comparative study on effect of steel and...

http://www.iaeme.com/IJCIET/index.asp 141 [email protected]

International Journal of Civil Engineering and Technology (IJCIET) Volume 8, Issue 4, April 2017, pp. 141–155 Article ID: IJCIET_08_04_019 Available online at http://www.iaeme.com/IJCIET/issues.asp?JType=IJCIET&VType=8&IType=4 ISSN Print: 0976-6308 and ISSN Online: 0976-6316 © IAEME Publication Scopus Indexed

COMPARATIVE STUDY ON EFFECT OF STEEL AND GLASS FIBERS ON COMPRESSIVE AND

FLEXURAL STRENGTH OF CONCRETE S. Ghouse Basha

PG Scholar, Department of Civil Engineering, KL University, Vaddeswaram, Andhra Pradesh, India

P. Polu Raju

Associate Professor, Department of Civil Engineering, KL University, Vaddeswaram, Andhra Pradesh, India

ABSTRACT Concrete has been used in the various forms of structures all over the world from

last two decades. The development of concrete has carried around the major essential need for essences of chemical as well as mineral for the improvement in the act of concrete. The usage of different types of fibers and their orientation in matrix have shown the positive response among the researchers. In this study the performance of fiber reinforced concrete (FRC) beams under two-point loading system is discussed and comparative studies were made with normal mix concrete. The mineral admixtures used in this study are steel fibers and glass fibers. In this study, we are casting the cubes for 3, 7, 28 days and beams only for 28days. The percentage addition by volume of concrete for mineral admixtures used is 0.5% and 3%. We are going to compare the results of compressive as well as flexural strength to normal concrete through different (0.5 and 3) percentages. The experimental study on normal strength concrete grade for 0.5% and 3% were also prepared respectively. Rebound hammer tests were conducted to assess the quality of concrete. Test results presented that the adding of suitable fraction volume of steel and glass fiber can improve the mechanical properties of the self-compacting concrete (SCC) and at the same time the flowing and passing abilities still within the accepted limits. In addition, incorporation of glass fibers had increased the ductility of self-compacting concrete. NDT tests discovered inclusion of fibers improve the surface hardness, homogeneity and quality of concrete. Key words: Steel fiber (SF), Glass fiber (GF), Two point loads, Flexural behaviour, Beams. Cite this Article: S. Ghouse Basha and P. Polu Raju, Comparative Study on Effect of Steel and Glass Fibers on Compressive and Flexural Strength of Concrete. International Journal of Civil Engineering and Technology, 8(4), 2017, pp. 141–155. http://www.iaeme.com/IJCIET/issues.asp?JType=IJCIET&VType=8&IType=4

