COLLEGE OF ARCHITECTURE AND CIVIL

ENGINEERIGN
DEPARTMENT OF CIVIL ENGINEERING
Probability and Statistics (Stat 271
)

Section – C
Group members
NAME ID
Hayat Abdulfetah ETS0754/14
Hayat Yenus ETS0752/14
Kaleb Seifu ETS0878/14
Kedir Faris ETS0898/14
Kibrom Fiesha ETS0915/14
Kidus Zerihun ETS0939/14
 Submitted to -Tesfay Gidey

Submission Date – 22, Dec,2023

Contents
EXPERIMENT 1: ATTERBERG LIMIT 3
Introduction 3
OBJECTIVE 3
Equipment 3
Method 4
Liquid limit test 4
Procedure 4
Plastic Limit Test 5
Procedure 5
Calculation and Result 6
Conclusion 7
EXPERIMENT 2: SIEVE ANALYSIS TEST 8
INTRODUCTION 8
OBJECTIVE 8
EQUIPMENT 8
Procedure 9
RESULTS AND CALCULATIONS 9
Conclusion 11
LABORATORY SOIL COMPACTION 12
PURPOSE OF MEASUREMENT 12
DEFINITIONS AND THEORY 12
EQUIPMENT 12
PROCEDURE 12
EXPERIMENT 1: ATTERBERG LIMIT
Introduction
The Atterberg limits test is a classification test used to determine the moisture content at which
fine-grained clay and silt soils transition between the different phases. The test for Atterberg
limits is performed on the fraction of soil that will pass through a No. 40 or 425µm or 0.425mm
sieve.
The test aids in the classification of soil and its plasticity characteristics and evaluates the
shrink/swell potential of near-surface soil. It can be used to distinguish between silt and clay in
its different types and determines the plastic limit (PL), and liquid limit (LL) of the soil sample.
The Atterberg limits test is named after the Swedish chemist Albert Atterberg who was the first to
develop a classification system to determine the different states and limits of soil consistency.
Karl Terzhagi and Arthur Casagrande later refined and standardized the tests which are now
widely used to determine the LL, PL, and SL of soils.
OBJECTIVE
The objective of this experiment is:
To determine the liquid limit (LL)
plastic limit (PL) of fine-grained cohesive soils.
Equipment
Balance: with 0.01g readability.
Casagrande’s liquid limit device
Grooving tool
Spatula: to mix, form and smooth the soil specimen.
Oven: for moisture content test.
Mixing dishes
Method
Liquid limit test
Liquid limit is the water content where the soil starts to behave as a liquid.
Liquid limit is measured by placing a clay sample in a standard cup and making a separation
(groove) using a spatula. The cup is dropped till the separation vanishes. The water content of the
soil is obtained from this sample. The test is performed again by increasing the water content.
Soil with low water content would yield more blows and soil with high water content would
yield less blows.

Procedure
1. Determine the mass of each of the three moisture cans
2. Mix about 300 g of the prepared soil (after 24 hours maturing) with a little distilled water
if necessary, using two spatulas, for at least 10 minutes
3. Place the spatula flat, and pull towards yourself to rake out the air bubbles. Spread across
 smoothly, and then rake out the bubbles again.
4. Cut a trough using the grooving tool Run at approx. 2 blows per second.
5. Count the blows. Once a closure of ~13mm is observed (shown),
6. Clean the dish (top and bottom) between each point. Cut more groves. Add more water.
Stir well. Blow counts for 2nd point should be 20-30 blows.
7. If your blow counts on the 2nd point are higher than the ones on the 1st point, then throw
out the 1st point and have the 2nd become the new 1st.
8. Run the 3rd (final point) as you did the first two. Blow count should be between 15-25
blows. Make sure you have one point below 25 blows. Set the points from the liquid limit
portion to the side.
9. Take a sample, using the spatula, from edge to edge of the soil pat. and place the can into
the oven.
10. Determine the water content from each trial by using the same method used in the first
laboratory.

