Experimental Study of Expansive Soil Stabilized with Terrazyme

Experimental Study of Expansive Soil Stabilized with Terrazyme

M. Baby

P.G. Student,

Department of Structural Engineering, SRG Engineering College,

Nammakal.

Abstract – In this experimental study, a step is taken to stabilize the black cotton soil for the construction of roads and buildings. A bio-enzyme called Terrazyme is used to stabilize the expansive soil. In this study, black cotton soil stabilized with Terrazyme of different dosages of 200ml/3m3, 200ml/2.5m3 and 200ml/2m3 are tested after the curing period of 0 days, 14 days and 28 days.

Keywords Terrazyme; Bio-Enzyme; Black Cotton Soil;

1. INTRODUCTION

   Black cotton soil mostly present in the districts of Tamil nadu like Salem, Ramanathapuram, Coimbatore etc. Black co f

   1. Gowshik, A. V. Karthick Rajeshwar

      M. Mohanasundram4

      U.G Student, Department of Civil Engineering, Chennai Institute of Technology,

      Chennai.

      7	Optimum moisture content %	22.80
      8	CBR Value %
      	Soaked	1.20
      	Un soaked	2.88
      9	Swelling Pressure	124
      10	Uniform confined strength	3.57
      11	Coefficient of permeability	1.6 * 10-8cm/sec

   2. Bio-enzyme

   The enzyme used for this experiment to stabilize the black cotton soil was Terrazyme.

   tton soil is good for agriculture because it is highly ertile.

   But it is not suitable for the construction of roads and foundation due to its instability. Black cotton soil is highly potential for shrinkage and swelling. Hence it is called as expansive soil. Even 5 cm rain can damage the roads and make unpassable.So it is necessary to stabilize the black cotton soil. When the expansive soil is up to a limit or small depth, the soil can be stabilized by replacing the soil with non-expansive soil. But when the black cotton soil is up to a greater depth, then the replacement is impossible. The other method to stabilize the black cotton soil is mixing the soil with chemical stabilizer.in this study, Terrazyme, a bio-enzyme is used to stabilize the black cotton soil. Terrazyme is a commercially available enzyme which improves the stability of the soil.

2. MATERIALS

   1. Black cotton soil

      The black cotton soil which was used for this experiment was collected from sankari which is located in the district of Salem.

      S.No	Properties	Value
      1	Specific Gravity	2.67
      2	Atterbergs limits
      	Liquid limit %	60.2
      	Plastic limit %	32
      	Plasticity index	28.2
      	Shrinkage limit %	10.2
      3	Grain size distribution
      	Gravel %	0
      	Coarse sand %	8.57
      	Fine sand %	18.20
      	Silt and clay %	73.23
      4	IS classification	CH
      5	Free swell index %	72.00
      6	Max dry density	15

      S.No	Properties	Value
      1	Specific Gravity	2.67
      2	Atterbergs limits
      	Liquid limit %	60.2
      	Plastic limit %	32
      	Plasticity index	28.2
      	Shrinkage limit %	10.2
      3	Grain size distribution
      	Gravel %	0
      	Coarse sand %	8.57
      	Fine sand %	18.20
      	Silt and clay %	73.23
      4	IS classification	CH
      5	Free swell index %	72.00
      6	Max dry density	15

      Table 1 Properties Of Black Cotton Soil

      Table 2 Properties of Terrazyme

      Properties	Value
      Boiling Point	212°F
      Specific Gravity	1.05
      Solubility	100%
      Appearance	Brown liquid
      Odour	Non-obnoxious

      1. Amount of Terrazyme

         The amount of Terrazyme varies from 200ml/3.5m3 to 200ml/2m3

         For specimen 1

         200ml for 3.0 m3 of soil = 1.56 * 3.0 *1000

         = 4680 kg of soil For 1 kg = 0.051 ml of enzyme

         For specimen 2

         200ml for 2.5m3 of soil = 1.56 * 2.5 * 1000

         = 3900 kg of soil For 1 kg = 0.051 ml of enzyme

         For specimen 3

         200ml for 2.0 m3 of soil = 1.56 * 2.0 * 1000

         = 3120kg

         For 1 kg = 0.064 ml of enzyme

         Table 3 Amount of enzyme

         200ml/m3 of soil	ml/kg of soil
         3.0	0.042
         2.5	0.051
         2.0	0.064

         UNCONFINED COMPRESSION

         STRENGTH KN/M2

         200ml/m3 of soil	ml/kg of soil
         3.0	0.042
         2.5	0.051
         2.0	0.064

         UNCONFINED COMPRESSION

         STRENGTH KN/M2

         9

         8

         7

         6

         5

         4

         3

         2

         1

         0

         9

         8

         7

         6

         5

         4

         3

         2

         1

         0

3. EXPERIMENTAL RESULTS

   1. Results on stabilized black cotton soil

      1. Atterberg limits

         The experiment gives the results of consistency limit for various proportions of black cotton soil with Terrazyme.

