This document presents information on determining the Atterberg limits of soils, which are important properties used to characterize soils in engineering. It discusses the purpose and procedures for determining the liquid limit and plastic limit through laboratory tests. The liquid limit is the moisture content where a soil changes from plastic to liquid state, while the plastic limit is where it changes from semi-solid to plastic. Factors like clay content and type, organic matter, and exchangeable cations can affect the Atterberg limits. The document describes the apparatus used and discusses the meaning and applications of these tests.

1. WELCOME TO OUR PRESENTATION
Prepared by:-
Rasty Abdalla
Awat Jabar
Hussein Salih
Shikar Marmar
Hawkar Abdalla
Sarkar Saedy
Submitted To
Bafrin Chalabi
M.sc. Highway
engineering
Erbil polytechnic university college of engineering
DEPARTMENT of highway engineering

2. DETERMINATION OF ATTERBERG
LIMITS OF SOIL
Presentation on

3. These test methods are used as an integral part of several engineering
classification systems to characterize the fine-grained fractions of
soilsand to specify the fine-grained fraction of construction materials
The liquid limit, plastic limit, and plasticity index of soils are also
used extensively, either individually or together, with other soil
properties to correlate with engineering behavior such as
compressibility, hydraulic conductivity (permeability), compactibility,
shrink-swell, and shear strength.
introducti
on

4. Purpose of this
test
This lab is performed to determine the plastic and liquid
limits of a fine grained soil.
The Atterberg limits are based on the moisture content of
the soil. The plastic limit:
is the moisture content that defines where the soil
changes from a semi-solid
to a plastic (flexible) state.
The liquid limit: is the moisture content that defines
where the soil changes from a
plastic to a viscous fluid state.

5. (i) Clay Content and Type of Clay
(ii) Organic MatterFactors Affecting the Atterberg Limits:

6. Apparat
us:

7. Soil Consistency - Atterberg Limits

8. Liquid Limit (LL): is defined as the moisture content at
which soil begins to behave as a liquid material and
begins to flow. (shear strength of the soil is approximately
2.5 kN / m2)
Liquid
limit:-

9. The moisture content
(%) at
which the soil when
rolled
into threads of
(1/8 in)
in diameter, will
crumble
Plastic
Limit:

10. Plasticity Index is the difference between the
liquid limit and plastic limit of a soil.
PI = LL – PL

11. For liquid and plastic limit we have two deference procedure:-
1.Place a portion of the prepared sample in the cup of the liquid limit device at the point where the
cup rests on the base and spread it so that it is 10mm deep at its deepest point.
2.Form a groove in the soil by drawing the grooving tool, beveled edge forward, through the soil from
the top of the cup to the bottom of the cup. When forming the groove, hold the tip of the grooving
tool against the surface of the cup and keep the tool perpendicular to the surface of the cup.
3.Lift and drop the cup at a rate of 2 drops per second. Continue cranking until the two halves of the
soil specimen meet each other at the bottom of the groove. The two halves must meet along a
distance of 13mm (1/2 in).
4.Record the number of drops required to close the groove.
5.Remove a slice of soil and determine its water content, w.
6.Repeat steps 1 through 5 with a sample of soil at a slightly higher or lower water content. Whether
water should be added or removed depends on the number of blows required to close the grove in
the previous sample
Procedure for Liquid Limit test

12. B) Procedure for determination of the plastic limit :-
1. From the 20g sample select a 1.5 to 2 g specimen for testing.
2. Roll the test specimen between the palm or fingers on the ground glass plate to from a
thread of uniform diameter.
3. Continue rolling the thread until it reaches a uniform diameter of 3.2mm or 1/8 in.
4. When the thread becomes a diameter of 1/8 in. reform it into a ball.
5. Knead the soil for a few minutes to reduce its water content slightly.
6. Repeat steps 2 to 5 until the thread crumbles when it reaches a uniform diameter of 1/8 in.
7. When the soil reaches the point where it will crumble, and when the thread is a uniform
diameter of 1/8", it is at its plastic limit. Determine the water content of the soil.

