A STUDY ON STRENGTH PARAMETRS OF FIBRE- REINFORCED CONCRETE USING POLYPROPYLENE FIBRE AND STEEL FIBE by IRJET Journal

A STUDY ON STRENGTH PARAMETRS OF FIBRE- REINFORCED CONCRETE USING POLYPROPYLENE FIBRE AND STEEL FIBER

BATTULA SUMANTH GOUD1 , Dr. D. SREEHARI RAO2

1 PG Student, Department of Civil Engineering, Sri Venkateswara University College of Engineering, Tirupati, Andhra Pradesh, India.

2 Asst. Professor, Department of Civil Engineering Sri Venkateswara University College of Engineering, Tirupati, Andhra Pradesh, India.

Abstract - Among all the construction materials that are available for construction, we know that concrete is a widely used construction material for building of various civil engineering structures. Concrete will give better durability and also its costs during construction as well as maintenance are very low when compared to other construction materials.

As we know that concrete is strong in compression and weak in tension and tends to fail because of its deficiencies such as low tensile strength, low strain at fracture. The weakness of concrete is due to the presence of micro cracks at mortar aggregate interface. To overcome the existing problems addition of fibres in the concrete has been come in to practice. In fibre reinforced concrete, the fibres are added to the concrete mix so that these discontinuous fibres will be uniformly distributed in the mix and improve the concrete properties in all directions. To get more improvement in the mechanical properties.

In present experimental work M30 grade of concrete mix was used. Mix design was calculated according to IS 10262:2019. Five different proportions of polypropylene fibres were added along with concrete ingredients. The proportions of fibres were added ratio i.e. 0%, 0.5%, 1.0%, 1.5% and 2%. Polypropylene fibres were added by weight replacement of cement. Concrete was tested in fresh state as well as in hardened state with all five different mix proportions of fibres. Fresh properties like workability, hardened properties like compressive strength, split tensile strength, flexural strength were assessed.

Keywords: Fiber, Polypropylene fibres,steel fibers, Compressive Strength, Split tensile Strength, Flexural Strength.

INTRODUCTION

Concrete is a versatile building material and is one of the oldest and most used construction materials in the world. It is mainly due to its low cost, availability, its long durability ability to sustain extreme weather environments. Due to its high strength and durability properties, it is largely used in all the sectors like multi story buildings, irrigation structures, pavements, reservoirs, foundations, dams etc. As we know that concrete is strong in compression and weak in tension and tendstofailbecauseofitsdeficienciessuchaslowtensilestrength,lowstrainatfracture.

Forimprovingthetensilepropertiesofplainconcretemanymethodshavebeen evolved.Manyofthemethodssucceededin makingtheconcretemembersresistanttotension,butnoneofthemincreasedtheinherenttensilepropertiesofplainconcrete. The dispersion of fibers in concrete matrix to improve its tensile properties must come into practice. The addition of small closelyspaceanduniformlydispersedfiberstoconcretewouldactascrackarresterandwouldsubstantiallyimproveitsstatic anddynamicproperties.Thetypeofconcreteisknownasfiberreinforcedconcrete.

Fibersusedinconcreteweregenerallysmallcloselyspacedanduniformlydispersed.Continuousmeshes,wovenfabricsand longwiresorrodsarenotconsideredtobediscretefibers.Fibersincludesteelfibers,glassfibers,syntheticfibers,andnatural fibers.Theweaknessintensioncanbeovercomeusingsufficientweightfractionofcertainfibers.Toimprovethemechanical propertiesofconcrete,itisgoodtomixcementwithfiberswhichhavegoodtensilestrength.Addingfiberstoconcretegreatly increases the toughness of material. The fibers also alter the behavior of the fiber matrix composite after it has cracked, therebyimprovesitstoughness.

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LITERATURE REVIEW

• Milind V. Mohod' et al., (2015) effectsofadditionofvariousproportionsofpolypropylenefibersonthepropertiesofHigh strengthconcrete(M30andM40mixes).An experimental program was carried out to explore its effects on compressive, tensile,flexuralstrengthunderdifferentcuringcondition.Themainaimoftheinvestigationprogramistostudytheeffect ofPolypropylenefibremixbyvaryingcontentsuchas0%,0.5%,1%,1.5%&2%andfindingtheoptimumPolypropylene fibrecontent.Theconcretespecimensweretestedatdifferentagelevelformechanicalpropertiesofconcrete,namely,cube compressivestrength,splittensilestrength,flexuralstrength.Adetailedstudywascarriedoutforcuringconditions.Half oftheconcretespecimenswereleftexposedtothesurroundingtocurebythemselvesandtheremaininghalfwerecured inacuringtank.Initiallytheconcretespecimen'sshowsappreciablestrengthforirregularcuringbutasthedaysadvances thecuringspecimensgavesatisfactorystrength.Anotableincreaseinthecompressive,tensileandflexural strengthwas observed. However, further investigations were highly recommended and should be carried out to understand more mechanicalpropertiesoffibrereinforcedconcrete.