S. Ghouse Basha and P. Polu Raju


1. INTRODUCTION Cement concrete utilization is limited due to the physical characteristics of easily damaged; this can be overcome by the addition of a smaller quantity of short and distinct randomly distributed fibers for example steel, glass, synthetic and natural fibers [1]. The shape of the fibers with extreme deviation in rounded smooth aggregates is same as normal coarse aggregates. The fibers interlock and entangle around the aggregate are considerably increases with workability whereas the combination becomes more consistent and less segregation [2]. During the mixing process, the fibers get discrete, spread randomly in concrete, and thus improve properties of concrete in all aspects. Hence, from this study discovers the possibility of using artificial fibers; and intention to do constant study on compressive and flexure strengths for a given grade of concrete, aspect ratio and several proportions of fibers [2]. For the reinforcing of concrete, the steel fibers used are defined as short and distinct length of steel having the aspect ratio of about 20 to 100 with any of several cross sections which square measure sufficiently little to be random spread in a very unhardened concrete mixture using usual mixing procedures. Steel fiber reinforced concrete (SFRC) has the capability of distinctive tensile strength, flexural strength, shock resistance, fatigue resistance, ductility and crack arrest. They also decrease permeability of concrete and thereby decrease the bleeding of water. It is, such a construction material is investigated for over 40 years as well as for pavement construction [3].Glass fiber has been used worldwide since the early 1970’s. FRC characteristics lead to using it as structural material. Among the synthetic fibers, the glass fibers are having the high strength. The glass fibers possess high strength and elastic modulus, brittle stress-strain characteristics, elongation at break and less creep at room temperature. Generally, glass fibers are round and straight with the diameter of 0.005 to 0.015mm [4].Glass fiber is a chemical inorganic fiber having tensile strength behavior. Mostly glass fibers are available in the form of thread or filament having diameter of around 14microns.In the literature review, it is noticed that addition of fibers improves strength of concrete. Variety of the researches have conducted experiments on concrete combining two fibers and reported that there is an improvement in strength of concrete. The experimental study aims at getting data on the impact of steel, glass fiber and its combination on workability, compressive strength, flexural strength and Non-Destructive Tests (NDT) such as Rebound Hammer, to evaluate the quality of concrete for SCC compared with VC. The number of experiments are carried out on mechanical properties of steel fiber reinforced (SFRC) and glass fiber reinforced concrete (GFRC) are done. Amit Rana et al. (2013) initiated the best quantity of steel fibers, which are required to attain the maximum flexural strength for M25 grade of concrete. By the increment of steel fiber in the concrete, it was found that there is a great increase in the flexural strength. For 1% of steel fiber content in the concrete it was noted that the flexural strength is increased to 6.46 N/mm2 but for 0% of steel fiber the flexural strength was 5.36 N/mm2, hence there was an increase of 1.1% flexural strength [5].Chandramouli et al. (2010) have determined that for the different grades of glass fiber concrete mixes; there is a percentage increase of compressive strength. The compressive strength was observed from 20 to 25%. Also for the flexural and split tensile strength of different grades of concrete mixes are compared at age of 28 days and is found out that there is a percentage increase from 15 to 20% [6].In the research work of Byung Hwan oh et al. (1992), mechanical properties of concrete are considered, from the results it is clear that the increase of strength of 6 to 17% compressive strength, flexural strength is from 20 to 25%, split tensile strength is of 14 to 49% and the modulus of snap is shown as 13 to 27% [7].The mechanical properties of concrete are studied in the research work of Barrows and Figueiras et al. (1992). From the results, it shown that increase in strength of 7 to 19% compressive strength, the flexural strength of 25 to 65%, split tensile strength is shown as 19 to 48% and for the modulus of elasticity as 7 to 25% respectively. Chen S. et al. (2004) examined the

Comparative Study on Effect of Steel and Glass Fibers on Compressive and Flexural Strength of Concrete


strength of 15 SFRC and plain concrete ground slabs. The dimensions of the slabs are shown as 2×2×0.12m, which are strengthened with hooked end steel fiber and mill cut steel fiber [7].Barluenga et al. (2007) find out that the effect of Alkali Resistant (AR) glass fiber on the cracking control in plain concrete and self-compacting concrete (SSC). From the results it shows that, at a particular age, the shrinkage on both plain concrete and SSC can be controlled with the all types of AR-glass fiber with small volume fractions. According to the research, the cracked surface can be detached by usage of AR-glass fiber on cracking control [8].The material characteristics of SFRC and steel fiber reinforced lightweight concrete (SFRLC) are evaluated by experimental investigation of Swamy & Jojagha et al. (1982) under the impact loads by means of drop hammer test and a drop ball test in relation with ACI 544.2R78. The normal weight and lightweight concrete are tested for three to four mixes respectively [9].

2. EXPERIMENTAL PROGRAMME The experimental program involves the various processes of material testing, combine proportions, mixing, casting and curing of test specimens. All the experiments were done in the material testing laboratory.

2.1. Materials Used Cement used in this work is ordinary Portland cement. All the properties of cement are confirmed to referring IS12269 – 1987. From the table 1 the physical properties of cement are shown. Nearby sand undergone 4.75mm IS sieve is used. The specific gravity of fine aggregate (Sand) conforming to zone III is 2.84.Material is collected from different local sources the maximum specific gravity and fineness modulus of 10mm size aggregates is 3.02 and 5.829. Local sources of portable water are used for mixing and curing of concrete specimens. The Steel Fibers are procured from STEWOLS INDIA (P) Ltd, Nagpur. The steel fibers used in this study is Hooked End Steel Fiber in size MSH 7560 (Cold Drawn Type) from Mild Steel Wire for General Engineering which is shown in Fig.1 The percentages adopted in this study are 0.5% and 3% by the total volume of concrete. Mechanical and chemical properties of steel fibers are shown from Tables 2 and 3. The glass fibers used in this study are Alkaline resistant (AR) of length 6 mm, aspect ratio 428 with an Elastic Modulus of 73 GPa which is shown in Fig.2. From the table 4 and 5 the physical and chemical properties of glass fiber are shown. Conplast SP430 is used as a super plasticizer. It is a chloride free, chemical admixture. To maintain the water cement ratio and to increase the workability of concrete mixes the super plasticizer is used.

