STUDY ON REINFORCED CONCRETE USING COCONUT FIBER

STUDY ON REINFORCED CONCRETE USING COCONUT FIBER

ANJALI DHAMALA1 , AAQIB FIRDOUS2 ,

1,2, PG Student, Department of Civil Engineering, Excel Engineering College. Komarpalayam

Abstract - Natural fibers are those fibers which are pollution free, environment friendly and do not have any bad effect on climate. Every year there is ample amount of wastages of natural fiber .If these natural fibers used as a construction material it could save the bio-reserves. They act as green construction material. Amongst all natural fibers, CF is the fiber which has the better physical and chemical property also it is renewable, cheap, resistant to thermal conductivity, more durable, highest toughness, most ductile then the other natural fiber, it is capable of taking strain four time more than other fibers. Hence, CF is a best material to be used in construction.

In the present study the behavior of specimen with respect to compressive strength and the cracking behavior of concrete and CFRC has been investigated. According toI.S.specification different test is conducted to enhance the workability and strength properties by addition of CF. different test such as slump test and flow table test on fresh concrete is carried out and compressive strength and split tensile strength is carried out on hard concrete.

The present study involves the use of super plasticizer, master glenium 8654 (0.4% by mass cone test) in M30 grade of concrete (grade ratio =1:1.918:2.898) which helps in enhancing the workability without affectingthestrengthwith CF (2%,3.5%,5%) and is compared with the conventional concrete of same grade.

Key Words: Fibres, Climate, Coconut fiber, Construction, Master glenium, Super plasticizer

1. INTRODUCTION

Coconutfibreisextractedfromtheoutershellofacoconut. The common name, scientific name and plant family of coconutfibreisCoir,CocosnuciferaandArecaceae(Palm) respectively.Therearetwotypesofcoconutfibres,brown fibre extracted from matured coconuts and white fibres extractedfromimmaturecoconuts.Coconutfibresarestiff andtoughandhavelowthermalconductivity.Coconutfibres arecommercialavailableinthreeforms,namelybristle(long fibres),mattress(relativelyshort)anddecorticated(mixed fibres).AccordingtoofficialwebsiteofInternationalYearfor Natural Fibres approximately, 500 000 tonnes of coconut fibresareproducedannuallyworldwide,mainlyinIndiaand SriLanka.IndiaandSriLankaarealsothemainexporters, followed by Thailand, Vietnam, the Philippines and Indonesia. Around half of the coconut fibres produced is exportedintheformofrawfibre.

1.1

Plainconcreteisabrittlematerialwithlowtensilestrength. There has been a steady increase in the use of short and randomlydistributednaturalfibrestoreinforcethematrix (paste, mortar and concrete). Fibres alter the behavior of concretewhenacrackoccursbybridgingacrossthecracks

Andthuscanprovidesomepostcrackingtoughness.Fibres crossingthecrackguaranteeacertainlevelofstresstransfer betweenbothfacesofcrack,providingaresidualstrengthto thecomposite,whosemagnitudedependsonthefibre,matrix andfibrematrixinterface

2. METHODOLOGY

Aconcretemixwasdesignedto achieve theminimum gradeasrequiredbyIS456–2000.Theinvestigationdone bythedifferentproportionofcoconutfibreintheconcrete mixdesign.Asthefibrecontentisincreasedthemixbecame morecohesive&theworkabilityisdecreased.Thereforethe

suitabilityofcoconutfibrereinforcedconcretewithsuper plasticizer is studied in comparison with different proportionofcoconutfiber

Byaddingthecoconutfibretheworkabilitywasnotachieved whichwasrequired.Thereforeasuperplasticizerisadded whichgavethegoodworkabilityandalsonotaffectonthe properties and strength of concrete. The optimum percentageofmastergylaniumisdeterminedwiththehelp ofmassconetest.

Minimumofthreetestspecimenwastakenforeachanalysis. Thefollowingtestsconductedontherespectivespecimens.

• CompressiveStrengthoncube

• SplittingTensileStrengthoncylinder

Concrete mixes of grade M30 was made using OPC. Replacement of cement was made using Supplementary Coconut Fibers, with defined percentage 2%, 3.5%, 5% respectively.

The concrete mixes tested for compressive strength at 3 days,14days,and28daysofcuring.

Followingsectionsdescribestheexperimentalprogramme and the procedures used for conducting various test involvedintheprogramme.

