# Comparison of the Flexural Behavior of High-Volume Fly AshBased Concrete Slab Reinforced with GFRP Bars and Steel Bars

^{1}

^{2}

^{3}

^{*}

## Abstract

**:**

## 1. Introduction

_{2}, the main ingredient of greenhouse gases, has become critical for ensuring a sustainable ecosystem. Cement is the prime ingredient in concrete, and its production leads to 7 to 10% of global carbon emissions. Because of its pozzolanic properties, fly ash can be utilized as a cement substitute in concrete slab elements. The pozzolanic properties of fly ash suggest that it could be utilized as a cement substitute in slab elements. Green concrete is becoming more popular in the construction business because of the disadvantages of traditional concrete. The various green concrete types available are geopolymer concrete, ultrahigh performance concrete, high-volume fly ash concrete, and lightweight concrete [1,2].

## 2. Materials and Methods

#### 2.1. Concrete

#### Reinforcing Bars

#### 2.2. Experimental Program

#### 2.2.1. Specimen Details

#### 2.2.2. Experimental Setup

## 3. Results and Discussion

#### 3.1. Crack Pattern

#### 3.2. Load–Deflection Behavior

#### 3.3. Strain Distribution

^{−6}mm/mm and 23,378 × 10

^{−6}mm/mm, respectively. The strain in the steel rod and GFRP rod of the fly ash concrete slab was 21,075 × 10

^{−6}mm/mm and 23,845 × 10

^{−6}mm/mm, respectively. The ultimate strain at the top of the OPC/fly ash concrete slabs lay in the range of 0.28% to 0.31% for the slab with steel reinforcement, and it ranged from 0.30% to 0.33% for the slab with GFRP reinforcement. The strain in the GFRP rods was higher than in steel rods in the OPC and fly ash concrete slab. From the graph, it can be observed that the concrete slab reinforced with GFRP rods has higher flexural strength than the steel-reinforced concrete slab [29,42].

#### 3.4. Moment–Curvature

_{c}is the compressive strain in concrete, ε

_{r}is the tensile strain in the reinforcement (steel/GFRP rod), and d is the effective depth of the slab.

#### 3.5. Displacement Ductility

## 4. Theoretical Prediction

#### 4.1. Equations Provided by ACI 44.1R-15

_{f}is the area of GFRP rods, b is the width of the cross-section, and d is the distance from the extreme compression fiber to the centroid of the GFRP rods.

_{f}is the elastic modulus of GFRP bars, and ${\epsilon}_{cu}$ is the ultimate strain in concrete (taken as 0.003).

_{1}can be calculated using Equation (4).

#### 4.2. Comparison of Experimental Results with Theoretical Predictions

## 5. Nonlinear Finite Element Analysis (NLFEA)

#### 5.1. Modeling

#### 5.2. Comparison of Experimental Results with NLFEA Results

## 6. Conclusions

- The slab specimens SRF, GRC, and GRF showed 17%, 19%, and 30% increases in their ultimate load-carrying capacity when compared with the control specimen SRC.
- The concrete surface strain was slightly higher for the fly ash concrete slab than for the OPC concrete slab, and the strain value of GFRP bars was higher than that of steel bars under the same loading. This shows that the flexural strength of the GFRP-reinforced concrete slab is higher than that of the steel-reinforced concrete slab.
- The ultimate moment capacity of the GRF slab was 12% higher than that of the SRF slab, and the ultimate moment capacity of the GRC slab was 20% higher than that of the SRC slab. The slabs reinforced with GFRP rods are capable of exhibiting more curvature before failure when compared to the slabs reinforced with steel.
- The average ductility of the steel rod was higher than that of the GFRP rod. Both the steel- and GFRP-reinforced slabs failed due to flexure with maximum strength and ductility.
- The analytical equations given by ACI 440.1R-15 for calculating the moment of resistance overestimated the experimental results by 18%. Thus, ACI 440.1R-15 can be used for the design of concrete slabs reinforced with GFRP rods.
- Only 10% deviation was observed between the experimental and the nonlinear finite element analysis (NLFEA) results. Hence, ANSYS 2022-R1 software can be used for the analysis of fly ash concrete slabs reinforced with GFRP bars.