         0 days

         0 days

         7 days

         7 days

         14 days 28 days

         14 days 28 days

         Dosage	Liquid limit	Plastic limit	Plasticity index
         Untreated	60.2	32	28.20
         200ml/3.0m3	59	31.50	27.50
         200ml/2.5m3	57.78	30.79	26.99
         200ml/2.0m3	56.53	30.09	26.44

         Dosage	Liquid limit	Plastic limit	Plasticity index
         Untreated	60.2	32	28.20
         200ml/3.0m3 /td>	59	31.50	27.50
         200ml/2.5m3	57.78	30.79	26.99
         200ml/2.0m3	56.53	30.09	26.44

         Table 4 consistency limits

         UNTREATED 200ML/3M3

         200ML/2.5M3 200ML/2M3

         UNTREATED 200ML/3M3

         200ML/2.5M3 200ML/2M3

      2. Standard proctor test

   For black cotton soil with different proportions of Terrazyme, standard proctor test was conducted and resulted below

   4. CBR test

   California Bearing Ratio test was conducted for different proportions of black cotton soil with Terrazyme. The mould is kept in water for 4 days and tested.

   Table 7 California bearing ratio

   Dosage	0 day	7 days	14 days	28 days
   Untreated	1.20
   200ml/3.0m3	1.21	1.33	2.42	5.23
   200ml/2.5m3	1.23	1.68	2.60	5.42
   200ml/2.0m3	1.25	1.95	2.92	5.67

   Dosage	0 day	7 days	14 days	28 days
   Untreated	1.20
   200ml/3.0m3	1.21	1.33	2.42	5.23
   200ml/2.5m3	1.23	1.68	2.60	5.42
   200ml/2.0m3	1.25	1.95	2.92	5.67

   Table 5 standard proctor test

   Dosage	Optimum moisture content %	Maximum dry density (g/cm3)
   Untreated	22.80	1.5
   200ml/3.0m3	22.20	1.542
   200ml/2.5m3	21.90	1.586
   200ml/2.0m3	21.80	1.612

   3. Unconfined compression test

   Unconfined compression strength of black cotton soil with Terrazyme was evaluated as follows

   Table 6 unconfined compression strength

   Dosage	0 days	7 days	14 days	28 days
   Untreated	3.57	3.82	4.07	4.69
   200ml/3.0m3	4.04	5.15	5.80	6.98
   200ml/2.5m3	4.68	5.58	6.40	7.90
   200ml/2.0m3	5.28	6.49	7.09	8.72

   0

   0

   0 days

   7 days

   14 days

   28 days

   0 days

   7 days

   14 days

   28 days

   untreated 200ml/3m3 200ml/2.5m3 200ml/2m3

   untreated 200ml/3m3 200ml/2.5m3 200ml/2m3

   5. Swelling pressure

   Swelling pressure test was conducted using consistometer and resulted and tabulated below.

   Table 8 Swelling pressure

4. CONCLUSION

   CBR %

   CBR %

   6

   6

   5

   5

   4

   4

   3

   3

   2

   2

   1

   1

   SWELLING PRESSURE KN/M2

   140

   120

   100

   80

   60

   40

   20

   0

   SWELLING PRESSURE

   0 days 7 days 14 days 28 days

   SWELLING PRESSURE KN/M2

   140

   120

   100

   80

   60

   40

   20

   0

   SWELLING PRESSURE

   0 days 7 days 14 days 28 days

   • It is found that the value of liquid limit decreases from60.2% to 56.53% and the plastic limit also decreases from 32% to 30.09%

   • The UCS value increases from 3.57% to 8.72% when compared to actual soil with 4 weeks of curing.

   • It is founded that the CBR value increases from 1.20

     % to 5.67 %.

   • This experiment shows that the Swelling pressure reduces from 124 KN/m2 to 85.2 %

   • Maximum dry density increases from 1.5 g/cm3 to 1.612 g/cm3.

   • Optimum moisture content decreases from 22.80% to 21.80%

   • Hence the clayey property of expansive soil is changed.

   Dosage	Swelling pressure
   Untreated	124
   200ml/3.0m3	120
   200ml/2.5m3	108
   200ml/2.0m3	85.2

   Dosage	Swelling pressure
   Untreated	124
   200ml/3.0m3	120
   200ml/2.5m3	108
   200ml/2.0m3	85.2

   REFERENCES

   1. Faizal ali, Stabilization Of Residual Soil Using Liquid Chemical (2012), Civil Engineering Department, Faculty Of Engineering, national Defence Ministry Of Malaysia, Kuala Lumpur Malaysia.

   2. Brazetti.R and Murphy.S.R (2000), General Usage Of Bio-Enzyme Stabilizers In Road Construction In Brazil, 32nd annual meeting on paving Brazil, October 2000.

   3. Marasteanu.M.O, Hozalski.r, clync.t.r & velasquez.r,(2005),Preliminary Laboratory Investigation of Enzyme Solution as a soil stabilizer,minnesta department of transportation, research services.

   4. Das.B.M,Principles of Geo technical Engineering,5th Edition,California State University, Sacramento

   5. Das.B.M,Advanced Soil Mechanics, New York: taylor and francis, pp.123-178.

   6. Brooks (2009),Effect Of Swelling On Black Cotton Soil By Stabilizing Rice Husk Fly Ash

   7. Joydeep Sen & Jitendra Prasad Singh, Stabilization Of Black Cotton Soil Using Bio-Enzyme For A Highway Material.

   8. Bajpai.P,(2014),Non-Conventional Soil Stabilization Techniques The Way Forward To An Aggregate Free Pavement And A Cost Effective Method Of Road Construction,International Journal Of Scientific And Engineering Research.