3. TESTS ON MATERIALS

3.1. Tests on coarse aggregate

Thecoarseaggregatepassingthrough20mmsizesieveand retainingon10mmsieveistestedasperIS:2386-1963and propertiesarelistedintable

Theapparatususedare–AsetofISSievesofsizes–80mm, 63mm, 50mm, 40mm,31.5mm, 25mm, 20mm, 16mm, 12.5mm,10mm,6.3mm,4.75mm,3.35mm,2.36mm,1.18mm, 600μm,300μm,150μmand75μm.

Theweightofsampleavailableshouldnotbelessthanthe weight given below: The sample for sieving should be preparedfromthelargersampleeitherbyquarteringorby meansofasampledivider.

Procedure to determine particle size distribution of Aggregates.

 The test sample is dried to a constant weight at a temperatureof110C.

 ThesampleissievedbyusingasetofISSieves.

 Oncompletionofsieving,thematerialoneachsieve isweighed.

 Cumulative weight passing through each sieve is calculated as a percentage of the total sample weight.

 Finenessmodulusisobtainedbyaddingcumulative percentageofaggregatesretainedoneachsieveand dividingthesumby100

PropertiesofAggregate

Tests on Fine aggregate

The fine aggregate passing through 4.75mm size sieve is testedasperIS:2386andpropertiesarelistedbelow.

Sieve analysis

Sieve analysis helps to determine the particle size distributionofthecoarseandfineaggregates.Thisisdoneby sievingtheaggregatesasperIS:2386(PartI)–1963.Inthis weusedifferentsievesasstandardizedbytheIScodeand thenpassaggregatesthroughthemandthuscollectdifferent sized particles left over different sieves. Fig.3a shows the distributionoffineaggregate.

SieveAnalysis

4. EXPERIMENTAL INVESTIGATION

4.1 Preparation of materials

Sample ofaggregate for eachbatchofconcrete shell be of desired grading and in air-dried condition. In general, the aggregate shall be separated into fine and coarse fraction andrecombinedforeachconcretebatchinsuchamannerso astoproducethedesiredgrading..

4.2 Proportioning

The proportioning of the materials including water in concretemixesfordeterminingthesuitabilityofthematerial available shall be similar in all aspects to those to be employedinwork.Wheretheproportionsoftheingredient ofconcreteusedonthesitearetospecifiedbyvolume,they shallbecalculatedfromtheproportionalbyweightusedin thetestcubesandtheunitweightofthematerials.

4.3 Weighing

The quantities of cement, each size of aggregate and water for each batch shall be determined by weight to an accuracyof0.1percentofthetotalweightofthebatch.

4.4 Mixing of concrete

The concrete shall be mixed by hand or perfectly in laboratorybatchmixerinsuchamannersoastoavoidloss ofwaterorothermaterials.Eachbatchofconcreteshallbe ofsuchasizesoastoleaveabout10percentexcessafter mouldingthedesirednumberoftestspecimen.

water at temperature of 24 – 30 Celsius until they are transportedtothetestinglaboratory Theyshallbesentto the testing laboratory well packed in a damp sand, damp sack or other suitable materials so as to arrive there in a dampconditionnotlessthan24hoursbeforethe time of test

5. Test on fresh concrete

5.1 Slump test:

The slump test is used to determine the workability of concretemixpreparedatthelaboratoryorconstructionsite. Theslumpvaluewasdeterminedforthevariousmixtobe preparedintheproject.Generallyconcreteslumpvalueis usedtofindouttheworkabilityofconcretewhichindicates water–cementratio.

Procedure:

• Cleantheinternal surfaceof themouldandapply oil.

• Placethemouldonsmoothhorizontalnon

porous baseplate.

• Fill the mould with the prepared concrete mix in fourapproximateequallayers.

• Tampeachlayerwith25stokesoftheroundedend of the tamping rod in a uniform manner over the cross-section of the mould. For the subsequent layers the tamping should penetrate into the underlyinglayer.

4.5 Compaction

Mixingofconcrete

Whencompactionbyhand,thestandardtampingrodshall beusedand thestokesoftherodshall bedistributedin a uniform manner over the cross section of the mould. The number of stokes per layer required to produce specified condition will vary according to the type of concrete. For cubical specimen, the concrete shall be subjected to 35 stokesperlayerfor15cmcubes.Thestokesshalltouchthe surfaceofunderlyinglayer.Wherevoidsareleftbytamping rod,thesidesofthemouldshallbetappedtoclosethevoids.