Table 1 Physical properties

Sl. No Properties Results 1 Specific gravity 3.15 2 Standard consistency 31.25% 3 Initial setting time in minutes 43 4 Final setting time in minutes 128



Figure 1 Steel Fibers

Table 2 Mechanical Properties of Steel Fibers

Table 3 Chemical Properties of SF

Figure 2 Glass Fibers

Table 4 Physical Properties of GF

Mechanical Properties of Steel Fibers Diameter 0.75MM Length 60MM Tensile Strength 1023MPa Tolerance for Diameter and Length

(+)10%(As Per ASTM)

Chemical Composition of Mild Steel wire

Percentages (%)

C 0.074 Mn 0.36 Si 0.065 P 0.01 S 0.009

Property Glass Fiber Specific gravity 2.4-2.8 Bulk density 2.53 Moisture content (%) Nil Fine particles less than 0.075mm %

12-15



Table 5 Chemical Properties of GF

2.2. Mix Proportion The mixture proportioning was done according to IS 10262:2009 and with conforming to IS 456:2000. The target strength for mix proportioning for M30 grade concrete was 38.25 N/mm2 [10, 11]. The w/c ratio was kept constant at 0.45. Cement, fine aggregate and coarse aggregate were properly mixed together in the ratio 1:2.62:3.78. Table 6 shows the details of quantity of constituent materials.

Table 6 Details of Quantity of Fundamental Materials

S.NO Material constituents Quantity,Kg/m3 Proportion 1 Cement 324 1 2 Fine aggregate 852 2.62 3 Coarse aggregate 1225 3.78 4 Steel fiber 84.035 0.25 5 Glass fiber 84.035 0.25 6 Water 157 0.48

2.3. Details of Reinforcement Ten RC beams were cast and tested under two-point load, using fiber at two different depths for eight beams and two control beams. All specimens were design according to IS: 456-2000 with identical sizes of 1000x150x150 mm and 1000×150×300mm.The investigated beams have been divided into two sets with and without the use of fiber at different depths of the beam. All beams were cast using mix concrete with compressive strength of 30 N/mm2. Details of the test specimens of two set with and without the use of fiber at different depths of the RC beam have been presented in Fig 3. Beam sizesare also adequately large to follow a real structural element.

Constituent Glass Fiber Silica (SiO2) 72.5 Alumina (Al2O3) 01.06 Iron Oxide (Fe2O3) 0.36 Lime (CaO) 08 Magnesia (MgO) 4.18 Sodium Oxide (Na2O) 13.1 Potassium oxide (K2O) 0.26 Sulphur Trioxide (SO3) 0.18



Figure 3 Longitudinal and Cross sections detail of RC beams

2.4. Test Beams Standard timber beam moulds were used for casting of beams of varying depth of the beams i.e., 150mm and 300mm. Timber moulds were fitted with screws and grease oil is applied inner side of the moulds. To compact the concrete, manual compaction was used for compacting the beam specimens. Mix ratio were kept steady and ready for concreting and then the moulds are filled with prepared concrete and hand compaction is done. The same procedure is adopted for all beam specimens. After specimens were, compacted top surface is leveled using trowel. Specimens were cast for varying percentage replacement of 0.5% and 3% of natural aggregates with fibers (Steel and Glass). The beam specimens were removed from the timber formwork for a period of 24 hrs of casting and then the removed beams from the moulds are covered with burlap bags for curing at age of28 days [13]. This process of curing is known as wet curing which is as shown in the Fig.4.

