International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
Volume: 12 Issue: 01 | Jan 2025 www.irjet.net p-ISSN: 2395-0072
Research on Concrete that uses M-Sand, Chemical admixture, and Fly ash to partially replace Cement
Kodcherwar Akshay Kumar1 , Gude Rama Krishna2 , Nallamothu Karthik Chowdhary3 , Chandragiri Shiva4
1,3,4UG Student, Department of Civil Engineering, Institute of Aeronautical Engineering, Hyderabad, Dundigal, India 2Assistant Professor, Department of Civil Engineering, Institute of Aeronautical Engineering, Hyderabad, Dundigal, India
Abstract - This study focuses on the impact of chemical admixtures, M-sand, and partial cement replacement with fly ash on the characteristics of concrete. An increasing demand for sustainable construction materials has resulted in the usage of alternatives suchas manufacturedsand(M-sand) and fly ash, both of whichhelp minimizeenvironmentalimpact and improve concrete quality. The current investigation analyses the mechanical characteristics and durability of concrete by using a chemical additive that increases workability, M-sand as a full replacement for natural sand, and fly ash as a partial replacement for cement. In order to replace cement, concrete samples were prepared with varying percentages of fly ash (10%, 20%, and 30%), for M40 mix and their compressive strength, split tensilestrength andworkabilitywereevaluated. According to the results, concrete that has been mixed with fly ash and M-sand has more strength and durability than traditional concrete. Chemical admixtures are used to further improve workability and performance, thereby making the modified concrete more suitable for environmentally friendly building methods. The results show that using fly ash and Msand together can produce high-performance, environmentally friendly concrete while using less natural sand and ordinary cement. This research develops our understanding of sustainable concrete materials andprovides useful advice for utilizing them in modern construction.
Key Words: Fly ash, Manufactured sand, Natural Sand, High-performance, Workability, Compressive Strength
1.INTRODUCTION
In recent years, there has been a rising demand to create sustainable alternatives that limit the use of natural resourcesinconcreteproduction.Thisstudyinvestigatesthe useofthreeimportantsustainablecomponentsinconcrete production: M-sand (Manufactured Sand), fly ash, and chemicaladmixtures.M-sand,createdbycrushingrocks,is an environmentally beneficial alternative to natural river sand, addressing sand depletion and environmental degradation. Fly ash, a byproduct of coal combustion in power plants, has been extensively researched as a supplemental cementitious material because of its pozzolanicqualities,whichcontributetoincreasedconcrete strength and durability. By partially substituting cement
with fly ash, cement production's overall environmental effect, especially carbon emissions, can be substantially reduced.Chemicaladmixturesarealsoutilizedtoimprove the performance and workability of concrete. These admixturesareanecessarypartofcontemporaryconcrete mixessincetheyimprovestrength,allowforbetterhandling, and lower water content. This study aims to assess the combinedimpactsonconcrete'sdurabilityandmechanical propertiesofflyashandchemicaladmixtures,M-sand,and partial cement replacement. This study seeks to provide information on how these components affect concrete's behavior in order to produce more high-performing and environmentally friendly concrete solutions for the constructionindustry.
2.MATERIALS
Thematerialsthatareusedare:
a. OPC53gradeCement
b. M-Sand(asfineaggregate)
c. Coarseaggregate
d. Flyash
e. Chemicaladmixture
Fig 1: RepresentingCement,M-sand,Coarseaggregateand Flyash
International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
Volume: 12 Issue: 01 | Jan 2025 www.irjet.net p-ISSN: 2395-0072
3.METHODOLOGY
InthisResearchthematerialswereselectedbasedontheir physical and chemical properties. The most important materialforthisresearchisM-Sandwhichischosenasafine aggregate with particle size of up to 4.75mm, and Coarse aggregatewithparticlesizeofupto20mm.Themainbinder usedintheconcretemixisOrdinaryPortlandCementof53 gradetoensurehighstrengthandDurability.Flyashisused asamineraladmixture,sinceitisacementitiousmaterialit bind aggregates together and improve the strength and durability of the concrete. So in order to improve the strengthofconcretecementispartiallyreplacedwithflyash (I.e. 10%, 20%, 30% of weight of cement). By partially replacingcementwithflyash,thestudyaimstooptimizethe mixdesigntoachievebothperformanceandenvironmental benefits.Theexperimentalresultswillguidetheproportion offlyashthatdeliversthebestbalance betweenstrength, durability,andcost-effectiveness.
3.1 Mix Design
InthisstudywearepreparingamixdesignforM40grade concretewithM-Sandasfineaggregate,partialreplacement of cement by fly ash, and chemical admixtures, it is importanttofollowthepropermethodology.Themixdesign should achieve the target strength and workability while takingintoaccountthespecificmaterialsandreplacement levelsofcement.
