Journal of the Civil Engineering Forum.
May 2026, 12.
:217-228 DOI 10.
22146/jcef.
Available Online at https://jurnal.
id/v3/jcef/issue/archive Experimental Investigation of Steel Fiber Diameter.
Volume Fraction, and Aspect Ratio on Concrete Mechanical Behavior Arka Prava Das1* .
Abul Hasan2 .
Md.
Ayanul Huq Chowdhury1 .
Md.
Iftakhar Ahmed1 1 Department of Civil Engineering.
Southern University Bangladesh.
Chattogram.
BANGLADESH 2 Department of Civil Engineering.
Chittagong University of Engineering and Technology.
Chattogram.
BANGLADESH *Corresponding author: arka@southern.
SUBMITTED 17 June 2025 REVISED 23 October 2025 ACCEPTED 06 November 2025 ABSTRACT Concrete is the most widely used construction material due to its versatility and ability to be molded into various shapes.
However, it inherently exhibits little tensile strength, limited ductileness, and poor crack resistance, often leading to brittle failure.
address these limitations, modern construction increasingly incorporates fibers into concrete to enhance its mechanical properties, durability, and overall performance.
Among various fiber types, steel fibers have demonstrated superior crack resistance and improved structural behavior.
This study focuses on evaluating the flexural strength behavior of Steel Fiber Reinforced Concrete (SFRC) using M30 grade concrete.
An experimental program was conducted involving the casting of 180 prisms .
y 100 y 500 m.
and 360 cubes .
y 100 y 100 m.
with steel fiber contents of 1%, 1.
5%, and 2% and aspect ratios of 50, 60, and 70.
The fiber used had a diameter of 1 mm.
The experimental program was limited to evaluating the mechanical performance of the concrete using compressive strength, flexural strength, and splitting tensile strength tests.
Special tamping.
micromechanical analysis and different workability methods have been omitted.
The results reveal that incorporating steel fibers significantly enhances the mechanical properties of concrete.
Notably, a mix containing 1.
5% steel fibers with an aspect ratio of 70 exhibited the highest strength improvements across all tests, including an 18% increase in compressive strength, a 35% increase in split tensile strength, and a 36% increase in flexural strength compared to control specimens.
These findings demonstrate that optimized steel fiber reinforcement not only improves flexural behavior but also contributes to superior structural integrity, making SFRC a promising material for high-performance construction applications.
KEYWORDS Steel Fiber Reinforced Concrete (SFRC).
Flexural Strength.
Aspect Ratio.
Mechanical Properties.
M30 Grade Concrete.
A The Author.
This article is distributed under a Creative Commons Attribution-ShareAlike 4.
0 International license.
1 INTRODUCTION
Concrete is the most extensively used building material due to its versatility and ability to replace traditional materials like stone and brick.
Its strength and durability can be enhanced by adjusting mix componentsAi cement, water, and aggregatesAiand adding specialized ingredients.
However, it has limitations, including low tensile strength, brittleness, limited ductility, and poor fatigue and impact resistance (Shende and Pande.
Shetty, 2.
Concrete naturally contains microcracks that propagate under load, leading to brittle failure (Khamees et al.
, 2.
Even before loading, drying shrinkage and volume changes can cause microcracks.
Researchers have improved concrete tensile behavior by using additional reinforcement methods.
Incorporating discrete, uniformly distributed fibers improves both stationary and dynamic properties of concrete.
Fiber-reinforced concrete (FRC) includes materials like steel, glass, carbon, polypropylene, coir .
fiber, and nylon.
Fibers are defined through their aspect ratio .
ength/diamete.
, typically between 30Ae150 (Khamees et al.
, 2.
Performance depends on fiber type, geometry, distribution, and bonding with the matrix (Rana, 2.
Steel fibers, commonly used in FRC, enhance flexural, fatigue, and impact strength despite minor rusting issues.
They are widely used in pavements, bridge decks, and thin structural elements (Vairagade and Kene, 2.
Interfacial bonding, critical for performance, can be improved through surface treatments.
