Btech Project Report Template-1

Probabilistic Seismic Hazard Analysis

mechanical properties of steel fibre reinforced concrete A report submitted in partial fulfilment of the requirements

for the degree of BACHELOR OF TECHNOLGY IN CIVIL ENGINEERINGby

sTUDENT NAME(Roll No. 954005)

SupervisorpROF. ***********

School of Civil Engineering

KIIT UNIVERSITY751024May 2011

acknowledgementIt is with immense pleasure that I express my sincere sense of gratitude and humble appreciation to Dr.Sanjaya kumar patro for his invaluable guidance, whole-hearted co-operation, constructive criticism and continuous encouragement in the preparation of this thesis. Without his support and guidance, the present work would have remained a dream.

I would also like to thank Prof. B.Das, Dean, School of Civil Engineering KIIT UNIVERSITY, for providing necessary facilities.

I take this opportunity to thank all my scholar friends & family for their valuable support and encouragement throughout the preparation of this work. I also thank all those who have directly or indirectly helped in completion of this work.

May 2011,

Rupak Kumar Patro

KIIT, BHUBANESWAR

(954005)

Declaration of scholarI hereby certify that the work which is being presented in the report entitle "****************************" in partial fulfilment of the requirements for the award of the degree of Bachelor of Technology in School of Civil Engineering under KIIT University, Bhubaneswar is an authentic record of my own work carried out during the period from 2014 to 2015 under the supervision of Dr.Sanjaya Kumar Patro.

The matter embodied in this thesis has not been submitted by me for the award of any other degree of this or any other University/Institute.signature(Name of Student)This is to certify that above statement made by the student is correct to the best of our knowledge.

Dr.Sanjaya Kumar Patro

(Supervisor)

School of Civil Engineering

abstract

The present investigation considers the influence of various types of steel fibers with different percentage on the mechanical properties of the ordinary concrete. Commercially available fibers used in this study are hooked end, flat crimped, crimped round. Experiment is carried out to get mechanical properties of ordinary concrete, and fibrous concrete with 0.5%, 0.75% and 1% of fibre by replacement of fine and coarse aggregate over volume of ordinary concrete. Mechanical properties are measured by determining compressive strength, split tensile strength, and flexural strength. Following fibrous concretes are prepared like hooked end steel fibre reinforced concrete (HSFRC0.5, HSFRC0.75 and HSFRC1.0); flat crimped steel fibre reinforced concrete (FSFRC0.5, FSFRC0.75 and FSFRC1.0); and crimped round steel fibre reinforced concrete (CSFRC0.5, CSFRC0.75 and CSFRC1.0). It is observed from experiment that influence of all types fibre is marginal for compressive strength of concrete over ordinary concrete at specified proportion of steel fiber replacement considered in this study. However the influence of all types of fiber is most significant for split tensile and flexural strength of concrete at 1% of steel fiber replacement. At 28 days, the compressive strength of HSRFC0.75, FSRFC0.75 & CSRFC0.75 are more than 8.79%, 3.75% and 6.91% over ordinary concrete. The split tensile strength of HSRFC0.75, FSRFC0.75 & CSRFC0.75 are more than 29.73%, 34.80% and 52.35% over ordinary concrete at 28 days. Similarly at 28 days, the flexural strength of HSRFC0.75, FSRFC0.75 & CSRFC0.75 are more than 21.91%, 25.79% and 26.60% over ordinary concrete. However the compressive strength of HSRFC1.0, FSRFC1.0 & CSRFC1.0 are more than 3.46%,2.42% and 1.33% over ordinary concrete; the split tensile strength of HSRFC0.75, FSRFC1.0 & CSRFC1.0 are more than 47.98%, 54.73% and 60.81% over ordinary concrete; and the flexural strength of HSRFC1.0, FSRFC1.0 & CSRFC1.0 are more than 29.05%, 30.41% and 30.68% over ordinary concretetable of contents

APPROVAL SHEETii

ABSTRACTiii

TABLE OF CONTENTSiv

LIST OF TABLESv

LIST OF FIGURESvi

LIST OF AbbreviationSviii

1. INTRODUCTION1

1.1 General1

1.2 Objectives of Present Study31.3 Organisation of Report32. LITERATURE REVIEW43. MATERIAL123.1 Cement123.2 Aggregates123.2.1 Corse Aggregate123.2.2 Fine Aggregate133.3 Steel Fiber132.4 Water134. EXPERIMENTAL POGRAM164.1 Preparation of concrete specimens164.2 Mixing Procedure164.3Testing of fresh concrete174.4 Casting-Compaction andCuring 174.4.1 Casting and Curing of Cube Specimens174.4.2 Casting and Curing of Cylinder Specimens174.3.2 Casting and Curing of Prism specimens184.5 Testing of Hardened Concrete184.5.1 Compressive strength of Concrete184.5.2 Split Tensile strength of Concrete194.5.3 Flexural strength of Concrete205. RESULT AND DISCUSSION225.1 Compresive Strength225.2 Split Tensile Strength235.3 Flexural strength246. CONCLUSION39REFERENCES40