4.6 Curing of test specimens

Thetestspecimensshallbestoredonthesiteataplace free from vibration, under damp matting, sacks or other similarmaterialsfor24hours+halfhourfromthetimeof addingthewatertotheotherincidents.Thetemperatureof theplaceofstorageshallbewithintherange22-32Celsius Aftertheperiodof24hours,thespecimenshallbemarked for the later identification removed from the mould and unless required for testing within 24 hours store in clean

• Remove the excess concrete and level the surface withatrowel.

• Cleanawaythemortarorwaterleakedoutbetween themouldandthebaseplate.

• Raisethemouldfromtheconcreteimmediatelyand slowlyinverticaldirection.

• Measuretheslumpasdifferencebetweentheheight ofthemouldandthatofhighestpointofspecimen beingtested

6. Tests on hardened concrete

6.1 Compressive strength test

• Oneofthemostimportantanduseful propertyof concrete.

• Primarily meant to withstand compressive stress and can be used as an approximate qualitative measureforotherpropertiesofhardenedconcrete.

• Compressivestrength testiscarriedoutoncubes forvariousmixesM1,M2,M3andM4.

• Thecompressivestrengthofcubeswastestedon3, 7and28days.

• Formulaforcompressivestrengthofconcrete: =Loadapplied(P)/Crosssectionalarea(A)=N/mm2

• Determine the diameter of the test specimen by averagingthethreediametersandthelengthofthe specimen by averaging at least two length measurements taken in the plane containing the linesmarkedonthetwoends.

• Placethespecimenontheplywoodstripandalign so that the lines marked on the ends of the specimen are vertical and centered over the plywood strip. Place a second plywood strip lengthwise on the cylinder, centered on the lines markedontheendsofthecylinder.

• Applytheloadcontinuouslyandwithoutshockata constantratewithintherange100to200psi/min [0.7 to 1.4 MPa/min] splitting tensile stress until failure of the specimen. Record the maximum applied load indicated by the testing machine at failure.Notethetypeoffailureandtheappearance oftheconcrete.

Calculation:

The splitting tensile strength of the specimen are given below:

T = 2P/πld

Compressivestrengthtest

6.2 Split tensile strength test

Thetensilestrengthofconcreteisoneofthebasicand important properties. Splitting tensile strength test on concrete cylinder is a method to determine the tensile strengthofconcrete.

Need: The concrete is weak in tension due to its brittle nature and is not expect to resist the direct tension. The concretedevelopscrackswhensubjectedtotensileforces. Thus it is necessary to determine the tensile strength of concrete to determine the load at which the concrete membermaycrack.

Procedure:

• Drawdiametriclinesoneachendofthespecimen usingasuitabledevicethatwillensurethattheyare inthesameaxialplane

Where,

T =splittensilestrengthin MPa

P = maximum applied load indicated by the testingmachineinN

l= lengthinmm

d= diameterinmm

7. CASTING OF CUBES

Tablegivenbelowshowthequantityofcubesrequiredfor differentmixes.

9. CONCLUSIONS

From the experimental study, the following results were obtained:

 Withrespecttocompressivestrength,incorporating asmallamountofCF2%enhancestheperformance of concrete, as expected and counters harmful shrinkageeffectsinconcrete.

 The results suggest that short coconut fibers are more effective in enhancing the performance of concrete

 The recommended threshold value of the fiber contentthatwillbenefitthelongtermdurabilityof theconcreteinallenvironmentsis2.0%.

 Thepropertiescanincreaseordecreasedepending uponfiberlengthanditscontent.Asaresultofthis CFRC strengths can be greater than that of plain concrete.

 ByreplacingcementcontentwithCF,decrementin theweightthusINERTIAOFSTRUCTUREmayresult intolowdensity,slenderandeconomicalaswellas greenstructures

 Withtheadditionofadmixturecohesivemixcanbe madesuitablyworkable.

8. TEST RESULTS

The observations of the various tests on Fresh And Hard CFRC was conducted such as flow tests, slump test, compressivetestofconcreteandsplittensiletestshavebeen analyzed and the behavior is studied. The results of the analysis are discussed in the subsequent sections. The various types ofcubesandcylinders of different mix were testedundercompressiontestingmachine.

8.1 Compressive strength of concrete

 It is a versatile material reported as most ductile and energy absorbent have wide scope in earthquake prone areas as well as in marine structures.

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BIOGRAPHIES

ANJALI DHAMALA is a Civil EngineerfromtheAnnaUniversity. Her academic record is very impressive and good. She is very hardworkingandintelligent.

AAQIB FORDOUS is a Civil EngineerfromtheAnnaUniversity. His latest paper was “Design and analysisof4in1schoolcomplex” publishedinIRJET.