FRC offers isotropic strength, improved fatigue resistance, and energy absorption, making it suitable for airfields, industrial floors, bridge decks, ducts, and prefabricated elements (Neeraja, 2.
AuWirand ConcreteAy is a trade name for SFRC, commonly used in the Historically, fiber like straw and horsehair were used in construction.
Modern fiber-reinforced concrete emerged in the 1950s, with extensive research continuing today (Naaman, 2.
Studies show SFRC improves compressive and tensile strength by 5Ae20%.
Journal of the Civil Engineering Forum Vol.
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flexural strength by 20Ae65%, and elastic modulus by 5Ae25%, depending on fiber content .
Ae8%) and aspect ratio .
Ae100%) (Shende and Pande, 2012.
Khamees et al.
, 2.
as chloride permeability and freeze-thaw resistance and observed significant improvements in hybrid fiber Confirmed long-term performance under aggressive conditions.
The field of fiber strengthening mechanics advanced significantly with RomualdiAos work in the early 1960s, where he introduced a fracture mechanics tactic to assess the breaking strength of masonry reinforced with closely spaced steel fibers (Romualdi and Batson, 1.
He also proposed a constitutive model to define the behavior of fiber-reinforced compositesAian innovative step at the time.
Despite its strength advantages.
SFRC suffers from reduced workability.
Xu et al.
and Sivanantham et al.
found that workability declines with higher fiber content, especially with long or hooked fibers.
Superplasticizers are often required to ensure homogeneity in mixes.
Later, the flexural capability of Steel Fiber Reinforced Concrete (SFRC) was estimated using constitutive relationships, assuming a mostly linear interfacial bond between fibers and matrix (Swamy and Mangat, 1.
These models aligned well with experimental data but were limited to tension-hardening composites that can sustain increasing stress after cracking.
To address this.
Lim introduced a model combining both tension hardening and softening to better represent SFRC behavior (Lim et al.
, 1.
Driven by the construction industryAos demand for alternative materials.
SFRC has gained use in industrial floors, pile-supported slabs, walkways, and tunnel linings.
This has led to significant progress in SFRC constitutive modeling (Hillerborg, 1980.
Barros and Figueiras, 1999.
Bernard and Pircher, 2000.
Soranakom et al.
, 2.
Studies have consistently shown that steel fibers enhance the compressive, tensile, and flexural properties of concrete.
The inclusion of hooked-end steel fibers improves post-cracking behavior and toughness (Ou et al.
, 2012.
Ni et al.
, 2.
demonstrated how steel fibers increase ductility and strain capacity under compression.
Fiber aspect ratio besides geometry has a pronounced impact on mechanical performance.
Research by Liang et al.
highlighted that higher aspect ratios improve flexural strength but reduce workability.
Khamees et al.
emphasized the synergistic properties of fiber length and type on compressive and splitting tensile strength.
Fiber volume fraction significantly affects crack control and energy dissipation.
Studies by Iqbal Khan and Abbas .
and Kim et al.
confirm that increasing fiber volume improves both compressive and flexural strengths up to an optimal limit.
However, exceeding this limit can lead to reduced workability and fiber clustering (Sable and Rathi, 2.
SFRC is resistant to environmental degradation due to improved crack control and matrix densification.
Zheng et al.
examined durability indicators such Several studies adopted statistical and numerical modeling techniques to optimize mix design and predict mechanical properties.
Mir .
applied regression models to identify critical fiber parameters influencing strength.
Ganapathy et al.
utilized machine learning for reliable strength prediction.
Meta-analyses and large-scale datasets such as those presented by Garcia-Taengua et al.
helped formulate predictive equations for SFRC flexural capacity.
Even though Steel Fiber Reinforced Concrete (SFRC) has advanced significantly, there are still several important research gaps that need to be filled.
First off, while numerous research has investigated the impact of certain fiber parameters, such aspect ratio or volume fraction, very few have thoroughly investigated how these parameters combine to affect a variety of mechanical properties in a typical laboratory setting.