APPENDIX43ACKNOWLEDGMENT45

LIST of tables

Chapter 3Table 3.1: Physical properties of 43 grade ordinary Portland concrete13Table 3.2: Chemical properties of 43 grade ordinary Portland concrete14Table 3.3: Physical properties of coarse aggregate14Table 3.4: Physical properties of fine aggregate14Table 3.5: Types of steel fiber 15Table 3.6: Physical properties of steel fiber15Table 3.7: Improvement of SFRC over Ordinary Concrete15Chapter 4Table 4.1: Various proportions and w/c ratio of fibrous concrete mix21Chapter 5Table 5.1: Variation of compressive strength of HSFRC with OC25Table 5.2: Variation of compressive strength of FSFRC with OC25Table 5.3: Variation of compressive strength of CSFRC with OC25Table 5.4: Variation of split tensile strength of HSFRC with OC25Table 5.5: Variation of split tensile strength of FSFRC with OC26

Table 5.6: Variation of split tensile strength of CSFRC with OC26Table 5.7: Variation of Flexural strength of HSFRC with OC26Table 5.8: Variation of Flexural strength of FSFRC with OC26Table 5.9: Variation of Flexural strength of CSFRC with OC26LIST of FIGURESChapter 5Figure 5.1: Effect of hooked steel fiber on compressive strength at different curing ages27Figure 5.2: Relationship between the hooked steel fiber content and increasing

Percentage in compressive strength at different ages27Figure 5.3: Effect of flat steel fiber on compressive strength at different curing ages28Figure 5.4: Relationship between the flat steel fiber content and increasing

percentage in compressive strength at different ages28Figure 5.5: Effect of crimped steel fiber on compressive strength at different curing ages29Figure 5.6: Relationship between the crimped steel fiber content and increasing percentage in compressive strength at different ages29Figure 5.7: Effect of hooked steel fiber on spliting tensile strength at different curing ages30Figure 5.8: Relationship between the hooked steel fiber content and increasing percentage in splitting tensile strength at different ages30Figure 5.9: Effect of flat steel fiber on splitting tensile strength at different curing ages31Figure 5.10: Relationship between the flat steel fiber content and increasing percentage in splitting tensile strength at different ages31Figure 5.11: Effect of crimped steel fiber on splitting tensile strength at different curing ages32Figure 5.12: Relationship between the crimped steel fiber content and increasing percentage in splitting tensile strength at different ages32Figure 5.13: Effect of hooked steel fiber on flexural strength at different curing ages33Figure 5.14: Relationship between the hooked steel fiber content and increasing percentage in flexural strength at different ages33Figure 5.15: Effect of flat steel fiber on flexural strength at different curing ages34Figure 5.16: Relationship between the flat steel fiber content and increasing percentage in flexural strength at different ages34Figure 5.17: Effect of crimped steel fiber on flexural strength at different curing ages35Figure 5.18: Relationship between the crimped steel fiber content and increasing percentage in flexural strength at different ages35Figure 5.19: Influence of 0.5% fiber replacement on compressive strength for HSRFC, FSFRC &CSFRC at different curing ages36Figure 5.20: Influence of 0.75% fiber replacement on compressive strength for HSRFC, FSFRC &CSFRC at different curing ages36Figure 5.21: Influence of 1.0% fiber replacement on compressive strength for HSRFC, FSFRC &CSFRC at different curing ages36Figure 5.22: Influence of 0.5% fiber replacement on splitting tensile strength for HSRFC, FSFRC &CSFRC at different curing ages37Figure 5.23: Influence of 0.75% fiber replacement on splitting tensile strength for HSRFC, FSFRC &CSFRC at different curing ages37Figure 5.24: Influence of 10% fiber replacement on splitting tensile strength for HSRFC, FSFRC &CSFRC at different curing ages37Figure 5.25: Influence of 0.5% fiber replacement on flexural strength for HSRFC, FSFRC &CSFRC at different curing ages38Figure 5.26: Influence of 0.75% fiber replacement on flexural strength for HSRFC, FSFRC &CSFRC at different curing ages38Figure 5.27: Influence of 1.0% fiber replacement on flexural strength for HSRFC, FSFRC &CSFRC at different curing ages38 Abbreviation

OC Ordinary concrete

SFRC Steel fiber reinforced concrete

HSFRC Hooked steel fiber reinforced concrete

FSFRC Flat steel fiber reinforced concrete

CSFRC Crimped steel fiber reinforced concrete

HSFRC 0.50 Hooked steel fiber reinforced concrete with 0.50% steel fifer by volume



FSFRC 0.50 Flat steel fiber reinforced concrete with 0.50% steel fifer by volume



CSFRC 0.50 Crimped steel fiber reinforced concrete with 0.50% steel fifer by volume



