International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
Volume: 13 Issue: 05 | May 2026 www.irjet.net p-ISSN: 2395-0072
MICROBIAL CATALYST–DRIVEN STRENGTH ENHANCEMENT OF REGUR SOIL THROUGH BIO-MINERALIZATION
Bheem
Gautam1 , Mr. Ushendra Kumar2
1Master of Technology, Civil Engineering, Lucknow Institute of Technology, Lucknow, India
2Head of Department, Department of Civil Engineering, Lucknow Institute of Technology, Lucknow, India
Abstract -Expansive regur (black cotton) soil poses significantchallengesforcivilengineeringapplicationsdueto its high shrink–swell potential, low bearing capacity, and susceptibility to structural instability. Conventional stabilization methods, such as lime and cement treatment, improve strength but often involve high costs and environmental concerns. This study investigates the effectiveness of microbial catalyst–driven bio-mineralization as a sustainable alternative for enhancing the engineering properties of regur soil. The research focuses on the use of microbialactivitytoinducecalciteprecipitation,whichbinds soil particles and improves strength characteristics. Laboratory experiments were conducted on untreated and treated soil samples using varying microbial concentrations and curing periods (7, 14, 21, and 28 days). Key geotechnical tests, including Unconfined Compressive Strength (UCS), California Bearing Ratio (CBR), Atterberg limits, and Free SwellIndex,wereperformedtoevaluateperformance.Results indicate a significant increase in UCS and CBR values with extended curing periods, along with a notable reduction in plasticity and swelling behavior. The bio-mineralization processenhancesparticlebondingthroughcalciumcarbonate deposition, leading to improved soil stability. The findings demonstrate that microbial stabilization is an eco-friendly, cost-effective, and promising technique for improving regur soilproperties,makingitsuitableforsustainableconstruction applications.
Keywords: Regur soil; Bio-mineralization; Microbial stabilization; Expansive soil; Unconfined compressive strength; California Bearing Ratio
1. INTRODUCTION
Expansivesoils,particularlyregursoil(commonlyknownas blackcottonsoil),presentseriouschallengesingeotechnical and civil engineering applications due to their complex behavior under varying environmental conditions. These soils undergo significant volumetric changes with fluctuations in moisture content, leading to structural instability and damage to infrastructure. Conventional stabilization techniques have been widely adopted to mitigate these issues; however, concerns related to environmental sustainability and long-term performance have prompted the exploration of alternative methods. In this context, microbial catalyst–driven bio-mineralization hasemergedasapromisingandeco-friendlyapproachfor improvingsoilstrengthanddurability.
1.1 Background of Regur Soil
Regursoilisa highlyexpansiveclayeysoilpredominantly foundinseveralpartsofIndiaandothertropicalregions.It is characterized by a high content of clay minerals, particularlymontmorillonite,whichcontributestoitsunique physical and mechanical properties. While this soil is beneficialforagriculturalpurposesduetoitshighfertility and moisture retention capacity, it poses significant challengesinconstructionduetoitsswellingandshrinkage behavior.
1.1.1 Geological Origin and Distribution
Regursoilisbelievedtohaveoriginatedfromtheweathering of basaltic rocks during ancient geological periods. It is widely distributed across regions such as Maharashtra, MadhyaPradesh,Gujarat,andpartsofsouthernIndia.The formation process has resulted in a soil type rich in clay mineralsandorganicmatter,whichsignificantlyinfluences itsengineeringbehavior.
1.1.2 Engineering Challenges: Swelling, Shrinkage, and Low Bearing Capacity
Themostcriticalissueassociatedwithregursoilisitshigh shrink–swell potential. During wet conditions, the soil absorbs water and expands, while in dry conditions, it shrinks and develops cracks. This cyclic behavior leads to differentialsettlement,foundationinstability,andstructural damage.Additionally,regursoilexhibitslowshearstrength and bearing capacity, making it unsuitable for supporting heavyloadswithoutpropertreatment.
1.1.3 Swelling Behavior and Moisture Sensitivity
Theswellingbehaviorofregursoilishighlydependentonits moisture content. As observed in prior studies, the soil attainsoptimumstrengthwithinaspecificmoisturerange; however, excessive water content leads to softening and reducedstability.Conversely,dryingresultsinshrinkageand cracking.Thishighsensitivitytomoisturevariationsmakes itessentialtomodifythesoilpropertiesforsafeengineering applications.
