Job-2 Relative Density

Job No.
2
“Determination of maximum and
minimum void ratio of granular soils”
2.1 Objective:
Determination of maximum To determine the limiting void ratio and level of compaction
and minimum void ratio of of a non-cohesive soil.
granular soils.
2.2 Reference:
Objective • ASTM D 4254-Standard Test Method for minimum
Reference index Density and unit weight of soils.
Apparatus • ASTM D 4253-Standard Test Method for maximum
Related Theory index Density and unit weight of soils using vibratory table.
Limitations
Procedure 2.2 Apparatus:
Calculations and 1. Vibrating Table
Observation 2. Mold and assembly
Graphical 3. Surcharge base plate, weights and handle
Representation 4. Dial Gauge, Balance and Straight edge.
Comments
2.3 Related theory:
2.2.1 Relative density:
Relative density or density index is the ratio of the difference
between the void ratios of a cohesion less soil in its loosest
state and existing natural state to the difference between its
void ratio in the loosest and densest states
݁௠௔௫ − ݁௙
‫ܦ‬௥ =
݁௠௔௫ − ݁௠௜௡
2.2.2 Relative Compaction:

The dry density of a soil in situ divided by the maximum dry
density of the soil as established by the Proctor compaction
test or any other standard test.
ߛௗ௥௬
ܴ. ‫= ܥ‬
ߛௗ௠௔௫
2.2.3 Void ratio:
It is the ratio of volume of voids to that of soil solids.
௏ೡ
݁ =
௏ೞ
2.2.4 Granular Soil:

In natural condition of soil, the grains itself may be
rounded, spherical, sub-angular, angular, well rounded,
and other complex geometric characteristics. The
composition of soil is solid (mineralogy of grain, grain
size and grain distribution, shapes and others), water, and
air. The appearance of different composition of solid,
water, and air in soil influences soil properties such as
shear strength, permeability, and settlement. In seismic
condition, granular materials such as sand are considered
as susceptible material to liquefy wherever there are
tendencies of the materials to re-arrange and may result in
loss of shear strength.
2.2.5 Surcharge load:

Any normal load applied permanently over the surface of the soil to simulate the
field conditions is called surcharge load.
Standard mold Volume Surcharge weight

Smaller mold 0.1 ft3 ± 1.5% 25.9 kg
Larger mold 0.5 ft3 ± 1.5% 86.2 kg

2.2.7 Pouring Criteria’s:
For larger size:
1. Shovel Funnel with 1.5” 2.spout diameter
For smaller size:

1. Shovel 2. Scoop Funnel with 1” 3. Spout diameter
2.2.8 Frequency used for different time interval:

Time (minutes) Amplitude (mm) Frequency (Hz)
8 0.3 60
10 0.4 50 1
2.4 Procedure:
1. Fill the mold with the soil as loosely as possible by pouring the soil using a
scoop or funnel. Care should be taken to minimize the particle segregation.
2. Trim off the excess soil with the top by carefully trimming the soil surface
with the straight edge.
3. Place the surcharge base plate on the surface of the soil and twist it slightly
several times so that it is placed firmly and tightly in contact with the soil
surface.
4. Remove the surcharge case plate handle
5. Attach the mold to the vibrating table
6. Determine the initial dial gauge reading by inserting the dial gauge bolder
in each of the guide brackets with the dial gauge stem in the contact with
the rim of the mold.
7. Vibrating the mold assembly and specimen for 8 minutes,
8. Determine the final gauge reading.
9. Remove the surcharge plate from the mold and determine the weight og
the sample in mold.
10. Measure the dimensions of the mold and calculate the volume.
Figure: 2.1 Compaction is being done on soil sample
2
Figure: 2.2 Vibrating Rable, Surcharge Base Plate and Dial indicator.
2.5 Observation and Calculations:

1. Diameter of mold = d = 6” = ______ cm
2. Height of mold = H = 6” = ______ cm
3. Volume of mold = V1 = _______ cm3
4. Specific Gravity = _____
Table 2.1 Calculation of maximum and minimum void ratios
Sample Difference H’ = Volume Weight Minimum Maximum Maximum Minimum
No. Change in H-ΔH (V2) of index index void ratio void ratio
ΔH (cm) (cm) cm3 Sample density density (emax) (emin)
(Ws) (ࢽࢊ࢓࢏࢔ ) ሺࢽࢊ࢓ࢇ࢞ ሻ
gms g/cm3 g/cm3
1
2
3
4
5
6
2.6 Data Analysis:
Mean of void ratio (max): 3
Emax(Mean) = 0.801
Mean of void ratio (min):
Emax(Mean) =
Serial
No. 1 2 3 4 5 6
emax
emin
emaxErr
eminErr
Table 2.2 Void Ratio Deviation evaluation
As from the above error evaluation, it is clearly shown that the columns (1,2, 3,
and 6) are deviating from the mean void ratios (emin and emax) by more than 5%
error. So we will discard these readings.
Now in order to calculate the Relative densities we will use the values of emax and
emin from column 4 and 5.
As given below:
2.6.1 Relative densities For emax = 0.787 and emin = 0.5:

Void Ratio (e) 0.787 0.748 0.700 0.652 0.604 0.556 0.508 0.5
Relative Density
(Dr)
Relative Density
(Dr) %
Table 2.3 Relative densities
2.6.2 Relative densities For emax = 0.768 and emin = 0.48:

Void Ratio (e) 0.768 0.728 0.68 0.632 0.584 0.536 0.488 0.48
Relative Density
(Dr)
Relative Density
(Dr) %
Table 2.4 Relative densities
Comments:
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4
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Job No.

2.2.2 Relative Compaction:

2.2.4 Granular Soil:

2.2.5 Surcharge load:

Standard mold Volume Surcharge weight

Larger mold 0.5 ft3 ± 1.5% 86.2 kg

For smaller size:

2.2.8 Frequency used for different time interval:

Figure: 2.1 Compaction is being done on soil sample

2.5 Observation and Calculations:

2.6.1 Relative densities For emax = 0.787 and emin = 0.5:

2.6.2 Relative densities For emax = 0.768 and emin = 0.48:

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