13. Calculation of plastic and liquid limit
To find w.c from both state we can use
this rule
w.c=(w2-w3)/(w3-w1)
w1=weight of tin(g)
w2=weight moist soil+tin(g)
w3=weight of dried soil+tin(g)
Calculate the plasticity index as
follows: PI = LL - PL where:
LL = liquid limit, and PL = plastic limit.

14. Liquid Limit
Determination

15. Plastic Limit Determination

17. This test is used To determine the liquid limit of a soil and To
determine the liquid limit of a soil the four states of consistency
in Atterberg limits are liquid, plastic, semisolid and solid. The
dividing line between liquid and plastic states is the liquid limit;
the dividing line between plastic and semisolid states is the
shrinkage limit. If a soil in the liquid state is gradually dried
out, it wills past through the liquid limit, plastic state, plastic
limit, semisolid state and shrinkage limit and reach the solid stage.
The liquid, plastic and shrinkage limits are therefore quantified in
terms of the water content at which a soil changes from the liquid to
the plastic state. The difference between the liquid limit and
plastic limit is the plasticity index. Because the liquid limit and
plastic limit are the two most commonly used Atterberg limits, the
following discussion is limited to the test procedures and
calculation for these two laboratory tests.
The liquid limit is that moisture content at which a soil changes
from the liquid state to the plastic state. It along with the plastic
limit provides a means of soil classification as well as being useful
in determining other soil properties.
discuss
ion

18. and semisolid states. From a physical standpoint, it is the water
content at which the soil will begin to crumble when rolled in small
threads.
These test methods are used as an integral part of several
engineering classification systems to characterize the fine-grained
fractions of soilsand to specify the fine-grained fraction of
construction materials The liquid limit, plastic limit, and
plasticity index of soils are also used extensively, either
individually or together, with other soil properties to correlate
with engineering behavior such as compressibility, hydraulic
conductivity (permeability), compactibility, shrink-swell, and shear
strength.
The liquid and plastic limits of a soil and its water content can be
used to express its relative consistency or liquidity index. In
addition, the plasticity index and the percentage finer than 2-μm
particle size can be used to determine its activity number.
These methods are sometimes used to evaluate the weathering
characteristics of clay-shale materials. When subjected to repeated
wetting and drying cycles, the liquid limits of these materials tend
to increase, The amount of increase is considered to be a measure of
a shale's susceptibility to weathering.
The liquid limit of a soil containing substantial amounts of organic
matter decreases dramatically when the soil is oven-dried before
testing. Comparison of the liquid limit of a sample before and after
oven-drying can therefore be used as a qualitative measure of organic

19. Meaning of this test
Factors Affecting of this test :
1- Clay Content and Type of Clay:
Amount and nature of clay colloids greatly influence the plasticity. An
increase in the percentage of clay causes plastic limits to be higher
with the moisture content and increases the plasticity number or index.
With the decrease in clay content in the soil, the upper plastic limit
decreases and thereby decreases the plasticity number or the index of
plasticity. Atterberg limits are raised as the surface is increased due
to higher amount of clay present in soil.
The clay content, therefore, determines the amount of surface that is
available for water adsorption. For a particular clay mineral, the
amount of absorbed water required at the plastic limit will increase
with the amount and size of the particles present.
2- Nature of Exchangeable Cations:
The exchangeable acations have considerable influence upon soil
plasticity.
3- Organic Matter:
Organic matter exhibits an interesting effect upon soil plasticity. It
has been found that the plasticity limits decreased due to oxidation of
organic matter with hydrogen peroxide.

20. The APPARATUS of PLASTIC LIMIT TEST
( Glass plate ,A separate glass plate for rolling of threads ,Spatulas
,Moisture content apparatus)
The average of water content from our test for Plastic limit test is 11%
PI = LL - PL
So the description of Pl is medium plasticity