Strength properties of steel fibre and glass fibre composites

1. Proceedings of the International Conference on Emerging Trends in Engineering and Management (ICETEM14)
30 – 31, December 2014, Ernakulam, India
188
STRENGTH PROPERTIES OF STEEL FIBRE AND GLASS
FIBRE COMPOSITES
Preetha V1
, Belarmin Xavier2
, K P Narayanan3
1
M.Tech, Department of Civil Engineering, Amal Jyothi College of Engineering, Kerala
2
Assistant Professor, Department of Civil Engineering, Amal Jyothi College of Engineering, Kerala
3
Head of Department, Department of Civil Engineering, Marian Engineering College, Kerala
ABSTRACT
Concrete is most widely used construction material in the world. Fibre reinforced concrete (FRC) is a concrete
in which small and discontinuous fibers are dispersed uniformly. The addition of fibres can dramatically increase the
compressive strength, tensile strength and flexural strength of concrete. In this paper effect of fibres on the strength of
concrete for M25 grade have been studied by varying the percentages of fibres in concrete. 0.5%, 0.75% and 1% volume
fraction of steel fibre and glass fibres of 0.15%, 0.2% and 0.25% weight of cement were used without any admixtures.
Keywords: Fibre Reinforced Concrete, Flexural Strength, Glass Fibre, Split Tensile Strength, Steel Fibre.
1. INTRODUCTION
Fibre reinforced concrete (FRC) is Portland cement concrete reinforced with more or less randomly distributed
fibres. (FRC) is concrete containing fibrous material which increases its structural integrity. So we can define fibre
reinforced concrete as a composite material of cement concrete or mortar and discontinuous discrete and uniformly
dispersed fibre. The addition of these fibers into concrete mass can dramatically increase the compressive strength, tensile
strength, flexural strength and impact strength of concrete. Steel fibre is one of the most commonly used fibre. Generally
round fibres are used. The diameter may vary from 0.25 to 1 mm. Glass fibres have very high tensile strength.
2. LITERATURE REVIEW
Amit Rana (2013) found out the optimum quantity of steel fibres required to achieve the maximum flexural
strength for M25 grade concrete was found out. From the exhaustive and extensive experimental work it was found that
with increase in steel fibre content in concrete there was a tremendous increase in Flexural strength. Even at 1 % steel fibre
content flexural strength of 6.46 N/mm² was observed against flexural strength 5.36 N/mm² at 0% hence increase of 1.1%
flexural strength [1].
Upendra Varma and A.D. Kumar (2013) conducted an experimental investigation with alkali resistance Glass
Fibres to study the effect on compressive, split tensile and flexural strength on M20, M40 and M60 grades of concrete for
addition of 0.03% of glass fibre. The percentage increase of compressive strength of various grades of glass fibre concrete
mixes compared with 28 days compressive strength is observed from 10 to 20%. The percentage increase of flexural and
split tensile strength of various grades of glass fibre concrete mixes compared with 28 days is observed from 10% to 20%
[2].
INTERNATIONAL JOURNAL OF CIVIL ENGINEERING AND
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Volume 5, Issue 12, December (2014), pp. 188-193
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2. Proceedings of the International Conference on Emerging Trends in Engineering and Management (ICETEM14)
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3. OBJECTIVE OF THE STUDY
The main objective of this study is to determine the optimum percentage of steel fibre and glass fibre for split
tensile strength and flexural strength and to find out the maximum percentage increase of split tensile strength and flexural
strength.
4. EXPERIMENTAL INVESTIGATION
4.1 Materials Used
Cement, fine aggregate, coarse aggregate, water and fibres were used.
1. Cement: the cement used was Ramco Supergrade PPC Cement with a specific gravity of 2.9. Initial and final
setting time was 70 min and 495 min respectively.
2. Fine Aggregate: M-Sand, conforming to zone II with specific gravity 2.52 and water absorption 1.42% was used,
conforming to IS 383:1970 [5].
3. Coarse Aggregate: Crushed angular metal of specific gravity 2.92 and water absorption 0.35% conforming to
graded aggregate of nominal size 20 mm as per IS 383:1970 [5] was used in this experimental study.
4. Water: Potable water was used in this experimentation. Water should be free from acids, oils, alkalies or other
organic impurities.
5. Steel Fibre: Crimped steel fibre of length 50 mm, diameter 1 mm and aspect retio 50 was used. Steel fibres of
0.5%, 0.75% and 1% of volume of concrete were used. Fig. 1 shows the dimension of the steel fibre used for the
experimental work.
6. Glass Fibre: Alkali-Resistant glass fibre of 12 mm length was used. Glass fibres of 0.15%, 0.2% and 0.25%
weight of cement were considered in this study. Fig. 2 shows the glass fibre used for the experimentation.
Fig.1: Dimensions of a crimped steel fibre
Fig.2: Alkali-Resistant Glass Fibre
4.2 Concrete Mix Proportion
The mixture proportioning was done according to IS 10262:2009 [4] and with reference to IS 456:2000 [3].
The target strength for mix proportioning for M25 grade concrete was 31.6 N/mm2
. The water-cement ratio was
kept constant as 0.5. Cement, fine aggregate and coarse aggregate were properly mixed together in the ratio 1:1.47:2.78.
Table 1 shows the details of quantity of constituent materials.

