Dynamic Flexural Stiffness of Steel Fiber-Reinforced Concrete Beams under Impact Loading
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Abstract
This study examines the rate-sensitive flexural stiffness behavior of steel fiber-reinforced concrete (SFRC) beams subjected to quasi-static and impact loading. An experimental program was conducted on prismatic SFRC beams containing 1% hooked-end steel fibers (30 mm length, aspect ratio 80), tested over a wide strain-rate range from 10-6 to 20 s-¹. Flexural responses were captured using load cells, accelerometers, and digital image correlation to accurately measure midspan deflection and stiffness evolution. The results indicate that the initial flexural stiffness of SFRC increases with strain rate, highlighting the important contribution of inertial effects and enhanced fiber–matrix interaction under high strain rate loading. The rate sensitivity was most pronounced in the range of impact rather than range of quasi-static. At very high strain rates, several fibers exhibited reduced deformation capacity due to more brittle pull-out behavior and occasional rupture, leading to a slight reduction in the efficiency of fiber bridging and limiting further stiffness enhancement. Based on the experimental results, new empirical relationships are proposed to characterize the dynamic increase factor of flexural stiffness. These findings provide a deeper understanding of SFRC behavior under impact conditions and contribute to the development of more reliable design strategies for protective concrete structures.
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Othman H, Marzouk H. An experimental investigation on the effect of steel reinforcement on impact response of reinforced concrete plates. Int J Impact Eng 2016;88:12–21. Available from: https://doi.org/10.1016/j.ijimpeng.2015.08.015
Bakhshi M, Barros JAO, Rezazadeh M, Valente IB, Ramezansefat H. A novel analytical framework for assessing the impact response of SFRC beam. Int J Impact Eng 2023;182:104768. Available from: https://doi.org/10.1016/j.ijimpeng.2023.104768
Bakhshi M, Valente IB, Ramezansefat H, Barros JAO. Evaluation of the inertia force in compressive impact loading on steel fiber-reinforced concrete. RILEM-fib Int. Symp. Fibre Reinf. Concr., Springer; 2021: 277–88. Available from: https://doi.org/10.1007/978-3-030-83719-8_25
Hassanshahi O, Majid TA, Lau TL, Yousefi A, Tahara RMK. Seismic performance of the typical RC beam–column joint subjected to repeated earthquakes. AIP Conf. Proc., vol. 1892, AIP Publishing LLC; 2017; 120014. Available from: https://doi.org/10.1063/1.5005755
Yousefi A, Bunnori NM, Khavarian M, Hassanshahi O, Majid TA. Experimental investigation on effect of multi-walled carbon nanotubes concentration on flexural properties and microstructure of cement mortar composite. AIP Conf. Proc., vol. 1892, AIP Publishing LLC; 2017; 20032. Available from: https://doi.org/10.1063/1.5005663
Banthia NP, Mindess S, Bentur A. Impact behaviour of concrete beams. Mater Struct 1987;20:293–302.
Ulzurrun G, Zanuy C. Flexural response of SFRC under impact loading. Constr Build Mater 2017;134:397–411. Available from: https://doi.org/10.1016/j.conbuildmat.2016.12.138
Zanuy C, Ulzurrún GSD. Rate effects of fiber-reinforced concrete specimens in impact regime. Procedia Eng 2017;193:501–8. Available from: https://doi.org/10.1016/j.proeng.2017.06.243
Yoo DY, Yoon YS, Banthia N. Flexural response of steel-fiber-reinforced concrete beams: Effects of strength, fiber content, and strain-rate. Cem Concr Compos 2015;64:84–92. Available from: https://doi.org/10.1016/j.cemconcomp.2015.10.001
Bakhshi M, Ramezansefat H, Rezazadeh M, Valente I, Barros JAO. An analytical approach for evaluating the impact response of steel fiber reinforced concrete beam. Proc. 3rd RILEM Spring Conv. Conf. Vol. 1 Strateg. a Resilient Built Environ. 3, Springer; 2021: 15–30. Available from: https://doi.org/10.1007/978-3-030-76547-7_2
Bakhshi M, Valente IB, Ramezansefat H, Barros JAO. Maximum Midspan Acceleration of Steel Fiber-Reinforced Concrete Beams Under Impact Loading. FIB Int. Conf. Concr. Sustain., Springer; 2024, p. 506–14.
