2. INTRODUCTION
SOIL STABILIZATION
METHODS OF SOIL STABILIZATION
BIO-ENZYME
ADVANTAGES OF BIO-ENZYME
TERRAZYME- A CLASSICAL EXAMPLE OF BIO-ENZYME
SELECTION OF BIO-ENZYME
MECHANISM OF SOIL STABILIZATION
NET EFFECT OF ENZYME
ENZYME DOSSAGE
CASE STUDY
SUCCESS STORY
CONCLUSION
REFERENCES 2
3. There are various methods that could be used to improve
the performance of poor quality soils. Commonly used
materials are fast depleting and this has led to an increase in
the cost of construction.
There is an urgent need to identify new materials to
improve the road structure and to expand the road
networks.
3
4. Contd..
This led to the development of soil stabilization techniques.
In order to stabilize soils for improving strength and
durability, a number of chemical additives, both inorganic
and organic, have also been used.
Bio-enzymes have emerged as a new chemical for soil
stabilization which are used to improve the stability of soil
sub base of pavement structures.
4
5. SOIL STABILIZATION
Soil Stabilization is the process of permanent physical and
chemical alteration of soils to enhance their physical
properties.
Improves the strength and durability of soil.
Increase the shear strength of soil.
It can be utilized on roadways, parking areas, site
development projects, airports and many other situations
where sub-soils are not suitable for construction.
5
6. METHODS OF SOIL STABILIZATION
Mechanical stabilization: -
Process of blending of available soil with
imported soil or aggregate so as to obtain a desired
particle size distribution thereby increasing the stability of
soil. It is also known as granular stabilization.
Chemical stabilization: -
Using chemicals in the soil by mixing or
injecting addictives.
6
7. Standard stabilizers Lime, cement, sodium silicate,
and calcium chloride, bituminous and resinous materials
Non-standard stabilizers Sulfonated oils,
ammonium chloride, enzymes and acrylic polymers.
7
8. A natural, non-toxic, non-flammable, non-corrosive liquid
enzyme formulation fermented from vegetable extracts.
It is easy to use as it can be mixed with water at optimum
moisture content and then it is sprayed over soil and
compacted
It is used to increase the Maximum Dry Density (MDD)
and Unconfined Compressive Strength (UCS).
8
9. E.g. of Bio-enzyme: -
• Terrazyme
• Endurazyme
• Earthzyme
• Permeazyme
9
10. Advantages of Bio-enzyme Stabilization
Increases the engineering properties of soil and facilitates
higher soil compaction.
Higher performance and extended life span.
Increases the California bearing ratio of soil.
Requires simple methods such as spraying for applying it
into the soil.
10
11. Contd…
Decreases the swelling capacity of soil and reduces
permeability.
Free from dust particles when compared to other chemical
stabilization methods with lime, cement, fly ash, etc.
Fuel consumption of vehicles will be reduced because of
the improved traffic flow on these roads.
Suitable for road in all weather seasons.
11
13. Terrazyme is non-toxic, non-corrosive, non-flammable
natural material which is formulated from vegetable
extract.
It is brown in color with smell of molasses.
It contains no bacteria nor known allergens.
They are produced in the United States by Nature Plus,
Inc. and are available worldwide through local
distributors such as Avijeet Agencies, Chennai, India.
13
14. Properties of Terrazyme:-
Perfectly soluble in water.
pH ranges from 4.30 to 4.60.
Boiling point: 212ºF.
Appears as brown clear liquid.
Specific gravity is same as water.
Provides better strength, performance and higher
resistance towards deformation
14
15. Selection of Bio-Enzyme
The various factors that depends on the selection of bio-
enzyme are
Availability of stabilizer.
Cost of stabilizer.
Long term effect on strength etc
15
16. Mechanism of Soil Stabilization
FIGURE: -2 Absorption of water
(Source: - Anjali Gupta, A review on stabilization of soil using bio-
enzyme, April 2017)
16
17. Contd..
Soil particle is surrounded by a negatively charged layer
making the particle prone to combine with positive charge
in order to neutralize.
The adsorbed water or double layer gives soil particles
their plasticity.
Spraying of terrazyme catalyses reaction between organic
cat-ions and soil .
Reaction thus accelerates cat- ion exchange process.
17
18. Net Effect of Enzyme
Film of adsorbed water is greatly reduced.
Voids in the soil particles get reduced and acquire a
tendency to get compacted more tightly.
