Understanding sieve analysis of sand

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Understanding sieve analysis of sand
video
1.0 Introduction
1.1 Title of test
Determination of particle size distribution of fine aggregates/sand.
1.2 Definitions
Particle size distribution analysis (PSD) we mean the grading or separation of fine
aggregates/sand into particles of different size. In practice this is done by passing the materials
through a set of sieves with openings of different diameter. By separating larger from smaller
particles, we can calculate the percentage passing each sieve.
Fine aggregates/sand is inert materials in particle form that pass the sieve of 4.75mm and
retained on sieve size 75μm/63μm (0.070/0.063mm).
Silt. These are particles in the range of 60μm (0.06mm) to 2μm (0.002mm), reduced to this size
by natural processes of weathering.
Clay. These are smallest particles less than 2μm (<0.002mm) formed by the decay of vegetable
matter (humus).
Dust. This is a fine material usually below 2μm formed during the process of conversion of rock
or gravel into coarse aggregates (80mm - 5mm) and fine aggregates/sand (4.75mm - 63μm).
1.3 Main principles
For fine aggregates free from silt, clay and other materials which cause agglomeration, Dry sieve
analysis method may be performed.
For fine aggregates which may contain silt, clay or other materials likely to cause agglomeration,
preliminary separation of impurities by washing the representative sample through a fine sieve of

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75μm is required before carrying out dry sieving1
.
1.4 Main Reference
BS 812: Part 103.1: 1985
1.5 Test Method
Dry Sieve analysis
1.6 Objective/purpose/significance of the test
This test method is used primarily to determine the grading of materials proposed for use as
aggregates or being used as aggregates.
The results are used to determine compliance of the particle size distribution with applicable
specification requirements and to provide necessary data for control of the production of various
aggregate products and mixtures containing aggregates2
.
Results of sieve analysis test can be used in the determination of: bio-sand filter materials;
quality sand used in concrete and mortar making; uniformity coefficient and coefficient of
curvature; and many others.
1.7 Tools
Test sieves of sizes 10.0mm, 6.3mm, 5.0mm/4.75mm, 3.35mm, 2.36mm, 1.7mm, 1.18mm,
825μm, 600μm, 425μm, 300μm, 212μm, 150μm and 75μm/63μm;
Drying oven capable of maintaining a temperature of 105 o
C 5 o
C;
Balance readable and accurate to 0.5g;
Metal trays;
Metal containers;
Riffle boxes;
Scoop;
Mechanical Sieve shaker (optional);
1
https://docs.google.com/file/d/0B3zQfrHwXs0aaXJmU0dUbFJuRjQ/edit
2
http://www.scribd.com/doc/66342752/CE-121-LAB-1

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Sieve brushes (soft brush and wire brush);
Lid and receiver.
2 Instructions
The instructions are procedures followed to achieve the results in this test of particle size
distribution test, these are briefly listed below and their detailed descriptions follows later.
2.1 Prepare the sample
2.1.1 Materials/Ingredients
Fine aggregate

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2.1.2 Apparatus
oven balance riffle box
scoop spade metal tray

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2.1.3 Procedures/Instructions
a)
The fine aggregate/sand sample about 12kg to be tested is taken to the laboratory and placed on
a metal tray.
The sample is then placed into the drying oven for a period of 12 to 24 hours at a temperature of
105 o
C 5 o
C until all the water/moisture is extracted from the sample.
b) The dried sample is removed and cooled up to room temperature.
Care should be taken that all the moisture/water is extracted from the sand, if this is not
achieved during the 24 hours, the sample should be left in the drying oven for another 24 hours.
c)
The sample is placed on a larger clean surface preferably in a cone shape and a representative
sample of about 1.5kg is got.
d) The representative sample is got using either quartering method or riffle boxes method.

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e) If quartering method is to be used, the sample to be tested is placed on a flat clean surface
then heaped in a cone shape. The sample is then divided into four (4) portions where by two
opposite quarters forming a diagonal. One diagonal is selected and the remaining diagonal is
discarded. The process continues until the sample is reduced from about 12kg to about 1.5kg and
the exact 1.5kg is weighed off on the balance.
Figure illustrating quartering method
f) If riffle boxes method is to be used, the dried sample is poured into the apparatus and the
operator should make sure that the pouring is uniformly distributed. The apparatus automatically
divides the sample into two (2) parts and each part goes in a separate box. Sample in one box is
retained and the other in another box is discarded. The retained sample is further divided until
the sample is reduced from say 12kg to say 1.5kg, then the exact 1.2kg is weighed off using the
balance.
g) The representative sample is then weight to get the exact 1.2kg which can be used to
carry out the test.

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h) For sand/fine aggregates which may contain silt, clay or other materials likely to cause
agglomeration, preliminary separation of impurities by washing the representative sample
through a fine sieve of 75μm/63μm is required before carrying out dry sieving.
Washing is done by using sieve 1.18mm and 75μm/63μm where by the 1.2kg representative
sample is placed on the top sieve of 1.18mm. Water is applied on sample, sand particles are
retained on sieve 1.18mm and 75μm/63μm. Silt and clay is let to run out with water.
The representative sample is assumed to be clean when the colour of water applied on the top
sieve is the same coming out of the lower sieve.
In case its hard to combine the two sieves while washing, then the sample is first washed using
sieve 1.18mm and the particles that goes through are collected on a metal tray. Then after, the
particles that went through the 1.18mm are placed on the sieve of 75μm/63μm, washed and water
coming out runs with silt and clay particles.
The reason why sieve 1.18mm is used is to ensure that sieve 75μm/63μm is not damaged due to
overloading. Otherwise sieve 75μm/63μm is the only important sieve here.
Care must be taken when using a sink not to block it otherwise its recommended to let water with
silt and clay run on the flow.
After washing the sample is collected onto one metal tray and placed in the drying oven for a
period of 12 hours to 24 hours at a temperature of 105 o
C + 5 o
C until all the water/moisture is
extracted from the washed sample.
After the sample is removed from the oven and cooled to room temperature; now its ready to be
sieved.