• Ahsana fathima k m, et.al (2014) entitled on Behavioral Study of Steel Fibre and Polypropylene Fibre Reinforced Concrete, Experimental program consisted of compressive strength test, split tensile strength test and flexural strength testsonsteelfibrereinforcedconcreteandpolypropylenefibrereinforcedconcrete.Threetypesoffibresusedwerehooked endsteelfibreoflength30mm,crimpedsteelfibreoflength25mmandenduro-600polypropyleneoflength50mmwith aspectratio50.Thesteelfibrereinforcedconcreteyieldhighercompressive,flexuralandsplittensilestrengthwithaddition of0.75%steelfibrebyvolumeofconcrete.Fibrereinforcedconcretewithcrimpedsteel fibreof25mmlengthwithaspect ratio50yieldedbetterstrengths(compressive,flexural andsplittensile)thanhookedendsteelfibreof30mmlengthwith aspect ratio 50. The polypropylene fibre reinforced concrete yield higher splitting tensile and flexural strengths with additionof0.5%polypropylenefibre

• Hoseini M; et.al (2013) study on The use of fiber for reinforcing concrete gives impermeable concrete, and this effectivelyreducestheflowofliquidsandgas,eveniftheconcreteisenergized.Theeffectofthegrainsizeandtextureon thecorrosivepropertiesofcommerciallypuretitaniumhasbeenstudied.Equalangularchannelpressing(ECAP)wasused to obtain different grain sizes and different crystallographic orientations. Electrochemical impedance spectroscopy was usedtomeasuretheoverallcorrosionresistanceoftherespectivesurfaces.

• Rapoport J; et.al (2009) studyonFiber-reinforcedconcrete(FRC)hasagreaterdeformationcapacitythanconventional concrete (PC), but the fibers minimize the permeability of concrete. Non-destructive single-sided wave reflection coefficient (WRF) has been applied to concrete with a variety of impurities, including accelerator, silicate smoke as a replacement,highimpurityrange,whichreduceswaterandadecelerator.TheWRFtestissensitivetoimpurities.

• M. A. Mashrei, Ali A; et.al (2018) Study on Effects of polypropylene fibers on Compressive and Flexural Strength of concrete material, The study concerns the compressive and flexural strength of concrete with polypropylene fiber (PF). Theexperimentalphaseof theresearchhasincluded testingfifteengroups ofconcretewithdifferentcharacteristics.The main variables considered in the experimental program are the percentage of polypropylene fiber, type of concrete mix and presence of steel reinforcement in a prism. The effect of these variables on the compressive and flexure strength of concrete was investigated. The results of this study indicated that the variation in the compressive and flexure strengthofconcretedependsmainlyonthepolypropylenefiberpercentage.Itwasfoundthatthecompressivestrengthof concrete increases by increasing the percentage of polypropylene fiber from 0 to 0.2%, while the increasing in the strength started to vanish when approached to 0.3% of PF. Similarly, the flexural strength of concrete has also increased by increasing the percentage of PF from 0 to 0.3%. By further increasing PF up to 0.5%, it was determined thatthecompressiveandflexuralstrengthofconcretestartedtodecreasesignificantlyascomparedtothecontrolmix.

• Peng Zhang; et al(2013) entitledonEffectofpolypropylenefibreondurabilityofconcretecompositecontainingflyashand silica fume, investigate the effect of polypropylene fiber on the workability and durability of the concrete composite containingflyashandsilicafume.Fourdifferentfibervolumefractions(0.06%,0.08%,0.1%and0.12%)wereused.The resultsindicatethattheadditionofpolypropylenefiberhasalittleadverseeffectontheworkabilityofconcretecomposite containing fly ash and silica fume. With the increase of fiber volume fraction, both of the slump and slump flow are

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decreasing gradually. However, the addition of polypropylene fiber has greatly improved the durability of the concrete composite containing fly ash and silica fume. The length of water permeability, the dry shrinkage strain and the carbonationdepthofconcretecontainingflyashandsilicafumearedecreasinggraduallywiththeincreaseoffibervolume fraction as the fiber volume fraction is below 0.12%. Besides, freeze–thaw resistance of polypropylene fiber reinforced concrete containing fly ash and silica fume was found to slightly increase when compared to the concrete composite withoutfibers.Moreover,thereisa tendencyofincreaseinthefreeze–thaw resistancewiththeincreaseof fibervolume fractionasthefibervolumefractionisbelow0.08%.However,thefreeze–thawresistancebeginstodecreaseslightlyafter thefibervolumefractionbeyond0.08%.

