SOIL STABILISATION USING BIO-ENZYME EXTRACTED FROM NEEMPresented By Ashokan K & Sreelekha B, M4, Geotechnical Engg,Dept of Civil Engineering.Guided by

Dr. K BALAN,Professor,Dept of Civil Engineering.

INTRODUCTIONMechanical stabilisationChemical stabilisationStandardNon standardEnzymeStabilization, in a broad sense, incorporates the various methods employed for modifying the properties of a soil to improve its engineering performance.*

STABILISATION USING ENZYMEEnzyme is an organic catalyst that speeds up a chemical reaction.

Natural, Non toxic, non flammable, Non Corrosive liquid enzyme formulation fermented from vegetable extracts.

Demonstrated by the termites and white Ants- Build the shelter by Ant Saliva.

Stabilization is achieved by Microbial process.*

MECHANISM OF SOIL STABILISATION BY ENZYMEClay Particle Water Relation

Negative charge on the surface of clay particles attracts positive (Hydrogen) end of water molecule.

Water molecules are arranged in a definite pattern-Adsorbed layer*

Absorbed water in the structure of soilElimination of the absorbed water in the soil

Removal of absorbed water by enzyme*

Role of Enzyme;

Catalyze the reaction between the clay and the organic cations and reduces the adsorbed layer thickness.

Replaces adsorbed water with organic cations, thus neutralizing the negative charge on a clay particle.

Promotes the development of cementatious compounds using the following, general reaction:

H2O + clay Enzyme Calcium Silicate Hydrates

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NEED FOR THE PRESENT INVESTIGATIONRecently developed technique.Can produce from locally available materialUnclear how these product will work and under what condition.To better understand their potential value for road construction.

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OBJECTIVESTo study the quantitative changes in geotechnical properties of soil with different dosage of enzyme.

To find out the optimum dosage of enzyme.

To evaluate the influence of curing period, on properties of soil*

MATERIALS USEDSoil sample obtained from Karamana river bankBio enzyme extracted from Neem

Bio EnzymeSoil sample*

LITERATURE REVIEW*

Andrew et al (2003) USAConducted laboratory experiment for effectiveness in sub grade.CBR value is a poor indicator of direct soil strengthIsaac et al (2003) IndiaConducted test on lateritic soil and clay type soil in KeralaSignificant increase in CBR ascuring period increasesManoj et al (2003)IndiaSix different types of soil with varying clay contentCBR and UCS increased considerably for soils with high clay contentRoger Bergmann(2000)USAPractical application for roadsMinimum 2% clay content is required for successful stabilisation

METHODOLOGYChemical analysis of bio-enzyme.Chemical analysis of Soil.Particle size analysis of soil.Atterberg limits of soil.Proctor compaction test for untreated soil.Proctor compaction test for soil treated with bio enzyme.CBR test for untreated soils in dry and soaked conditionsCBR test for soils treated with bio enzyme in soaked conditions and after curing period.

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Geotechnical Properties of soil;*TEST RESULTS

Sl. No.PropertyValue1Specific gravity2.612Particle size GravelNil Sand Coarse0.25 Medium2.90 Fine57.98 Silt38.87 ClayNil

Sl. No.PropertyValue Cu12.22 Cc3.64 IS ClassificationSM4Liquid limit32.05Max. Dry density, g/cc1.7086Opt. moisture content18.697CBR Unsoaked9.74 Soaked6.21

Particle size distribution curve;*TEST RESULTS Contd

ClaySiltSandFineMediumCoarse

Liquid limit curve;*TEST RESULTS Contd

Chemical composition;a. Soilb. Enzyme*TEST RESULTS Contd

Sl NoChemical ConstituentsPercentage1N1.742C3.843H10.814S0

LocationChemical ConstituentsSulphate(mg/100gm of soil)Chloride(mg/100gm of soil)Organic matterMankattu Kadavu(Top Layer)13203519Mankattu Kadavu (Bottom Layer)11003011

TEST RESULTSCompaction curve;* Contd

Variation of MDD;TEST RESULTS Contd*

Variation of OMC;TEST RESULTS Contd*

Variation of MDD;TEST RESULTS Contd*

Variation of CBR (Soaked);TEST RESULTS Contd*

ANALYSIS OF RESULTS Untreated soil;

The soil contains 0.25% coarse, 2.90% medium, 57.98% Fine sand and 38.87% silt & clay. IS classification is SM (silty sand)

The liquid limit of the soil is 32.00%.