Furthermore, there is disagreement on the best fiber arrangements, particularly for uses like precast elements, pavements, or slabs.
Efforts to create unifying design guidelines are made more difficult by inconsistent experimental procedures and findings with inadequate Furthermore, workability issues brought on by longer or larger fiber volumes are frequently mentioned but not statistically examined in relation to mechanical performance, which creates real-world implementation obstacles.
Additionally, there is a dearth of experimental data relevant to a given region, especially from developing countries where economic constraints, material availability, and construction procedures differ from those expected in much international research.
To fill these gaps, this study examines how the volume fraction and steel fiber aspect ratio interact to affect the concreteAos flexural, splitting tensile, and compressive To evaluate mechanical behavior across various fiber topologies and take workability concerns into account, the research used a methodical experimental This study not only closes a significant research gap but also provides a methodical examination of how steel fiber diameter, aspect ratio, and volume fraction interact to affect compressive, tensile, and flex- Vol.
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Journal of the Civil Engineering Forum ural strength in M30-grade concrete under identical mixing and curing protocols.
If recent papers such as Zhao et al.
and Veeramanikandan et al.
are studied, synergistic effects of all parameters combined still need to be studied.
This paper helps to identify deviations and suggest improvements by validating and improving current predictive models using highfidelity experimental data.
The knowledge gained also lays the foundation for future simulation and machinelearning techniques to predict SFRC behavior, connecting theoretical developments with practical engineering applications.
These insights provide practical mixdesign guidelines for optimizing SFRC performance in resource-constrained construction environments like Bangladesh.
2 Specimen types 2 METHODS The materials were tested to ensure proper mix design and integrity of the work.
The tests results of those materials is discussed in this section.
To ascertain the effects of steel fiber on concrete, this research program includes an examination of the literature and experimental analyses.
Control specimens and SFRC were cast, and 30 grade concrete was chosen as most of the construction works here in Bangladesh uses 20Ae40 MPa concrete.
1 Selection of Steel Fiber Parameters For this study we selected steel fiber contents of 1.
5 and 2.
0%, diameters 0.
5 mm and 1.
0 mm, and aspect ratios 50, 60 and 70 because these ranges are commonly used in experimental investigations and represent a practical compromise between enhanced crackbridging/post-crack toughness and acceptable workability (Choi et al.
, 2019.
Biswas et al.
, 2021.
Yusuf et al.
These parameters enable a systematic assessment of how fiber slenderness and dosage influence tensile, flexural and post-cracking behavior, while the two diameters allow evaluation of the trade-off between fiber dispersion .
avored by finer fiber.
and individual fiber pull-out resistance .
avored by coarser Based on prior work, we expect increased volume fraction and aspect ratio to improve toughness and residual strength but to reduce fresh-state workability Ai an effect mitigated here through controlled mixing and admixture use (Gao et al.
, 1997.
Biswas et al.
Also, if thought economically, steel fibers within 0Ae2.
0% volume range are economically viable for local infrastructure projects, where cost-efficiency and material availability are critical also mentioned in in ACI 544.
4R-18, which emphasizes the use of microfibers in the range of 0.
5Ae2.
0% by volume for structural applications such as slabs-on-ground, precast elements, and tunnel linings (American Concrete Institute, 2.
Specimen sizes of 100 y 100 y 100 mm cube and 100 y 100 y 500 mm beam were selected.
The test specimens after casting were subjected to plain water curing for 7 days, 14 days and 28 days.
The specimens underwent a series of destructive tests to determine their strength after the specific exposure period.
Workability test and three destructive tests: of .
cube compressive i.
cube splitting tensile strength.
beam flexural strength were conducted in the experimental program discussed in section 2.
3 Materials 1 Cement According to ASTM C150 (ASTM C01 Committee, 2.
Type I specifications.
Ordinary Portland Cement (OPC) was employed in the investigation.
The physical and chemical characteristics are listed in Table 1 and Table 2 respectively.
Table 1.
Physical properties of portland cement used Characteristics Results 075 mm .