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2.2 Arrange the sieves

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2.2.2 Apparatus
receiver/pan and lid/cover hard sieve brush
soft sieve brush
a) The sieves to be used in the test are selected.
b)
The sieves are cleaned thoroughly well such that no particles are present in the mesh holes.
If these particles are not removed this can bring an error since after carrying out the test more

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particles will be added to the original 1.2kg representative sample.
Care must be taken such that sieves are not damaged. The particles should be removed carefully
but not with force.
cleaning of sieve
c) Cleaning of the sieves is done by using the hard sieve brush on sieves above 1.0mm
(10.0mm, 6.3mm, 5.0mm/4.75mm, 3.35mm, 2.36mm, 1.7mm, 1.18mm) and soft sieve brush on
sieve sizes below 1.0mm (825μm, 600μm, 425μm, 300μm, 212μm, 150μm and 75μm/63μm)
hard sieve brush soft sieve brush
d)
After cleaning the sieves, they can be arranged in such a way that the ones with bigger aperture
are places above and those with smaller aperture are placed below.
This will ensure that bigger particles of sand remain on top and smaller particles of sand
retained on the lower sieves during the sieving process.

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e) After arranging the sieves, the receiver/pan is placed at the bottom to trap all particle that
goes through 75μm/63μm sieve (particles like silt and clay) during the sieving process. Also the
lid/cover is placed on top of the top most sieve (10.0mm) to prevent particles from falling out
during the sieving process.
receiver/pan lid/cover

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2.3 Carry-out sieving
1.2kg represtantative sand
2.3.2 Apparatus
set of sieves, lid, pan sieve shaker metal tray

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a) The representative sample of 1.2kg is carefully placed on the top most sieve (10.0mm)
and then the lid is replaced.
Carefully pour in 1.2kg sand representative sample on the top sieve
b) The sieving process is carried out either manually or mechanically.
c) For manual sieving method,
The representative sample is placed on a single sieve starting with one of the bigger aperture that
is to say sieve 10.0mm.
Sieving is done by shaking the sieve using hands, the sample that goes through is collected onto
a tray and that retained on the sieve (10mm) is put separate to be weighed later.
Care must be taken that no particles are lost during this process otherwise the test is invalid.
Particles that have got stuck in between the holes of the sieve mesh should be re-examined
carefully to see where the pass through or not.
The manual sieving method is time consuming, though gives better results than mechanical

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sieving method.
d) For mechanical sieving method,
The sieve shaker is properly checked to see whether it is working properly.
A set of sieves with pan at the bottom and lid on top containing 1.2kg of repersentative sand is
securely tightened on the sieve shaker.
The machine is switched on and allowed to to shake the sample for about 15 -30 minutes.
The machine will stop automatically or a timer should be used.
After the machine is switched off and disconnected from power line.
The set of sieves is carefully removed from the sieve shaker and taken next to the weighing scale
(balance).
2.4 Weigh materials retained on each sieve
youtube video showing this step

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A set of sieves (10.0mm, 6.3mm, 5.0mm/4.75mm, 3.35mm, 2.36mm, 1.7mm, 1.18mm, 825μm,
600μm, 425μm, 300μm, 212μm, 150μm and 75μm/63μm) with a lid and receiver containing
graded sand particles.
2.4.2 Apparatus

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video
The balance should be checked to see whether its in good working condition.
The lid is carefully removed from the sieve set.
The top most sieve (10.0mm) is carefully removed, on an empty metal tray it should be re-
shaken using hands to see whether no other materials doesn’t go through.
The particles retained sieve 10.0mm are removed and weighed.
Care must be taken while removing the particles otherwise some particles may be lost in the
process.
All particles should be removed from the sieve.
The weight of particles retained on each sieve is recorded in a record sheet corresponding to each
sieve.
All sieves should be treated the same way as above.
Particles on the Pan are also recorded in the record sheet, in most cases when the sample is

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washed first, the weight of particles retained of the pan is not necessary.
After recording all the weights retained on each sieve, add them up and they should total to the
original weight which is 1200g (1.2kg) as seen below.

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2.5 Calculate Percentage passing
2.5.2 Apparatus

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After recording all the weights retained on each sieve (g), the task now is to calculate percentage
(%) weight retained (%), cummulative % weight retained (%) and cummulative % weight
passing each sieve (%).
For % weight retained (%) for this example lets us calculate a, b, and c as per the figure above
% weight retained = { }
{ }
{ }
{ }

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For cummulative % weight retained (%) we are going to determine for x, y, and z as per the
figure above.
For cummulative % passing (%) we are going to determine for i, ii, and iii as per figure
above.
The rest is completed as seen in the figure below.

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2.6 Make conclusions
From the plotted graph one can deduce whether the fine aggregates/sand particles are well
graded or poorly graded (uniformly graded or gap graded). Also form the plotted graph
one can extract values to be used in calculating uniformity coefficient and coefficient of
curvature.

Understanding sieve analysis of sand

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