Azimi N, Oliveira DV, Ghiassi B, Dalalbashi A, Lourenço PB. Evaluation of creep effects on textile-reinforced mortar via single-lap shear testing. Constr Build Mater 2025;497:143897. Available from: https://doi.org/10.1016/j.conbuildmat.2025.143897
Yoo DY, Banthia N. Impact resistance of fiber-reinforced concrete–A review. Cem Concr Compos 2019;104:103389. Available from: https://doi.org/10.1016/j.cemconcomp.2019.103389
Bakhshi M, Valente IB, Ramezansefat H, Barros JAO, Pereira ENB, Peixinho NRM. Experimental and analytical study of the high-strain-rate compressive behavior of SFRC. Mech Adv Mater Struct 2023:1–24. Available from: https://doi.org/10.1080/15376494.2023.2199420
Bakhshi M, Valente IB, Ramezansefat H. New model for evaluating the impact response of steel fiber reinforced concrete subjected to the repeated drop-weight. Constr Build Mater 2024;449:138459. Available from: https://doi.org/10.1016/j.conbuildmat.2024.138459
Bakhshi M, Valente IB, Ramezansefat H, Barros JAO, Pereira ENB, Peixinho NRM. Experimental and analytical study of the high-strain-rate flexural behavior of SFRC. J Mater Civ Eng 2023. Available from: https://doi.org/10.1061/JMCEE7.MTENG-16559.
Ramezansefat H, Rezazadeh M, Barros JAO, Valente IB, Bakhshi M. Modeling the Compressive Behavior of Steel Fiber Reinforced Concrete Under High Strain Rate Loads. Fibre Reinf. Concr. Improv. Innov. RILEM-fib Int. Symp. FRC 2020 10, Springer; 2021; 703–13. Available from: https://doi.org/10.1007/978-3-030-58482-5_63
Ramezansefat H, Rezazadeh M, Barros J, Valente I, Bakhshi M. Modelling the High Strain Rate Tensile Behavior of Steel Fiber Reinforced Concrete Using Artificial Neural Network Approach. Int. Conf. Fibre-Reinforced Polym. Compos. Civ. Eng., Springer; 2021; 1099–109.
Hassanshahi O, Salati M, Azimi N, Bakhshi M. Hybrid Steel Fibers and RCA in RCC Pavements: Mechanical Recovery, Freeze–Thaw Durability, and Eco-Efficiency. Infrastructures 2025;10:321.
Hassanshahi O, Karimzadeh S, Bakhshi M, Azimi N. Synergistic Role of Recycled Concrete Aggregates and Hybrid Steel Fibers in Roller-Compacted Concrete Pavements: A Multi-Criteria Assessment for Eco-Efficiency Optimization. Buildings 2025;15:4279.
ACI Committee 544. Report on Measuring Mechanical Properties of Hardened Fiber Reinforced Concrete 2017.
Bakhshi M, Valente IB, Ramezansefat H, Barros JAO. Effect of inertia and test approach on the high-strain-rate tensile behavior of steel fiber reinforced concrete. Cem Concr Compos 2025:106095.
Bakhshi M, Valente IB, Ramezansefat H, Barros JAO. Evaluation of inertia force and maximum midspan acceleration in steel fiber reinforced concrete beam at high-strain rates. Cem Concr Compos 2025:106384. Available from: https://doi.org/10.1016/j.cemconcomp.2025.106384
Bakhshi M, Valente IB, Ramezansefat H, Barros JAO, Pereira ENB, Peixinho NRM. Experimental investigation of the effect of high strain rate loading on the flexural behaviour of the steel fibre-reinforced concrete. Fib Symp 2021;2021-June:604–13.
Qin Z, Zheng D, Li X, Wang H. Influence of Inertia on the Dynamic Compressive Strength of Concrete. Materials (Basel) 2022;15:7278.
Wang Z, Ma G, Ma Z, Zhang Y. Flexural behavior of carbon fiber-reinforced concrete beams under impact loading. Cem Concr Compos 2021;118:103910. Available from: https://doi.org/10.1016/j.cemconcomp.2020.103910
Wu M, Chen Z, Zhang C. Determining the impact behavior of concrete beams through experimental testing and meso-scale simulation: I. Drop-weight tests. Eng Fract Mech 2015;135:94–112. Available from: https://doi.org/10.1016/j.engfracmech.2014.12.019
Azimi N, Schollbach K, Oliveira D V, D’Antino T, Lourenço PB. Durability of natural hydraulic lime–pozzolan mortars for TRM strengthening systems under acidic aging: Linking microstructural degradation to mechanical performance via chemo-mechanical modeling. Constr Build Mater 2025;500:144244. Available from: https://doi.org/10.1016/j.conbuildmat.2025.144244
Hassanshahi O, Kameli S, Mohammadpour R, Bakhshi M, Mahboob A. Experimental Investigation of Sustainable Roller-Compacted Concrete Pavement (RCCP) Reinforced with Natural Fibers: Mechanical Performance, Durability, and Environmental Impacts. Int J Pavement Res Technol 2025:1–24.
Banthia N, Gupta P, Yan C. Impact resistance of fiber reinforced wet-mix shotcrete part 1: Beam tests. Mater Struct 1999;32:563–70.
Malvar LJ. Review of static and dynamic properties of steel reinforcing bars. Mater J 1998;95:609–16.