Siev.
passing (%) Blaine Specific surface .
m2 /.
3,030 Normal Consistency (%) Soundness .
Initial Setting Time .
Final Setting Time .
Specific Gravity Compressive Strength 3-days (MP.
Compressive Strength 7-days (MP.
Compressive Strength 28-days (MP.
All of the values of our OPC fall under the guidelines prescribed in the ASTM C150.
2 Coarse Aggregate In this study, coarse aggregate in the form of quartzite rock chips was utilized.
In this investigation, stone chips were collected from ready mix concrete company.
The coarse aggregateAos maximum nominal size was 20 Journal of the Civil Engineering Forum Vol.
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Table 2.
Portland cementAos chemical compositions used Table 4.
Properties of fine aggregate Oxide Common Name Results (%) Properties Fine Aggregate CaO Lime Fineness modulus SiO2 Silica Specific gravity Al2 O3 Alumina Unit weight .
g/m3 ) 1,495 Fe2 O3
Ferric oxide Absorption capacity (%) MgO
Magnesia
Total moisture (%) K2 O
Alkalis Chloride content (%) Na2 O
Alkalis Sulfate content (%) SO3
Sulfur trioxide CO2
Carbon dioxide Ai
H2 O
Water BogueAos Potential Compound Composition:
3CaO.
SiO2 Tricalcium silicate 2CaO.
SiO2 Dicalcium silicate 3CaO.
Al2 O3 Tricalcium aluminate 4CaO.
Al2 O3 .
Fe2 O3 Tetracalcium The Coarse aggregate properties are tabulated in Table 3.
Table 3.
Properties of coarse aggregate Properties Result Specific gravity Figure 1.
Grain size distribution curve of fine and coarse Unit weight .
g/m ) 1,560 Absorption capacity (%) Total moisture (%) 3 Fine Aggregate Concrete has been made with Sylhet sand, a good quality sand as the fine aggregate.
Table 4 provides the pertinent properties of fine aggregate.
In the Figure 1, the grain size distribution of fine aggregate and coarse aggregate is shown.
5 Steel Fiber Steel fiber is a small carbon, cold-drawn wire fiber mass-produced in compliance with ASTM A820/A820M (ASTM A01 Committee, 2.
Steel fibers deliver higher energy absorption and rises concrete ductibility.
Readily available steel fiber was collected from the local market and then cut it into different lengths as per aspect ratio.
The steel fiber utilized in this investigation is shown in Figure 2.
4 Water The quality of water has a considerable impact on concrete preparation.
Water contaminants can reduce concrete strength and durability while also interfering with the cementAos ability to set.
The quality records of test results provide information about the suitability of the Total solids, pH, chloride, hardness, dissolved oxygen, turbidity etc.
were checked to ensure that the water was potable.
Figure 2.
Steel fiber used in this investigation.
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Journal of the Civil Engineering Forum 4 Mix Design and Ratio Table 6.
Sample designation To determine the ratio of constituents ACI 211.
mix design was followed (American Concrete Institute.
In this investigation.
SF has been utilized.
weight of the total mix, steel fiber was added to the Three different percentages of steel fiber i.
1%, 1.
5% and 2% were used by weight.
For comparison, a concrete mix of 100% OPC was included in this A particular mix ratio was used for making the test specimen.
Specimens of Ordinary Portland Cement (OPC) concrete were created and subjected to an ordinary water environment.
The concrete test specimens were made with varying percentages of steel The various test variables including different materials are listed below.
Table 5.
Mix proportion of the concrete Mixture Constituent Properties Grade of Concrete (MP.
Cement .
g/m3 ) Sand .
g/m3 ) Stone Chips .
g/m3 ) 1,150 Water Cement Ratio Water .
g/m3 ) The concrete mixture was prepared by thoroughly blending coarse aggregate, portland cement, steel fiber, and fine aggregate, followed by one minute of dry mixing before gradually adding water.
After three more minutes of mixing, the mixture was poured to create 540 specimens .
prisms and 360 cube.