1. introduction

1.1 generalFibre reinforced concrete (FRC) may be defined as a composite materials made with Portland cement, aggregate, and incorporating discrete discontinuous fibres. Plain, unreinforced concrete is a brittle material, with a low tensile strength and a low strain capacity. The role of randomly distributes discontinuous fibres is to bridge across the cracks that develop provides some post- cracking ductility. If the fibres are sufficiently strong, sufficiently bonded to material, and permit the FRC to carry significant stresses over a relatively large strain capacity in the post-cracking stage. There are, of course, other (and probably cheaper) ways of increasing the strength of concrete. The real contribution of the fibres is to increase the toughness of the concrete (defined as some function of the area under the load vs. deflection curve), under any type of loading. That is, the fibres tend to increase the strain at peak load, and provide a great deal of energy absorption in post-peak portion of the load vs. deflection curve. When the fibre reinforcement is in the form of short discrete fibres, they act effectively as rigid inclusions in the concrete matrix. Physically, they have thus the same order of magnitude as aggregate inclusions; steel fibre reinforcement cannot therefore be regarded as a direct replacement of longitudinal reinforcement in reinforced and prestressed structural members. However, because of the inherent material properties of fibre concrete, the presence of fibres in the body of the concrete or the provision of a tensile skin of fibre concrete can be expected to improve the resistance of conventionally reinforced structural members to cracking, deflection and other serviceability conditions. The fibre reinforcement may be used in the form of three dimensionally randomly distributed fibres throughout the structural member when the added advantages of the fibre to shear resistance and crack control can be further utilised. On the other hand, the fibre concrete may also be used as a tensile skin to cover the steel reinforcement when a more efficient two dimensional orientation of the fibres could be obtained.1.2 objectives of the present study

The specific objectives of the present study are as below.

1. To carry out literature review for detail understanding of steel fibre reinforced concrete.2. The behavior of SFRC can be understood better, when a relative study is made. To facilitate this, SFRC concrete specimens were tested under the same conditions of ordinary concrete specimens.3. To study the influence of compressive strength of various steel fibrous reinforced concrete with different percentage (0.5, 0.75 & 1.0) of fibre replacement over ordinary concrete.4. To study the influence of split tensile strength of various steel fibrous reinforced concrete with different percentage (0.5, 0.75 & 1.0) of fibre replacement over ordinary concrete.5. To study the influence of flexural strength of various steel fibrous reinforced concrete with different percentage (0.5, 0.75 & 1.0) of fibre replacement over ordinary concrete.1.3 organisation of the report

The present work has been organised into six chapters. Following is a brief outline of the report.

In the second chapter, general overview of literatures from various journals and publication are overviewed and discussed.

The third chapter presents the general overviews of various materials used in this study are discussed.

The fourth chapter presents the experimental program like mixing procedure, specification, detail of various tests and their procedure.

The fifth chapter deals with the various results and discussions of the study. As a result of the study carried out, overall conclusions, contribution are presented in the last chapter to bring out the outcome of the present work.

2 literature review

Shakir A.Salih. [1] investigate the effect of steel fiber content on the mechanical properties of the concrete matrix. The experimental result showed the using of steel fibers in concrete led to a considerable improvement in mechanical properties of concrete. The result exhibited that the addition of 1% steel fiber to concrete increases the compressive strength significantly. Also the result show that the addition of 1.5% steel fiber increases the splitting and flexural strength significant.

Peillere et al. [2] investigated the effect of fiber addition on the autogenously cracking of silica fume concrete. The tests showed that steel fibers can lengthen the time elapsed before cracking and can provide confinement after cracking of concrete. As in the case of conventional concrete, the use of steel fiber substantially increases the energy of high strength concrete. The tests also show that the resulting concrete can be kept reasonably workable by modifying the aggregate ratio in composition of the concrete and using fibers having a relatively low aspect ratio.

Al sakiny [3] investigate the effect of steel fiber content, high range water reducing agent (HRWRA) and effect of rise husk ash (RHA) in producing ultra high strength fiber reinforced concrete. The result demonstrated that reference concrete modified with 2%, 2.5%, 3% steel fiber by volume showed a slight reduction in compressive strength at early age of curing. On the other hand this concrete showed a significant increase in other properties. The result also demonstrated that the incorporation of HRWRA in concrete led to a considerable improvement in compressive splitting tensile, flexural strength, static modulus of elasticity, Poissons ratio and impact resistance. Where the inclusion of 8%RHA,as partial replacement by weight of cement with HRWRA showed superior performance in those properties over those of HRWRA concrete.