For light compaction test, the MDD and OMC are 1.708 gm/cc and 18.69% respectively.

CBR values for unsoaked and soaked condition for light compaction are 9.74% and 6.21%.

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Soil treated with enzyme;The seven different enzyme dosages are used to stabilize the soil for finding the optimum dosage. Effect on Light Compaction;There is no significant variation in MDD for dosage up to 0.70% and further increase in dosage, MDD values are decreasing. Effect on CBR;CBR test is conducted with 19% Enzyme dosage for curing period of one and two weeks under soaked condition. Soaked CBR value after two weeks curing increased by 81% ANALYSIS OF RESULTS Contd*

CONCLUSIONMDD of the soil sample has been reduced considerably after increasing the dosage of bioenzyme. This may be due to the soil sample is being sandy soil are less reactive with enzyme.

Reasonable amount of clay content (min. 2%) is essential for better result.

The CBR value under soaked condition has increased by 81% on addition of enzyme and after a curing period of two weeks.

The recommendation of bioenzymes for field use has to be done only after conducting independent laboratory testing.*

REFERENCESAndrew, R.T., Fadi, M.S., Nicholos, E.H. and Elahe, M., (2003), An Evaluation of Strength change on Sub grade soils stabilized with an Enzyme Catalyst solution using CBR and SSG comparisons, Geomatrics, Inc. Columbia, Sc 29210, USA.Bergmann, R., (2000), Soil Stabilizers on Universally Accessible Trials, Federal Highway Administration, Unites States Department of Transportation.Brazetti, R. and Murphy, S.R., (2000), General usage of Bio-Enzyme stabilizers in Road Construction in Brazil, 32nd annual meeting on paving BrazilHitam, A. and Yusof, A., (1998), Soil stabilizers for plantation road, National seminar on Mechanisation in Oil Palm Plantation, Selangor, Malaysia.Isaac, K.P., Biju, P.B. and Veerararagavan, A., (2003), Soil stabilization using Bio-Enzyme for Rural Roads, Presented at the IRC Seminar: integrated Development of Rural an Arterial Road Networks for Socio- Economic development, New Delhi.Lacuoture, A. and Gonzalez, H., (1995), Usage of Organic Enzymes for the stabilization of Natural base soils and sub bases in Bagota, Pontificia Universidad Jevariana, Faculty of Engineering.

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7.Manoj Shukla, Sunil Bose and Sikdar, P.K., (2003), Bio-Enzyme for stabilization of soil in Road construction a cost effective approach, Presented at the IRC Seminar: Integrated Development of Rural and Arterial Road Networks for Socio-Economic development, New Delhi.8.Mohd Raihan Taha, Tanveer A Khan, Ibtehaj Taha Jawad, Ali Akbar Firoozi and Ali Asghar Foroozi,(2013), Recent Experimental Studies in Soil Stabilisation with Bio-Enzyme-A Review, Electronic Journal of Geotechnical Engineer-ing, Vol.18,Bund.R.,pp 3881-3894.9.Ravi Shankar, A.U., Harsha Kumar, Rai and Ramesha Mithanthaya, I.,(2009), Bio-enzyme stabilized lateritic soil as a highway material. Journal of Indian Road Congress, 553, pp 143-151.10.Shirsavkar,S.S. and Karanne,S.S.,(2010),Innovation in road construction using natural polymer, Electronic Journal of Geotechnical Engineer-ing, Vol.15,Bund.O.,pp 1614-1624.REFERENCES Contd*

THANK YOU

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