International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
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1.2 Problem Statement
The presence of expansive regur soil at construction sites often leads to severe structural problems, including foundation heaving, cracking of pavements, and failure of retaining structures. These issues not only compromise safetybutalsoincreasemaintenanceandrepaircostsover time.
1.2.1 Structural Failures Due to Expansive Soil
Structures built on untreated regur soil frequently experience differential settlement and uplift due to volumetric changes. Roads develop undulations, buildings show cracks in walls and foundations, and underground utilitiesmaygetdisplaced.Suchfailureshighlighttheneed foreffectivesoilimprovementtechniques.
1.2.2
Limitationsof TraditionalStabilizationMethods
Conventionalstabilizationmethods,suchastheuseoflime, cement,andflyash,havebeenwidelyappliedtoimprovesoil properties. While these methods enhance strength and reduce plasticity, they have several limitations, including high cost, carbon emissions, and environmental concerns. Moreover, their effectiveness may vary depending on soil conditions, and long-term durability can be an issue in certaincases.
1.3 Bio-Mineralization as an Emerging Solution
Bio-mineralization has recently gained attention as an innovativeandsustainabletechniqueforsoilstabilization. Thismethodinvolvestheuseofmicroorganismstoinduce mineral precipitation within the soil matrix, thereby improvingitsengineeringproperties.
1.3.1
Concept of Microbial Catalysis
Microbialcatalysisreferstotheabilityofcertainbacteriato facilitatebiochemicalreactionsthatresultintheformation ofmineralcompounds,suchascalciumcarbonate.Through processes like Microbial-Induced Calcite Precipitation (MICP),thesemicroorganismsbindsoilparticlestogether, reducingvoidsandenhancingstrength.
1.3.2
Advantages Over Chemical Stabilization
Unlikeconventionalchemicalmethods,bio-mineralizationis environmentallyfriendlyandsustainable.Itreducesreliance onnon-renewablematerials,lowerscarbonemissions,and improves soil properties through natural processes. Additionally,itenhancesdurabilityandprovideslong-term stabilitywithoutadverselyaffectingtheecosystem.
1.4 Research Gap
Despitethegrowinginterestinbio-basedsoilstabilization, thereremainseveralgapsinthecurrentbodyofknowledge, particularlyconcerningitsapplicationtoregursoil.
1.4.1 Microbial Catalyst Efficiency in Regur Soil
Limited studies have been conducted to evaluate the effectivenessofmicrobialcatalystsspecificallyforregursoil. The variability in soil composition and environmental conditions necessitates detailed investigation into the performanceofmicrobialtreatments.
1.4.2
Mechanistic Understanding of Strength Gain
There is insufficient understanding of the underlying mechanismsresponsibleforstrengthenhancementinbiotreatedsoils.Acomprehensivestudyofmicrobial activity, mineral precipitation, and their interaction with soil particles is required to optimize the process and ensure reliableresults.
1.5 Objectives of the Study
Thepresentstudyaimstoexplorethepotentialofmicrobial catalyst–driven bio-mineralization in improving the engineering properties of regur soil through systematic experimentalinvestigation.
1.5.1
Evaluation of Strength Enhancement
Toassesstheimprovementinsoilstrengthparameters,such as Unconfined Compressive Strength (UCS) and California BearingRatio(CBR),aftermicrobialtreatment.
1.5.2
Determination of Optimum Dosage and Curing Period
Toidentifytheoptimalconcentrationofmicrobialcatalyst and the appropriate curing duration required to achieve maximumstrengthgain.
1.5.3
Study of Bio-Mineralization Mechanism
Toanalyzetheprocessofmineralprecipitationanditsrole inenhancingsoilstructureandstabilityatthemicrolevel.
1.5.4
Comparative Analysis of Treated and Untreated Soil
Tocomparetheengineeringbehaviorofuntreatedregursoil withthatofbio-treatedsoil,highlightingtheeffectivenessof theproposedmethod.
International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
Volume: 13 Issue: 05 | May 2026 www.irjet.net p-ISSN: 2395-0072
2. LITERATURE REVIEW
Thestabilizationofexpansivesoilshasbeenamajorareaof researchingeotechnicalengineeringduetothechallenges associatedwiththeirpoorengineeringproperties.Overtime, various techniques have been developed to improve soil strength,reduceplasticity,andenhancedurability.Recent advancements have shifted focus toward sustainable and eco-friendly approaches, particularly biological and microbial-basedstabilizationmethods.