Ameir [4] investigated the engineering properties of high performance lightweight aggregate concrete containing various types of chemical, mineral admixtures and steel fiber. Result indicate that, HRWRA steel fiber reinforced light weight aggregate concrete showed considerable improvement in compressive, splitting, flexural strengths, impact resistance, static modulus of elasticity and Poissons ratio are compared to fiber reinforced lightweight aggregate concrete with out HRWRA. On the other hand, the inclusion of RHA as partial replacement by weight of cement with optimum doge of HRWRA showed superior performance over those of HRWRA fiber reinforced concrete.

Potrzebowski [5] (1983) researched on the splitting test applied to steel fiber reinforced concrete. He tested on cube specimen cut from flexural test prisms, which were themselves obtained from slabs. The results show that the splitting tensile strength is strongly influenced by the number of fibers intersecting the failure plane and their orientation. Specimens subjected to the loads perpendicular to the plane of vibration are shown to give consistent results where as specimens loaded parallel to the plane of vibration gave low results.

Zollo [6] (1997) overviewed on fiber reinforced concrete over the 30 years of development. It discusses commonly applied terminology and models of mechanical behavior that form a basis for understanding material performance without presenting mathematical details. They reviewed properly about FRC rather than as historical reporting.

Parviz Soroushian and Cha-Don Lee [7] Measurements were made of the number of fibers per unit cross-sectional area in steel fiber reinforced concrete specimens incorporating various volume fractions of fibers of different types. Based on statistical evaluation of the measured values, the differences in fiber concentration at different location on the cross section were assessed. Theoretical expressions were derived for the number of fibers per unit cross-sectional area in the fiber reinforced concrete, with due consideration given to the effects of the surrounding boundaries. The effects of vibration on reorientation of steel fibers in concrete were investigated through comparisons between the computed and measured values of number of fibers per unit cross-sectional area

3. materials3.1 cementCement has different properties and characteristics which depend upon their chemical compositions. By changing in fineness of grinding, oxide compositions cement have exhibit different properties and different kind of cement. The use of additives, changing chemical composition, and use of different raw materials have resulted the availability of many types of cements.

Cement used in the experimental work is ORDIRARY PORTLAND CEMENT of 43 grades conforming to IS: 8112/1989. The physical properties & chemical properties of the cement obtained on conducting appropriate tests are as per IS: 269/4831 and the requirements as per IS: 8112/1989 are given in the Table 3.1 & Table 3.23.2 AGGREGATES Aggregates are the important constituents in concrete. They give body to the concrete, reduce shrinkage and effect economy. The fact that the aggregates occupy 70-80 present of volume of concrete, it has some impact on various characteristics and properties of concrete. Earlier, aggregates were considered as chemically inert material but now it has been recognised that some of the aggregate are chemical active and also certain aggregates ere exhibit chemical bond at the interface of aggregate and paste.3.2.1 Corse aggregateCrushed granite of 10mm & 20mm size are used as coarse aggregate. The sieve analysis of aggregates confirms to the specifications of IS: 383-1970. The Physical Properties are given in the Table 3.33.2.2 Fine Aggregate Fine aggregate which satisfied the required properties for experimental work and conforms to zone as per the specification of IS: 383-1970. . The Physical Properties are given in the Table 3.43.3 STEEL FIBRE Steel fibers are produced by cutting or chopping the wire & thin flat sheet. A number of steel-fiber types Indented round, Crimped round, Machined round, Hook-ended round, Flat sheet and crimped flat are available as reinforcement to concrete conforming IS: 280-1976 with an aspect ratio 30-250. Three different mild steel fibers Crimped Round MSC 45 -30, Hooked End MSH 60-30 & Crimped Flat MSCF 50mm are used. The various physical properties of steel fiber are given in Table 2.6 & improvements of SFRC over ordinary concrete are given in Table 3.73.4 waters

Clean potable water as obtained from laboratory of Civil Engineering Department of KITT University was used for mixing and curing of concrete Table 3.1 Physical Properties of 43 grade ordinary Portland cementSL.NOPARTICULARSTEST RESULTSREQUIREMENT OF IS:8112/1987

12

3

4Fineness obtained (inM2/Kg)

Setting time (Minutes)

1. Initial

2. Final

Soundness

1. Lechatiler expansion (mm)

2. Autoclave (%)

Compressive strength (Mpa)

1. 72+1Hr

2. 168+2Hr

3. 672+4Hr310

170

235

1.500.012

30.2

40.1

52.8225 (min)

30 (min)

600 (max)

10(max)

0.8(max)

23.0(min)

33.0(min)

43.0(min)

Table 3.2 Chemical Properties of 43 grade ordinary Portland cementSL.NOPARTICULARSTEST RESULTSREQUIREMENT OF IS:8112/1987

1

2

3

4

5

6

7

8

9

10

11Lime (% by mass)

Soluble silica (% by mass)

Alumina (% by mass)

Iron Oxide(% by mass)

Magnesia(% by mass)

Sulphuric Anhydride(% by mass)

Loss on Ingnistion(% by mass)

Insoluble Reside(% by mass)