Plastic Limit Test

The Plastic Limit (PL or wPL), also known as the lower plastic limit, is the water content at
which a soil changes from the plastic state to a semisolid state. The Plastic limit test is performed
by repeated rolling of an ellipsoidal-sized soil mass by hand on a non-porous surface.
Casagrande defined the plastic limit as the water content at which a thread of soil just crumbles
when it is carefully rolled out to a diameter of 3 mm (1/8”). If the thread crumbles at diameter
smaller than 3 mm, the soil is too wet. If the thread crumbles at a diameter greater than 3 mm,
the soil is drier than the plastic limit. The sample can then be remolded and the test repeated.
Procedure
1. Mix approximately 20 g of dry soil with water from the plastic squeeze bottle.
2. Determine the weight of the empty moisture can.
3. Prepare several small, ellipsoidal-shaped masses of soil and place them in the plastic
limit device. Place two fresh sheets of filter paper on either face of the plates.
4. Roll the upper half of the device which has a calibrated opening of 3.18 mm with the lower
half plate.
5. If the soil crumbles forming a thread approximately the size of the opening between the
plates (around 3 mm diameter), collect the crumbled sample, and weigh it in the moisture
can to determine the water content. Otherwise, repeat the test with the same soil, but dry
 it by rolling it between your palms.
6. Determine the weight of the dry soil + moisture can.
7. The water content obtained is the plastic limit.

Calculation and Result

Liquid Limit Determination
TRIAL 1 2 3
MC = Mass of empty, clean can (gm) 14 14 14

MCMS = Mass of can, and moist soil (gm) 22.1 20.0 19.0
MCDS = Mass of can, and dry soil (gm) 20.0 18.1 17.2

Mw = Mass of pore water(grams) 2.1 1.9 1.8

MS = Mass of soil solids (gm) 6 4.1 3.2
w = Water content, w% 35% 46.34% 56.25%

No. of Blows (N) 28 24 19

For Trial No. 01,

Number of blow, N= 28 (recorded during test)
Wt. of container = 14 gm
Wt. of container + wet soil = 22.1 gm
Wt. of container + dry soil = 20 gm
Wt. of water, Ww= 22.1-20 = 2.1 gm
Wt. of dry soil, Ws = 20-14= 6 gm
Water content, w = 35.0%
 60 56.25

50 46.34
WATER CONTENT(%)

40 35

30

20

10

0
0 5 10 15 20 25 30
NO OF BLOWS (MM)

Liquid limit (LL) is the corresponding moisture content at 25, in our experiment is around 42.7%
as we can obtain from the graph.

- Plastic limit (PL) = Average water % = (35 + 46.34 + 56.23)/3 = 45.86%

- Liquid Limit (LL) = 42.7%

- Plastic index = liquid limit – plastic limit = - 3.16%

Conclusion
The Atterberg limit test is an essential tool for characterizing the plasticity of fine-
grained soils. It aids in understanding the soils behaviour and provides valuable
information for geotechnical engineers and construction professionals when
designing and constructing structure on such soils.
EXPERIMENT 2: SIEVE ANALYSIS TEST
INTRODUCTION
The grain size analysis test is performed to determine the percentage of each size of grain that is
contained within a soil sample, and the results of the test can be used to produce the grain size
distribution curve. This information is used to classify the soil and to predict its behaviour. The
two methods generally used to find the grain size distribution are:

 Sieve analysis which is used for particle sizes larger than 0.075 mm in diameter and

 Hydrometer analysis which is used for particle sizes smaller than 0.075 mm in diameter

Sieve analysis is a method that is used to determine the grain size distribution of soils that are
greater than 0.075 mm in diameter. It is usually performed for sand and gravel but cannot be
used as the sole method for determining the grain size distribution of finer soil. The sieves used in
this method are made of woven wires with square openings.

OBJECTIVE
 To obtain the grain size distribution curve for a given soil sample.
EQUIPMENT
 Stack of sieves with a cover,

 Mortar and pestle or a mechanical soil pulverized

 Balance, sensitive to 0.1 g

 Oven
Procedure
1. Obtain a representative oven-dried soil sample.
2. Pulverize the soil sample as finely as possible, using a mortar and pestle or a mechanical
soil pulveriser.
3. Obtain a soil sample of about 500 g and determine its mass W0 (g).
4. Stack the sieves so that those with larger openings (lower numbers) are placed above
those with smaller openings (higher numbers). Place a pan under the last sieve (#200) to
collect the portion of soil passing through it. The #4 and #200 sieves should always be
included in the stack.
5. Make sure the sieves are clean, If soil particles are stuck in the openings, use a brush to
poke them out.
6. Weigh the pan and all of the sieves separately.
7. Pour the soil from above into the stack of sieves and place the cover on it. set a timer for 10
to 15 minutes, and start shaking.

8. measure the mass of each sieve and retained soil.