Laboratory Work

Figure 4 Flow chart of casting & curing of beams



2.5. Testing Procedure Each beam was tested in the loading frame under two-point load. Strain gauge was used to measure the compressive strain in pure bending at the top surface of the beam.The load control mode was maintained at 50-100 increments until failure occurs which was shown in Fig. 5

Figure 5 FRC beam set-up

Loading point distance was kept constant at 200 mm. Deflections were measured at various load increments. 1stcrack load, Ultimate load, crack formation, Variation of deflection etc., were noted.

3. RESULTS AND DISCUSSIONS All the beams are confirmed to the typical behaviour in flexure. The contrast is done for adding variable amount of glass fibers and steel fibers, control concrete with zero percent fiber with the same material. The results of the workability, rebound hammer, compressive strength and flexural strength are as presented in below.

3.1. Workability The result of previous researches shows that addition of fibers reduces the slump value. The slump value for nominal mix was about 115 mm. However, for 0.5% and 3% the steel fiber slump value increased when compared to glass fiber. Fig.6 shows the reduction of the slump value in different mixes.

Figure 6 Slump Test



3.2. Surface Hardness Test The instrument as shown in Fig.7 is used for determining surface hardness and it is known as Schmidt rebound hammer. It works on the principle of rebound of elastic mass when it gets contact against surface tested [14]. Rebound Hammer test is performed on specimens at the age of 28 days of curing to compute the effect of fibers on surface hardness of concrete.

Figure 7 Rebound Hammer Test on Beams From table number 7, it is noted that the inclusion of fibers increases the rebound number

of concrete compared to plain specimens. The specimens with combination of fibers have more rebound number and more velocity than plain specimen. It shows that the inclusion of fibers enhances the surface hardness and uniformity of concrete.

Table 7 Rebound Hammer Values

3.3. Compressive Strength At early age construction, the most suitable method for evaluating the behaviour of SFRC is compressive strength test. Due to the various cases like tunnels, SFRC is mainly subjected to compression. As per IS 516:1959 [15] the compressive strength of NMC and FRC were calculated. In concrete when the distinct types of fibers are present we get to know that due to bonding of fibers in the concrete the propagation of cracks is reduced and helps in changing the mode of failure from brittle failure to a long ductile one, resulting in improvement of post cracking load and energy absorption capacity. By the addition of steel and glass fiber the compressive strength is slightly increased for all ages. In this study we are casting the cubes and beams for 3, 7, 28 days. The percentage addition by weight of concrete for mineral admixtures used is 0.5% and 3%.

Types of Fibers

Percentage Adding by Weight of Concrete N/mm2 Depth 150 mm Depth 300 mm

0% 0.5% 3% 0% 0.5% 3%

Steel fibers 19.7 21 22.8 20.6 24.7 28.2

Glass fibers 18 19.8 21.5 21.8 23.6 25.9



05

101520253035404550

0 0.5 3

Com

pres

sive

Stre

ngth

N/m

m2

% Of Replacement of Fibers

STEEL FIBERS

GLASS FIBRE

Figure 8 Compressive Strength at 28 days

Figure 9 Compressive strength for all FRC

3.5. Flexure Test

3.5.1. Load-Deflection Behavior A deflection is the degree to which a structural member is displaced under a load. The typical load-deflection curves for fiber reinforced concrete and normal mix concrete beam specimens with varying depths are shown in Fig10 & Fig11.In beam depth of 150mm,the maximum load occurs in steel fiber 0.5% where as in beam depth of 300mm, the maximum load at glass fiber 0.5%.

10

15

20

25

30

35

40

45

50

0 0.5 1 1.5 2 2.5 3 3.5

Com

pres

sive

Stre

ngth

inM

Pa

Replacement of fine aggregate by SF and GF

3 days 7 days 28 days 3 days 7 days 28 days



0102030405060708090

100

0 0.5 1 1.5 2 2.5 3 3.5 4

App

lied

Load

(kN

)

Mid-span Deflection (mm)

NCSF-0.5%SF-3%GF-0.5%GF-3%

Figure 10 Load Vs Deflection of beam depth 150mm

Figure 11 Load Vs Deflection of depth 300mm

3.5.2. Crack Pattern The crack pattern of FRC is in zigzag way as shown in Fig 12 where as normal concrete is in horizontal cracks. The crack value for FRC is more when compared to the normal concrete. The crack formed for normal concrete for the beam depth of 150mm is 60kN and for depth 300mm is 107kN.