Chlorides (% by mass)

Lime saturation Factor

Al2O3/Fe2O360.87

20.55

5.36

4.00

0.74

1.83

3.10

2.93

0.0173

0.90

1.346 (max)

3 (max)

4 (max)

5(max)

0.05 (max)

0.66-1.02

0.66(min)

Table 3.3 Physical Properties of coarse aggregate

SL.NOPARTICULARSTEST RESULTS

1Specific Gravity2.7

2Fineness Modulus6.2

3Water Absorption0.4(%)

Table 3.4 Physical Properties of fine aggregate

SL.NOPARTICULARSTEST RESULTS

1Specific gravity2.65

2Fineness Modulus2.47

3Water Absorption0.85(%)

4Free Surface Moisture0.90(%)

Table 3.5 Types of steel fiber TYPES OF STEEL FIBRESHAPESDIMENSION

RoundIndentedCrimpedMachinedHook-Ended

0.25-0.75 ()

Rectangular or FlatFlat Sheet

Flat Crimped

0.15-0.41(thick)

0.25-0.90(width)

Table 3.6 Physical Properties of steel fiber

TYPE OF FIBERSMSH6030MSC

4530MSCF

50

Specific gravity7.867.867.86

Effective modulus (Gpa)200200200

Tensile strength (Mpa)350350350

Elongation at breaking point (%)3.53.53.5

Aspect ratio5066.7760

Table 3.7 Improvement of SFRC over ordinary concrete of sPROPERTYIMPROVEMENT OVER ORDINARY CONCRETE

Ductility5 -10

Impact resistance100-500 %

Cracking & flexural strength80-120 %

Bearing strength50-100 %

Fatigue resistance in flexureUp to a large extend

Fatigue resistance in compressionSignificant

Confinement of concrete in compressive stressSignificant

4. experiment pogram4.1 preparation of concrete specimens Different mix of SFRC & Ordinary concrete obtained to conduct compression test on standard BIS specimen of size 150150150 mm, split tensile test on standard BIS specimen of size 150 mm(diameter) & 300 mm (height), flexural test on standard BIS specimen of size 100100500 mm. The curing period for the BIS specimen are 7 &28 days respectably.4.2mixing procedure

Uniform mixing of concrete should be ensured to get correct test results of the specimen. For ordinary concrete, initially the coarse aggregate is weighed for required quantity per mix proportioning in tray 1; the Sand is weighed and poured into another mixing tray2, which is completely dry. Cement is weighed and uniformly spread on the surface of sand into tray 2 and uniform mixing is ensured. Mixed cement and sand from tray 2 is uniformly spread on the coarse aggregate in tray 1, dry mixing is carried out, later water mixed with the dry mix, mixing is ensured up to a minimum of 5 minutes until uniform colour of concrete is seen. Immediately the concrete is measured for slump and placed in moulds as per procedure.

For Steel fiber Reinforced concrete (SFRC), the above-explained procedure is followed except that before adding cement and sand to coarse aggregate. Fiber is thoroughly mixed with cement and sand, then the mixture of fiber, sand and Cement is mixed with aggregate and further procedure is followed to achieve the different types of fibrous concrete (HSFRC, FSFRC, CSFRC) with 0.5%, 0.75% and 1% by replacement of fine and coarse aggregate over volume of ordinary concrete.

4.3 testing of fresh concreteThe slump test was conducted to measure the degree of workability for ordinary concrete and steel fibrer reinforced concrete. The factor which has a major effect on workability is the aspect ratio (l/d) of the fibres. The workability decreases with increasing aspect ratio, in practice it is very difficult to achieve a uniform mix if the aspect ratio is greater than about 100. The water cement ratios used in this study for a slump value of 70 5mm are shown in Table 4.1.4.4 casting compaction and curing4.4.1 Casting and Curing of Cube Specimens The steel cube moulds were coated with oil on their inner surface and were placed on granite platform. The amount of cement, sand, coarse aggregates required for cubes, were weighed. The materials were first dry mixed then mixed with 1/3rd amount of total water. Slump test is conducted to measure the degree of workability of mix. Concrete was poured in to the moulds in three layers: each layer was uniformly tamped by a tamping rod with 25 numbers of blows. The top surface was finished using a trowel.

Moulds were safely demoulded causing no damage to the specimen and immediately concrete cube specimens and immediately concrete cube specimens were kept in curing tank, completely immersed in for curing.4.4.2 Casting and Curing Of Cylinder SpecimensThe steel cylinder moulds were coated with oil on their inner surfaces and were placed on a granite platform. The amount of cement, sand, coarse aggregates required for cylinders were weighed. The materials were first dry mixed, then mixed with, 1/3rd amount of total water, Chemical admixture mixed with left amount of water is now added and mixed thoroughly to get a homogeneous mix. Slump lest conducted to measure the degree of workability of mix. Slump lest conducted to measure the degree of workability of mix. Concrete was poured in to the moulds in four equal Layer each layer as uniformly tamped by a tamping rod with 35 numbers of blows. The top surface was finished using a trowel.