Each specimen was cast in two equal layers and manually compacted using a 16 mm diameter, 0.
45 m long tamping rod with 25 blows per layer.
In this study, no special methods were applied for tamping.
It was done as cautiously as it could be done to limit entanglement of the After 24 hours, they were demolded and cured in plain water for 7, 14, and 28 days, after which they were tested at different ages as per the test program.
For sample declaration, a common theme was prescribed: First term represent steel fiber Diameter .
, 2nd term AuSFRCAy represent Steel Fiber Reinforce Concrete, 3rd term represent steel fiber % and last term represent Aspect Ratio.
Similarly, 9 more ratios were chosen using 1 mm diameters wire and changing the fiber percentage and aspect ratio as shown as in Table 6.
Designation Constituents 0SFRC0.
Concrete without steel fiber 5SFRC1.
5mm diameters.
SFRC, 1.
AR= 50
5SFRC1.
5 mm diameters.
SFRC, 1.
AR= 60
5SFRC1.
5 mm diameters.
SFRC, 1.
AR= 70
5SFRC1.
5 mm diameters.
SFRC, 1.
AR= 50
5SFRC1.
5 mm diameters.
SFRC, 1.
AR= 60
5SFRC1.
5 mm diameters.
SFRC, 1.
AR= 70
5SFRC2.
5 mm diameters.
SFRC, 2.
AR= 50
5SFRC2.
5 mm diameters.
SFRC, 2.
AR= 60
5SFRC2.
5 mm diameters.
SFRC, 2.
AR= 70
5 Mechanical Strength Tests 1 Compressive Strength The most crucial factor in predicting how well concrete will work is its compressive strength.
Utilizing a digital compression machine in agreement with BS 1881-116:1983 (British Standards Institution, 1.
, the concrete cube compressive strength was assessed.
Loads were applied with a uniform rate other than casting faces.
The concrete cube compressive strength (E.
MP.
was determined using the following expression:
Where.
P = the specimenAos maximum load at failure (N).
A = the machineAos plungerAos mean surface area in contact .
m2 ).
2 Split Tensile Strength An additional crucial factor for forecasting the tensile properties of concrete is cracking strength.
It is also employed to assess concreteAos shear resistance.
The test yields more consistent results than other tests and is easy to administer.
After setting up the standard test configuration for this test, as shown in Figure 3, the concrete splitting tensile strength was estimated using the same compressive strength equipment.
The specimenAos ultimate load was noted, and the concrete splitting tensile strength .
MP.
was then estimated using the formula provided by Bureau of Indian Standards .
Aa2 Where.
P = the specimenAos maximum load at failure (N), a = dimension of the cube .
m2 ).
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3 RESULTS 1 Workability Figure 5 illustrates the slump values of SFRC compositions with different fiber diameters .
5 mm and 1 The slump value, which measures the workability of concrete, generally decreases as the fiber content increases.
Concrete with 1 mm diameter fibers exhibits lower slump values compared to 0.
5 mm fibers across all compositions, indicating reduced flowability with larger fibers.
This research scope did not include other workability tests as it was not self-compacting Figure 3.
Splitting test apparatus.
3 Flexural Strength Beam flexural strength is one way to calculate concrete tensile strength.
It is a measurement of a concrete beamAos capacity to withstand bending at failure.
After 28 days, it is measured by loading a specimen with dimensions of 100 mm by 100 mm by 500 The ASTM C293 .
standard test methods .
enter-point-loadin.
were applied to ascertain the flexural strength of the concrete beam.
Figure 4 depicts the beam testing setup that was utilized to ascertain the flexural strength.
The specimen was continuously shock-free loaded.
Up to the breaking point, the rate of application of the load was constant.
The flexural strength (R.
MP.
was calculated using the following .
BD2 Where.
P = maximum load (N).
L = distance between supports in .
B = width of the specimen .
D = thickness of the specimen .
Figure 5.
Slump values of different percentages of steel The highest slump value is observed in the control sample .
SFRC0.
), while the lowest occurs in specimens with 2.