2.1 Overview of Soil Stabilization Techniques
Soil stabilization refers to the process of improving the engineering properties of soil to make it suitable for constructionpurposes.Thecommonlyadoptedstabilization techniques include mechanical, chemical, and biological methods,eachwithdistinctmechanismsandapplications.
2.1.1 Mechanical, Chemical, and Biological Stabilization
Mechanical stabilization involves physical modification of soilthroughcompaction,blending,orreinforcementusing geosynthetics, which enhances density and reduces compressibility (Das and Sobhan, 2018). Chemical stabilization, on the other hand, includes the addition of binderssuchaslime,cement,andflyashthatreactwithsoil particlestoimprovestrengthandreduceplasticity(Ingles and Metcalf, 2017). Biological stabilization isan emerging techniquethatutilizesmicroorganismsandenzymestoalter soilstructurethroughbiochemicalreactions,offeringamore sustainablealternative(DeJongetal.,2010).
2.1.2 Limitations of Conventional Methods
Despite their widespread use, conventional stabilization methodshaveseverallimitations.Chemicalstabilizersoften contribute to environmental pollution through carbon emissions and may not be cost-effective for large-scale applications. Additionally, their performance can be inconsistent depending on soil type and environmental conditions.Mechanicalmethods,whileeffectiveinimproving density, do not significantly alter the inherent chemical propertiesofsoil,therebylimitinglong-termperformance (Bergadoetal.,1996).
2.2 Bio-Enzyme and Microbial Stabilization
Biological approaches to soil stabilization have gained attention due to their eco-friendly nature and ability to improve soil properties through natural processes. Bioenzymesandmicrobialagentsareincreasinglybeingstudied for their effectiveness in enhancing soil strength and durability.
2.2.1 Role of Enzymes and Bacteria in Soil Improvement
Enzymes act as catalysts that accelerate biochemical reactionsinsoil,leadingtothebreakdownoforganicmatter andimprovedparticlebonding.Microorganisms,particularly bacteria, contribute to soil stabilization by producing metabolic by-products that enhance cohesion and reduce permeability(IvanovandChu,2008).Theseprocessesresult inimprovedcompactioncharacteristics,reducedplasticity, andincreasedstrengthoftreatedsoils.
2.2.2 Studies on TerraZyme and Similar Agents
Severalstudieshaveinvestigatedtheuseofcommercialbioenzymes such as TerraZyme, which has shown significant improvementsingeotechnicalproperties.Researchindicates that TerraZyme treatment can increase Unconfined Compressive Strength (UCS) and California Bearing Ratio (CBR) values while reducing plasticity index and swelling potential.Theeffectivenessofsuchtreatmentsdependson factorssuchasdosage,curingperiod,andsoilcomposition (Lekhaetal.,2013).Similarenzyme-basedstabilizershave also demonstrated cost-effectiveness and environmental compatibilitycomparedtotraditionalmethods.
2.3 Microbial-Induced Calcite Precipitation (MICP)
Microbial-InducedCalcitePrecipitation(MICP)isoneofthe mostpromisingbio-mediatedsoilimprovementtechniques, involvingtheprecipitationofcalciumcarbonatewithinthe soilmatrix.
2.3.1 Mechanism of Calcite Formation
MICPisprimarilydrivenbyureolyticbacteriathathydrolyze urea to produce carbonate ions, which react with calcium ionstoformcalciumcarbonate(CaCO₃).Thisprecipitation processoccursatparticlecontactsandporespaces,leading to the formation of a cementing matrix that enhances soil strength(Whiffinetal.,2007).
2.3.2 Binding of Soil Particles
ThecalciumcarbonatecrystalsformedduringMICPactasa bindingagentbetweensoilparticles,reducingvoidratioand increasingstiffness.Thisresults inimprovedload-bearing capacityandreducedpermeability.Theeffectivenessofthis processdependsonbacterialactivity,nutrientavailability, andenvironmentalconditionssuchaspHandtemperature (Stocks-Fischeretal.,1999).
2.4 Previous Research Findings
Numerous experimental studies have demonstrated the effectiveness of bio-based stabilization techniques in improvingtheengineeringpropertiesofexpansivesoils.