## Author Contributions

## Funding

## Institutional Review Board Statement

## Informed Consent Statement

## Data Availability Statement

## Conflicts of Interest

## References

- Liew, K.; Sojobi, A.; Zhang, L. Green concrete: Prospects and challenges. Constr. Build. Mater.
**2017**, 156, 1063–1095. [Google Scholar] [CrossRef] - Barbuta, M.; Bucur, R.; Serbanoiu, A.; Scutarasu, S.; Burlacu, A. Combined Effect of Fly Ash and Fibers on Properties of Cement Concrete. Procedia Eng.
**2017**, 181, 280–284. [Google Scholar] [CrossRef] - Siddique, R. Effect of fine aggregate replacement with Class F fly ash on the mechanical properties of concrete. Cem. Concr. Res.
**2003**, 33, 539–547. [Google Scholar] [CrossRef] - Detwiler, R.J. Substitution of Fly Ash for Cement or Aggregate in Concrete: Strength Development and Suppression of ASR; RD127; Portland Cement Association: Skokie, IL, USA, 2002. [Google Scholar]
- Siddique, R. Performance characteristics of high-volume Class F fly ash concrete. Cem. Concr. Res.
**2004**, 34, 487–493. [Google Scholar] [CrossRef] - Joanna, P.S.; Rooby, J.; Prabhavathy, A.; Preetha, R.; Pillai, C.S. Behaviour of reinforced concrete beams with 50 percentage fly ash international journal of civil engineering and technology. Int. J. Civ. Eng. Technol.
**2013**, 4, 36–48. [Google Scholar] - Malhotra, V.M. High-Performance, High Volume FlyAsh Concrete. Concr. Int.
**2002**, 24, 30–34. [Google Scholar] - Saha, A. Effect of class F fly ash on the durability properties of concrete. Sustain. Environ. Res.
**2018**, 28, 25–31. [Google Scholar] [CrossRef] - Thomas, M.D.A. Optimizing the Use of Fly Ash in Concrete; Portland Cement Association: Skokie, IL, USA, 2007. [Google Scholar]
- 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
**2021**, 14, 3322. [Google Scholar] [CrossRef] - Hu, W.; Li, Y.; Yuan, H. Review of Experimental Studies on Application of FRP for Strengthening of Bridge Structures. Adv. Mater. Sci. Eng.
**2020**, 2020, 8682163. [Google Scholar] [CrossRef] - Mertol, H.C.; Rizkalla, S.; Scott, P.; Lees, J.M.; El-Hachal, R. Durability of concrete beams prestressed with CFRP. Symp. Pap.
**2007**, 245, 1–20. [Google Scholar] - Shave, J. The time has come for high strength, low maintenance fibre reinforced plastics. New Civil Eng.
**2014**, 11. [Google Scholar] - Yooprasertchai, E.; Dithaem, R.; Arnamwong, T.; Sahamitmongkol, R.; Jadekittichoke, J.; Joyklad, P.; Hussain, Q. Remediation of Punching Shear Failure Using Glass Fiber Reinforced Polymer (GFRP) Rods. Polymers
**2021**, 13, 2369. [Google Scholar] [CrossRef] [PubMed] - Mussa, M.H.; Radzi, N.A.M.; Hamid, R.; Mutalib, A.A. Fire Resistance of High-Volume Fly Ash RC Slab Inclusion with Nano-Silica. Materials
**2021**, 14, 3311. [Google Scholar] [CrossRef] [PubMed] - Zaghloul, M.M.Y.; Mohamed, Y.S.; El-Gamal, H. Fatigue and tensile behaviors of fiber-reinforced thermosetting composites embedded with nanoparticles. J. Compos. Mater.
**2018**, 53, 709–718. [Google Scholar] [CrossRef] - Zaghloul, M.M.Y.; Steel, K.; Veidt, M.; Heitzmann, M.T. Wear behaviour of polymeric materials reinforced with man-made fibres: A comprehensive review about fibre volume fraction influence on wear performance. J. Reinf. Plast. Compos.
**2022**, 41, 215–241. [Google Scholar] [CrossRef] - Zaghloul, M.M.Y.; Zaghloul, M.M.Y. Influence of flame retardant magnesium hydroxide on the mechanical properties of high density polyethylene composites. J. Reinf. Plast. Compos.
**2017**, 36, 1802–1816. [Google Scholar] [CrossRef] - Zaghloul, M.Y.M.; Zaghloul, M.M.Y.; Zaghloul, M.M.Y. Developments in polyester composite materials—An in-depth review on natural fibres and nano fillers. Compos. Struct.
**2021**, 278, 114698. [Google Scholar] [CrossRef] - Mohamed, Y.S.; El-Gamal, H.; Zaghloul, M.M.Y. Micro-hardness behavior of fiber reinforced thermosetting composites embedded with cellulose nanocrystals. Alex. Eng. J.
**2018**, 57, 4113–4119. [Google Scholar] [CrossRef] - Zaghloul, M.M.Y.M. Mechanical properties of linear low-density polyethylene fire-retarded with melamine polyphosphate. J. Appl. Polym. Sci.
**2018**, 135, 46770. [Google Scholar] [CrossRef] - Zaghloul, M.M.Y.; Zaghloul, M.Y.M.; Zaghloul, M.M.Y. Experimental and modeling of mechanical-electrical behavior of polypropylene composites filled with graphite and MWCNT fillers. Polym. Test.
**2017**, 63, 467–474. [Google Scholar] [CrossRef] - Bedon, C.; Louter, C. Structural glass beams with embedded GFRP, CFRP or steel reinforcement rods: Comparative experimental, analytical and numerical investigations. J. Build. Eng.