0% steel fibers and an aspect ratio of 70 (SFRC2.
This is a clear indication that increasing fiber content and aspect ratio negatively affects workability, requiring adjustments in mix design to maintain adequate flow while achieving desired improvements.
2 Compressive Strength Figure 4.
Flexural strength apparatus.
The Compressive strengths of SFRC and OPC concrete subjected to a plain water curing are shown graphically in Figure 6 and Figure 7.
Steel Fiber Reinforced Concrete (SFRC) compressive strength was evaluated with varying steel fiber contents .
%, 1.
5%, and 2%) over curing periods of 7, 14, and 28 days.
All three tests were shown in the graph, but mean values were taken into The results demonstrated that adding steel fibers pointedly enhances compressive strength, with the most notable increase observed in specimens 5% steel fibers and an aspect ratio of 70, showing an 18% improvement over control samples.
Compressive strength increased with both steel fiber content and aspect ratio, confirming that higher aspect ratios yield better reinforcement benefits.
Vol.
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Journal of the Civil Engineering Forum et al.
, 2.
, which documented a 19.
5% improvement in compressive strength.
Given the observed results, it is recommended to incorporate 1.
5% steel fibers in concrete mixtures to maximize compressive strength, especially for applications requiring enhanced durability and load resistance.
Figure 6.
Compressive strength of varying percentage of 5 mm steel fiber, aspect ratios and curing periods.
At 14 days, specimens with 1%, 1.
5%, and 2% steel fibers achieved higher compressive strength than the controller sample, with values ranging from 26.
9 MPa 3 MPa.
After 28 days, the compressive strength further increased, reaching up to 36.
3 MPa for specimens with 2% steel fibers.
The consistent trend indicates that steel fibers enhance concreteAos ability to resist compressive forces, making it a viable reinforcement material for construction applications.
The synergistic effect of aspect ratio and fiber percentage has a good impact creating the maximum compressive The best performance in fiber-reinforced concrete is achieved at 1.
5% fiber volume with an aspect ratio (AR) of 70, resulting from a synergistic balance of mechanical enhancement and fresh mix workability.
At this dosage, the fiber density is adequate to bridge microcracks and delay macrocrack propagation, enhancing post-crack ductility and toughness while preventing fiber balling or segregation.
The AR of 70 guarantees that fibers are long enough to create effective bond strength and anchoring inside the matrix, increasing pull-out resistance and energy absorption during fracture, but short enough to maintain uniform dispersion and minimize alignment difficulties.
3 Split Tensile Strength Figure 8 and Figure 9 depict the comparison of SFRC and OPC subjected to normal curing for different days.
The split tensile ability of Steel Fiber Reinforced Concrete (SFRC) was evaluated with varying steel fiber contents .
%, 1.
5%, and 2%) after curing for 7, 14, and 28 days.
The results indicate that specimens containing steel fiber consistently achieved higher split tensile strength than control samples, with the most significant improvement ( 35%) observed in specimens with 5% steel fibers and an aspect ratio of 70.
Strength values progressively increased with curing time, reaching up to 4.
61 MPa at 28 days, demonstrating the reinforcing effect of steel fibers.
Figure 7.
Compressive strength of varying percentage of 1 mm steel fiber, aspect ratios and curing periods.
ANOVA analysis for both the cases was checked.
For 5 mm and 1.
0 mm steel fiber diameters, p(< 0.
values were found to be 0.
0081 and 0.
0001 respectively which is a clear indication that, some of the values have a significant change in strength which is consistent with the result.
These findings support are consistent with previous research, such as Shende and Pande .
, which reported a 24% increase in flexural strength and (Mahadik Figure 8.
Split Tensile strength of varying percentage of 5 mm steel fiber, aspect ratios and curing periods.
At 7 days, split tensile strength ranged from 2.
36 MPa 3 MPa, while at 14 days, it improved further, reaching up to 4.
21 MPa.
The 28-day curing period yielded Journal of the Civil Engineering Forum Figure 9.
Split Tensile strength of varying percentage of 1 mm steel fiber, aspect ratios and curing periods.
