LAB EXPERIMENT #2 & 3: SIEVE & HYDROMETER ANALYSIS FOR SOIL GRAIN SIZE DISTRIBUTION

Sieve Data:
Sieve
Number
Sieve
Opening
Size (mm)
Mass of
Sieve (g)
Mass
Retained
(Sieve +
Soil)(g)
Mass Retained
(Sieve + Soil)(g)
Group 1 ,2 Groups 3, 4, 5
4 4.760 499.60 509.60 514.6
8 2.360 475.90 491.00 485.9
10 2.000 481.50 495.00 494
16 1.180 435.40 515.80 509.9
20 0.850 405.80 454.80 460.8
40 0.425 386.40 502.50 486.8
50 0.300 370.60 436.31 405.2
60 0.250 372.40 396.70 390.8
100 0.150 349.30 399.18 414.3
200 0.075 304.20 324.15 338.4
PAN 183.46 238.33 263.86
TOTAL
Lab #3- Hydrometer Analysis Data Sheet
Description of soil: _ Look at table below
Temperature.: _______20 degree Celsius___model 152H__

Location: ____Soils lab_____________
Date: ______09/22/2020____________________
Time
(t, min.)
Hydrometer Reading
(R)
Group #1 Group #2,4 Group #3, 5
Brown
Sandy clay
Clayey Silt Silt
0.25 51 51 No reading
0.5 50 50 48
1 49 49 47
2 48 47 42
4 47 45 37
8 46 44 33
15 45 43 30
30 44 41 26
60 43 39 23
120 41 37 No reading
240 39 34 No reading
480 37 31 18
1440 35 27 No reading
2880 No reading 24 No reading
GRAIN SIZE ANALYSIS OF SOILS
DEFINITION
Grain size analysis is the determination of the size grain
of particles present in a soil. It is expressed as a
percentage of the total dry weight. Two tests are
generally used to find particle size distribution of soil:
(1) Sieve analysis. (2) Hydrometer analysis.
INTRODUCTION
• The sieve analysis is generally applied to the soil fraction larger
than 75 µm (retaining on the No. 200 Sieve). Grains smaller than
75 µm (0.075 mm) are sorted by using sedimentation process
(hydrometer analysis).
The basic principles for sieve analysis and
hydrometer analysis are described in the following two
sections.
SECTION ONE
SIEVE ANALYSIS
DEFINITION
Sieve analysis consists of shaking the soil sample through a set of
sieves that have progressively smaller openings.
INTRODUCTION
• Fortunately, not all soils contain the full range of particle sizes so the test
can be simplified. Soils that are non-cohesive may only require dry sieving.
It is usually considered that the sedimentation procedure is not necessary
if the soil contains less than 10% fines.
• Soils may be divided on the basis of their dominating particle size six
arbitrary categories which are called boulders, cobbles, gravel, sand, silt
and
clay.
Sieve Designation
0.002 0.06 2 60mm
colloids fine medium coarse
CLAY SILT SAND GEAVEL COBBLES
Particle Size 1 5 75 425µm 2.00 4.75 75 mm
No.200 No.40 No.10 No.4
(a) U.S.A. ASTM: American Society for Testing and Material D422
Particle Size 2 6 20 60 200 600µm 2 6 20 60 200 mm
(b)BS 1377:1975 British Standard
PARTICLE SIZE DISTRIBUTION CURVE
• The particle size distribution curve, also known as a gradation
curve, represents the distribution of particles of different sizes in
the soil mass.
A coarse soil is described as:

  1. Well graded if there is no absence of particles in any size range
    and if no intermediate sizes are lacking. The smooth concave
    upward grading curve is typical of well-graded soil, which is
    shown by curve (1) in Fig (a).
  2. Poorly graded if:
    a. A high proportion of the particles have sizes with narrow limits (a
    uniform soil or narrowly graded soil) as shown by curve (2).
    b. Particles of both large and small sizes are present but with
    relatively low proportion of the particles of intermediate sizes
    (a gap-graded or step- graded soil) as shown by curve (3).
    • Soil particles have sizes ranging from greater than 200 mm down
    to less than 0.002 mm (2 µm).
    CLAY SILT SAND GEAVEL COBBLES BOULDERS
    fine medium coarse fine medium coarse fine medium coarse
    Figure (a)
    PURPOSES
    To determine the grain size distribution curve of a soil sample by
    which soil can be classified and their engineering properties assessed.
    APPARATUS
    The equipment used in sieve analysis includes:
  3. A series of standard sieves of square mesh, including cover plate and
    bottom pan. Two recommended sieve stacks (having successively smaller
    mesh sizes) are as shown in table (1):
    Table (1)
    Typical Sieve Stack Alternative Sieve Stack
    Sieve No. Opening, mm Sieve No. Opening, mm
    Lid Lid
    4 4.75 4 4.75
    10 2 10 2
    20 0.85 30 0.6
    40 0.425 50 0.3
    60 0.25 100 0.15
    140 0.106 200 0.075
    200 0.075 Pan
    Pan
  4. Sieve shaker.
  5. Balance sensitive to 0.1g.
  6. Mortar and pestle (or pulverizer for breaking up aggregations of soil
    particles).
    Curve 1
    Curve 3
    Curve 2
    percentfiner(%)
  7. Brush (for cleaning sieve).
  8. Oven.
    PREPARATION OF SOIL SAMPLE
    The aggregations or lumps of soil tested are thoroughly broken up
    with the mortar and pestle or (pulverizer).The specimen to be tested
    should be large enough to be representative of the soil in the field. It
    should also be small enough not to overload sieves. The size of
    representative specimen depends on the maximum particle size. Table
    (2) gives some guidelines for selecting the maximum sample weight.
    Table (2)
    Maximum Particle Size Minimum Weight of Sample (g)
    7.5 cm 6000
    5 cm 4000
    2.5 cm 2000
    1 cm 1000
    Finer than No. 4 sieve 200
    Finer than No. 10 sieve 100
    PROCEDURE
  9. Oven dry the sample, allow it to cool. Then take 500 g (depending on
    maximum particle size) of oven dried soil.
  10. Select a stack of sieves suitable to the soil being tested. Weigh each sieve
    and a pan to be used Wo (make sure each sieve is clean before weighing it,
    by using a brush to remove grains stuck in mesh openings).
  11. Arrange the stack of sieves so that the largest mesh opening is at the top
    and the smallest is at the bottom and attach the pan at the bottom of the
    sieve stack.
  12. Pour the dry sample on the top sieves. Add a cover plate (to avoid dust and
    lost particles while shaking).
  13. Place the stack of sieves in the mechanical shaker and shake for 10 min.
  14. Remove the stack of sieves from the shaker, and measure the weight of
    each sieve and the pan with the soil retained on them Wf.
  15. Subtract the weights obtained in step (2) from those of step (6) to give the
    weight of soil retained on each sieve. Their sum is compared to the initial
    sample weight; both weights should be within about 1%. If the difference is
    greater than 1%, too much material was lost, and weighing and/or sieving
    should be repeated /Wf – Wo/ > 1%.
    CALCULATION
    § % Retained on each sieve = Weight of soil retained *100

§ % Finer (passing) than any sieve size = 100 – Cumulative of %Retained
§ The gain-size distribution curve can be used to determine some of the basic
soil parameters such as the:

  1. Effective size (D10); is the diameter in the particle size distribution curve
    corresponding to 10% finer.
  2. Uniformity coefficient (Cu); is a measure of the slope of the curve. It is

defined as Cu

D60
D10
Where D 60 = diameter corresponding to 60% finer.
(D )
2

  1. Coefficient of gradation or concavity (Cc); is defined as Cc = 30
    D60 * D10
    Where D 30 = diameter through which 30% of the total soil mass is
    passing.
    § Find gravel, sand and (silt and clay) percentage according o ASTM.
    § Find coarse, medium and fine sand according to ASTM.
    DISCUSSION
    In addition of the general questions (from Report Writing) answer the following
    questions
  2. Which type of curve (Soil) is better to be used in filter design?
  3. When we use sieves with wide range opening?
  4. Under what conditions should you use wet sieving instead of dry sievin
    1
    SIEVE ANALYSIS DATA SHEET
    Name: …………………………………..
    Class: …………………
    Group No.: …………………
    Total sample mass =…………………
    (1)
    ASTM
    Sieve
    number
    (2)
    Sieve
    opening
    (mm)
    (3)
    Weight
    of sieve
    (g)
    (4)
    Weight of
    sieve + soil
    retained (g)
    (5)
    Weight of
    soil retained
    (g)
    (6)
    %Retained
    on each
    sieve (g)
    (7)
    Cumulative
    of
    %Retained
    (8)
    %Passing
    (finer)
    4 4.750
    10 2.000
    20 0.850
    30 0.600
    40 0.425
    100 0.150
    200 0.075
    Pan