3. Proceedings of the International Conference on Emerging Trends in Engineering and Management (ICETEM14)
30 – 31, December 2014, Ernakulam, India
190
TABLE 1: Details of quantity of constituent materials
Material Quantity Proportion
Cement 420 kg/m3
1
Fine Aggregate 617.843 kg/m3
1.47
Coarse Aggregate 1168.07 kg/m3
2.78
Water 210 l/m3
0.5
Crimped steel fibres of 0.5%, 0.75% and 1% volume of concrete and alkali-resistant glass fibres of 0.15%, 0.2%
and 0.25% weight of cement are considered in this study. Table 2 shows the proportion of steel fibre and glass fibre used
in the experimental work.
TABLE 2: Proportion of steel fibre and glass fibre
Specimen
Steel Fibre (% by
volume of concrete)
Glass Fibre (% by
weight of cement)
S1 0 0
S2 0.5 0.15
S3 0.5 0.2
S4 0.5 0.25
S5 0.75 0.15
S6 0.75 0.2
S7 0.75 0.25
S8 1 0.15
S9 1 0.2
S10 1 0.25
5. METHODOLOGY
The tests have been performed to determine the mechanical properties such as split tensile strength and flexural
strength of concrete mix with hybrid fibre content.
5.1 Split Tensile Strength Test
The test was conducted as per IS 5816:1999 [6]. For tensile strength test, cylindrical specimens of dimension 150
mm diameter and 300 mm length were cast. The specimens were demoulded after 24 hours of casting and were transferred
to curing tank where in they were allowed to cure for 28 days. The load shall be applied without shock and increased
continuously at a nominal rate within the range 1.2 N/(mm2
/min) to 2.4 N/(mm2
/min). Maintain the rate, once adjusted,
until failure. In each category, three cylinders were tested and their average value was reported.
Split tensile strength was calculated as follows:
Split Tensile Strength (MPa) = 2P/ π DL (1)
Where, P = Failure Load (N)
D = Diameter of Specimen (mm)
L = Length of specimen (mm)
Fig. 3 shows the split tensile testing of cylinder.
Fig.3: Split tensile testing of cylinder

4. Proceedings of the International Conference on Emerging Trends in Engineering and Management (ICETEM14)
30 – 31, December 2014, Ernakulam, India
191
5.2 Flexural Strength Test
The test was conducted as per IS 516:1959 [7]. The bed of the testing machine shall be provided with two steel
rollers, 38 mm in diameter, on which the specimen is to be supported, and these rollers shall be so mounted that the
distance from centre to centre is 40 cm for 10 cm specimens.
The load shall be applied through two similar roller, mounted at the third points of the supporting span, that is,
spaced at 13·3 cm centre to centre. The load shall be divided equally between the two loading rollers, and all rollers shall
be mounted in such a manner that the load is applied axially and without subjecting the specimen to any torsional stresses
or restraints.
The load shall be applied without shock and increasing continuously at a rate such that the extreme fibre stress
increases at approximately 7 kg/sq cm/min. i.e., at a rate of loading of 400 kg/min for the 15 cm specimen and at a rate of
180 kg/min for the 10 cm specimens, The load shall be increased until the specimen fails, and the maximum load applied
to the specimen during the test shall be recorded. Fig. 4 shows the flexural strength testing of beams.
Modulus of rupture, σr = Pl/bd2
(2)
Where,
b = measured width in cm of the specimen,
d = measured depth in cm of the specimen at the point of failure,
l = length in cm of the span on which the specimen was supported, and
P = maximum load in N applied to the specimen
Fig.4: Flexural strength testing of beams
6. EXPERIMENTAL RESULTS
6.1 Split Tensile Strength of Cylinders
Split tensile strength of cylinders at 28 days of curing was tested and the results obtained are tabulated in Table 3.
Fig. 5 shows the average value of split tensile strength of cylinders of different proportions.
TABLE 3: Split tensile strength of different proportions
Mix
Split Tensile Strength (N/mm2
) Average Split
Tensile
Strength
(N/mm2
)
1 2 3
S1 2.263 2.433 2.230 2.308
S2 2.659 2.617 2.716 2.664
S3 2.688 2.758 2.800 2.748
S4 2.829 2.971 3.000 2.933
S5 3.140 3.280 3.270 3.230
S6 3.466 3.508 3.320 3.430
S7 2.801 2.971 2.716 2.829
S8 2.857 2.688 2.758 2.767
S9 2.970 3.041 3.140 3.050
S10 3.110 3.310 3.050 3.157

