Multifunctional Concrete using Photo catalyst and Fully Replacing Coarse Aggregate with Crushed Styr

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056

Volume: 13 Issue: 04 | Apr 2026 www.irjet.net p-ISSN: 2395-0072

Multifunctional Concrete using Photo catalyst and Fully Replacing Coarse Aggregate with Crushed Styrofoam

Komarina Dileep Chowdary1, Grandhi Gopal Guptha2 , Karni Dharani3 , Nakka Santosh Kumar4 , Vechalapu Paavana Sai Lakshmi5

1Assistant Professor, Dept. of Civil Engineering, Sanketika Vidya Parishad Engineering College, VSP, India

2B.tech graduate student, Dept. of Civil Engineering, Sanketika Vidya Parishad Engineering College, VSP, India

3B.tech graduate student, Dept. of Civil Engineering, Sanketika Vidya Parishad Engineering College, VSP, India

4B.tech graduate student, Dept. of Civil Engineering, Sanketika Vidya Parishad Engineering College, VSP, India

5B.tech graduate student, Dept. of Civil Engineering, Sanketika Vidya Parishad Engineering College, VSP, India

Abstract - Concrete is one of the most widely used construction materials, but its production consumes large amounts of natural resources and contributes to environmental problems. At the same time, waste materials like Expanded Polystyrene (EPS), or Styrofoam, create serious disposal challenges because they do not decompose easily. This project aims to address both issues by developing a sustainable, multifunctional lightweight concrete using recycled Styrofoam and photo catalyst materials.

In this study, crushed EPS is used as a partial replacement for coarse aggregate, making the concrete lighter and improving its thermal and acoustic insulation properties. Additionally, titanium dioxide (TiO₂) nanoparticles are incorporated into the concrete as a photo catalyst. These particles give the material self-cleaning and air-purifying abilities. When exposed to sunlight, especially ultraviolet (UV) rays, TiO₂ reacts with oxygen and moisture in the air to break down harmful pollutants such as nitrogen oxides (NOx) and volatile organic compounds (VOCs), converting them into less harmful substances that can be washed away byrain.

ThecombinationofEPSandphotocatalystmaterialsresults in a concrete that is not only lightweight but also environmentally beneficial. While EPS helps reduce the overall density and improves insulation, TiO₂ enhances the surfacefunctionalityofthe concretebyactivelyreducing air pollution.

This research highlights how innovative use of waste materials and advanced technologies can improve the performance of construction materials. Overall, the study demonstrates that multifunctional concrete can support sustainable constructionbyreducingenvironmentalimpact, improving energy efficiency, and contributing to cleaner air inurbanareas.

Key Words: Lightweight (EPS) Concrete, Sustainable Construction, Titanium Dioxide (TiO₂), Self-cleaning (Photo catalyst) Concrete, Air Purification, Waste Utilization, Multifunctional Concrete, Thermal Insulation

1. INTRODUCTION

Concrete is one of the most commonly used construction materials because of its strength, durability, and versatility. However, its production consumes large amounts of natural resources and contributes to environmental issues like carbon emissions. At the same time, non-biodegradable waste such as Styrofoam (Expanded Polystyrene – EPS) creates serious disposal problems.Toaddressthesechallenges,thisstudyexplores the development of multifunctional concrete using recycledStyrofoamandphotocatalystmaterials.

The concept of multifunctional concrete goes beyond traditional strength by adding properties like lightweight performance, thermal insulation, and pollution reduction. In this study, crushed Styrofoam is used asa replacement for coarse aggregates, significantly reducing the weight of concrete while improving thermal and sound insulation. Additionally, titanium dioxide (TiO₂) is incorporated as a photo catalyst, enabling the concrete to break down harmfulairpollutantssuchasnitrogenoxides(NOx)when exposed to sunlight. This also provides self-cleaning, antibacterial,andaestheticdurabilitybenefits.

The main objectives of the study are to develop sustainable concrete, reduce self-weight, utilize waste materials, and evaluate mechanical and functional propertiessuchascompressivestrength, workability,and air-purifyingability.TheuseofStyrofoampromoteswaste management, while TiO₂ enhances environmental performance.

The scope of the study focuses on laboratory-scale evaluation of concrete properties with different EPS proportionstodeterminetheoptimalmix.Althoughlargescaleapplicationsarenotincluded,theresearchhighlights the potential of this material for lightweight structures, partitionwalls,andeco-friendlyconstructionsolutions.r.

1.1 Objectives of the Study

 To develop multifunctional concrete using photo catalystmaterialsandExpandedPolystyrene(EPS).

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056

Volume: 13 Issue: 04 | Apr 2026 www.irjet.net p-ISSN: 2395-0072

 To study the feasibility of using waste Styrofoam in concrete.

