Soil Mechanics - II

Practical Portion

Experiment No. 07

Class Outlines

Determination of Field Density

Sand Replacement Method Determination of Lab Density

Standard Proctor Compaction Test

Modified Proctor Compaction Test

Experiment No. 07(a)

Designation

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

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

Apparatus

Excavated test hole

ASTM, AASHTO sand-cone apparatus BS sand replacement apparatus

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

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:

1V

Wsand

V

W

WWV

b

sand

1

32

CalculationsWhere,

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 funnelW1 = 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.).

100

1mb

d

100soildry of Mass

waterof Massm

Experiment No. 07(b)

Designation

ASTM: D 698-70 AASHTO: T 99-97

Apparatus Mold with detachable collar and detachable

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

determination

Apparatus

Compaction mold and hammers

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

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, γb in kilograms per cubic meter .

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, γb, 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

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 .

Moisture-Density Relationship The dry densities of the soil shall be plotted as

ordinates and the corresponding moisture content as abscissas .

mopt

Water content

γd max

Dry

de

nsity

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”

Observations & Calculations

Test data

Test repetitions

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)

Observations for moisture content determination

Observations & CalculationsObservations for determination of Density = Weight/Volume (kg/m3)

Test data

Test repetitions

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.5*1060

Row -7 Dry density (kg/m3)

GraphMoisture ~ Density Relationship

1500

1550

1600

1650

1700

1750

1800

5 10 15 20 25

Moisture Content

Dry

De

ns

ity

Experiment No. 07(b)

Designation

ASTM: D 1557-70 AASHTO: T 180-97

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

Apparatus

Compaction mold and hammers

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.