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
Mechanical stabilisation Chemical stabilisation Standard Non standard EnzymeStabilization, in a broad sense, incorporates the various methods employed for modifying the properties of a soil to improve its engineering performance.
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.
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
Absorbed water in the structure of soil
Elimination 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
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.
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
MATERIALS USED
Soil sample obtained from Karamana river bank Bio enzyme extracted from Neem
Bio Enzyme Soil sample
Andrew et al (2003)
USA Conducted laboratory experiment for effectiveness in sub grade.
CBR value is a poor indicator of direct soil strength
Isaac et al (2003)
India Conducted test on lateritic soil and clay type soil in Kerala
Significant increase in CBR as curing period increases
Manoj et al (2003)
India Six different types of soil with varying clay content
CBR and UCS increased considerably for soils with high clay content
Roger
Bergmann (2000)
USA Practical application for roads
Minimum 2% clay content is required for successful stabilisation
LITERATURE REVIEW
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.
Sl.
No. Property Value
1 Specific gravity 2.61 2 Particle size Gravel Nil Sand Coarse 0.25 Medium 2.90 Fine 57.98 Silt 38.87 Clay Nil Sl.
No. Property Value
Cu 12.22 Cc 3.64 IS Classification SM 4 Liquid limit 32.0 5 Max. Dry density, g/cc 1.708
6 Opt. moisture content 18.69 7 CBR
Unsoaked 9.74 Soaked 6.21
Geotechnical Properties of soil;
12
100 99.75 99.56 96.85 91.78 75.02 38.87 22.68 15.12 12.60 10.08 0 10 20 30 40 50 60 70 80 90 100 0.001 0.010 0.100 1.000 10.000 Per cent a g e finer % Particle size in mm
Clay Silt Sand
Fine Medium Coarse
Particle size distribution curve;
13
117 160 212 273 100 120 140 160 180 200 220 240 260 280 20 25 30 35 40 Pe n etr ation Water content in %
Liquid limit curve;
14
Chemical composition; a. Soil
Sl No Chemical Constituents Percentage
1 N 1.74 2 C 3.84 3 H 10.81 4 S 0 Location Chemical Constituents Sulphate (mg/100gm of soil) Chloride
(mg/100gm of soil) Organic matter Mankattu Kadavu (Top Layer) 1320 35 19 Mankattu Kadavu (Bottom Layer) 1100 30 11 b. Enzyme 15
1.45 1.50 1.55 1.60 1.65 1.70 1.75 12 14 16 18 20 22 24 26 28 30 Dry Density in gm/cc Water content in % 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
TEST RESULTS
Compaction curve; 16 … Contd1.708 1.717 1.705 1.701 1.40 1.45 1.50 1.55 1.60 1.65 1.70 1.75 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 Dry Dens ity in gm/ cc Enzyme in % 1.588 1.575 1.598 1.554 7.0 8.0 9.0 10.0 11.0 12.0 Enzyme in % Variation of MDD;
TEST RESULTS
… Contd18.69 18.79 19.22 19.8 15 16 17 18 19 20 21 22 23 24 25 0. 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 OM C in % Enzyme in % 22.5 22.32 22.87 22.34 7.0 8.0 9.0 10.0 11.0 12.0 Enzyme in % Variation of OMC;
TEST RESULTS
… Contd1.347 1.404 1.44 1.388 1.334 1.20 1.25 1.30 1.35 1.40 1.45 1.50 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 Dry Den sity in gm/c c Enzyme dosage in % Variation of MDD;
TEST RESULTS
… Contd6.21 10.00 11.25 1 2 3 4 5 6 7 8 9 10 11 12 0 1 2 CB R in % Period in weeks Variation of CBR (Soaked);
TEST RESULTS
… ContdANALYSIS 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%.
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
… ContdCONCLUSION
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.
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
Bio-Enzyme 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.
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,
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