 To reduce the self-weight of concrete by replacing naturalcoarseaggregateswithEPS.

 Toevaluatemechanicalpropertiessuchascompressive strengthandworkability.

 To analyze photo catalytic properties like air purificationandself-cleaningability.

 To promote sustainable construction through waste utilizationandreducedresourceconsumption.

1.2 Objectives of Additional Materials

Photo catalyst (TiO₂):

 Toreduceharmfulairpollutants(airpurification).

 Toprovideself-cleaningproperties.

 Toofferantibacterialandantifungaleffects.

 Toimproveaestheticdurabilityofconcretesurfaces.

Styrofoam (EPS):

 Toproducelightweightconcrete.

 Toenhancethermalinsulation.

 Toimprovesoundinsulation/absorption.

 To support waste management by recycling plastic materials.

Combined Objective:

Todevelopa sustainable, lightweight, and eco-friendly concretewithinsulationandair-purifyingcapabilities.

1.3

Scope of the Study

 TodevelopandtestmultifunctionalconcreteusingEPS andphotocatalystmaterials.

 To study physical and mechanical properties such as density,workability,andcompressivestrength.

 To determine the optimum percentage of EPS replacement.

 To evaluate self-cleaning and air-purifying performanceoftheconcrete.

 To promote sustainable construction using waste materials.

 The study is limited to laboratory-scale testing and doesnotincludelarge-scalestructuralapplications.

1.3 Problem Statement

 Excessive use of natural aggregates in construction leads to resource depletion and environmental degradation.

 Disposal of non-biodegradable plastic waste like EPS (Styrofoam)isagrowingenvironmentalconcern.

 Conventional concrete lacks environmental benefits such as pollution reduction and self-cleaning properties.

 There is a need for innovative, sustainable construction materials with added functional benefits.

 Theprojectaimstodevelop multifunctional concrete using crushed EPS as partial aggregate replacement and incorporating photo catalysts for improved environmentalperformance.

2. METHODOLOGY

Materialselection

Materialstests

EPSpreparation

2.1 Materials used and their properties

Cement

Cement is a binding material, used for construction that sets,hardens,andadherestoothermaterialstobindthem together. Ordinary Portland cement (OPC) of 53 grade, of JK Super (Build strong) brand available in local market is used in the investigation. The cement used for all tests is fromthesamebatch.

Table I: Testresultsoncement

S.no Properties Test results observed

1. Finenessofcement 9%

2. StandardConsistency 30%

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Fine Aggregate

Fineaggregate(commonlyreferredtoassand)isacritical component of concrete and mortar, typically consisting of granular materials that pass througha 4.75 mm sieve and are retained on a 75 µm sieve. The used fine aggregate is riversand.

Table II: Testresultsonfineaggregate

S.no Properties Test results observed

1. FinenessModulus 2.2

2. Zoneofsand ZoneIII

3. SpecificGravity 2.65

4. BulkDensity 1450kg/m³

5. Moisturecontent 2.04%

6. BulkingofSand 20%

7. Siltcontent 0%

Coarse Aggregate

Coarse aggregate is a foundational component of concrete which consists of large-sized particles retained on a 4.75 mm sieve, typically ranging up to 37.5 mm in diameter, though sizes can go up to 75 mm for mass concrete. Well gradedcoarseaggregateof10and20mmareused.

Fig. 3: 20mm

Table III: Testresultsoncoarseaggregate

S.no Properties Test results observed

1. SpecificGravity 2.72

2. BulkDensity 1623.75kg/m³

3.

6. AggregateImpactValue 5.7%

Crushed Styrofoam (EPS)

Crushed Expanded Polystyrene (EPS) or Styrofoam, particularly in the 2–5 mm size range, is used in concrete as a lightweight aggregate to produce Expanded PolystyreneConcrete(EPSConcrete).

Fig. 5: CrushedStyrofoam

Table IV: TestresultsonCrushedStyrofoam

S.no Properties Test results observed

1. BulkDensity 21kg/m³

Titanium Dioxide (TiO₂ – Anatase)

Anatase Titanium Dioxide (TiO₂) is widely used in concrete as a photo catalytic additive, typically at 0.5%–5% by weight of cement, to impart self-cleaning (decolourization of organics) and smog-abating (reduction) properties. It improves compressive/flexural strength and durability, with 2%–3% deemed optimal for balancingperformancewithcost.

Fig. 4: 10mm coarseaggregate

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2.3 Mix Design Proportioning

TheconcretemixwasdesignedforM20andM25gradeas perIS10262:2019andIS456:2000

 Coarse aggregate was fully replaced by crushed Styrofoambyvolume.