Figure 12 Crack Pattern of Beam

0

20

40

60

80

100

120

140

160

180

0 0.5 1 1.5 2 2.5

App

lied

Load

(kN

)

Mid-span Deflection (mm)

NCSF-0.5%SF-3%GF-0.5%GF-3%



During loading of the beam no vertical cracks are occurred on the beam and this indicate that there is no bond failure. During testing, it is found that, in all beam specimen’s cracks tend to appear earlier in fiber reinforced concrete beam specimens (Glass). The cracks observed was more for glass fiber specimen as shown in Fig.13, likewise from Fig.14 steel fiber shows more crack value compared to other beams specimens.

Figure 13 Comparison of nominal mix concrete with 0.5% replacement of FIBERS

Figure 14 Comparison of nominal mix concrete with 3% replacement of FIBERS

3.5.3. Determination of Ultimate Load The ultimate load of RC beams test was conducted on varying the depth sizes i.e. 150mm and 300mm beams cast by M30 grade. The beams were examined under two-point load test. From Figs. 15 & 16 it shows, moment vs. deflection graphs for two different depths.

0

20

40

60

80

100

120

140

160

180

App

lied

Load

(kN

)

Beams

Nominal Mix 150mmNominal mix 300mmSteel Fiber 150mmSteel Fiber 300mmGlass Fiber 150mmGlass Fiber 300mm

0

20

40

60

80

100

120

140

App

lied

Load

(kN

)

Beams

Nominal Mix 150mmNominal Mix 300mmSteel Fibers 150mmSteel Fibers 300mmGlass Fibers 150mmGlass Fibers 300mm



Figure 15 Test results of ultimate load for control and FRC beams of depth 150mm

Figure 16 Test results of ultimate load for control and FRC beams of depth 300mm

Figure 17 Test results for beam depth 150mm

0

0.0005

0.001

0.0015

0.002

0.0025

0.003

0 0.5 1 1.5 2 2.5 3 3.5 4

Mu/

Fckb

d2 (10

3 )

Δ (mm)

NCGF-0.5%GF-3%SF-0.5%SF-3%

0

0.0005

0.001

0.0015

0.002

0.0025

0.003

0.0035

0 0.25 0.5 0.75 1 1.25 1.5 1.75 2 2.25 2.5

Mu/

Fckb

d2 (10

3 )

Δ (mm)

NCGF-0.5%GF-3%SF-0.5%SF-3%

0

0.02

0.04

0.06

0.08

0.1

0 0.25 0.5 0.75 1 1.25 1.5 1.75 2 2.25 2.5

P u/f c

kbd(

103 )

Δ (mm)

NCGF-0.5%GF-3%SF-0.5%SF-3%



Figure 18 Test results for beam depth 300mm

3.5.4. Moment vs. Curvature From figure 19 & 20 it shows that glass fiber 3% shows more moment than other specimens.

Figure 19 M – Ø relation for FRC beams of depth 300mm

Figure 20 M – Ø relation for FRC beams of depth 300mm

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0 0.5 1 1.5 2 2.5 3 3.5

P u/f c

kbd(

103 )

Δ (mm)

NCGF-0.5%GF-3%SF-0.5%SF-3%

0

15

30

45

60

75

90

105

120

0 0.0001 0.0002 0.0003 0.0004 0.0005 0.0006 0.0007

MU

(kN

-m)

Curvarute in radians

NCSF-0.5%SF-3%GF-0.5%GF-3%

02.5

57.510

12.515

17.520

22.525

27.530

0 0.0001 0.0002 0.0003 0.0004 0.0005 0.0006 0.0007

MU

(kN

-m)

Curvarute in radians

NCGF-0.5%GF-3%SF-0.5%SF-3%



4. CONCLUSIONS From the study conducted on the strengthening of concrete beams using Fibers at different depths of beam; the following conclusions were drawn:

The FRC of all types have shown improvement in terms of first crack, ultimate load and deflection characteristics when compared to that of control beam.

By the addition of steel and glass fibers the surface hardness increases slightly.