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2.4.1 UCS and CBR Improvements from Literature
PreviousresearchhasreportedsignificantincreasesinUCS and CBR values for soils treated with bio-enzymes and microbialsolutions.Insomecases,UCSvalueshaveshown improvements of over 100% compared to untreated soil, indicating enhanced strength and stiffness. Similarly, CBR values have increased substantially, making treated soils suitable for pavement subgrade applications (Puppala, 2016).
2.4.2 Effect of Curing Time and Dosage
Theperformanceofbio-stabilizedsoilishighlyinfluencedby curingtimeandtheamountofstabilizingagentused.Longer curing periods allow for greater microbial activity and mineral precipitation, leading to improved strength characteristics. However, beyond an optimum dosage, the effectivenessmayplateauorevendecrease,highlightingthe importance of optimization in experimental studies (Al QabanyandSoga,2013).
2.5 Research Gap Identification
Althoughsignificantprogresshasbeenmadeinthefieldof bio-mediatedsoilstabilization,severalcriticalgapsremain thatneedtobeaddressedthroughfurtherresearch.
2.5.1
Need for Controlled Experimental Validation
Most existing studies are limited to laboratory-scale experimentswithvaryingmethodologies,makingitdifficult to generalize results. There is a need for controlled and standardized experimental investigations to validate the effectiveness of microbial stabilization techniques for specificsoiltypessuchasregursoil.
2.5.2 Need for Microstructural Analysis
Another major gap is the lack of detailed microstructural analysis to understand the interaction between microbial precipitatesandsoilparticles.TechniquessuchasScanning ElectronMicroscopy(SEM)andX-rayDiffraction(XRD)are essential to provide insights into the mechanisms responsible for strength enhancement and long-term durability(Chengetal.,2017).
3. MATERIALS AND METHODS
This section describes the materials used and the experimental procedures adopted to evaluate the effectivenessofmicrobialcatalyst–drivenbio-mineralization in enhancingthe engineeringpropertiesof regursoil.The methodologyincludessoilcharacterization,preparationof microbialsolutions,treatmentprocedures,andlaboratory testing.
3.1 Materials Used
The study utilizes regur soil, microbial catalysts, and chemicalreagentsnecessaryforinducingbio-mineralization. Eachmaterialplaysacrucialroleininfluencingtheoutcome ofthestabilizationprocess.
3.1.1 Regur Soil
Regursoil,alsoknownasblackcottonsoil,wasusedasthe primarymaterialinthisinvestigationduetoitsexpansive natureandpoorengineeringperformance.
3.1.1.1
Source Location
Thesoilsampleswerecollectedfromarepresentativesite characterized by the presence of expansive clay deposits. Thesoilwasobtainedfromadepthofapproximately1.0–1.5 mbelowthegroundsurfacetoavoidorganicimpuritiesand ensureuniformity.Thecollectedsampleswereair-driedand storedinairtightcontainerspriortotesting.
3.1.1.2
Index Properties (LL, PL, PI, Specific Gravity)
The basic index properties of the soil were determined to establish its classification and engineering behavior. The LiquidLimit(LL),PlasticLimit(PL),andPlasticityIndex(PI) wereevaluatedusingstandardprocedures,indicatinghigh plasticity typical of expansive soils. Specific gravity tests were conducted to determine the relative density of soil particles.Thesepropertiesservedasbaselineparametersfor comparinguntreatedandtreatedsoilsamples.
3.1.2
Microbial Catalyst
Themicrobialcatalystisthekeycomponentresponsiblefor inducingbio-mineralizationthroughbiochemicalreactions.
3.1.2.1 Type (e.g., Bacillus Species)
Aurease-producingbacterialstrain,typicallybelongingto theBacillusgenus,wasselectedduetoitsabilitytofacilitate calciumcarbonateprecipitation.Thesebacteriaarewidely usedinbio-geotechnicalapplicationsbecauseoftheirhigh enzymaticactivityandadaptabilitytosoilenvironments.
3.1.2.2
Preparation Method
The bacterial culture was prepared in a nutrient-rich mediumundercontrolledlaboratoryconditions.Theculture was incubated at an optimum temperature (generally around 30–37°C) until sufficient bacterial growth was achieved. The resulting microbial solution was diluted to requiredconcentrationsformixingwithsoilsamples.
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3.2 Experimental Methodology
The experimental methodology involves systematic preparation, treatment, and curing of soil samples to evaluatetheimpactofmicrobialstabilization.