Moulds were safely demoulded causing no damage to the specimen and immediately concrete cylinder specimen were kept in curing tank completely immersed for Curing up to desired period.4.4.3 Casting and Curing Of Prism SpecimensThe steel prism moulds were coated with oil on their inner surfaces and were placed on a granite platform. The amount of cement, sand, coarse aggregates required for 9 prisms were weighed. The materials were first dry mixed then mixed with 1/3rd amount of total water. Slump test is conduced to measure the degree of workability of mix. Concrete was poured in to the moulds in two equal layers: each layer was uniformly tamped by a tamping rod. The top surface was finished using a trowel.

Moulds were safely demoulded causing no damage to the specimen and immediately Concrete prism specimen and immediately Concrete prism specimens were kept in curing tank completely immersed for Suring up to desired period.

4.5 testing of hardened concrete

4.5.1Compressive Strength of concrete The compressive strength of concrete i.e. Ultimate strength of concrete is defined as the load to which causes failure of the specimen divided by the area of the cross section in uniaxial compression, under a given rate of loading. To avoid large variation in the results of compression test, a great care is taken during the casting of the test specimens and loading as welt. It is however realized that in an actual structure, the concrete at any point is in a complex stress condition and not in uniaxial compression. However it is customary to conduct the test in uniaxial compression only. Concrete under triaxial state can offer more resistance and will fail only after considerable large deformations, the use of 150mm cubes has been made as per code of practices IS 456. The advantage of selection of Section IS-516 1959 (24) cube, as the standard test specimen is that tow plane and parallel surfaces can always he found between which the load can he applied. Compression testing machine is used to test the concrete cubes. The compression strength is calculated using the formula.

Compression Strength = N/mm2 4.5.1.1 Testing of cube specimenAt each desired curing periods, cube specimen were taken out of water and kept for surface drying. The cubes were tested in 40T compressive testing machine to get the compressive strength of concrete. 4.5.2 Split tensile Strength of concreteThe split tensile strength of concreter can be obtained indirectly by subjecting a concrete cylinder to the action of a compressive force along two opposite ends of a base of compression testing machine. Due to the compressive force, the cylinder is subjected to a large magnitude of the compressive tress near the loading region. The large portion corresponding to a depth of about 87% and length of the cylinder is subjected to a uniform tensile stress (St) is taken as an index of the tensile strength of concrete and is given by the formula. sp = 0.637 Where, sp = the indirect tensile strength of concrete in N/mm2. P= Load causing rupture in KN

d= Diameter of cylinder in mm.

l= length of cylinder in mm.The load has to be applied to be cylinder through a packing plate of rubber or plywood. The packing plate should be of a width of not more than 13mm and thickness 3mm.

4.5.2.1 Testing of cylinder specimen

At each desired curing period, the cylinder specimen were taken out of water and kept for drying. The cylinders were tested in a 40T capacity compressive testing machine to get the split tensile strength of concrete. Each specimen is carefully placed in position, so that loading is uniformly distributed over the length of the specimen, in split tensile test; the specimen is supported with two timber pieces on top and bottom of the specimen and uniformly distribute the load. Load is applied without shock and increased continuously until no greater load can be sustained. Maximum load applied on the specimen is recorded.4.5.2 Flexural Strength of concreteModulus of rupture is defined as the normal tensile stress in concrete, when cracking occurs in flexure test (IS 516-1599). This tensile stress is the flexural strength of concrete and is calculated by the use of the formula, which assumes that the section is homogeneous.

Fb = pl/bd2Where,Fb= Modulus of rupture, N/mm2b= Measured depth in mm

l= span length in mm

P= Max, Load in KN applied to the specimen.The symmetrical two points loading creates a pure bending zone with constant bending moment in the middle third span and thus the modulus of rupture obtained is not affected by shear, as in the case of single concentrated load acting on the specimen. The concrete test specimen is a prism of cross section 100mm 100mm and 500mm long. It is loaded on a span of 400mm. Modulus of Rupture is useful as design criterion or concrete pavements and for evaluating the cracking moment (Mcr), which is the moment that causes the first crack in a prestressed concrete or partially prestressed concrete beam..0 cm specimen, or less than 11.0cm for a 10.0 cm specimen, the result of the test be discarded]4.5.1.1 Testing of prism specimen

At each desired curing periods the Prism specimens were taken out of water and kept for surface drying. The prisms were tested in Flexure testing machine by arranging two point loading system m. each Specimen is carefully placed in position. Load is applied without shock and rate of increase in loading is maintained. Maximum load applied on the specimen is recorded at the point of failure of the specimen and flexural strength is calculated. Table 4.1 Various proportion and w/c ratio of fibrous concrete mix