From the study, it shows that the compressive strength of steel fiber with control specimen increases 4.48N/mm for 0.5% and 10.24N/mm for 3%

From the results, it shows that the compressive strength of glass fiber with control specimen increases 2.9N/mm for 0.5% and 5.64N/mm for 3%

The deflection of FRC beams was greater than the NMC specimens

The cracking behaviour of FRC beam specimens shows greater strength with those of NMC beam specimens.

Addition of Steel Fibers give the better strength compared to that of Glass Fibers.

REFERENCES [1] Shrikant M. Harle” Review on the Performance of Glass Fiber Reinforced Concrete”

International Journal of Civil Engineering Research. ISSN 2278-3652 Volume 5, pp. 281-284

[2] Tejas R Patil (2013) “Comparative Study of Steel and Glass Fiber Reinforced Concrete Composites” International Journal of Science and Research (IJSR) ISSN (Online): 2319-7064 Index Copernicus Value (2013): 6.14 | Impact Factor (2015): 6.391.

[3] Shrikant Harle (2014) “Steel Fiber Reinforced Concrete & Its Properties” International Journal of Engineering Sciences & Research Technology ISSN: 2277-9655 Impact Factor: 1.852

[4] Shrikant Harle (2014) “Glass Fiber Reinforced Concrete & Its Properties” International Journal of Engineering Sciences & Research Technology ISSN: 2277-9655Impact Factor: 1.852

[5] Preetha V (2014) “Strength Properties of Steel Fiber and Glass Fiber Composites” International Journal of Civil Engineering and Technology (IJCIET)ISSN 0976 – 6308 (Print) ISSN 0976 – 6316(Online) Volume 5, Issue 12, pp. 188-193.

[6] Sai Kiran T. (2016) “Comparison of Compressive and Flexural Strength of Glass Fiber Reinforced Concrete with Conventional Concrete” International Journal of Applied Engineering Research ISSN 0973-4562 Volume 11, pp 4304-4308

[7] Kavita S Kene (2012) “Experimental Study on Behavior of Steel and Glass Fiber Reinforced Concrete Composites” Bonfring International Journal of Industrial Engineering and Management Science, Vol. 2, No. 4

[8] Kamal M.M (2013) “Characterization of Recycled Self-Compacting Concrete Prepared with Glass Fibers” International Journal of Engineering and Applied Sciences ISSN2305-8269 Vol. 3, No.4

[9] Othman Hameed (2014)”Influence of steel fibers on the behavior of light weight concrete made from crushed clay bricks” American Journal of Civil Engineering. Vol. 2, No. 4, pp. 109-116. doi: 10.11648/j.ajce.20140204.11

[10] IS 10262:2009, “Indian Standard, recommended guidelines for concrete mix designs”, Bureau of Indian Standard, New Delhi.



[11] IS 456: 2000, “Indian Standard, Plane and reinforced concrete- Code of practice”, Bureau of Indian Standard, New Delhi, 2000.

[12] Delsye C. L. Teo (2006) “Flexural Behaviour of Reinforced Lightweight Concrete Beams Made with Oil Palm Shell (OPS)” Journal of Advanced Concrete Technology Vol. 4, No. 3, 1-10.

[13] Wahid Omar (2002) “The Performance of Pre-Tensioned Pre-Stressed Concrete Beams Made with Lightweight Concrete” Journal of Civil Engineering Vol.14, No.1.

[14] Mandeep Singh Saroe (2014) “Experimental Study of Non-Destructive Test on Steel Fiber Reinforced Concrete” International Journal of Engineering, Business and Enterprise Applications (IJEBEA) ISSN (Print): 2279-0020 ISSN (Online): 2279-0039

[15] IS 516:1959, “Method of Tests for Strength of concrete”, Bureau of Indian Standard, New Delhi.

[16] D.B.Mohite and S.B.Shinde, Experimental Investigation on Effect of Different Shaped Steel Fibers on Flexural Strength of High Strength Concrete. International Journal of Civil Engineering and Technology, 4(2), 2013, pp.332–336.

[17] Ramesh Chandra Mohapatra, Antaryami Mishra and Bibhuti Bhushan Choudhury, Investigations on Tensile and Flexural Strength of Wood Dust and Glass Fibre Filled Epoxy Hybrid Composites. International Journal of Civil Engineering and Technology, 4(4), 2013, pp.180–187.

comparative study on effect of steel and...

Documents