International Research Journal of Engineering and Technology (IRJET) e-ISSN:2395-0056
Volume: 12 Issue: 09 | Sep 2025 www.irjet.net p-ISSN:2395-0072
AN EXPERIMENTAL STUDY ON FIBER REINFORCED CONCRETE BY USING
COPPER SLAG & POLYPROPYLENE FIBRE IN CONCRETE
KANCHANA BHARATHI1 , 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 - This study explores the use of copper slag, an industrial by-product from copper manufacturing, as a partial replacement for natural sand in concrete to address sustainability and environmental concerns. Various concrete mixes were evaluated for compressive, tensile, and flexural strength to determine the optimal copper slag content. Additionally, polypropylene fibers were incorporated at different volumes (0.5% to 2.0%) to enhance the mechanical properties of the concrete. The results indicated that 1.5% fiber content yielded the best overall performance, demonstrating significant improvements in strength compared to conventional concrete.
Keywords: Natural sand, Copper slag, Polypropylene Fibre, Compressive Strength, Split tensile Strength and Flexural Strength of concrete
INTRODUCTION
Concreteservesasa fundamental elementinmoderninfrastructure, essential forconstructing buildings, bridges, roads, and various other structures. Made from a mix of cement, water, aggregates, and admixtures, it is known for its strength, durability, and adaptability. With global production exceeding 20 billion tons annually, concrete remains the most commonly used construction material. Its popularity stems from its cost-effectiveness and impressive structural properties, particularlyitshighcompressivestrength.However,rising environmental concerns andthe demand forsustainablebuilding practiceshavedriventhedevelopmentofmoreinnovativeandeco-friendlyconcretesolutions.Theimportanceofconcretein modern society cannot be underestimated. Concrete is one of the seemingly simple but actually complex material. The properties of the concrete mainly depend on its constituents. The main important materials used for making concrete are cement, fine aggregate, coarse aggregate and water. The properties of cement, sand, crushed stone and water influences the quality of concrete. In addition to this, workmanship, quality control and method of placing also plays leading role on the propertiesofconcrete.
Cement acts as the main binder in concrete, providing strength and durability by holding aggregate particles together. Its primary use is in producing mortar and concrete for strong, long-lasting structures. With growing environmental concerns, utilizingindustrial wasteinconstructionhasbecomea sustainablesolution.Industriesgeneratelargeamountsofwaste,and incorporating these by-products such as fly ash, copper slag, silica fume, and ground granulated blast furnace slag into concrete not only reduces landfill pressure but also improves the material’s performance in both fresh and hardened states. Properuseofsuchmaterialshelpsconservenaturalresourcesandminimizesenvironmentaldamage.Concrete,composedof cement, fine and coarse aggregates, and water, may include admixtures to further enhance its properties, with strength and durabilitydependingonaccuratemixproportionsandpropercompaction..
LITERATURE REVIEW
Abhisheka Honnakkalavar(2018) This study aims to evaluate the impact of using copper slag as a partial replacement for fine aggregate in concrete. An M25 grade concrete mix was used, and the physical properties of cement, fine aggregate, coarse aggregate, and copper slag were examined for mix design. Concrete specimens were testedforcompressivestrength,splittensilestrength,andflexuralstrengthwithcopperslagreplacingfine aggregate at varying levels: 0%, 20%, 40%, 60%, and 80%. The results showed that a 40% replacement yielded the highest
International Research Journal of Engineering and Technology (IRJET) e-ISSN:2395-0056
Volume: 12 Issue: 09 | Sep 2025 www.irjet.net p-ISSN:2395-0072
compressive strength at both 7 and 28 days. Similarly, the split tensile and flexural strengths reached their peak at thesame40%replacementlevelafter28days.
Wei Wua et al.(2010) Thisresearchexaminedthemechanical performanceofhigh-strengthconcreteusingcopper slagasapartialreplacementforfineaggregate.Thestudyfoundthatreplacingsandwithcopperslagatlevelsbelow 40% produced concrete with strength comparable to or greater than the control mix. However, beyond 40% replacement, the strength began to decline significantly. Six different concrete mixes were tested, with copper slag replacing sand in 20% increments from 0% to 100%. The findings showed improved strength and significantly increased workability in mixes with less than 40% copper slag. Microscopic analysis revealed minimal differences between the control mix and those with up to 40% copper slag. The study concluded that the optimal copper slag contentshouldbedeterminedbasedonthetargetcompressivestrengthoftheconcrete.