RESULTS AND CALCULATIONS

No of sieve= 8

Mass of sample= 1951.0gm

opening (mm) Retained % Retained cumulative % Finer

weight (gm)
75.00 0.00 0.00 0.00 100.00
50.00 0.00 0.00 0.00 100.00
25.00 0.00 0.00 0.00 100.00
19.00 0.00 0.00 0.00 100.00
9.50 147.50 7.56 7.56 92.44
4.75 1776.10 91.00 98.56 1.44
0.03 28.20 1.44 100.00 0.00
pan 0.00 0.00 100.00 0.00
1951.80
 retained w
% Retained = x 100
Total w
cumulative % retained = 2nd %retained + 1st cumulutive%
%finer = 100 - Cumullitive %

110.00

100.00

90.00

80.00

70.00

60.00
% finer

50.00

40.00

30.00

20.00

10.00

0.00

-10.00
0.10 1.00 10.00 100.00
sieve size (mm)

D60= 8mm

D10= 5.8mm

D30= 7mm
 D60
UC = = 1.37
D10
D302
CC = = 1.056
D10XD60

NOTE:
A soil that has a UC < 4 contains particles of uniform sizes (approximately one size). The
minimum value of UC is 1 and corresponds to an assemblage of particles of the same size. The
gradation curve for a uniform soil is almost vertical. Higher values of (UC > 4) indicate a wider
assortment of particle sizes. A soil that has a UC > 4 is described as a well-graded soil and has a
flat curve.
The CC is between 1 and 3 for well-graded soils. The absence of certain grain sizes, termed gap-
graded, is diagnosed by a CC outside of the range 1 to 3 and a sudden change of slope in the
particle size distribution curve

Conclusion
The sieve analysis test is a crucial test for determining the particle size distribution of granular
materials. It provides valuable information for engineers and researchers in assessing the
properties and behaviour of these materials, enabling them to make informed decisions
regarding their engineering applications
LABORATORY SOIL COMPACTION
PURPOSE OF MEASUREMENT
Geotechnical engineers compact fine-grained soil to improve its engineering properties.
Properties such as shear strength, compressibility, and hydraulic conductivity are
dependent upon the methods used to compact the soil. Compacted soil is extensively
used for many geotechnical structures, including earth dams, landfill liners, highway base
courses and subgrades, and embankments. To predict the performance of compacted soil,
and to develop appropriate construction criteria, compaction is performed in the
laboratory using standardized test methods.

DEFINITIONS AND THEORY

Two types of compaction tests are routinely performed: (1) The Standard
Proctor Test, and (2) The Modified Proctor Test.
1. In the Standard Proctor Test, the soil is compacted by a 5.5 lb hammer falling a
distance of one foot into a soil filled mold. The mold is filled with three equal
layers of soil, and each layer is subjected to 25 drops of the hammer.
2. The Modified Proctor Test is identical to the Standard Proctor Test except it
employs, a 10 lb hammer falling a distance of 18 inches, and uses five equal layers
of soil instead of three. each soil layer must receive 56 blows instead of 25

EQUIPMENT
The following equipment is required for laboratory compaction testing:

• Standard proctor compaction hammer;

• Modified proctor compaction hammer;
• 4.0-in. diameter compaction mold, collar, and stand;
• cutting bar;
• scale capable of measuring to the nearest 0.01 g;
• drying oven;
• moisture containers
PROCEDURE
1) Obtain a sample of moist soil that has been prepared by the instructor.
2) Determine the weight of the soil sample as well as the weight of the compaction mold
with its base
3) Add water to the soil, and then mix it thoroughly into the soil using the trowel
4) Assemble the compaction mold, stand, and collar. Measure and record the height and
diameter of the mold. Tighten the wingnuts and seat all the pieces together properly, and
spray the inside of the assembly with an aerosol spray lubricant.
5) Compact the soil in lifts for modified. Use 56 blows/lift and scarify the compacted surface
between lifts with the screwdriver. Place enough loose soil into the mold prior to
compaction of each lift such that the compacted material will occupy approximately one-
third or one-fifth of the mold (depending on the compaction effort). The top of the final
lift should be just above the top of the mold such that it will need to be trimmed slightly.
6) Remove the collar and trim the excess soil off the top of the mold
7) Extrude the specimen and obtain the net mass of the compacted soil in grams
8) Obtain samples from the top, middle, and bottom of the specimen, and perform water
content measurements on the samples to obtain the average water content, wavg, for the
specimen.
9) Calculate the dry unit weight of the soil.
10) Repeat steps 3 through 9 until, based on wet mass, a peak value is reached followed by
two slightly lesser compacted soil masses.