Grameen Sampark Final April 0... - pmgsy

EXPERIMENTAL WORK
Materials Used
The soil used in the study was collected from 10 km
distance from Jalna. The soil used was black cotton soil.
Table 1 shows geotechnical properties of soils collected
for experimentation. Polypropylene fibres of average
diameter 0.25 mm with aspect ratios of 20, 40 and 80
were used.
Sample Preparation
Fibre reinforced soil samples were prepared at
maximum dry density and optimum moisture content
obtained by conducting standard Proctor test on unreinforced
soil and reinforced soil. The fibre reinforced
specimens were prepared by hand mixing the dry soil,
water and polypropylene fibres. The percentage of fibre
used in samples was 1, 2, and 3 percent by dry weight of
soil. The water was added prior to fibre to prevent
floating problems. fibre reinforced soil samples were
prepared at the maximum dry density and the optimum
Table1: Geotechnical properties of soil
Pradhan Mantri Gram Sadak Yojana
moisture content obtained from standard proctor tests
on reinforced soil. Un-drained direct shear tests were
conducted on reinforced samples with varying
percentages of fibres and aspect ratio. California
bearing ratio (C.B.R) tests were conducted under soaked
conditions. Unconfined compression strength tests
were conducted on cylindrical specimen at Proctors
maximum dry density and optimum moisture content.
Specific Liquid Plastic Plasticity Maximum Dry Cohesion Angle of Internal
Gravity Limit % Limit % Index %
3
Density (gm/cm )
2
(kN/m ) Friction (Degrees)
2.49 56 27 29 1.53 34 16
RESULTS AND DISCUSSION
The influence of aspect ratio and fibre concentration on
the properties of soil were studied. The OMC and dry
density test results on black cotton soil with different
aspect ratio and fibre content are reported in Table 2.
These data indicate that maximum dry density
decreases gradually with increase in the fibre content,
which is due to lower density of the fibre than the soil
particles. An increase in Optimum moisture content
was observed due to adsorption of water particles on the
surface of polypropylene fibres.
Table 2: Proctor's test results for un-reinforced and reinforced soil
Sr. No. Description Aspect Ratio % O.M.C MDD (gm/cm3)
1. Soil without reinforcement - 24.6 1.53
2. Soil with 1 % Polypropylene fibres 20 24.7 1.52
3. Soil with 2 % Polypropylene fibres 20 24.9 1.51
4. Soil with 3 % Polypropylene fibres 20 25.1 1.50
5. Soil with 1 % Polypropylene fibres 40 24.8 1.52
6. Soil with 2 % Polypropylene fibres 40 25.0 1.50
7. Soil with 3% Polypropylene fibres 40 25.3 1.48
8. Soil with 1 % Polypropylene fibres 80 24.9 1.50
9. Soil with 2 % Polypropylene fibres 80 25.2 1.47
10. Soil with 3% Polypropylene fibres 80 25.4 1.44
Grameen Sampark 23