TYPESSTEEL FIBER CONTENT BY VOLUME (%)

CEMENTCONTENT (kg)

FINE AGGREGATE(kg)CORSE AGGREGATE(kg)

STEEL FIBER (kg)W/C RATIO FOR SLUMP70 5 (mm)

OC0409613122700.50

HSFRC 0.50FSFRC 0.50CSFRC 0.500.50409600.21200.339.250.43

HSFRC 0.75

FSFRC 0.75CSFRC 0.750.75409593.71187.458.875

0.46

HSFRC 1.00

FSFRC 1.00

CSFRC 1.001.00409587.21174.378.50.48

5. result And disscusionThis chapter deals with the presentation of test result, and discussion on compressive strength, tensile strength and flexural strength development of ordinary concrete over steel fiber reinforced concrete of HSFRC,FSFRC,CSFRC at different percentage (0.5,0.75,1) and different curing period.5.1 compressive strengthThe compressive strength is the main criterion for the purpose of structural design. The strength development in steel fiber reinforced concrete (SFRC) studied at 7 & 28 days. The variation of compressive strength on HSFRC, FSFRC & CSFRC with different percentage (0.5, 0.75, 1) of steel fiber over OC are given in Table 5.1, Table 5.2 & Table 5.3The compressive strength development at various curing ages for all type of concrete are presented in tabular form. Result of all concrete specimens exhibited increase in compressive strength with increase of curing age.

5.2 Split tensile strength In RCC construction, the strength of concrete in compression is only taken into consideration the tensile strength of concrete is generally neglected, as it is relatively low in comparison to the compressive strength. But there are some current structures; where the tensile strength of concrete also finds a good place during design. Therefore it is necessary to assess the tensile strength of concrete. The use of Steel Fiber increases the tensile strength of concrete. The variation of splitting tensile strength on HSFRC, FSFRC & CSFRC with different percentage (0.5, 0.75,1) of steel fiber over OC are given in Table 5.3,Table 5.4 & Table 5.5 The splitting tensile strength was determined at ages of 7 & 28 days for moist cured concrete specimens. The test result of the splitting tensile strength are indicated that in general, all types of concrete specimens exhibited continued increase in splitting strength with development of curing ages.

From graphs it is observed that the splitting tensile strength of SFRC increases at all ages of curing compared with the ordinary concrete. This increase maybe ascribed to the significant reduction in capillary porosity of the cement matrix as well as a good dispersion of the cement grains throughout the mix, there by increasing bond strength leading to a significant increase in splitting tensile strength.5.3 flexural strengthIt is seen that strength of concrete in compression and tension in both direction (i.e. direct tension and flexural tension) are closely related, but the relationship is not of direct proportionality. The ratio of two strengths depends on general level of strength of concrete. In other words, for higher compressive strength of concrete shows higher tensile strength, but the rate of increase of tensile strength is increasing order. The use of steel fiber increases the tensile strength of concrete the variation of flexural strength on HSFRC, FSFRC & CSFRC with different percentage (0.5,0.75,1) of steel fiber over OC are given in Table 5.7,Table 5.8 & Table 5.9The percentage of increase in flexural strength of CSFRC relative to ordinary concrete at 7 days and 28 days were 8.45%, 26.12% & 35.86% and 9.68%, 26.60% & 30.68% for CSFRC with 0.50%, 0.75% and 1.00% of crimped steel fiber content.Table 5.1 Variation of compressive strength of HSFRC with OCTYPESCOMPRESSIVE STRENGTH (Mpa)

7 DAYS28 DAYS

OC21.9832.98

HSFRC 0.50 %22.5634.51

HSFRC 0.75 %22.6635.88

HSFRC 1.00 %22.4134.12

Table 5.2 Variation of compressive strength of FSFRC with OCTYPESCOMPRESSIVE STRENGTH (Mpa)

7 DAYS28 DAYS

OC21.9832.98

FSFRC 0.50 %22.3833.96

FSFRC 0.75 %22.4334.22

FSFRC 1.00 %22.1833.78

Table 5.3 Variation of Compressive strength of CSFRC with OCTYPESCOMPRESSIVE STRENGTH (Mpa)

7 DAYS28 DAYS

OC21.9832.98

CSFRC 0.50 %22.4234.38

CSFRC 0.75 %22.4835.26

CSFRC 1.00 %22.2633.42

Table 5.4 Variation of Split tensile strength of HSFRC with OCTYPESSPLIT TENSILE STRENGTH (Mpa)

7 DAYS28 DAYS

OC1.932.96

HSFRC 0.50 %2.343.41

HSFRC 0.75 %2.823.84

HSFRC 1.00 %3.084.38

Table 5.5 Variation of Split tensile strength of FSFRC with OCTYPESSPLIT TENSILE STRENGTH (Mpa)

