Soil Mechanics - II

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Soil Mechanics - II

• Practical Portion

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Experiment No. 07

Determination of Relative Density of Soil
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Class Outlines

• Determination of Field Density
• Sand Replacement Method
• Determination of Lab Density
• Standard Proctor Compaction Test
• Modified Proctor Compaction Test

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Experiment No. 07(a)

Determination of Field Density of Soil Using
Sand Cone Method
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Designation

• ASTM D 1556-64 (1982)
• AASHTO T 191-93 (1996)

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Apparatus

• Sand-cone apparatus .
• Tray with hole
• Balance
• Stove or oven.
• Hand chisels for digging test hole
• Container for moisture samples (tin cans).
• Container for retaining excavated soil

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Apparatus
ASTM, AASHTO sand-cone apparatus BS sand
replacement apparatus
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Procedure

• Determine the volume of the bottle or cylinder
  and attachments including the volume of the
  valve.
• Determine the bulk density of the sand to be used
  in the field test
• Determine the weight of sand required to fill the
  funnel.
• Determine the density of soil in place

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Calculations

• Calculate the volume of the density apparatus as
  follows
• V1 G
• Where, V1 Volume of density apparatus, in
  cubic centimeters.
• G Grams of water required to fill the
  apparatus.
• Calculate the density of the sand as
  follows
• W Grams of sand required to fill the apparatus.
• V1 Volume of apparatus in cubic
  centimeters as determined in 1st step 
• Calculate the in-place density of the soil as
  follows

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Calculations

• Where,
• V Volume of test hole or volume of the
  excavated soil.
• W2 Weight of sand used to fill the test
  hole and funnel.
• W3 Weight of sand in funnel
• W1 Weight of soil excavated from the test
  hole
• Calculate the dry density of the soil in place as
  follows
• Dry density of soil
• Where, m is the moisture content determined
  as follows from the sample taken at step (4-g.).
  

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Experiment No. 07(b)

Determination of Lab Density of Soil Using
Standard Proctor Compaction Test
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Designation

• ASTM D 698-70
• AASHTO T 99-97

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Apparatus

• Mold with detachable collar and detachable base
  plate .
• Rammer with a mass of 2.5-kg. (5.5lb)
• Weighing Balance
• Drying oven .
• Straightedge for trimming the soil
• Sieve No. 4 (4.75-mm.)
• Containers for moisture content determination

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Apparatus
Compaction mold and hammers
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Procedure

• Take 3-kg. soil passing 4.75-mm. (No.4) sieve .
• Thoroughly mix the selected sample with
  sufficient water to dampen it to approximately
  4-percent below the expected optimum moisture
  content .
• Compact the soil in the mold with collar
  attached, in three approximately equal layers to
  give a total compacted depth of 125-mm. (5-in) .
• Following compaction of each of the first two
  layers, any soil adjacent to the mold walls that
  has not been compacted or extends above the
  compacted surface shall be trimmed and be evenly
  distributed on top of the layer

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Procedure

• Compact each layer by 25 uniformly distributed
  blows of the rammer dropping free from a height
  of 305-mm. (12-in.) above the level of the soil .
• After compaction, remove the collar, trim the
  compacted soil even with the top of the mold, and
  determine the weight of mold and soil in
  kilograms or pounds .
• For weight recorded in kilograms, multiply the
  weight of the compacted specimen and the mold,
  minus the weight of the mold, by 1060, and record
  the result as the wet density of the compacted
  soil, ?b in kilograms per cubic meter .

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Procedure

• For weight recorded in pounds, multiply the
  weight of the compacted specimen and the mold,
  minus the weight of the mold, by 30, and record
  the result as wet density of the compacted soil,
  ?b, in pounds per cubic foot .
• Remove the material from the mold and take a
  representative sample to find the moisture
  content
• Thoroughly break the molded specimen and add to
  remaining portion of the test sample .
• Add water to increase the moisture content of the
  soil by one to two percent and repeat the above
  procedure for each increment of water added

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Procedure

• Continue this series of determinations until
  there is either a decrease or no change in the
  wet density of compacted soil .
• If the soil particles are fragile and grain size
  will be reduced by repeated compaction, separate
  and new sample shall be used in each test
  repetition
• Calculate the moisture content and the dry
  density of the compacted soil for each trial, and
  determine the Moisture-Density Relationship as
  follows .

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Moisture-Density Relationship

• The dry densities of the soil shall be plotted as
  ordinates and the corresponding moisture content
  as abscissas .

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Procedure

• Optimum Moisture Content
• The moisture content corresponding to the peak
  of the moisture-density curve is termed the
  Optimum Moisture Content of the soil.
• Maximum Density
• The dry density of the soil at optimum
  moisture content is termed maximum density

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Observations Calculations
Observations for moisture content determination
Test data Test data Test repetitions Test repetitions Test repetitions Test repetitions Test repetitions Test repetitions
Test data Test data 1 2 3 4 5 6
Row -1 weight of can wet soil
Row -2 weight of can dry soil
Row -3 Wt. of water (row.1-row.2) (gm)
Row -4 weight of can, (gm)
Row -5 weight of dry soil, (gm) (row.2-row.4)
Row -6 Moisture content, m (row.3/row.5)
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Observations Calculations
Observations for determination of Density
Weight/Volume (kg/m3)
Test data Test data Test repetitions Test repetitions Test repetitions Test repetitions Test repetitions Test repetitions
Test data Test data 1 2 3 4 5 6
Row -1 Wt. of water added for each trial
Row -2 Moisture content, m
Row -3 weight of soil mold, (gm)
Row -4 weight of mold, (gm)
Row -5 weight of soil (gm) kg (row.3-row.4)
Row -6 Wet density (kg/m3) Row.51060
Row -7 Dry density (kg/m3)
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Graph


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Experiment No. 07(b)

Determination of Lab Density of Soil Using
Modified Proctor Compaction Test
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Designation

• ASTM D 1557-70
• AASHTO T 180-97

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Apparatus

• Mold with detachable collar and detachable base
  plate .
• Rammer 4.54-kg. (10-lb.)
• Weighing Balance
• Drying oven .
• Straightedge for trimming the soil
• Sieve No. 4 (4.75-mm.)
• Containers for moisture content determination

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Apparatus
Compaction mold and hammers
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Procedure

• All the steps are same as in Standard Proctor
  Compaction Test except
• Mould will be filled in five (5) equal layers
  instead of three(3).
• Weight of the Rammer used will be 4.54 kg (10lb)
  instead of 2.5kg (5.5lb).
• Height of drop of the Rammer will be 18-in
  instead of 12-in.