**2019**, 22, 227–241. [Google Scholar] [CrossRef] - Jalal, A.; Hakim, L.; Shafiq, N. Mechanical and Post-Cracking Characteristics of Fiber Reinforced Concrete Containing Copper-Coated Steel and PVA Fibers in 100% Cement and Fly Ash Concrete. Appl. Sci.
**2021**, 11, 1048. [Google Scholar] [CrossRef] - ACI 440.1R-15; Guide for the Design and Construction of Concrete Reinforced with Fiber Reinforced Polymers (FRP) Bars; American Concrete Institute: Farmington Hills, MI, USA, 2015.
- Balendran, R.; Rana, T.; Maqsood, T.; Tang, W. Application of FRP bars as reinforcement in civil engineering structures. Struct. Surv.
**2002**, 20, 62–72. [Google Scholar] [CrossRef] - Balafas, I.; Burgoyne, C. Economic design of beams with FRP rebars or prestress. Mag. Concr. Res.
**2012**, 64, 885–898. [Google Scholar] [CrossRef] [Green Version] - Hollaway, L. A review of the present and future utilisation of FRP composites in the civil infrastructure with reference to their important in-service properties. Constr. Build. Mater.
**2010**, 24, 2419–2445. [Google Scholar] [CrossRef] - Jabbar, S.; Farid, S. Replacement of steel rebars by GFRP rebars in the concrete structures. Karbala Int. J. Mod. Sci.
**2018**, 4, 216–227. [Google Scholar] [CrossRef] - Kemp, M.; Blowes, D. Concrete Reinforcement and Glass Fibre Reinforced Polymer. Qld. Roads Ed.
**2011**, 11, 40–48. [Google Scholar] - Borosnyói, A. Corrosion-resistant concrete structures with innovative Fibre Reinforced Polymer (FRP) materials. Epa.-J. Silic. Based Compos. Mater.
**2013**, 65, 26–31. [Google Scholar] - Sólyom, S.; Balázs, G.L.; Borosnyói, A. Material characteristics and bond tests for FRP rebars. Concr. Struct.
**2015**, 16, 38–45. [Google Scholar] - Patil, V.R. Experimental Study of Behavior of RCC Beam by Replacing Steel Bars with Glass Fiber Reinforced Polymer and Carbon Reinforced Fiber Polymer (GFRP). Int. J. Innov. Res. Adv. Eng.
**2014**, 1, 205–210. [Google Scholar] - Goonewardena, J.; Ghabraie, K.; Subhani, M. Flexural Performance of FRP-Reinforced Geopolymer Concrete Beam. J. Compos. Sci.
**2020**, 4, 187. [Google Scholar] [CrossRef] - Adam, M.A.; Erfan, A.M.; Habib, F.A.; El-Sayed, T.A. Structural Behavior of High-Strength Concrete Slabs Reinforced with GFRP Bars. Polymers
**2021**, 13, 2997. [Google Scholar] [CrossRef] [PubMed] - Jayajothi, P.; Kumutha, R.; Vijai, K. Finite element analysis of FRP strengthened RC beams using Ansys. Asian J. Civ. Eng.
**2013**, 14, 631–642. [Google Scholar] - Gherbi, A.; Dahmani, L.; Boudjemia, A. Study on two way reinforced concrete slab using Ansys with different boundary conditions and loading world academy of science. Eng. Technol. Int. J. Civ. Environ. Eng.
**2018**, 12, 1151–1156. [Google Scholar] - ANSYS 2022-R1; Manual Set. ANSYS Inc.: Canonsburg, PA, USA, 2022.
- Gu, H.S.; Zhu, D.Y. Flexural Behaviours of Concrete Slab Reinforced with GFRP bars. Adv. Mater. Res.
**2011**, 243–249, 567–572. [Google Scholar] [CrossRef] - Moon, J.; Reda Taha, M.M.; Kim, J.J. Flexural Strengthening of RC Slabs Using a Hybrid FRP-UHPC System Including Shear Connector. Adv. Mater. Sci. Eng.
**2017**, 2017, 4387545. [Google Scholar] [CrossRef] [Green Version] - Dhipanaravind, S.; Sivagamasundari, R. Flexural Behaviour of Concrete One-way Slabs Reinforced with Hybrid FRP Bars. Int. J. Appl. Eng.
**2018**, 13, 4807–4815. [Google Scholar] - Venkatesan, G.; Raman, S.R.; Sekaran, M.C. Flexural behaviour of reinforced concrete beams using high volume fly ash concrete confinement in compression zone. J. Civ. Eng. (IEB)
**2013**, 41, 87–97. [Google Scholar] - El Zareef, M.; El Madawy, M. Effect of glass-fiber rods on the ductile behaviour of reinforced concrete beams. Alex. Eng. J.
**2018**, 57, 4071–4079. [Google Scholar] [CrossRef] - Thamrin, R.; Zaidir, Z.; Iwanda, D. Ductility Estimation for Flexural Concrete Beams Longitudinally Reinforced with Hybrid FRP–Steel Bars. Polymers
**2022**, 14, 1017. [Google Scholar] [CrossRef] - Gunes, O.; Lau, D.; Tuakta, C.; Büyüköztürk, O. Ductility of FRP–concrete systems: Investigations at different length scales. Constr. Build. Mater.
**2013**, 49, 915–925. [Google Scholar] [CrossRef] - Ahmed, H.; Jaf, D.; Yaseen, S. Comparison of the Flexural Performance and Behaviour of Fly-Ash-Based Geopolymer Concrete Beams Reinforced with CFRP and GFRP Bars. Adv. Mater. Sci. Eng.
**2020**, 2020, 3495276. [Google Scholar] [CrossRef] [Green Version]

