APPARATUS
1. Proctor mould having a capacity of 944 cc with an internal diameter of
10.2 cm and a height of11.6cm. The mould shall have a detachable collar
assembly and a detachable base plate.
2. Rammer: A mechanical operated metal rammer having a 5.08 cm diameter face
and a weight of 2.5kg. The rammer shall be equipped with a suitable
arrangement to control the height of drop to a free fall of 30 cm.
3. Sample extruder.
4. A balance of 15 kg capacity.
5. Sensitive balance.
6. Straight edge.
7. Graduated cylinder.
8. Mixing tools such as mixing pan, spoon, towel, spatula etc.
9. Moisture tins.
PROCEDURE
1. Take a representative
oven-dried sample, approximately 5 kg in the given pan. Thoroughly mix the sample
with sufficient water to dampen it to approximately four to six percentage points
below optimum moisture content
2. Weigh the proctor mould without base plate and collar. Fix the collar and
base plate. Place the soil in the Proctor mould and compact it in 3 layers
giving 25 blows per layer with the 2.5 kg rammer falling through.
3. Remove the collar, trim the compacted soil even with the top of the mould by
means of the straight edge and weigh.
4. Divide the weight of the compacted specimen by 944
cc and record the result as the wet weight γ wet in grams per cubic centimeter
of the compacted soil.
5. Remove the sample from the mould and slice vertically through and obtain a
small sample for moisture determination.
6. Thoroughly break up the remainder of the material until it will pass a no.4
sieve as judged by the eye. Add water in sufficient amounts to increase the
moisture content of the soil sample by one or two percentage points and repeat
the above procedure for each increment of water added.
7. Continue this series of determination until
there is either a decrease or no change in the wet unit weight of the compacted
soil.
CALCULATION
Wet density gm/cc =weight of compacted soil / 944.
Dry density = wet density/(1+w)
Where w is the moisture content of the soil.
Plot the dry density against moisture content and find out the maximum dry
density and optimum moisture for the soil.
OBSERVATIONS
|
Density |
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Determination No |
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Water to be added (percent) |
|
|
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Weight of water to be added (gm) |
|
|
|
Weight of cylinder + compacted soil |
|
|
|
Weight of compacted soil (gms) |
|
|
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Average moisture content |
|
|
|
Wet density (gm /cc) |
|
|
|
Dry density (gm/cc) |
|
|
|
Water content |
|
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Container No. |
|
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Wt. Of container + wet soil gms. |
|
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Wt. Of container + dry soil gms |
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Wt of container alone gms. |
|
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Wt. Of water gm |
|
|
|
Wt. Of dry soil gms. |
|
|
|
Percentage of water Content |
|
|
RESULT
1.
Maximum dry density=____________
2. Optimum moisture content =_________
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