MATERIALS

Cement

The study utilized ordinary Portland cement, specifically grade 53 JSW cement which is widely available in the local market.Tomaintainexperimentalconsistency,thesamebatchofcementwasusedforeverytest.Thecement’s properties were carefully evaluated against various parameters outlined in IS 4031-1988, confirming that it complies withtheIS12269-1987standard.Table1outlinesthedetailedphysicalcharacteristicsofthecement.

Table -1: PhysicalQualitiesofCement

Fine Aggregate

Locally sourced River sand, which adheres to the Zone II requirements as per IS 383-1970, was utilized. Detailed informationonthephysicalpropertiesofthisfineaggregate isprovidedinTable2.Notably,thesandusedhasparticle sizes smallerthan4.75mm.

Table -2: CharacteristicsofFineAggregate

Coarse Aggregate

Coarseaggregate,withmaximumsizesof20mmand12.5mm,wasemployed.InlinewiththestandardsIS383-1970and IS2386-1983,anexperimentalinvestigationwascarriedouttoassessthepropertiesofthecoarseaggregates.Thefindings aredetailedinTable3.

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Table -3: CharacteristicsofCoarseAggregate(20mm)

Polypropylene

fibre

Polypropylene fibre is composed of crystalline and non-crystalline (amorphous) regions. The fibre range in size from fractions of a micrometer to centimeters in diameter. And appearance of this fibre is in fibrillated bundles, mono filament. Thesefibreshavedifferentcutlengthsof12mm,24mm,40mm.

Steel Fibre

Steelfiberisametalreinforcement.Steelfiberforreinforcingconcreteisdefinedasshort,discretelengthsofsteelfiberswith anaspectratio(ratiooflengthtodiameter)fromabout20to100,withdifferentcross-sections,andthataresufficientlysmall to be randomly dispersed in an unhardened concrete mixture using the usual mixing procedures. Different Types of Steel Fibersmostcommonlyusedarehookedends,crimped,gluehookedendetc.Theirsizewillbeofdiameter0.25to0.75mm.

Water

Fresh tap water conforming to IS:456-2000 standards was usedfor thecasting ofgeopolymer concreteelementsinthe laboratory.Beforethemixingprocess,thenecessaryvolumeofwaterwascarefullymeasuredwithagraduatedjarandwas thencombinedwiththedryingredients.

MIX DESIGN

IS 10262-2019, IS 456-2000 and literature were consulted in order to create different grades of geopolymer concrete. Tables4illustratestheDesignmixratioforM30gradeconcrete.

Table -4: M30GradeDesignMixRatio

DISCUSSIONS OF TEST RESULTS

Compressive Strength

Cube specimens measuring 0.15 × 0.15 × 0.15 meterswere castandtestedusingacompressiontestingmachine(CTM) aftercuringperiodsof7,28,56and90days,corresponding tovariousconcretemixratios.Foreachcuringageandmix, the average strength was calculated from three samples. Compression test of the Concrete specimen is most widely used test to measureitsCompressivestrength.Compressivestrengthisthecapacityofamaterialorstructuretowithstandloadstending to reduce size as opposed to tensile strength. Compressive Strength of concrete is the most common performance measure

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used by the engineer in designing buildings and other structures. Compression test is the most common test conducted on hardened concrete, because most of desirable characteristics properties of concrete are quantitatively related to its compressivestrength

Comp Strength

Split Tensile Strength

Thetensilestrengthisoneofthebasicandimportantpropertiesoftheconcrete.Theconcreteisnotusuallyexpectedtoresist the direct tension because of its low tensile strength and brittle nature. However, the determination of tensile strength of concreteisnecessarytodeterminetheloadatwhichtheconcretemembersmaycrack.ThisisconductedbyCTMataloadrate of140Kg/cm²/min.Splittensilestrengthfor28dayswasillustratedatchart.