As a result of cat-ionic exchange, swelling capacity and
permeability of the soil get reduced.
Soil become more workable and less sensitive to
moisture.
18
19. ENZYME DOSAGE
Insufficient quantity of terrazyme may lead to less
stabilization of soil.
On the other hand, excess quantity may result in
ineffective and uneconomical stabilization.
For best results, optimum terrazyme quantity to be added
is determined
The optimum enzyme dosage is obtained from
consistency limits, CBR ,UCS and permeability test.
Expressed in terms of ml per m3 of soil.
19
20. Contd..
Dosage Amount of dosage
per 200/ m³ of soil
Amount required
(ml)/kg of soil
1 3.5 0.029
2 3.0 0.0338
3 2.5 0.0406
4 2.0 0.050
TABLE: -1 ENZYME DOSAGE
20
21. CASE STUDY
OBJECTIVES:-
To determine engineering properties and strength
characteristics of lateritic soil and blended lateritic soil
with and without stabilization with bio-enzyme.
To determine various strength parameters such as
unconfined compressive strength and CBR with and
without stabilization for certain curing period.
To study the performance of road constructed using
stabilized soil.
21
22. Tests Conducted :-
1. Lateritic soil
22
Sl. No. Property Value
1 Specific gravity 2.45
2 GRAIN SIZE DISTRIBUTION
Gravel (%)
Sand (%)
Silt (%)
Clay (%)
Co-efficient of Uniformity, Cu
Co-efficient of Curvature, Cc
19
50
29
2
115.4
0.74
3 CONSISTANCY LIMITS
Liquid limit (%)
Plastic limit (%)
Plasticity index (%)
Shrinkage limit (%)
35
25
10
16.6
23. 4 IS Soil Classification SM-GM
5 ENGINEERING PROPERTIES
IS Light compaction
(a) Max. Dry Density, kN/m3
(b) OMC (%)
IS Heavy Compaction
(a) Max. Dry Density, kN/m3
(b) OMC (%)
19.32
13.50
19.95
11.40
6 CBR (%)
IS Light Compaction
(a) at OMC
(b) Soaked
IS Heavy Compaction
(a) at OMC
(b) Soaked
10
04
14
08 23
24. 7 UCC
(a) IS Light Compaction (kPa)
(b) IS Heavy Compaction (kPa)
108
142
8 CO-EFFICIENT OF PERMEABILITY
(a) IS Light Compaction (m/s)
(b) IS Heavy Compaction (m/s)
4.78×10-8
2.87×10-8
TABLE: - 2 Properties of lateritic soil
24
25. Effect of enzyme on consistency limit of soil:-
LL and PI of soil mixed with variable dosage of
terrazyme are tested after 1,2,3 and 4 weeks of curing.
The results are obtained from table 3.
Little improvement in consistency limits by treating soil
with enzyme.
25
27. Effect of Enzyme on CBR of Soil
Soil was treated with 4 dosages of enzyme at OMC on
7,14,21 and 28 days of curing.
CBR values of soil treated with different enzymes
dosages in various curing days are given in table 4.
Dosage 4 improves CBR to a higher range.
27
29. Effect of Enzyme on UCS of Soil
UCS of soil was evaluated by stabilization with variable
enzyme dosage for 1,2,3 and 4 weeks. The results are
Dosage Treated Weeks
1st 2nd 3rd 4th
UCS of soil in (kPa) for period of treatment
Untreated 142
1
2
3
4
205
262
330
428
272
324
434
513
343
398
532
607
447
513
716
782
TABLE: - 5 UCS of soil treated with enzyme
29
30. Effect of Enzyme on Permeability of soil
Tests were conducted on a soil treated with enzyme at
OMC on 7,14,21 and 28 days of curing. The results are
shown in table 6.
Effect of enzyme on permeability characteristics of soil is
found to be marginal.
Dosage Treated Weeks
1st 2nd 3rd 4th
Co-efficient of permeability (K) m/sec (x10-8)
1
2
3
4
2.87
2.63
1.91
1.91
2.87
2.39
1.91
1.67
2.63
2.39
1.91
1.67
2.63
2.39
1.67
1.67
TABLE: - 6 Co-efficient of permeability of soil treated with Enzyme 30
31. 2. Blended Soil (Lateritic soil- sand )
Sand passing through 4.75mm sieve and retained on 425µ
is collected and its properties are found out which is
given in Table 7.