 Water–cementratiowasmaintainedlessthan0.50.

 TiO₂wasaddedat5%ofcementcontentandSuper plasticizerof1%ofcementwasusedtoimprove workability.

Table V: TestresultsonCrushedStyrofoam

Fig. 7: Polycarboxylate ether

Super plasticizer (Polycarboxylate ether (PCE))

Polycarboxylate ether (PCE) super plasticizer is a highperformance, water-reducing, and eco-friendly concrete admixture that drastically reduces water content (up to 30-40%) while enhancing flow ability, strength, and durability

2.2 Preparation of Crushed Styrofoam

Waste Styrofoam was crushed into 2–5 mm particles, washed, and lightly pre-wetted to minimize water absorptionandfloatingduringmixing.

Water–cementratiousedis0.40

Table VI: TestresultsonCrushedStyrofoam

Fig 8: Waste Styrofoamblocks

Water–cementratiousedis0.40

S.no Material Quantityfor 1m3

Fig 9: Simplifying Styrofoamblocks IntoSmallpieces

OPC53Cement

Fig 10: Crushed/Shredded Styrofoam

2.7 Mixing, Casting and Curing

Fig 11: Sieving through5mmsieve

Dry Mixing

 Mixcementandsandfor2-5min

 Add TiO₂ powder and mix properly to ensure even distribution.

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 Add crushed Styrofoam slowly to the mix and mix carefully to avoid segregation (Styrofoam is very lightweight).

Wet Mixing

 Add 70 % of water gradually (water–cement ratio ~0.4–0.5).

 Mixitfor3–4minutes

 Addsuperplasticizertotheremaining30%water

 Addsuperplasticizermixedwatertothemix

 Mixuntilitisuniform,workablemixisobtained.

 AvoidovermixingtopreventfloatingofStyrofoam.

Casting Process

 PreparationofMoulds

 Use standard moulds (cube: 150×150×150 mm, cylinder,orprism).

 Clean and apply oil to the inner surface to prevent sticking.

 PlacingofConcrete

 Pourtheconcretemixintomouldsin3layers.

 Compaction

 Uselighttampingorhandcompaction.

 Give25-35blowsforeachlayer.

 Avoidheavyvibrationbecause:

 Styrofoammayfloattothetop

 Segregationmayoccur

 LevellingandFinishing

 Levelthesurfaceusingatrowel.

 Ensureasmoothandevenfinish.



Initial Setting

 Keep the moulds undisturbed for 24 hours at room temperature.

 Cover the surface with plastic sheets or wet cloth to preventmoistureloss.

De-moulding

 After 24 hours, carefully remove specimens from moulds.

 Handle gently since early strength may be low due to Styrofoamcontent.

Curing Process

 Method:WaterCuring

 ImmersethespecimensinWaterTank

 Placespecimensincleanwatertanks.

 Maintaintemperaturearound20–27°C.

 Curing Duration: Immerse the specimens for a curing periodof:

 7 days (early strength), 14 days, 21 days, and 28 days (finalstrength)

Precautions

 Donotuseheavyvibration

 UseuniformsizeofcrushedStyrofoam

 Maintainproperwater-cementratio

 Handlespecimenscarefullyduringde-moulding

 Ensurepropercuringtoimprovestrength

2.8 Thermal Insulation of this Concrete

 This concrete mix has improved thermal insulation mainly due to the use of EPS (Expanded Polystyrene) andtheremovalofcoarseaggregates.

 EPSplaysakeyroleeveninsmallquantitiesbecauseit is about 98% air. This air content disrupts heat flow, making the material a good insulator. In contrast, cementandsandconductheatmuchmoreeasily.

 Theabsenceofcoarseaggregatesalsohelps.Innormal concrete, these aggregates act as thermal bridges, allowing heat to pass through quickly. Removing them reducesheattransfer.

 Lowerdensityisanotherimportantfactor.Lightweight concretenaturallyprovidesbetterinsulationbecauseit contains more air and less solid material for heat conduction.

Labelling each specimen

Eachcubeandcylinderwas clearlylabelledwitha unique IDindicating:

 Mixtype(control,percentage,oradditive)

 Dateofcasting

 Smaller EPS particles (2–5 mm) ensure uniform distribution, creating evenly spaced air voids. This leads to consistent insulation performance throughout theconcrete.

 Thermal insulation depends on thermal conductivity (kvalue).

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Lowerkvalue→higherinsulation

Higherkvalue→Lowerinsulation

 Material - k(W/mK)

Normalconcrete - 1.5–1.8

Ourcube - 0.6–1.0

EPS - 0.03–0.04

 Conclusion

By replacing about 40–50% of the volume with 2–5 mmcrushedEPS(withaverylowdensityof21kg/m³), theconcretetrapsmoreairandreducesheatflow.Asa result, it offers much better thermal insulation comparedtoconventionalconcrete.