**Figure 10.**Load–strain behavior of (

**a**) SRC and (

**b**) SRF. RS—reinforcement strain; CS—concrete strain.

**Figure 11.**Load–strain behavior of (

**a**) GRC and (

**b**) GRF. RS—reinforcement strain; CS—concrete strain.

**Figure 14.**Displacement Ductility (Thamrin et al. [44]).

**Figure 19.**Comparison between experimental and numerical load–deflection behavior of (

**a**) SRF and (

**b**) GRF.

Chemical Composition | Content (% by Mass) |
---|---|

SiO_{2} | 52.52 |

Al_{2}O_{3} | 32.63 |

Fe_{2}O_{3} | 6.16 |

CaO | Nil |

NA1-20 | 0.02 |

SO_{3} | 4.95 |

MnO | 0.03 |

LOI | 1.08 |

Specimen Type | Compressive Strength ${{\mathit{f}}^{\prime}}_{\mathit{c}}$ (MPa) | Split Tensile Strength (MPa) | ||
---|---|---|---|---|

28 Days | 56 Days | 28 Days | 56 Days | |

Control concrete | 34.23 | 36.27 | 3.94 | 5.01 |

60% Fly ash concrete | 26.39 | 37.74 | 3.16 | 5.79 |

Reinforcement Material | Diameter (mm) | Tensile Strength ${\mathit{f}}_{\mathit{f}\mathit{u}}$ (MPa) | Modulus of Elasticity E_{f}(MPa) | Density (Kg/m^{3}) |
---|---|---|---|---|

STEEL rod | 10 | 650 | 200,000 | 7800 |

GFRP rod | 10 | 1100 | 55,000 | 1900 |

Specimen | Concrete Material | Reinforcement Material | Diameter (mm) |
---|---|---|---|