Signature: ………………..
2
B. HYDROMETER
Introduction
Hydrometer analysis is a widely used method of obtaining an estimate of the distribution of soil particle sizes from
the No. 200 (0.075 mm) sieve to around 0.01 mm. The data are presented on a semilog plot of percent finer vs.
particle diameters and may be combined with the data from a sieve analysis of the material retained (+) on the
No.200 sieve. The principal value of the hydrometer analysis appears to be to obtain the clay fraction (generally
accepted as the percent finer than 0.002 mm). The hydrometer analysis may also have value in identifying particle
sizes < 0.02 mm in frost susceptibility checks for pavement subgrades. This test is done when more than 20% pass
through No.200 sieve and 90% or more passes the No. 4 (4.75 mm) sieve.
The hydrometer analysis is based on Stokes’ Law, which gives the relationship among the velocity of fall of spheres
in a fluid, the diameter of the sphere, the specific weights of the sphere and of the fluid, and the fluid viscosity. In
equation form this relationship is
2 (Gs – Gf )
v = —- * ———— * (D / 2)2
9 h
where,
v = velocity of fall of the spheres (cm/s)
Gs = specific gravity of the sphere
Gf = specific gravity of fluid (varies with temperature)
h = absolute, or dynamic, viscosity of the fluid (g /(cm * s))
D = diameter of the sphere (cm)
Solving the equation for D and using the specific gravity of water Gw, we obtain


D = Ö 18 h v / ( Gs – Gw)

v = L / t


A = Ö 18 h / ( Gs – Gw)


D = AÖ L (cm) / t (min)
where 0.002 mm < D < 0.2 mm
Equipment

  1. Hydrometer (152H model preferable)
  2. Quantity (about 2.5L per test) of distilled water
  3. Sedimentation cylinder (1000mL cylinder) also termed a hydrometer jar
  4. Graduated 1000 mL cylinder for control jar
  5. Soil-dispersion device (malt mixer or air-jet dispersion)
  6. Dispersion agent (NaPO3 or Na2 SiO3)
    3
  7. Hydrometer jar bath (optional, for temperature control)
  8. Thermometer
    Corrections to hydrometer readings
    • Zero Correction (Fz): If the zero reading in the hydrometer (in the control cylinder) is below the water
    meniscus, it is (+), if above it is (–), if at the meniscus it is zero.
    • Meniscus Correction (Fm): Difference between upper level of meniscus and water level of control cylinder.
    • Temperature correction (Ft): The temperature of the test should be 20°C but the actual temperature may vary.
    The temperature correction is approximated as
    Ft = -4.85 + 0.25 T (for T between 15°C to 28°C)
    Procedure
  9. Prepare the control jar by adding 125 ml of 4% sodium metaphosphate (NaPO3) solution and sufficient distilled
    water to produce 1000 ml. (This solution can be made by mixing 40g of dry chemical with enough water to
    make 1000 ml). Put the hydrometer into the control cylinder and record zero and meniscus correction; then
    record the temperature by putting the thermometer in it
  10. Weigh out exactly 50g of soil passing the No. 200 sieve. Mix the soil with 125 ml of 4% sodium
    metaphosphate (NaPO3) solution. Allow the soil mixture to stand about 12 hours.
  11. At the end of the soaking period, transfer the mixture to a dispersion (or malt mixer) cup and add tap water until
    the cup is about two-thirds full. Mix for 1 minute. After mixing, carefully transfer all the contents of the
    dispersion cup to the sedimentation cylinder. Rinse any soil in the dispersion cup by using a plastic squeeze
    bottle or adding stabilized water and pour this into the sedimentation cylinder. Now add distilled water to fill
    the cylinder to the 1000 ml mark.
  12. Cap the sedimentation cylinder with a No. 12 rubber stopper and carefully agitate for about 1 min. Agitation is
    defined as turning the cylinder upside down and back 60 turns for a period of 1 min. An upside down and back
    movement is 2 turns.
  13. Put the sedimentation cylinder beside the control cylinder and start the stopwatch immediately. This is
    cumulative time t = 0. Insert the hydrometer into the sedimentation cylinder.
  14. Take hydrometer readings at cumulative times t = 0.25 min., 0.5min., 1 min. and 2 min. Always read the upper
    level of meniscus. Remove and place the hydrometer in the control jar.
  15. Continue taking hydrometer and temperature readings at approximate elapsed times of 8, 15, 30 and 60 min.
    and then 2, 4, 8, 24 and 48 hr. For each reading, insert the hydrometer into the sedimentation cylinder about 30
    sec before reading is due. After the reading is taken, remove the hydrometer and put it back into the control
    cylinder.
    Calculation
    4
  16. Calculate corrected hydrometer reading for percent finer, RCP = R + Ft + Fz
  17. Calculate percent finer = (A * RCP * 100) / Ws
    where,
    Ws = dry weight of soil used for hydrometer analysis
    A = correction for specific gravity (as hydrometer is calibrated for Gs = 2.65 )
    therefore,
    A = 1.65 * Gs / ((Gs – 1 ) * 2.65 )
  18. Calculate corrected hydrometer reading for determination of effective length, RCL = R + Fm
  19. Determine L (effective length) corresponding to RCL given in Table 1.
  20. Determine A from Table 2