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Figure 10.
Flexural strength of varying percentage of 0.
mm steel fiber, aspect ratios and curing periods.
the highest values, confirming that longer curing enhances fiber-reinforced concrete performance.
Additionally, strength increases with higher aspect ratios, reinforcing the relationship between fiber distribution and load resistance.
These results align with findings from (Shende and Pande, 2.
, who reported a 41% increase in split tensile strength, supporting the effectiveness of steel fiber reinforcement.
Given the observed improvements, incorporating 1.
5% steel fibers by weight is recommended for maximizing split tensile strength, making SFRC a strong candidate for structural applications requiring enhanced durability and tensile resistance due to itAos tensile strength.
From the ANOVA results both cases of fiber diameter had the p-values of 0.
00061 and 0.
00001 which proves the significance of ratios which are better than other 4 Flexural Strength The flexural strengths of SFRC and OPC concrete subjected to plain water curing are shown graphically in Figure 10 and Figure 11.
The flexural strength of Steel Fiber Reinforced Concrete (SFRC) was assessed with varying steel fiber contents .
%, 1.
5%, and 2%) at curing periods of 7, 14, and 28 days.
The results demonstrated a consistent increase in flexural strength with the inclusion of steel fibers, with the highest improvement ( 36%) observed in specimens containing 1.
steel fibers and an aspect ratio of 70.
Strength values progressively increased over time, reaching up to 7.
MPa after 28 days of curing, reinforcing the role of steel fibers in enhancing concrete performance.
At 7 days, flexural strength ranged from 4.
12 MPa to 59 MPa, while at 14 days, the values improved further, reaching a maximum of 6.
82 MPa.
After 28 days, flexural strength peaked at 7.
72 MPa, confirming the effectiveness of steel fiber reinforcement over extended Figure 11.
Flexural strength of varying percentage of 1 mm steel fiber, aspect ratios and curing periods.
curing periods.
Additionally, strength increased with higher aspect ratios, highlighting the importance of fiber distribution and orientation in improving load resistance.
P-values from ANOVA showed values so low as 10Oe11 which determines that compressive strength is strongly dependent on the mix.
Different fiber dosages give clearly different strengths.
These findings align with previous research, including (Mahadik et al.
, 2.
which reported a 43.
29% improvement in flexural Based on the observed results, it is recommended to incorporate 1.
5% steel fibers by weight in concrete to maximize flexural strength, making SFRC an optimal choice for applications requiring enhanced durability and bending resistance.
5 Correlations among SFRC Properties Past research has used compressive and tensile strengths as key indicators for SFRC mechanical properties in structural design.
The flexural and splitting Vol.
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Journal of the Civil Engineering Forum tensile tests were preferred for measuring tensile strength due to their efficiency and cost-effectiveness compared to the direct tensile test.
Several empirical equations are recommended by various researchers which are tabulated in Table 7.
All empirical equations are nonlinearly correlated using power function, as shown in the following equation:
ft = a.
cA )b two fiber types is listed in Table 8.
For the 0.
5 mm diameters and 1 mm fiber diameters, coefficient of determination (R2 ) were found to be 0.
95 and 0.
96 respectively showing a substantial correlation.
The experimental data were mostly resembling Xu and Shi .
and Perumal .
This paperAos proposed equations are presented in Table 8AeTable 10.
where ft .
is the tensile strength or flexural strength, fcA .
is the compressive strength, and a and b are coefficients.
Our experimental results are therefore fitted into this function to make such empirical equations.
Table 7.
Concrete equation from previous research Source Equations Compressive Strength and Tensile Strength Relations ACI 318 (American Concrete Institute, ft = 0.
cA )0.
CEB-FIP (Myller and Hilsdorf, 1.
ft = 0.
cA )0.
Choi and Yuan (Choi and Yuan, 2.
ft = 0.
cA )0.
Xu and Shi (Xu and Shi, 2.
ft = 0.
cA )0.
Perumal (Perumal, 2.
ft = 0.
cA )0.