7 DAYS28 DAYS

OC1.932.96

FSFRC 0.50 %2.383.41

FSFRC 0.75 %2.863.84

FSFRC 1.00 %3.114.38

Table 5.6 Variation of Split tensile strength of CSFRC with OCTYPESSPLIT TENSILE STRENGTH (Mpa)

7 DAYS28 DAYS

OC1.932.96

CSFRC 0.50 %2.443.75

CSFRC 0.75 %2.924.48

CSFRC 1.00 %3.184.76

Table 5.7 Variation of Flexural strength of CSFRC with OCTYPESFLEXURAL STRENGTH (Mpa)

7 DAYS28 DAYS

OC4.024.905

HSFRC 0.50 %4.335.36

HSFRC 0.75 %4.985.98

HSFRC 1.00 %5.426.33


7 DAYS28 DAYS

OC4.024.905

FSFRC 0.50 %4.355.37

FSFRC 0.75 %5.036.17

FSFRC 1.00 %5.446.39


7 DAYS28 DAYS

OC4.024.905

CSFRC 0.50 %4.365.38

CSFRC 0.75 %5.076.21

CSFRC 1.00 %5.466.41

Figure 5.1Effect of hooked steel fiber on compressive strength at different curing ages

Figure 5.2 Relationship between the hooked steel fiber content and increasing percentage in compressive strength at different ages

Figure 5.3Effect of flat steel fiber on compressive strength at different curing ages

Figure 5.4 Relationship between the flat steel fiber content and increasing percentage in compressive strength at different age

Figure 5.5 Effect of crimped steel fiber on compressive strength at different curing age

Figure 5.6 Relationship between the crimped steel fiber content and increasing percentage in compressive strength at different ages

6. CONCLUSIONIn this present study an effort has been taken to enlighten the use of different types of commercial available steel fiber to obtain the fiber reinforced concrete and comparing their mechanical properties with ordinary concrete. Based on the experimental observation in current study following conclusions can be made. Compressive strength of steel fibrous concrete at 0.5%, 0.75% and 1% of steel fiber increases compare to ordinary concrete. However it is observed that compressive strength of fibrous concrete with 1% of steel fibre decreases with compare to 0.75% of steel fibrous concrete. It is noted that compressive strength increases with age at all percentage of fibre content. The splitting tensile strength and flexural strength also increases with age and steel fiber content. It has been observed that at all percent of steel fibre content splitting tensile strength of steel fibre concrete increases about 50 to 60% over ordinary concrete. It is found that at all percent of steel fibre content flexural strength of steel fibre concrete increases about 30% over ordinary concrete. However it is seen that the influence is maximum for both split and flexural strength at 1% steel fiber content. Hooked end steel fibre reinforced concrete at all percent of fiber content has maximum influence on compressive strength as compare to flat and crimped steel fiber reinforced concrete. Where as influence is maximum at 0.75% of hooked steel fiber content. Crimped steel fiber reinforced concrete at all percent of fiber content has maximum influence on split tensile and flexural strength as compare to hooked and flat steel fiber reinforced concrete. Where as influence is maximum at 1% of crimped steel fiber content.7. references[1] Shakir A.Salih, Saeed K. Rejeb and Khalid B. Najem Effect of steel fibres on the properties of high performance concrete A1-Rafidain Engineering ,vol.13, no.4, 2005.

[2] Paillere A.M., Buil M., and Serrano J.J., Effect of Fibre Addition on the Autogenous Cracking of Silica fume concrete, ACI Materials journal, Vol.86, No.2, pp.139-144. 1989 [3] A1-Sakiny, Z.H. Engineering Properties of ultra High Strength fiber Reinforced Concrete, M.Sc. Thesis, Baghbad, 2002.

[4] Ameir, G.T. Engineering properties of high performance fiber reinforced light weight aggregate concrete,M.Sc.Thesis, University of Technology, Baghdad, 2002.

[5] Potrzebowski Janusz, The splitting test applied to steel fiber reinforced concrete, The International Journal of Cement Composites and Lightweight Concrete, Vol. 5, No. 1,

[6] Zollo F. Ronald Fiber-reinforced Concrete: an Overview after 30 Years of

Development, Cement & Concrete Composite, vol. 19, 1997, 107-122

[7] Parviz Soroushian and Cha-Don Lee Distribution and Orientation of Fibers in Steel Fiber Reinforced Concrete ACI materials Journal, vol. 87, 1990, pp.433-439

[8] A. K. Sharma Shear Strength of Steel Fiber Reinforced Concrete Beams ACI material journal, vol. 83, 1986, pp.624-628

[9] R. N. Swamy and Saad A. AI-Taan Deformation and Ultimate Strength in Flexure of Reinforced Concrete Beams Made with Steel Fiber Concrete vol.78, 1981, pp.395-405

[10] Duane E. Otter and Antoine E. Naaman Properties of Steel Fiber Reinforced Concrete under Cyclic Load vol. 85, 1988, pp.254-261

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