Laboratory Report on Grain Size Analysis

This laboratory report provides an analysis of grain size distribution using sieve analysis technique. It includes the theory, procedure, calculations, and results of the experiment. The report concludes that the soil sample is uniformly graded and suitable for construction purposes.

LABORATORY REPORT ON GRAIN SIZE ANALYSIS.
Lab Report
Name of the Student:
Name of the Institution:

LABORATORY REPORT ON GRAIN SIZE ANALYSIS.
GRAIN SIZE ANALYSIS EXPERIMENT.
1. Introduction
Particle size distribution is an important factor that ought to be considered for any granular
substance as it is an indicator of various properties of the material such as the texture, the
porosity, permeability, compressibility and the shear strength (Jajurie, 2016). The length,
dimension and technique of measurement influence the particle size. Sieve analysis is therefore
the most preferred technique of obtaining the particle size and particle size distribution of
substances which is for particles larger than 0.075 mm and obtained a smaller particle related to
hydrometer (Jajurie, 2016).
2. Theory
Among the oldest methods used for classification of soil is grain size analysis technique. The
technique is also used during the determination of specific soils that are used for construction of
roads, airfields or dams since this method is offers accurate results from analysis (Jajurie, 2016).
For large soil particles the method utilizes sieves through which smaller grain particles sizes pass
through leaving behind the larger grain particle sizes. Particular grain sizes can be obtained
through using a series of sieves in the system in order to separate the grain sizes into various
particle sizes. According to Jajurie (2016), very small particle sizes are not well analyzed by the
sieves technique but they rather employ the method of hydrometer analysis. The method of
analysis is based on Stokes` Law that outlines that the greater the size of the grain, the larger the
fluid settling velocity (Jajurie, 2016). The hydrometer method is very efficient for the separation

LABORATORY REPORT ON GRAIN SIZE ANALYSIS.
of the small sized soil sample particles effectively compared to the sieve method which may
incur errors especially during the agitation step.
In sieve method analysis, particles of an entirely particular size are known as uniform sizes. Any
grain diameter greater than 10% of the particles by weight is referred to as the effective grain
size which is associated with the soil`s porosity and permeability. The permeability and porosity
traits of a soil sample will determine the specific use the soil sample will be put to. The ratio
between size grains with 60% of the sample coarser than itself to than of 90% by weight of the
sample coarser than itself is known as the uniformity coefficient of an oil sand. The effective size
of an oil sand is composed of 10% small grain particle sizes and 90% large coarse grain size
particles. The well screen pipe size is defined as the opening size lesser than twice the efficient
an oil sand size.
3. Definitions and equations
Standard (graphic) Deviation:
∂ⱷ = [(ⱷ84 - ⱷ16)/4] + [(ⱷ95 - ⱷ5)/6.6] (Falk and Ward Approximation 1957)
Geometric (graphic) Mean:
Ge = (ⱷ16 + ⱷ50 +ⱷ84)/3 ( Falk and Ward Approximation 1957)
Approximated permeability (darcies)
K = 760 (Ge)2 * e(-1.31∂ⱷ) ( Falk and Ward Approximation 1957)

LABORATORY REPORT ON GRAIN SIZE ANALYSIS.
4. Objective
The main purpose of this experiment was to find out the size distribution and the frequency
distribution of the several grain sizes present through screen analysis technique.
5. Procedure.
The opening of the mesh screen and the ratio between the openings of the successive screens had
the foundation of the set put as 200 mesh sieve and an opening of 75 micron. The ratio between
the various sizes of the screen was taken as 1.189 whereas the width of the successive opening
was also taken as 1.189 times the previous sieve`s opening. The sample to be examined was
thereafter placed on the upper screen and a lid was placed over the top and a pan was placed on
the bottom of the nest. Thereafter, screen test shaking was done for 15 minutes and after the
sample was agitated, the sample`s parts were found to have separated on the various screens
corresponding to the particle size distribution.
6. Calculation
 Weight of sand retained on each screen and the pan, (g) = wi
= (weight of empty sieve + sand)- (weight of empty sieve)
338.54-338.5= 0.04
326.04-324.86=1.18
432.55-309.08=123.47
345.2-290.29=54.91
285.6-282.5=3.1
289.76-287.65=2.11
274.61-272.67=1.94

LABORATORY REPORT ON GRAIN SIZE ANALYSIS.
275.88-271.92=3.96
279.16-275.33=3.83
278.34-275.71=2.63
274.74-273.24=1.5
270.76-269.62=1.14
267.1-266.76=0.34
∑ of weight of sand retained=200.14
 Total weight of sand retained on each screen and the pan, (g) = ∑wi
∑ Weight of empty sieve+ sand = 3938.28
∑ Weight of empty sieve= 3738.13
∑ Weight of sand retained = 200.15
 Percent by weight of sand retained on each screen and the pan, (%) = wi / ∑wi.
0.04/200.15
1.18/ 200.15
123.47/200.15
54.91/200/15
3.1/200.15
2.11/200.15
1.94/200.15
3.96/200.15
3.83/200.15
2.63/200.15