Ankit Nainwal et al.(2020) Thisstudypresentsfindingsonthemechanicalanddurabilitypropertiesofconcretein whichcopperslag(CS)partiallyreplacesfineaggregates(FA)sourcedfromtheBeasRiver.Thesubstitutionlevelsof CSweresetat0%,20%,40%,and60%.Mechanicalpropertieswereevaluatedthroughcompressiveandsplittensile strengthtests,whiledurabilitywasassessedbasedoninitialsurfacewaterabsorptionandoverallwaterabsorption. The results indicated that the optimal performance in both strength and durability was achieved when 40% of the fineaggregateswerereplacedwithcopperslag.
Divya S Dharan, Aswathy Lal(2015) In this study, polypropylene fibers were added to concrete in varying proportions (0.5%, 1%, 1.5%, and 2%) along with the optimal replacement of fine aggregate using steel slag. The concrete specimens were tested for workability, compressive strength, flexural strength, split tensile strength, and modulus of elasticity. The results showed that incorporating 1.5% polypropylene fibers led to a 21% increase in compressivestrengthcomparedtoconventionalconcrete.Additionally,improvementswereobservedinsplittensile strength(26%),flexuralstrength(29%),andmodulusofelasticity(15%)overthetraditionalmix.
P.RamaLingam(2017) This study focuses on M25 grade concrete, evaluating its compressive, split tensile, and flexural strengths. Copper slag was used as a partial replacement for fine aggregate, with up to 40% substitution yieldingthehigheststrengthresultsacrossalltests.Additionally,polypropylenefiberswereincorporatedinvarying proportions(0.5%,1%,and1.5%)relativetothevolumeofcement.Thecombinationof40%copperslagwith0.5% fibercontentproducedthemostsignificantimprovement,resultinginastrengthincreaseofupto52%.
J. Anne Mary(2016) The primary aim of this study is to evaluate and compare the strength properties and performanceofbothfreshandhardenedconcretemadewithandwithoutcopperslag,usedasapartialreplacement for fine aggregate. Globally, around 24.6 million tonnes of copper slag are produced annually as a by-product of coppermanufacturing(Goraietal.,2003).Inthisresearch,copperslagwasusedtoreplacefineaggregateatvarying levels 20%, 40%, 60%, 80%, and 100%. Among these, the 40% replacement level showed the most significant improvement in strength, achieving a 37.55% increase in compressive strength, a 5.3% increase in split tensile strength,anda40.72%boostinflexuralstrengthcomparedtotheconventionalconcretemixafter28days.
G.V.V.Satyanarayana(2019) This study focuses on evaluating the use of copper slag as an alternative material to replacefineaggregateinconcrete.Itspecificallyexamineshowthissubstitutionaffectsthemechanicalpropertiesof concrete,particularlycompressiveandflexuralstrength.Theresultsindicateanotableimprovementincompressive strength when copper slag is used within acceptable limits. A 30% replacement of fine aggregate with copper slag ledtoa23%increaseincompressivestrengthcomparedtoconventionalconcrete.Thefindingssuggestthatcopper slagcaneffectivelyreplaceupto50%offineaggregate,offeringbothenvironmentalandeconomicadvantageswhile maintainingorenhancingconcreteperformance.
International Research Journal of Engineering and Technology (IRJET) e-ISSN:2395-0056
Volume: 12 Issue: 09 | Sep 2025 www.irjet.net p-ISSN:2395-0072
MIX RESOURCES
Cement
The study employed ordinary Portland cement, specifically grade 53 JSW cement, commonly available in the local market.Toensureconsistencythroughouttheexperiments,thesamecementbatchwasusedfor alltests.Thecement’s properties were thoroughly assessed according to the criteria specified in IS 4031-1988, verifying compliance with the IS12269-1987standard.Table1providesadetailedsummaryofthecement’sphysicalcharacteristics.
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.
Table -3: CharacteristicsofCoarseAggregate(20mm)
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Polypropylene fibre
Polypropylene fiber (PP) consists of both crystalline and amorphous (non-crystalline) regions. The fibers vary in diameter, rangingfromfractionsofa micrometertoseveral centimeters.Theytypicallyappearasfibrillatedbundlesormonofilaments andareavailableindifferentcutlengths,including12mm,24mm,and40mm.
Copper slag
Copper slag (CS) isa granular material utilized in the production of concrete or mortar, particularly when the particles are fineenoughtopassthrougha4.75mmsieve.
ThecopperslagusedinthisstudywassourcedfromAstraChemicals,Chennai.
Water
Fresh tap water meeting IS:456-2000 standards was used for casting concrete specimens in the laboratory. Prior to mixing, the required amount of water was accurately measured using a graduated jar and then mixed with the dry materials.