  1. Determine D (mm) = A Ö L (cm.) / t (min.)
    Table 1. Variation of L with Hydrometer Reading
    Hydrometer
    Reading
    L
    (cm)
    Hydrometer
    Reading
    L
    (cm)
    Hydrometer
    Reading
    L
    (cm)
    Hydrometer
    Reading
    L
    (cm)
    0
    1
    2
    3
    4
    5
    6
    7
    8
    9
    10
    11
    12
    16.3
    16.1
    16.0
    15.8
    15.6
    15.5
    15.3
    15.2
    15
    14.8
    14.7
    14.5
    14.3
    13
    14
    15
    16
    17
    18
    19
    20
    21
    22
    23
    24
    25
    14.2
    14
    13.8
    13.7
    13.5
    13.6
    13.2
    13
    12.9
    12.7
    12.5
    12.4
    12.2
    26
    27
    28
    29
    30
    31
    32
    33
    34
    35
    36
    37
    38
    12
    11.9
    11.7
    11.5
    11.4
    11.2
    11.1
    10.9
    10.7
    10.6
    10.4
    10.2
    10.1
    39
    40
    41
    42
    43
    44
    45
    46
    47
    48
    49
    50
    51
    9.9
    9.7
    9.6
    9.4
    9.2
    9.1
    8.9
    8.8
    8.6
    8.4
    8.3
    8.1
    7.9
    Table-2 Variation of A with Gs
    Temperature (°C)
    Gs 17 18 19 20 21 22 23
    2.5
    2.55
    2.6
    2.65
    2.7
    2.75
    2.8
    0.0149
    0.0146
    0.0144
    0.0142
    0.0140
    0.0138
    0.0136
    0.0147
    0.0144
    0.0142
    0.0140
    0.0138
    0.0136
    0.0134
    0.0145
    0.0143
    0.0140
    0.0138
    0.0136
    0.0136
    0.0134
    0.0143
    0.0141
    0.0139
    0.0137
    0.0134
    0.0133
    0.0131
    0.0141
    0.0139
    0.0137
    0.0135
    0.0133
    0.0131
    0.0129
    0.0140
    0.0137
    0.0135
    0.0133
    0.0131
    0.0129
    0.0128
    0.0138
    0.0136
    0.0134
    0.0132
    0.0130
    0.0128
    0.0126
    Temperature (°C)
    Gs 24 25 26 27 28 29 30
    2.5
    2.55
    2.6
    2.65
    0.0137
    0.0134
    0.0132
    0.0130
    0.0135
    0.0133
    0.0131
    0.0129
    0.0133
    0.0131
    0.0129
    0.0127
    0.0132
    0.0130
    0.0128
    0.0126
    0.0130
    0.0128
    0.0126
    0.0124
    0.0129
    0.0127
    0.0125
    0.0123
    0.0128
    0.0126
    0.0124
    0.0122
    5
    2.7
    2.75
    2.8
    0.0128
    0.0126
    0.0125
    0.0127
    0.0125
    0.0123
    0.0125
    0.0124
    0.0122
    0.0124
    0.0122
    0.0120
    0.0123
    0.0121
    0.0119
    0.0121
    0.0120
    0.0118
    0.0120
    0.0118
    0.0117
    Combined Analysis
  2. Calculate the percent passing the No. 200 sieve. (This should be equal to the percent finer for the soil retained
    on No. 200 sieve from the Sieve Analysis)
  3. The modified percent finer = percent finer for hydrometer method x percent passing No. 200 sieve from Step 1.
  4. The total modified percent finer for samples retained on No. 200 sieve and above would be the same as
    calculated in sieve analysis; for samples passing No. 200 sieve, the same as calculated in Step 2.
    Note: Plot the percent finer versus grain size for both Hydrometer Method and Combined Method. Use arithmetic
    scale and vertical axis for percent finer and log scale and horizontal axis for grain size. This curve is called grain
    size distribution curve. Comment on results.
    6
    DATA SHEET: Hydrometer Analysis
    Description of soil: ____________________
    Sample No.: ___________________________
    Location: ___________________________
    Tested by: ___________________________
    Group No.: ___________________________
    Date: __________________________________
    Time
    (t, min.)
    Hydrometer
    Reading
    (R)
    RCP Percent finer
    ARCP100 /
    50
    RCL L
    (cm)
    A D
    (mm)
    0.25
    0.5
    1
    2
    4
    8
    15
    30
    60
    120
    240
    480
    1440
    2880

Sample Solution

ACED ESSAYS