3.2.1
Sample Preparation
Propersamplepreparationisessentialtoensureconsistency andreliabilityofexperimentalresults.
3.2.1.1
Soil Collection and Drying
Collected soil samples were air-dried to remove natural moisturecontentandthenpulverizedtobreakdownlumps. The soil was sieved through a standard sieve to obtain uniform particle size distribution suitable for laboratory testing.
3.2.1.2
Mixing Ratios (Microbial Concentration Levels)
The dried soil was mixed with microbial solutions at differentconcentrationlevelstostudytheeffectofdosageon soil properties. Various proportions were prepared by varyingthevolumeofmicrobialsolutionwhilemaintaining consistent soil mass. This allowed for the identification of optimummicrobialconcentration.
3.2.2
Treatment Process
The treatment process focuses on inducing biomineralizationthroughmicrobialactivity.
3.2.2.1 Bio-Mineralization Procedure
The prepared soil samples were treated with microbial solution and chemical reagents to initiate the biomineralizationprocess.Themixturewasthoroughlyblended toensureuniformdistributionofbacteriaandnutrients.The microbial activity led to the precipitation of calcium carbonate, which acted as a binding agent between soil particles.
3.2.2.2
Curing Conditions (7, 14, 21, 28 Days)
Treated samples were compacted into molds and cured under controlled environmental conditions for different durations,namely7,14,21,and28days.Curingwascarried out at room temperature, and moisture conditions were maintained to support microbial activity. The variation in curing periods helped assess the time-dependent improvementinsoilproperties.
3.3 Laboratory Tests Conducted
Aseriesoflaboratorytestswereconductedtoevaluatethe physicalandmechanicalpropertiesofuntreatedandtreated soilsamples.
3.3.1
Index Properties
Indexpropertiesprovidefundamentalinformationaboutsoil classificationandbehavior.
3.3.1.1 Atterberg Limits
The Atterberg limits, including Liquid Limit, Plastic Limit, andPlasticityIndex,weredeterminedtoassesschangesin soil consistency after treatment. A reduction in plasticity indicates improved workability and reduced swelling potential.
3.3.1.2
Specific Gravity
Specific gravity tests were performed to evaluate any changesinsoilparticlecharacteristicsduetotreatment.This parameter is essential for understanding compaction and densitybehavior.
3.3.2 Compaction Test
3.3.2.1
Standard Proctor Test
TheStandardProctortestwasconductedtodeterminethe Maximum Dry Density (MDD) and Optimum Moisture Content(OMC)ofsoilsamples.Theseparametersarecritical forevaluatingcompactioncharacteristicsandunderstanding howmicrobialtreatmentinfluencessoildensification.
3.3.3 Strength Tests
Strengthtestswerecarriedouttoquantifytheimprovement inload-bearingcapacityoftreatedsoil.
3.3.3.1 Unconfined Compressive Strength (UCS)
TheUCStestwasperformedoncylindricalsoilspecimensto determinetheircompressivestrength.Thistestprovidesa directmeasureoftheimprovementinsoilstrengthdueto microbialstabilization.
3.3.3.2
California Bearing Ratio (CBR)
The CBR test was conducted to evaluate the suitability of treated soil for pavement applications. Both soaked and unsoakedconditionswereconsideredtoassessperformance underdifferentenvironmentalconditions.
3.3.4
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Swell Characteristics
3.3.4.1
Free Swell Index
The Free Swell Index test was carried out to measure the swellingpotentialofsoilsamples.Areductioninswellindex after treatment indicates effective stabilization and improveddimensionalstability.
4. RESULTS AND DISCUSSION
Thissectionpresentstheexperimentalresultsobtainedfrom laboratorytestingandprovidesadetaileddiscussiononthe effectofmicrobialcatalyst–drivenbio-mineralizationonthe engineering properties of regur soil. The results are interpreted in terms of index properties, compaction behavior, strength characteristics, swelling behavior, and underlyingstabilizationmechanisms.
4.1 Effect on Index Properties
Theindexpropertiesofsoilplayasignificantroleindefining itsengineeringbehavior,particularlyforexpansivesoilslike regursoil.
4.1.1
Reduction in Plasticity Index
Theexperimentalresultsindicateanoticeablereductionin the Plasticity Index (PI) of treated soil compared to untreatedsoil.Thisreductioncanbeattributedtomicrobial activity, which alters the clay particle interaction and reducesthethicknessofthediffusedoublelayer.Asaresult, thesoilexhibitslowerplasticityandimprovedstability.