Description Test value
Specific gravity 2.64
Fineness modulus 2.18
Loose density (kN/m3) 14.13
Vibrated dense density (kN/m3) 17.13
Grain size analysis
Gravel (%)
Sand (%)
Silt (%)
Clay (%)
2
98
Trace
0
TABLE: - 7 Properties of blended soil
31
32. Consistency limit test were conducted on blended soil with
different percentages of sand which is shown in Table 8.
Lateritic
soil (%)
Sand
(%)
Liquid
limit (%)
Plastic
limit (%)
Plasticity
index (%)
100
90
80
70
60
0
10
20
30
40
35
31
28
25
22
25
23
21
20
19
10
8
7
5
3
TABLE: - 8 Consistency limit of blended soil
32
33. Compaction, CBR and permeability tests are then
conducted on blended soil with different percentages of
sand which is shown in Table 9.
Compaction, CBR and Permeability test results
Lateritic
soil (%)
Sand (%) OMC (%) MDD
(kN/m3)
CBR (%)
(soaked)
Co-efficient of
Permeability, K
(m/s)
100
90
80
70
60
50
40
0
10
20
30
40
50
60
11.4
11.0
10.7
10.4
9.98
10.2
11.0
19.95
20.35
20.61
20.80
21.39
21.10
20.60
8
10
14
18
22
20
14
2.87x10-8
5.75x10-8
10.5x10-8
18.4x10-8
26.8x10-8
57.4x10-8
89.6x10-8
TABLE: - 9 Compaction, permeability and CBR test of blended soil 33
34. Effect of Enzyme on CBR of Blended Soil
The CBR values of different percentage of blended soil
were studied by treated with enzyme dosage of 200 ml/2
m3 for one, two, three and four weeks of curing. The test
results have been tabulated in Table 10.
Soil blend
soil-sand (%)
Treated Weeks
1st 2nd 3rd 4th
CBR (%)
100-0
90-10
80-20
70-30
60-40
25
27
24
22
21
29
30
29
27
24
30
31
30
28
27
31
32
31
30
28
TABLE: - 10 CBR of Blended Soil treated with enzyme 34
35. RESULT
The lateritic soil properties have been improved by
adding sand.
The lateritic soil properties have been much improved by
stabilizing with enzyme dosage of 200ml/2m³.
For a higher dosage of 200 ml/ 2m³ of soil, CBR, UCS
and consistency limit reaches within the required limits.
Unconfined compressive strength of the soil increased by
450 and permeability decreases by 42 percent.
35
36. SUCCESS STORY
Field study was conducted by Prof. Hitam & Yusof of Palm
oil research Institute ,Malaysia (1998) in the plantation
roads.
27 kms of road was constructed with terrazyme treated
soil.
The section of the road was monitored for four monsoons.
No surface damage was observed
36
38. Roads Constructed Using Terrazyme
In India
FIGURE: - 4 Tamilnadu FIGURE: - 5 GOA
(Source: - www.google.com/terrazymestabilizedroads ) 38
39. CONCLUSION
Use of Bio-enzyme results in higher compressive strength
and increased hardness of stabilized soil.
It provides flexibility and durability to pavement.
It reduces the formation of cracks
The period of treatment of enzymatic soil plays an
important role in improvement of strength.
It is very economical compared to other stabilization
methods.
39
40. REFERENCES
1. IRC: SP: 20-2002, “Rural Roads Manual”, The Indian Roads
Congress, New Delhi.
2. 2. Dr. A.U. Ravi Shankar, Harsha Kumar Rai and Ramesha
Mithanthaya I. (2009), (2012) “Bio-enzyme Stabilized Lateritic
Soil as a Highway Material”, Journal of Indian Road Congress.
3. Puneet Agarwal, Suneet Kaur (2014) “Effect of Bio-Enzyme
Stabilization on Unconfined Compressive Strength of
Expansive Soil”, International Journal of Research in
Engineering and Technology (IJRET), May 2014.
4. Anjali Gupta, Vishal Saxena (2017) “Review Paper on Soil
Stabilization by Terrazyme”, International Journal of
Engineering Research and Application (IJERA), April 2017.
5. Sandeep Panchal, Md. Mohsin Khan (2017) “Stabilization of
Soil Using Bio-Enzyme", International Journal of Civil
Engineering and Technology (IJCIET), January 2017.
40
