSN 2224-5790 (Paper) ISSN 2225-0514 (Online); Vol.6, No.11, 2014
[5]  Wong Y.L., Poon C.S. and Chung KF. Effects of Fire on Durability of RC Structures; Annual Concrete Seminar - Standing Committee on Concrete Technology, The Hong Kong Polytechnic. February 3, 2005.
[6]  Zhaohui H., Ian W. B.and Roger J. P.Behaviour of Reinforced Concrete Structures in Fire;January 2006; Available online at:
[7]  Adam Levesque. Fire Performance of Reinforced Concrete Slabs; A Thesis Submitted to the Faculty of the Worcester Polytechnic Institute in partial fulfillment of the requirements for the Degree of Master of Science in Civil Engineering, May 2006.
[8]  Ian F., Audun B., Neil H. and Stephen W. Performance of Concrete in Fire: A Review of the State of the Art, With a Case Study of the Windsor Tower Fire; University of Edinburgh, School of Engineering and Electronics, Edinburgh, EH9 3JL, UK, 2006.
[9]  Khoury A. G.Fire and Concrete; Encontro Nacional Betao Estrutural 2008, Guimaraes- 5, 6.7 de Novembro de 2008.
[10]  David N. B. and Mahmoud E. K. Fire and Concrete Structures; Structures 2008: Crossing Borders, ASCE 2008.
[11]  Helder Francisco B. X. Analysis of Reinforced Concrete Frames Exposed to Fire; Dissertation Submitted in partial fulfillment of the requirements for the degree of Master in Civil Engineering- Structural Engineering Branch, Faculdade de Engenharia- Universidade do Porto, July 2009.
[12]  Annelies De Wit. Behaviour and structural design of concrete structures exposed to fire; Master of Science Thesis, Royal Institute of Technology (KTH) Stockholm, Sweden 2011.
[13]  Hager I. Behaviour of cement concrete at high temperature; Bulletin of the Polish Academy of Sciences- Technical Sciences, 61 (1): 1-10, 2013.
[14]  Rao C. B. K. and Rooban K. A Study on Behaviour of Normal Strength Concrete and High Strength Concrete Subjected to Elevated Temperatures World Academy of Science, Engineering and Technology, International Journal of Civil and Environmental Engineering, :9 (3):283- 287, 2015.
[15]  Wouter B. and Robby C. Post-cooling properties of concrete exposed to fire; Fire Safety Journal 92 (2017) 142-150.
[16]  Phuke R.M. and Jayesh G. B. Impact of Fire on Concrete and Concrete Structures; International Journal of Interdisciplinary Innovative Research & Development (IJIIRD), ISSN: 2456-236X, 02 (2018) Issue 02: 77-86.
[17]  Tomasz D., Wioletta J., Jerzy G. and Ritoldas Š. Assessment of Mechanical Properties of High Strength Concrete (HSC) after Exposure to High Temperature; Journal of Civil Engineering and Management. ISSN 1392-3730 / eISSN 1822-3605, 24 (2018) Issue 2: 138-144.
[18]  Yakudima A.G., Ruban S.and Hassan A. M. Impact of Fire on Steel Reinforcement in Reinforced Concrete Structures; International Journal of Scientific and Research Publications, 5(10):1-14, October 2015.
[19]  Hedayati M., Mendis P. A., Sofi M.and Ngo T. Fire Spalling of Concrete Members; 6th International Conference on Structural Engineering and Construction Management, Kandy, Sri Lanka, 11th-13th December 2015.
[20]  Kigha F., Sadeeq J. A. and Abejide O. S. Effects of Temperature Levels and Concrete Cover Thickness on Residual Strength Characteristics of Fire Exposed Reinforced Concrete Beams;Nigerian Journal of Technology (NIJOTECH, 34(2015), 3: 429-437.
[21]  Rahul.M. P and Jayesh G.B.Review Paper on Impact of Fire on Concrete and Concrete Structure; International Journal of Interdisciplinary Innovative Research & Development (IJIIRD) ISSN: 2456-236X, 02 (2017) 01:73-77.
[22]  Flavio S., Fausto M., Paola M. and Gianfranco C. Integrated Approach for Post-fire Reinforced Concrete Structures Assessment; Periodica Polytechnica Civil Engineering, 61 (4): pp. 677-699, 2017.
[23]  BS 812-103. 1. Testing aggregates- Part 103: Methods for determination of Particle size distribution- Section 103.1 Sieve test. British Standard Institute, London 1985.
[24]  BS1881 Part 101. Testing concrete- Part 101: Method of sampling fresh concrete on site. British Standard Institute, London 1983.
[25]  Abubakar A. B., Oumarou M. B., and Oluwole F. A. Design and Development of a Forward Curved Blower for Downdraft Gasifier Reactor. Arid zone Journal of Engineering and Technology. 14(2): 292-303, 2018.
[26]  Abubakar A. Bukar, M. Ben Oumarou, Fasiu A Oluwole and SahaboAbubakar. Testing and Performance Evaluation of a Forward Curved Blower for Thermal Applications; American Journal of Mechanical Engineering, 6(3): 114-126, 2018.
[27]  Michael Ashby. Materials Selection in Mechanical Design, Butterworth- Heinermann. 2011, Pp: 40.
[28]  Hodgkinson J.M. Mechanical Testing of Advanced Fibre Composites; Cambridge Woodhead publishing. Ltd, 2000, Pp: 132-133.
[29]  William D. Callister Jr. Materials Science and Engineering; Hoken; John Wiley & Sons Inc. 2003.
[30]  ASTM C1161-02C-e1. Standard Test Method for Flexural Strength of Advanced Ceramics at Ambient Temperature, West Conshohocken, PA.
[31]  Robert J. Fire Spalling of Concrete: Theoretical and Experimental Studies; Doctoral Thesis in Concrete Structures, Stockholm, KTH Architecture and the Built Environment, Sweden 2013.
[32]  Fernando J. M. Fire Resistance of Corroded Structural Concrete; A Thesis Submitted to the Faculty of The College of Engineering and Computer Science in Partial Fulfillment of the Requirements for the Degree of Master of Science, Florida Atlantic University- Boca Raton, Florida, December 2014.
[33]  Krzysztof C. and Szymon S. Structural Fire Design Methods for Reinforced Concrete Members; Technical Transactions- Civil Engineering 1-B/ 2013, pp: 15-36.
[34]  IndraD., Vidhya S. and Prabu Kumar P.K.An experimental study on residual characteristics of concrete subjected to elevated temperature; International Journal of Scientific Engineering and Applied Science (IJSEAS), 4 (March 2018), Issue-03: 36-48.
[35]  Jagadeesh C. and Sowjanya V. V. Comparative Study on Effect of Cooling Methods on Compressive Strength of Standard And High Strength Concrete Subjected To Real Fire; American Journal of Engineering Research (AJER), 6 (2017) 12: 167-172.
[36]  Marian A. and Robert K. The influence of short time water cooling on the mechanical properties of concrete heated up to high temperature, Journal of Civil Engineering and Management, 11 (2005) 2:85-90.
[37]  Tanacan L., Halit Y.E. and Umit A. Effect of high temperature and cooling conditions on aerated concrete properties, Construction and Building Materials (2008).
[38]  Sangluaia C., Haridharan M. K.,Natarajan C. and Rajaraman A. Behaviour of Reinforced Concrete Slab Subjected to Fire; International Journal Of Computational Engineering Research (,3 (January 2013) Issue. 1; 195-206.
[39]  Joakim A., Mathias F., Jan E. L. and Robert J. Assessment of concrete structures after fire; Fire Technology SP Report 2011:19.