Lok TS, Zhao PJ. Impact response of steel fiber-reinforced concrete using a split Hopkinson pressure bar. J Mater Civ Eng 2004;16:54–9.
CEB-FIP. Model code 2010. Com Euro-International Du Bet 2010.
CEB-FIP. Design code 1990. Com Euro Int Du Bet 1990:51–9.
Ghomian M, Dehestani M, Garshasbi S, Azimi N. Optimizing fracture resistance in steel fiber-reinforced self-consolidating concrete: Insights from mode II and mode I fracture energy analysis. Structures, Elsevier; 2025; 75: 108707. Available from: https://doi.org/10.1016/j.istruc.2025.108707
Othman H, Marzouk H, Sherif M. Effects of variations in compressive strength and fibre content on dynamic properties of ultra-high performance fibre-reinforced concrete. Constr Build Mater 2019;195:547–56. Available from: https://doi.org/10.1016/j.conbuildmat.2018.11.093
Zhang XX, Abd Elazim AM, Ruiz G, Yu RC. Fracture behaviour of steel fibre-reinforced concrete at a wide range of loading rates. Int J Impact Eng 2014;71:89–96. Available from: https://doi.org/10.1016/j.ijimpeng.2014.04.009
Wang S, Zhang MH, Quek ST. Effect of specimen size on static strength and dynamic increase factor of high-strength concrete from SHPB test. J Test Eval 2011;39:898–907. Available from: https://doi.org/10.1520/JTE103370
Chen C, Geng P, Yang Q, Zhao Y, Gu W, He C, et al. Dynamic constitutive modeling of steel fiber reinforced concrete considering damage evolution under high strain rate. Constr Build Mater 2024;440:137433.
Sun X, Zhao K, Li Y, Huang R, Ye Z, Zhang Y, et al. A study of strain-rate effect and fiber reinforcement effect on dynamic behavior of steel fiber-reinforced concrete. Constr Build Mater 2018;158:657–69. Available from: https://doi.org/10.1016/j.conbuildmat.2017.09.093
ACI Committee 544. State-of-the-art report on fiber reinforced concrete 1996.
Wang S, Zhang M-H, Quek ST. Effect of high strain rate loading on compressive behaviour of fibre-reinforced high-strength concrete. Mag Concr Res 2011;63:813–27.
Barros JAO, Costa IG, Frazão CM V, Valente TDS, Lourenço LAP, Melo FJSA. Innovative prefabricated lightweight slab system of high structural performance. Eng Struct 2022;259:114146.
Barros JAO, Valente TDS, Costa IG, Melo FJSA. Integrating Hybrid Reinforced Concrete Technology and Advanced FEM-Based Numerical Modelling for Crack Control in Long Concrete Foundations Without Joints. RILEM Int. Conf. Numer. Model. Strateg. Sustain. Concr. Struct., Springer; 2022; 33–46.
Tlemat H, Pilakoutas K, Neocleous K. Flexural toughness of SFRC made with fibres extracted from tyres. Proc. Int. Symp. Adv. Waste Manag. Recycl. (in Recycl. Reuse Waste Mater. Dundee, 2003, p. 365–74.
B E. 12390‑4. Testing hardened concrete–Part 4 : Compressive strength – Specification for testing machines. Br Stand Inst London, UK 2019.
En BS. 12390-13. Testing hardened concrete–Part 13: determination of secant modulus of elasticity in compression. Br Stand Inst London, UK 2013.
EN BS. 14651: 2005+ A1: 2007. Test method for metallic fibre concrete–Measuring the flexural tensile strength (limit of proportionality (LOP), residual). Br Stand Inst London, UK 2005.
Bakhshi M, Azimi N, Hassanshahi O. Effect of Strain Rate on the Energy Dissipation Capacity of Steel Fiber Reinforced Concrete Beams. J Build Eng 2026:115527. Available from: https://doi.org/10.1016/j.jobe.2026.115527
Zhu Yan-yan. Numerical Simulation on Impact Resistance of Steel-fiber Reinforced Concrete. Eng Mater Sci 2007.
Rasheed MA, Prakash SS. Behavior of hybrid-synthetic fiber reinforced cellular lightweight concrete under uniaxial tension–Experimental and analytical studies. Constr Build Mater 2018;162:857–70.
Park JK, Kim SW, Kim DJ. Matrix-strength-dependent strain-rate sensitivity of strain-hardening fiber-reinforced cementitious composites under tensile impact. Compos Struct 2017;162:313–24.
Banthia N, Mindess S, Bentur A, Pigeon M. Impact testing of concrete using a drop-weight impact machine. Exp Mech 1989;29:63–9. Available from: https://doi.org/10.1007/BF02327783
Bentur A, Mindess S. Fibre reinforced cementitious composites. Crc Press; 2006.