MIX DESIGN
IS10262-2019, IS456-2000 andliterature wereconsulted inorder tocreate differentgrades ofgeopolymerconcrete. Tables4illustratestheDesignmixratioforM30gradeconcrete.
Table -4: M30GradeDesignMixRatio
DISCUSSIONS OF TEST RESULTS
Compressive Strength
Cube specimens with dimensions of 0.15 × 0.15 × 0.15 meters were cast and tested for compressive strength using a compression testing machine (CTM) after curing for 7, 28, 56, and 90 days, based on different concrete mix ratios. For eachcuringperiodandmix,theaveragestrengthwasdeterminedfromthreesamples.Thecompressiontestisthemost commonly used method to assess the compressive strength of concrete, which measures the material's ability to resist loadsthattendtoreduceitssize,incontrasttotensilestrength.Compressivestrengthisakeyperformanceindicatorfor engineers when designing buildings and other structures. This test is widely performed on hardened concrete because manyimportantpropertiesofconcretearecloselyrelatedtoitscompressivestrength.
International Research Journal of Engineering and Technology (IRJET) e-ISSN:2395-0056
Volume: 12 Issue: 09 | Sep 2025 www.irjet.net p-ISSN:2395-0072
Compstrength(N/mm2)
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Split Tensile Strength
Tensilestrengthisafundamentalandimportantpropertyofconcrete.Althoughconcretetypicallyhaslowtensilestrengthand is brittle, making it unsuitable for resisting direct tension, measuring its tensile strength is essential to identify the load at whichconcrete elementsmaybegintocrack.Thistestisperformedusinga compressiontestingmachine(CTM)ata loading rateof140kg/cm²perminute.Thesplittensilestrengthresultsafter28daysarepresentedintheaccompanyingchart.
Chart 2: SplitTensileStrengthofconcrete
AverageTensilestrength(N/mm2)
%Additionofcopperslag&%Polypropylene fiber
Flexural Strength
Flexural strength, also referred to as modulus of rupture, bend strength, or fracture strength, is a mechanical property that indicatesa brittlematerial’s resistancetodeformationunderload.Itiscommonlymeasuredusinga transverse bendingtest, where a specimen with a circular or rectangular cross-section is subjected to bending until it fractures or yields, typically throughathree-pointflexuraltestmethod.Theflexuralstrengthcorrespondstothemaximumstressthematerialexperiences atthepointoffailure.Theflexuralstrengthresultsafter28daysareshowninthechart.
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CONCLUDING REMARKS
%Additionofcopperslag&%Polypropylene fiber
*Theoptimalcopperslagdosage(CS40)achievedcompressivestrengthsof48.44N/mm²at28days,53.96N/mm²at 56days,and56.15N/mm²at90days,surpassingthestrengthofthecontrolconcretemix.
* Incorporating polypropylene fibers further improved the strength of copper slag concrete. The best results were observed with the CS40PP1.5 mix (40% copper slag and 1.5% polypropylene fiber), which reached compressive strengthsof53.94N/mm²at28days,55.33N/mm²at56days,and62.03N/mm²at90days.
* The control mix exhibited a split tensile strength of 3.56 N/mm² at 28 days, which increased to 3.89 N/mm² with 40%copperslagreplacement(CS40).Addingfibersboostedthetensilestrengthfurther,withthehighestvalueof4.32 N/mm²recordedforCS40PP1.5,approximately21%higherthanthecontrol.
* At a fiber content of 2.0%, split tensile strength slightly decreased to 3.80 N/mm², indicating that 1.5% polypropylenefiberistheoptimaldosage.
*Theflexuralstrengthofthecontrolconcretewas4.92N/mm²at28days,increasingto5.61N/mm²with40%copper slag (CS40) and reaching 6.10 N/mm² for the CS40PP1.5 mix, representing around a 24% improvement over conventionalconcrete.
*Mixeswithhigherfibercontent(CS40PP2.0)showedaslightreductioninstrengthcomparedtoCS40PP1.5,likelydue toissuessuchaspoorfiberdispersion,fiberballing,anddecreasedworkability.
* Overall, the study demonstrates that replacing 40% of fine aggregate with copper slag combined with 1.5% polypropylenefiberdeliversthemostbalancedenhancementincompressive,tensile,andflexuralstrength.
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International Research Journal of Engineering and Technology (IRJET) e-ISSN:2395-0056
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ACKNOWLEDGEMENT
The present study was conducted at Sri Venkateswara University College of Engineering, Tirupati, Andhra Pradesh, India.
REFERENCES
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