Split Tensile Strength

Chart 1: CompressiveStrengthofconcrete

Chart 2: SplitTensileStrengthofconcrete

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Flexural Strength

Flexural strength, also known as modulus of rupture, bend strength, or fracture strength a mechanical parameter for brittle material, is defined as a material's ability to resist deformation under load. The transverse bending test is most frequently employed, in whicha specimenhaving either a circular or rectangularcross-sectionis bent until fractureoryielding usinga three-point flexural test technique. The flexural strength represents the highest stress experienced within the material at its momentofrupture.

Flexuralstrengthfor28daysillustratedatchart.

Chart 3: FlexuralStrengthofconcrete

Flexural Strength

CONCLUDING REMARKS

• CompressiveStrengthofPolypropylenefiberreinforcedconcretewithpercentageofproportionsof0.5%,1%,1.5%,2% increasedattherateofabout8.7%,16.5%,12.3%and9.24%respectivelywhencomparedwithconventionalconcrete.

• For1.5%ofpolypropylenefibrecontenttherewasdecreaseinthepercentageincreaseinstrengthcomparedtothatof 1%fibrecontent.Butthestrengthobtainedfrom1.5%fibrecontentwasmorethanthatofconventionalconcrete.

• TheCompressiveStrengthofpolypropylenefibreconcreteisincreasedat1%for28daysascomparedtoconventional concrete.

• Polypropylenefibrereinforcedconcretemixof1%wasfoundoptimum.

• CompressiveStrengthoffiberreinforcedconcretewithstreelfiberspercentageofproportionsof0.5%,1%,1.5%,2%at 1.5%optimum ofpolypropylene increasedat the rateof about4.2%,24.9%,16.3% and18.1% respectivelyfor56days whencomparedwithconventionalconcrete.

• CompressiveStrengthoffiberreinforcedconcretewithstreelfiberspercentageofproportionsof0.5%,1%,1.5%,2%at 1.5%optimum ofpolypropylene increasedat the rateof about9.7%,30.1%,21.8% and21.9% respectivelyfor90days whencomparedwithconventionalconcrete.

• The Flexural Strength of fibre reinforced concrete is increased at 1.5% for 28 days as compared to conventional concrete.

• TheTensileStrengthoffibrereinforcedconcreteisincreasedat1.5%for28daysascomparedtoconventionalconcrete.

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ACKNOWLEDGEMENT

Thepresent study was conductedat Sri Venkateswara University College of Engineering, Tirupati, Andhra Pradesh, India.

REFERENCES

• MilindV.Mohod“PerformanceofSteelfibreReinforcedConcrete.(IJES)Vol.1,Issue.12,Dec2012pp-01-04.

• Aiswarya Sukumar, Elson John “FIBRE ADDITION AND ITS EFFECT ON CONCRETE STRENGTH (IJIRAE) Vol. 1, Issue. 8, Sep2014pp-144-149.

• Song P.S., S Hwang, (2004), Mechanical properties of high steel fibre reinforce concrete, Construction and Building Materials,Volume18,Issue9,Pages669-673,ISSN0950-0618.

• Dave U. V. and Desai Y. M. “Effect of Polypropylene, Polyester and Glass fibres on various strength of ordinary and standard concrete”, The First International Conference On Recent Advance In Concrete Technology, Sep. 2007,WashingtonD.C.U.S.A.

• Bentur,A.,andMindess,S.,FiberReinforcedCementitiousComposites,London,ElsevierAppliedScience,1990.

• PRITI A PATEL and Dr. ATUL K DESAI were studied on “Evaluation of engineering properties for polypropylene fiber reinforcedconcrete’’January-march,2012.

• VIKRANTH S. and KAVITA S were studied on “effects of fibrillated polypropylene fiber on plain cement concrete composites”july2012.

• IS 456:2000 – Indian Standard “Plain and Reinforced Concrete” – Code of Practice , IS 10262:2019 – Indian Standard “Concretemixproportioning”–guidelines.

• IS383:1970–IndianStandard“SpecificationsforCoarseandFineaggregatesformnaturalsourcesforConcrete.

• IS 2386:1997 (PART I) Method of Test for Aggregate for Concrete – Particle Size and Shape, IS 2386:1997 (PART III) Method of Test for Aggregate for Concrete – Specific Gravity, Density, Voids, Absorption and Bilking. Bureau of Indian Standards.IS2386:1997(PARTIV)MethodofTestforAggregateforConcrete–MechanicalProperties.BureauofIndian Standards.

• IS4031-1998(PART-V)Methodsofphysicaltestsforhydrauliccement