5. Proceedings of the International Conference on Emerging Trends in Engineering and Management (ICETEM14)
30 – 31, December 2014, Ernakulam, India
192
Fig.5: Average split tensile strength of cylinders of different proportions
The split tensile strength was increased by 48.61% for S6 specimen. i.e., by the addition of 0.75% volume of
concrete of steel fibre and 0.2% weight of cement of glass fibre.
6.2 Flexural Strength of Beams
Flexural strength of beams at 28 days of curing was tested and the results obtained are tabulated in Table 4. Fig. 6
shows the average value of flexural strength of beams of different proportions.
TABLE 4: Flexural strength of different proportions
Mix
Flexural Strength (N/mm2
) Average
Flexural
Strength
(N/mm2
)
1 2 3
S1 3.200 2.720 3.440 3.12
S2 3.360 3.680 4.080 3.710
S3 4.000 4.320 3.840 4.050
S4 4.800 4.480 4.320 4.530
S5 5.360 5.040 5.760 5.386
S6 6.340 6.240 6.000 6.190
S7 5.600 5.920 5.600 5.706
S8 5.520 5.280 5.600 5.467
S9 5.680 6.000 5.760 5.813
S10 6.080 5.760 6.24 6.026
0
1
2
3
4
5
6
7
S1 S2 S3 S4 S5 S6 S7 S8 S9 S10
AverageFlexuralStrength
(N/mm2)
Different Proportions
Fig.6: Average flexural strength of beamss of different proportions

6. Proceedings of the International Conference on Emerging Trends in Engineering and Management (ICETEM14)
30 – 31, December 2014, Ernakulam, India
193
The flexural strength was increased above 95% for S6 specimen. i.e., by the addition of 0.75% volume of
concrete of steel fibre and 0.2% weight of cement of glass fibre. In all specimens, failure occurs at mid-span by pulling out
of the steel fibers at maximum deflection and not by breaking up of the transverse sections.
7. CONCLUSION
The purpose of this experimental study was to quantify the effects of the addition of steel fibre and glass fibre
composites within ordinary concrete specimens by examining their mechanical properties including split tensile strength
and flexural strength. The highest value of split tensile strength has 48.61% increase and flexural strength above 95%. It
was observed that the addition of hybrid fibres to the concrete increases the properties of concrete up to a certain limit.
Thus, we can increase the properties of concrete by using 0.75% volume of concrete of steel fibre and 0.2% weight of
cement of glass fibre.
8. REFERENCES
[1] Amit Rana (2013), “Some Studies on Steel Fiber Reinforced Concrete”, International Journal of Emerging
Technology and Advanced Engineering, Volume 3, Issue 1.
[2] Upendra Varma and A.D. Kumar (2013), “Glass Fibre Reinforced Concrete”, International Journal of Engineering
Research and Applications, Vol. 3, Issue 5, pp.1914-1918.
[3] IS 456:2000, “Code of Practice for Plain and Reinforced Concrete”, Bureau of Indian Standards, New Delhi, India.
[4] IS 10262:2009, “Recommended Guidelines for Concrete Mix Design”, Bureau of Indian Standards, New Delhi,
India.
[5] IS 383:1970, “Specification for coarse and fine aggregates from natural sources for concrete”, Bureau of Indian
standards, New Delhi, India.
[6] IS 5816:1999, “Method of Test for Splitting Tensile Strength of Concrete”, Bureau of Indian Standards, New
Delhi, India.
[7] IS 516:1959, “Methods of Tests for Strength of Concrete”, Bureau of Indian Standards, New Delhi, India.
[8] N.Ganesan, Bharati Raj, A.P.Shashikala and Nandini S.Nair, “Effect of Steel Fibres on the Strength and Behaviour
of Self Compacting Rubberised Concrete”, International Journal of Civil Engineering & Technology (IJCIET),
Volume 3, Issue 2, 2012, pp. 94 - 107, ISSN Print: 0976 – 6308, ISSN Online: 0976 – 6316.
[9] Dr. P.Muthupriya, “An Experimental Investigation on Effect of GGBS and Glass Fibre in High Performance
Concrete”, International Journal of Civil Engineering & Technology (IJCIET), Volume 4, Issue 4, 2013,
pp. 29 - 35, ISSN Print: 0976 – 6308, ISSN Online: 0976 – 6316.
[10] Manav Mittal, Deependra Singh and Aditya Dhagat, “Effect of Polypropylene Fiber, Steel Fiber & Glass Fiber on
Properties of Concrete”, International Journal of Civil Engineering & Technology (IJCIET), Volume 4, Issue 4,
2013, pp. 163 - 169, ISSN Print: 0976 – 6308, ISSN Online: 0976 – 6316.