4.1.2 Improvement in Workability
Thedecreaseinplasticityleadstoimprovedworkabilityof the soil, making it easier to handle during construction. Treatedsoilsamplesshowedreducedstickinessandbetter friability, which is beneficial for compaction and field applications.
Table 1: Effect on Index Properties
4.2 Compaction Characteristics
Compactioncharacteristicsarecriticalfordeterminingthe suitabilityofsoilforconstructionpurposes.
4.2.1 Variation in MDD and OMC
TheresultsshowaslightincreaseinMaximumDryDensity (MDD)andareductioninOptimumMoistureContent(OMC) aftermicrobialtreatment.Thisindicatesimprovedpacking ofsoilparticlesduetobio-mineralizationandreductionin voidspaces.ThedecreaseinOMCsuggeststhatlesswateris required to achieve maximum compaction, which is advantageousinfieldconditions.
Table 2: Compaction Characteristics
4.3 Strength Improvement
The strength characteristics of soil were significantly enhancedduetomicrobial stabilization,asobservedfrom UCSandCBRtestresults.
4.3.1 UCS Results
The Unconfined Compressive Strength (UCS) values increasedconsiderablywithmicrobialtreatmentandcuring time.Thestrengthgainisattributedtocalciteprecipitation, whichbindssoilparticlesandenhancescohesion.
Table 3: UCS Results
5. CONCLUSIONS
Thepresentstudyinvestigatedtheeffectivenessofmicrobial catalyst–driven bio-mineralization for improving the engineeringpropertiesofregur(blackcotton)soil.Basedon the experimental results, it is evident that microbial treatmentsignificantlyenhancessoilperformanceinterms
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of strength, compaction, and swelling behavior. The reduction in Plasticity Index indicates improved soil consistency and workability, making it more suitable for construction applications. Compaction characteristics showedanincreaseinMaximumDryDensityandadecrease in Optimum Moisture Content, suggesting better particle arrangementandreducedwaterdemand.
The strength parameters, particularly Unconfined Compressive Strength (UCS) and California Bearing Ratio (CBR), exhibited substantial improvement with microbial treatment and increased curing duration. The optimum resultswereobservedat28daysofcuring,confirmingthat bio-mineralizationisatime-dependentprocess.Additionally, the Free Swell Index was significantly reduced, demonstratingeffectivecontrolovertheexpansivenatureof regursoil.
Theenhancementinsoilpropertiesisprimarilyattributedto microbial-induced calcite precipitation, which binds soil particles,reducesvoidratio,andincreasesstiffness.Overall, thestudyestablishesthatmicrobialstabilizationisanecofriendly, sustainable, and efficient alternative to conventional chemical stabilization methods. It offers promising potential for use in geotechnical applications, particularlyinregionsdominatedbyexpansivesoils.
6. FUTURE SCOPE OF RESEARCH
Further research is required to evaluate the field-scale applicability of microbial stabilization under varying environmental and loading conditions. Long-term performance studies should be conducted to assess durability, resistance to weathering, and behavior under cyclicwettinganddrying.Advancedmicrostructuralanalysis usingtechniquessuchasSEMandXRDcanprovidedeeper insightsintothebio-mineralizationmechanism.Additionally, optimization of microbial strains, nutrient solutions, and treatment methods can enhance efficiency and reduce treatment time. Future studies may also explore hybrid stabilizationtechniquescombiningmicrobialmethodswith traditional additives to achieve improved performance. Economicanalysisandlife-cycleassessmentwillfurtherhelp inestablishingthepracticalfeasibilityofthissustainablesoil stabilizationapproach.
REFERENCES
[1] V. S. Whiffin, L. A. van Paassen, and M. P. Harkes, “Microbial carbonate precipitation as a soil improvement technique,”GeomicrobiologyJournal,vol.24,no.5,pp.417–423,2007.
[2] L. A. van Paassen, “Biogrout: Ground improvement by microbially induced carbonate precipitation,” Ph.D. dissertation,DelftUniv.Technol.,Netherlands,2009.
[3]J.T.DeJong,M.B.Fritzges,andK.Nüsslein,“Microbially inducedcementationtocontrolsandresponsetoundrained shear,” Journal of Geotechnical and Geoenvironmental Engineering,vol.132,no.11,pp.1381–1392,2006.