3.2 Casting Process
Aftermixing,theready-madeconcreteispouredintomolds measuring150x150x150mm.Forconductingcompressive strengthtestsandothertestsaswelltheconcretemustbe molded into standard cube forms with these molds. The Casting is done according to the various mix proportions givenintable-2I.e.0%,10%,20%,and30%replacement levelsofcement
Toavoidairpocketsorvoidsinthemixture,theconcreteis carefullypouredintothemolds.Theconcrete-filledmolds arevibratedafterpouringtoremovetrappedairandensure proper compaction. Subsequently, the molds are not disturbedforanentiredayinordertoeasetheconcrete's solidification.
3.2 Curing Process
Theconcretespecimensareremovedfromthemoldsafter 24hours.Propercuringisessentialtoimprovethestrength anddurabilityofconcrete.Curingkeepstheconcreteatthe propertemperatureandmoisturelevel.Thecastedcubesare curedfor28daystoattainmaximumstrength.Thecuring processtakesataroomtemperatureof27°C.Theduration and temperature are monitored closely to ensure the concrete's perfect hydration, allowing it to attain its maximum strength and durability. Regular monitoring duringthecuringprocessensuresthattheconcreteremains sufficiently wet and protected, which improves its overall performanceandlifetime.
Table -1: MixProportions
Table -2: QuantitiesofMaterialsforM40mix@1m3
Fig 2: ConcreteCubesinthemolds
Fig 3: ConcreteCubesintheCuringtank
International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
Volume: 12 Issue: 01 | Jan 2025 www.irjet.net p-ISSN: 2395-0072
4. EXPERIMENTAL TESTS AND RESULTS
4.1 Workability Test
Workabilityreferstothewayreadilyfreshconcretecanbe mixed,placed,compacted,andfinishedwithoutsegregation or bleeding. The slump test is often used to evaluate workability. In this study, we aim for a 75 mm slump and used superplasticizer in our concrete mix to increase workability while reducing water content. Since we are utilizingM-sand,weneedtousesuperplasticizer.Concrete compositions with M-sand had a slightly lower initial workabilitythanthosewithnaturalsand.However,theuse offlyashandchemicaladmixtures,suchassuperplasticizers, significantly improved workability. The process involves fillingtheslumpconewithconcreteinthreeseparatesteps andcompactingeachlayerwithausualtampingrodsoasto eliminateair bubblesandmakesureuniformcompaction. Oncetheconehasbeenremoved,thelossinconcreteheight ismeasuredtocalculatetheslump.A75mmslumpindicates amediumconsistency,whichofferstherequiredworkability fortheconcretemixture.
Slump (mm)
4: WorkabilityoftheConcrete
After performing the slump cone test on the first sample wherecementwascompletelyused(i.e.,0%replacementof cement), we obtained the slump value of 75mm, which is true slump and was exactly what we expected. Because duringthemixdesigncalculationswehaveaimedforaslump of75mmasperIS10262:2019.
Theslumpvalueforthesecondsample,inwhich10%fly ashreplacesforcement,is93mm.Theslumpvalueforthe thirdsample,in which 20%flyash replaces forcement,is 110mm.Furthermore,theslumpvalueforthefourthsample, which replaces 30%fly ashforcement, is 124mm.Asthe amount of fly ash has increased, we have observed a progressiveimprovementinworkability.
4.2 Compressive Strength Test
Compressivestrengthtestingisanimportanttechniqueto measureconcrete'sdurabilityandload-bearingcapacity.This
testisimportantfordeterminingifconcreteissuitablefor structural applications since it analyzes the material's resistancetoaxialloads.
The compressive strength of a specimen is calculated by dividing its cross-sectional area by the maximum load appliedtoit.Thecompressivestrengthofeachspecimenis determinedandnoted.Thetestneedstobedonethreetimes foreachblendinordertomakesureaccuratedataandtake intoconsiderationanyvariationsintheresults.
Theaveragecompressivestrengthisthencalculatedfrom thesetriplicateteststoprovideanoverallevaluationofthe concrete'sperformance.
=F/A
F=AppliedLoad,A=AreaCross-sectional
The7-daycompressivestrength is primarilyinfluencedby thehydrationofcement.Inmixeswithoutorwithlowflyash content,the7-daystrengthistypicallyaround60-70%ofthe 28-daystrength.However,astheflyashcontentincreases, the early strength decreases due to the slower pozzolanic reactionofflyash.Thus,the7-daystrengthinflyashmixes tends to be lower, especially at higher replacement levels (e.g.,20%and30%).
Fig
Fig 5: PerformingCompressiveStrengthTestonaCube
Fig 6: CompressiveStrengthat7days
International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
Volume: 12 Issue: 01 | Jan 2025 www.irjet.net p-ISSN: 2395-0072
Days
By28days,theconcretehasreacheditsdesignedstrength (40 MPa for M40 concrete). Fly ash, especially at 10-20% replacement,enhancesthecompressivestrengthafter7days duetoitsreactionwithcalciumhydroxide,formingadditional C-S-Hgel.Thisleadstodenserconcreteandimprovedlongterm performance. At 30% fly ash, the strength reaches a pointclosetothecontrolmix,buttheearlystrengthsuffers duetothereducedcementcontent
Strengthand7daysand28 days
At20%flyashreplacementisoptimalformaximizing28-day compressivestrengthinM40concrete,offeringperformance andsustainabilitybenefits.M-Sandisaviablesubstitutefor riversand,withcompressivestrengthexceedingormeeting thetargetstrengthof40MPa.The30%flyashreplacement has slightlylower 28-daystrength than the 10%and 20% replacements, but the long-term strength and durability benefitsofhigherflyashcontentshouldbeexploredfurther. The combined use of fly ash and M-Sand creates an ecofriendly concrete mix, contributing to sustainable construction practices by reducing reliance on natural resourcesandmitigatingenvironmentalimpacts.