2.9 Tests done on Concrete

Laboratory tests were carried out the prepared concrete samples.Thefollowingtestswereconducted:

1.Testsonfreshconcrete-

 Workabilitytest(Slumpconetest)

 Density/Unitweighttest

2.Testsonhardenconcrete-

 Compressive strength test at 7, 14, 21 and 28 days

 Splittensilestrengthtestat7,14,21and28days

 Waterabsorptionafter28days

 Self-cleaning and photo catalytic performance undersunlightusingmethyleneblue

3. CONCRETE TEST ANALYSIS AND EVALUATION OF RESULTS

Test results were analysed and compared with conventionalM20andM25concretetoevaluatetheeffect ofTiO₂additionandfullEPSreplacementonstrengthand multifunctional performance. The results were presented using tables, pictures and graphs. Conclusions and recommendationsweregivenattheendoftheproject.

3.1 Slump cone Test (Workability):

Table -VII: SlumpconeTest(Workability)values

Chart -1:SlumpconeTest(Workability)results

3.2 Unit weight:

Table -VIII: UnitweightTestvalues

Chart -2:Unitweighttestresults

3.3 Compressive Strength Test (28 Days):

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Table -XI: CompressiveStrengthTestvalues

Chart -3:CompressiveStrengthTestresults

3.4 Split Tensile Strength Test (28 Days):

Table -X: SplitTensileStrengthTestvalues

M20 conventional concrete mix

M20 multifunctional concrete mix

M25 conventional concrete mix

M25 multifunctional concrete mix

Chart -4:SplitTensileStrengthTestresults

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3.5 Water absorption test:

Table -XI: WaterabsorptionTestvalues Chart -5:Waterabsorptiontestresults

3.6 Photo-catalyst effect test:

Method 1 -

• Prepared a dye solution of light blue color by adding Methylene Blue to water in a bucket or Transparentglassbeakers

• Kepttheconcretecubespecimeninthissolution.

• ThebucketisthenkeptinsunlightorUVlight

Method 2 -

• Poured a few drops of Methylene Blue solution ontotheconcretespecimensurface

• Keepindarkfor30minutes(adsorptionstage)

• ExposetheconcretecubetosunlightorUVlight

Then observe

• Takephotosatregularintervals(0,1,2,3,4hrs.)

• Comparecolorfadingvisually

4. CONCLUSIONS

 This study explores how waste EPS (expanded polystyrene)canbeusedinconcretetomakeitlighter and more environmentally friendly, while also adding photocatalyticbenefits.

 The results show that replacing traditional materials withcrushedEPSsignificantlyreducesthedensityand overall weight of concrete, making it suitable for lightweightapplications.

 The workability of the concrete improves slightly compared to conventional mixes. However, because EPSislightweight,thedensitydropsquiteabit about 31%forM20and37%forM25mixes.

 This reduction in weight is useful, but it also leads to lower compressive and tensile strength. Even so, the strength levels are still acceptable for non-structural uses.

 Water absorption increases slightly, but remains within acceptable limits (below 5%). In terms of cost, M20 multifunctional concrete becomes much more expensive, while M25 shows only a small increase, makingM25themorepracticaloption.

 Photo-catalyst test confirmsstrong photo catalytic activity.Thespecimeneffectivelydegradedthesurface pollutantswithina4–10hour,provingitspotentialfor "self-cleaning" applications in real-world environments

 Overall, while using 100% EPS reduces strength, adjusting the percentage can help strike a balance betweenstrength,reducedweight,andsustainability.

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056

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 The study highlights how recycled materials like EPS can contribute to greener, more innovative constructionpractices.

5. FUTURE SCOPE

The present study provides a foundation for further research on multifunctional concrete. The following areas canbeexploredinthefuture:

 Investigation of different percentages of EPS replacement to determine the optimum proportion thatprovidesbothstrengthandlightweightproperties.

 Study of additional mechanical properties such as tensilestrength,flexuralstrength,anddurabilityofEPS concrete.

 Evaluation of long-term performance and durability underdifferentenvironmentalconditions.

 UseofotherwastematerialsalongwithEPStoimprove thesustainabilityofconcrete.

 Detailed analysis of photo catalytic efficiency in reducing air pollutants in real environmental conditions.

 Application of multifunctional concrete in practical construction projects such as non-load bearing walls, panels,pavements,andinsulationstructures.

 Development of improved mix designs to enhance the strengthanddurabilityofEPS-basedconcrete.

 Furtherresearchintheseareascanhelpin developing more efficient, durable, and environmentally friendly construction materials for future infrastructure development.

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