soil stabilization using bioenzyme

SOIL STABILISATION USING BIO-ENZYME EXTRACTED FROM NEEM

Presented By

Ashokan K & Sreelekha B, M4, Geotechnical Engg, Dept of Civil Engineering.

Guided by

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

INTRODUCTION Stabilization, in a broad sense, incorporates the various methods employed for modifying the properties of a soil to improve its engineering performance.  Mechanical stabilisation  Chemical stabilisation  Standard  Non standard

 Enzyme

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STABILISATION USING ENZYME  Enzyme 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.

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MECHANISM OF SOIL STABILISATION BY ENZYME Clay 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

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Removal of absorbed water by enzyme

Absorbed water in the structure of soil

Elimination of the absorbed water in the soil

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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 INVESTIGATION  Recently developed technique.  Can produce from locally available material  Unclear how these product will work and under what condition.  To better understand their potential value for road construction.

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OBJECTIVES  To 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

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MATERIALS USED  Soil sample obtained from Karamana river bank  Bio enzyme extracted from Neem

Bio Enzyme

Soil sample 9

LITERATURE REVIEW Andrew et al USA Conducted laboratory CBR value is a poor indicator (2003) experiment for of direct soil strength effectiveness in sub grade. Isaac et al (2003)

India Conducted test on lateritic Significant increase in CBR as soil and clay type soil in curing period increases Kerala

Manoj et al (2003)

India Six different types of soil CBR and UCS increased with varying clay content considerably for soils with high clay content

Roger Bergmann (2000)

USA Practical roads

application

for Minimum 2% clay content is required for successful stabilisation

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METHODOLOGY  Chemical 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 conditions  CBR test for soils treated with bio enzyme in soaked conditions and after curing period.

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TEST RESULTS Geotechnical Properties of soil; Sl. No.

Property

1

Specific gravity

2

Particle size Gravel

Value

Sl. No.

2.61 Nil

Sand

Property

Value

Cu

12.22

Cc

3.64

IS Classification

SM

4

Liquid limit

32.0

Coarse

0.25

5

Max. Dry density, g/cc

1.708

Medium

2.90

6

Opt. moisture content

18.69

Fine

57.98

7

CBR

Silt

38.87

Clay

Nil

Unsoaked

9.74

Soaked

6.21

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TEST RESULTS

… Contd

Particle size distribution curve; Sand Clay

Silt

Percentage finer %

Fine

100 90 80 70 60 50 40 30 20 10 0 0.001

Medium

96.85 91.78

99.56

Coarse

100

99.75

75.02

38.87 22.68 12.60 10.08 15.12

0.010

0.100 Particle size in mm

1.000

10.000

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TEST RESULTS

… Contd

Penetration

Liquid limit curve; 280 260 240 220 200 180 160 140 120 100

273

212

160

117

20

25

30 Water content in %

35

40

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TEST RESULTS

… Contd

Chemical composition; a. Soil Chemical Constituents Sulphate Chloride Organic matter (mg/100gm of soil) (mg/100gm of soil)

Location Mankattu Kadavu (Top Layer) Mankattu Kadavu (Bottom Layer)

1320

35

19

1100

30

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b. Enzyme Sl No Chemical Constituents

1 2 3 4

N C H S

Percentage

1.74 3.84 10.81 0

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TEST RESULTS

… Contd

Compaction curve;

Dry Density in gm/cc

1.75 1.70

Untreated soil Soil+0.5% Enzyme Soil+0.6% Enzyme Soil+0.7% Enzyme Soil+8% Enzyme Soil+9% Enzyme Soil+10% Enzyme Soil+11% Enzyme

1.65 1.60 1.55 1.50 1.45

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14

16

18

20

22

24

26

28

30

Water content in %

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TEST RESULTS

… Contd

Variation of MDD; 1.708

1.717

1.705

1.70 1.701

1.65 1.588

1.60

1.598 1.575 1.554

1.55 1.50 1.45

Enzyme in %

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

1.40

0.0

Dry Density in gm/cc

1.75

7.0

8.0

9.0 10.0 11.0 Enzyme in %

12.0

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TEST RESULTS

… Contd

25 24 23 22 21 20 19 18 17 16 15

22.5

22.32

22.87 22.34

Enzyme in %

0.8

0.7

19.22 19.8

0.6

0.5

0.4

0.3

18.79

0.2

0.1

18.69

0.0

OMC in %

Variation of OMC;

7.0

8.0

9.0 10.0 Enzyme in %

11.0

18

12.0

TEST RESULTS

… Contd

Variation of MDD;

Dry Density in gm/cc

1.50 1.44

1.45 1.404 1.40

1.35 1.30

1.388 1.347 1.334

1.25

1.20 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 Enzyme dosage in %

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TEST RESULTS

… Contd

CBR in %

Variation of CBR (Soaked); 11.25

12 11 10 9 8 7 6 5 4 3 2 1

10.00

6.21

0

1 Period in weeks

2

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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%. 21

ANALYSIS OF RESULTS

… Contd

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% 22

CONCLUSION  MDD 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. 23

REFERENCES 1. Andrew, 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. 2. Bergmann, R., (2000), “Soil Stabilizers on Universally Accessible Trials”, Federal Highway Administration, Unites States Department of Transportation. 3. Brazetti, R. and Murphy, S.R., (2000), “General usage of Bio-Enzyme stabilizers in Road Construction in Brazil”, 32nd annual meeting on paving Brazil 4. Hitam, A. and Yusof, A., (1998), “Soil stabilizers for plantation road”, National seminar on Mechanisation in Oil Palm Plantation, Selangor, Malaysia. 5. Isaac, K.P., Biju, P.B. and Veerararagavan, A., (2003), “Soil stabilization using BioEnzyme for Rural Roads”, Presented at the IRC Seminar: integrated Development of Rural an Arterial Road Networks for Socio- Economic development, New Delhi. 6. 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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REFERENCES

… Contd

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 SocioEconomic 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), “Bioenzyme 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.

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