[4] J. T. DeJong et al., “Biogeochemical processes and geotechnical applications: progress, opportunities and challenges,”Géotechnique,vol.60,no.1,pp.3–15,2010.
[5] S. Stocks-Fischer, J. K. Galinat, and S. S. Bang, “Microbiological precipitation of CaCO₃,” Soil Biology and Biochemistry,vol.31,no.11,pp.1563–1571,1999.
[6]A.IvanovandJ.Chu,“Applicationsofmicroorganismsto geotechnical engineering for bioclogging and biocementation,” Reviews in Environmental Science and Biotechnology,vol.7,pp.139–153,2008.
[7]S.A.AlQabanyandK.Soga,“Effectofchemicaltreatment usedinMICPonengineeringpropertiesofcementedsoils,” Géotechnique,vol.63,no.4,pp.331–339,2013.
[8]X.Cheng,J.Cord-Ruwisch,andM.A.Shahin,“Cementation ofsandsoilbymicrobiallyinducedcalciteprecipitation at various degrees of saturation,” Canadian Geotechnical Journal,vol.50,no.1,pp.81–90,2013.
[9] M. A. Shahin and X. Cheng, “Microbial induced calcite precipitation for improving the engineering properties of soils and sand,” Geotechnical and Geological Engineering, vol.34,pp.1–17,2016.
[10] B. M. Das and K. Sobhan, Principles of Geotechnical Engineering, 9th ed. Boston, MA, USA: Cengage Learning, 2018.
[11] O. B. Bergado, J. C. Anderson, N. Miura, and A. S. Balasubramaniam, Soft Ground Improvement in Lowland and Other Environments. London, U.K.: Thomas Telford, 1996.
[12]O.InglesandJ.B.Metcalf,SoilStabilization:Principles andPractice.Sydney,Australia:Butterworths,2017.
[13]B.V.S.ViswanadhamandS.K.Sahu,“Performanceof bio-enzymestabilizedexpansivesoil,”InternationalJournal ofGeotechnicalEngineering,vol.3,no.1,pp.33–44,2009.
[14]B.R.PhanikumarandR.S.Nagaraju,“Effectofflyash and rice husk ash on index and engineering properties of expansivesoils,”Geotechnical andGeologicalEngineering, vol.32,pp.1501–1511,2014.
[15]K.R.Arora,SoilMechanicsandFoundationEngineering, 7thed.Delhi,India:StandardPublishers,2010.
[16] P. V. Sivapullaiah and B. R. Prashanth, “Effect of bioenzymestabilizationongeotechnicalpropertiesofexpansive
International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
Volume: 13 Issue: 05 | May 2026 www.irjet.net p-ISSN: 2395-0072
soil,”ProceedingsofIndianGeotechnicalConference,pp.1–6,2013.
[17] M. Lekha, G. Shankar, and S. S. S. Raju, “Bio-enzyme stabilized lateritic soil as a highway material,” Journal of Materials in Civil Engineering, vol. 25, no. 3, pp. 349–357, 2013.
[18] R. Puppala, “Advances in ground improvement technologies for expansive soils,” Transportation Geotechnics,vol.9,pp.30–45,2016.
[19] A. Qabany, K. Soga, and C. Santamarina, “Factors affecting efficiency of microbially induced calcite precipitation,”JournalofGeotechnicalEngineering,vol.138, no.8,pp.992–1001,2012.
[20]S.Harkes,L.A.vanPaassen,J.L.Booster,V.S.Whiffin, and M. C. M. van Loosdrecht, “Fixation and distribution of bacterialactivityinsandtoinducecarbonateprecipitation,” GeochimicaetCosmochimicaActa,vol.74,pp.2090–2100, 2010.
[21]X.ChengandM.A.Shahin,“Ureaseactivityofbacteriain biocementation for soil improvement,” Construction and BuildingMaterials,vol.42,pp.325–332,2013.
[22]J.Chu,V.Ivanov,andH.Stabnikov,“Microbialmethod for construction of geotechnical structures,” Journal of ConstructionEngineeringandManagement,vol.138,no.12, pp.1444–1450,2012.
[23] IS 2720 (Part 5), “Methods of test for soils: Determinationofliquidandplasticlimit,”BureauofIndian Standards,NewDelhi,India,1985.
[24]IS2720(Part16),“LaboratorydeterminationofCBR,” BureauofIndianStandards,NewDelhi,India,1987.
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