4.3 Split Tensile Strength
In a universal testing machine (UTM), the cured cylindrical specimensarepositionedhorizontallybetween two loading plates. The application is made uniform and centered by applying the load progressively until failure occurs.
Thetestdeterminestheloadatwhichthespecimenbreaks, whichusuallyhappenswhentensile strains from the applied load cause vertical cracks along the diameter. The following formula is used to get the split tensilestrength(fct):
fct=2P/πdl
Where:
P=Loadatfailure(inNewtons)
d=Diameterofthecylinder(inmm)
l=Lengthofthecylinder(inmm)
9: TensileStrengthofconcreteat7daysand28 days
The 7-day tensile strength is largely dependent on the amountofcementinthemix.Sinceflyashreactsmoreslowly than cement, mixes with higher fly ash content (20% and 30%)tendtohavelowerearlytensilestrengthcomparedto the control mix. However, the addition of chemical admixtures (such as superplasticizers) helps maintain workability,ensuringproperbondingbetweentheM-Sand andcementitiousmaterials,eveninmixeswithflyash.By28 days,thepozzolanicreactionofflyashhashadsufficienttime tocontributetostrengthdevelopment.Mixeswith10-20% fly ash replacement show an improvement in split tensile strengthcomparedtothecontrolmix,indicatingthatflyash helpsimprovethelong-termtensilepropertiesofconcrete. However,at30%flyash,thetensilestrengthgainstabilizes orslightlydecreases,asthereducedcementcontentlimitsthe early strength gain, and fly ash cannot fully compensate within28days
Fig 7: CompressiveStrengthat28
Fig 8: ComparingCompressive
Fig
International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
Volume: 12 Issue: 01 | Jan 2025 www.irjet.net p-ISSN: 2395-0072
5. CONCLUSION
ThisstudyexaminestheperformanceofM40concretein termsofcompressiveandsplittensilestrengthcomparedto aconventionalmix.Thestudyfoundthatthe20%flyashmix significantlyimprovedcompressivestrength,reaching42.89 MPa. The optimal combination of early strength andlongtermperformancewasfoundwith10-20%flyash,withthe 20% mix yielding the highest split tensile strength at 4.3 MPa. The study also found that M-Sand can effectively replace natural sand in concrete production, indicating its potential as a workable and environmentally friendly substitute.
Overall, this study demonstrates that fly ash can be replaced up to 10% to 20% of cement and M-Sand can successfullyreplaceconventionalmaterialsinM40concrete, enhancing long-term compressive strength and tensile strengthwhileofferingenvironmentalandeconomicbenefits.
6. REFERENCES
[1]T. Shanmugapriya1, R. N. Uma “Optimization of Partial Replacement Of M-Sand by Natural Sand In High PerformanceConcreteWithSilicaFume”
[2]Zubaid Hamid, Suhail Rafiq “An experimental study on behaviorofwoodashinconcreteaspartialreplacement ofcement”
[3]Martins Pilegis, Diane Gardner and Robert Lark “An Investigation into the Use of ManufacturedSandasa 100%ReplacementforFineAggregateinConcrete”
[4] T.Kavitha,Dr.P.Partheeban“InvestigationofDurability PropertiesofManufacturedSandinConcrete”
[5]Prof. Jayesh kumar Pitroda1, Dr.L.B.Zala, and Dr.F.S.Umrigar “ExperimentalInvestigationsOnPartial Replacement Of Cement With Fly Ash In Design Mix Concrete”
[6]Chetan, Maneeth P D, Brijbhushan S “Mechanical Properties of Fiber Reinforced Concrete by Partial ReplacementofCementbyFlyAsh&NaturalSandbyMSand”
[7] V.Visnu, R.M.Karthikeyan, and Dr. G. Prince Arulraj Experimental “Investigation on High Performance ConcretewithPartialReplacementsofFineAggregate byM-SandandCementbyFlyAsh”
[8]Rajapriya Raja, Ponmalar Vijayan, Sanjeev Kumar “Durability studies on fly-ash based laterized concrete: A cleaner production perspective to supplement laterite scraps andmanufacturedsandas fineaggregates”
[9]Sheelan,M.Hama,andNahlaN.Hilal“Freshpropertiesof self-compactingconcretewithplasticwasteaspartial replacementofsand”
[10] Siddika, Ayesha, Amin, Md. Ruhul, Rayhan, Md. Abu “Performance of Sustainable Green Concrete IncorporatedWithFlyAsh,RiceHuskAsh,AndStone Dust”