SRC | OPC (C) | Steel rod (SR) | 10 |

SRF | Fly ash (F) | Steel rod (SR) | 10 |

GRC | OPC (C) | GFRP rod (GR) | 10 |

GRF | Fly ash (F) | GFRP rod (GR) | 10 |

Specimen ID | First Crack Load P_{cr}(kN) | Ultimate Load P _{u} (kN) |
---|---|---|

SRC 1 | 15.7 | 24 |

SRC 2 | 16.3 | 23.8 |

SRF 1 | 19.1 | 28.5 |

SRF 2 | 18.5 | 27.3 |

GRC1 | 15.2 | 29 |

GRC2 | 16.3 | 28.1 |

GRF 1 | 17.6 | 31.8 |

GRF 2 | 18.5 | 30.3 |

Slab Designation | Max. Load (P _{u}) (kN) | Deflection at Max Load (Δ) (mm) | Ultimate Moment (M_{Exp}) (kNm) | Ultimate Strain in Concrete $\left({\mathit{\epsilon}}_{\mathit{c}\mathit{u}}\right)$ % | Ultimate Strain In Reinforcement $({\mathit{\epsilon}}_{\mathit{f}})$ % | Ductility Ratio |
---|---|---|---|---|---|---|

SRC 1 | 24.0 | 16.2 | 3.20 | 0.28 | 2.00 | 11.77 |

SRC 2 | 23.8 | 19.2 | 3.17 | 0.31 | 1.90 | 11.87 |

SRF 1 | 28.5 | 17.9 | 3.70 | 0.30 | 2.19 | 12.27 |

SRF 2 | 27.3 | 18.2 | 3.64 | 0.30 | 2.02 | 11.33 |

GRC 1 | 29.0 | 17.1 | 3.87 | 0.31 | 2.30 | 7.33 |

GRC 2 | 28.1 | 15.8 | 3.75 | 0.32 | 2.36 | 7.72 |

GRF 1 | 31.8 | 13.6 | 4.24 | 0.33 | 2.39 | 8.35 |

GRF 2 | 30.3 | 16.7 | 4.04 | 0.33 | 2.37 | 7.88 |

Specimen | Reinforcement Ratio $\left({\mathit{\rho}}_{\mathit{f}}\right)$ | Failure Mode | Moment of Resistance | Percentage of Deviation (%) | |
---|---|---|---|---|---|

M,Exp (kN·m) | M,ACI (kN·m) | ||||

GRC 1 | 1.44${\rho}_{fb}$ | Compression failure | 3.87 | 4.48 | 15.9 |

GRC 2 | 1.44${\rho}_{fb}$ | Compression failure | 3.75 | 4.48 | 19.6 |

GRF 1 | 1.44${\rho}_{fb}$ | Compression failure | 4.24 | 4.48 | 5.84 |

GRF 2 | 1.44${\rho}_{fb}$ | Compression failure | 4.04 | 4.48 | 11.0 |

Specimen Id. | Ultimate Load (kN) | Deflection at Mid-Span (mm) | ||
---|---|---|---|---|

Experimental | NLFEA (ANSYS) | Experimental | NLFEA (ANSYS) | |

SRF | 28.5 | 27 | 17.9 | 16.4 |

GRF | 31.8 | 30 | 13.6 | 12.3 |

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. |

© 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).

## Share and Cite

**MDPI and ACS Style**

Madan, C.S.; Munuswamy, S.; Joanna, P.S.; Gurupatham, B.G.A.; Roy, K.
Comparison of the Flexural Behavior of High-Volume Fly AshBased Concrete Slab Reinforced with GFRP Bars and Steel Bars. *J. Compos. Sci.* **2022**, *6*, 157.
https://doi.org/10.3390/jcs6060157

**AMA Style**

Madan CS, Munuswamy S, Joanna PS, Gurupatham BGA, Roy K.
Comparison of the Flexural Behavior of High-Volume Fly AshBased Concrete Slab Reinforced with GFRP Bars and Steel Bars. *Journal of Composites Science*. 2022; 6(6):157.
https://doi.org/10.3390/jcs6060157

**Chicago/Turabian Style**

Madan, Chinnasamy Samy, Swetha Munuswamy, Philip Saratha Joanna, Beulah Gnana Ananthi Gurupatham, and Krishanu Roy.
2022. "Comparison of the Flexural Behavior of High-Volume Fly AshBased Concrete Slab Reinforced with GFRP Bars and Steel Bars" *Journal of Composites Science* 6, no. 6: 157.
https://doi.org/10.3390/jcs6060157