LABORATORY REPORT ON GRAIN SIZE ANALYSIS.
1.5/200.15
1.14/200.15
0.34/200.15
 Losses in the sand weight, (g) = Original weight of sample, W - ∑wi
Original weight W = 200g
200-200.15= -0.15
 Losses distribution on each screen and the pan, (g) = The total losses * (wi / ∑wi)
-0.15 * (0.04/200.15)= -0.0000299775
…
-0.15 * (0.34/200.15)= -0.0002548089
 Total weight of sand retained on each screen and the pan, (g) = wt = (Losses + Weight of sand
retained) on each screen and the pan.
Losses+ weight of sand retained
0.04- 0.0000299775= 0.0399700225
…
0.34- 0.0002548089= 0.3397451911
 Total weight percent of sand retained on each screen and the pan, (%) = (wt / W).
0.03997/ 200= 0.00019985

LABORATORY REPORT ON GRAIN SIZE ANALYSIS.
…
0.3397/200= 0.0016985
c) Screen size in  (units) = - log 2 d = - (log 10 d / log 10 2) Where: d = screen size in mm.
-(log 10 2/ log 10 2)
= -1
Note that: The negative sign is affixed so that commonly encountered sand size sediments can be
described using positive  values.
7. Plots

LABORATORY REPORT ON GRAIN SIZE ANALYSIS.
Figure 1: Sieve analysis
Retained on 20
Retained on 40
Retained on 60
Retained on 100
Retained on 140
Retained on 200
Pan
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
frequency distribution curve
Total percent by weight
Retained %

LABORATORY REPORT ON GRAIN SIZE ANALYSIS.
Results and calculations
1. Using the grain size analysis results, calculate:
a) Uniformity Coefficient.
from the distribution curve,
Cf = d60/d90
=0.250/0.150
=1.67
b) The Effective size
Es =d90
= 0.150
c) Select the proper screen pipe size
= 2 * d90
2 * 0.150
=0.30
d) Geometric mean
Ge = (ⱷ16 + ⱷ50 +ⱷ84)/3
150/3
=50
e) Standard deviation
∂ⱷ = [(ⱷ84 - ⱷ16)/4] + [(ⱷ95 - ⱷ5)/6.6]
=16+90/6.6
=29.636
f) Approximated permeability

LABORATORY REPORT ON GRAIN SIZE ANALYSIS.
K = 760 (Ge)2 * e(-1.31∂ⱷ)
760 (502 ) * e(-1.31∂ⱷ)
= 512658.1071
2. According to the grain size analysis results predict the porosity ranges of the sample.
The effective grain size is 0.15 which is less than 2.0 indicating uniform particle size
distribution and hence the sample is uniformly porous throughout the sample. This gives
the soil great shear strength and resistance to the natural forces that would act on the
particles of the soil.
3. State the experiment precaution.
The soil sample should not be allowed to spell out during the agitation process of the
sample and also all the readings of the experiment should be noted carefully.
4. a) Plot the log of the total cumulative weight percent against the log of the screen opening
size graph to give a frequency distribution curve.
1 10 100
0.01
0.1
1
Frequency distribution curve
Log of screen opening size
Log of cumulative weight

LABORATORY REPORT ON GRAIN SIZE ANALYSIS.
Discussion.
Classification of soils is mainly done by particle size analysis and the data that is obtained is
used in obtaining soil hat is specifically used for the construction of various areas like dams,
airspaces and roads. The experiment focused on soil particle size distribution which influences
the porosity, compaction and shear strength properties of the soil. The soil frequency distribution
plot obtained was used to determine the grades of the soil under study. From the obtained results
the soil sample was found to have a uniform curvature and this implied that the soil sample was
uniformly graded. These uniformly graded soils were found to be important in the use as
construction material because the soil had excellent compaction properties and had very little
voids present. This therefore offered the soil sample great strength to resist the normal natural
forces that act on it hence, making it suitable for construction. Despite the experimental success
various errors were present due to the recording of results however, the errors were minimal and
thus, the results were reliable to a great extent.
Conclusion.
It was concluded that the soil sample was uniformly graded. This made the soil sample suitable
for use I the construction industry of roads, dams and airstrips because the soil had little number
of voids in it, it had excellent compaction trait and it also had great strength to resist the forces
acting on it.

LABORATORY REPORT ON GRAIN SIZE ANALYSIS.
References.
Jajurie, N. (2016). Particle Size Analysis of Soils. Academia. Available from,
https://www.acadmia.edu/28124221/Lab_Report_1_Particle_Size_Analysis_of_Soils