Al-Baghdadi .
(Al-Baghdadi et al.
, ft = 0.
cA )1.
Al-Baghdadi .
ft = 0.
cA )1.
Flexural Strength and Tensile Strength Relations Xu and Shi (Xu and Shi, 2.
ft = 1.
f )0.
Perumal (Perumal, 2.
ft = 1.
f )0.
Al-Baghdadi .
(Al-Baghdadi et al.
, ft = 0.
f )1.
Al-Baghdadi .
ft = 0.
f )1.
Figure 12.
Relation between the compressive strength and splitting tensile strength of 0.
5 mm .
and 1 mm .
Table 8.
Proposed equations for compressive vs.
tensile strength Fiber type Equations 5 mm steel diameters ft = 0.
cA )1.
1 mm steel diameters ft = 0.
cA )1.
Same analysis was done to determine the relationship between Flexural strength and split tensile strength.
For the regression analysis.
R2 was found to be 0.
97 for both cases.
In these cases the values were closely related to Al-Baghdadi et al.
Compressive Strength and Flexural Strength Relations ACI 318 (American Concrete Institute, ff = 0.
cA )0.
Ahmed and Shah (Shah and Ahmad, ff = 0.
cA )0.
Xu and Shi (Xu and Shi, 2.
ff = 0.
cA )0.
Perumal (Perumal, 2.
ff = 0.
cA )0.
Al-Baghdadi .
(Al-Baghdadi et al.
, ff = 0.
cA )1.
Al-Baghdadi .
ff = 0.
cA )1.
In Figure 12, the correlation between compressive and split tensile strength was conducted using regression.
From the figure, the empirical relationship between Figure 13.
Relation between the flexural strength and splitting tensile strength of 0.
5 mm .
and 1 mm .
Journal of the Civil Engineering Forum Table 9.
Proposed equations for flexural vs.
tensile strength Fiber type Equations 5 mm steel diameters ff = 0.
f )1.
1 mm steel diameters ff = 0.
f )1.
Finally, the regression assessment was carried out for compressive strength and flexural strength.
The results showed a significant relationship between them as R2 values were 0.
97 and 0.
96 respectively.
Data was closely correlated and matched with data of Perumal .
Vol.
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ues in all strength parametersAicube compressive strength, split tensile strength, and beam flexural strengthAicompared to the control specimen .
% fiber conten.
Considering aspect ratios, specimens with an aspect ratio of 70 exhibit higher strength properties compared to those with aspect ratios of 50 and 60.
The flexural strength of SFRC increases by approximately 36% with the addition of steel fibers compared to the control sample.
The concrete cube split tensile strength increases by about 35% with the inclusion of steel fibers.
SFRC containing 1.
5% steel fiber with an aspect ratio of 70 is found to be the most effective in terms of strength development.
The results of this study are consistent with several previous research findings.
The proposed empirical equations not only provide retrospective validation but also establish a framework for predictive modeling of fiberreinforced concrete behavior under varying fiber dosages and aspect ratios.
These equations can be integrated into computational frameworks or parametric design tools to simulate performance under different loading and environmental conditions.
DISCLAIMER
The authors declare no conflict of interest.
Figure 14.
Relation between the compressive strength and flexural strength of 0.
5 mm .
and 1 mm .
Table 10.
Proposed equations for flexural vs.
tensile strength Fiber type Equations 5 mm steel diameters ff = 0.
cA )1.
1 mm steel diameters ff = 0.
cA )1.
4 CONCLUSION
The findings of the study undertaken on different Steel Fiber-Reinforced Concrete (SFRC) mixtures for curing periods up to 28 days have been presented in the previous chapters.
Based on the limited number of variables examined, the following conclusions are drawn:
In comparison to specimens without steel fibers, the compressive strength of concrete containing 1%, 1.
5%, and 2% steel fibers is higher.
Relative to the control sample, the compressive strength increases by approximately 18% with the inclusion of steel fibers.
SFRC with 1.
5% fiber content shows higher val226
REFERENCES