Sieve analysis

KNS 2591 CIVIL ENGINEERING LABORATORY 3 FACULTY OF ENGINEERING UNIVERSITI MALAYSIA SARAWAK

LAB S2 : SIEVE ANALYSIS

THEORY : The method covers the quantitative determination of the particle size distribution in a soil from the coarse sand size to the clay size.

OBJECTIVE : The objective of the test is to determine the grain-size distribution of soil by sieve analysis.

RESULTS / ANALYSIS : 1. The mass retained on each sieve is obtained by subtracting the sieve mass from the sieve mass + retained soil. These values are recorded on the data sheet under column headed "Mass Retained”. 2. Now this column of masses (including that in the pan) is summed and the mass obtained are compared. 3. The percent retained on each sieve is computed by dividing the weight retained on each sieve by the original sample mass. This is valid, since any material passing the No.200 sieve will pass any sieve above it in the stack. 4. The percent passing (or percent finer) is computed by starting with 100 percent and subtracting the percent retained on each sieve as a cumulative procedure.

5. Each individual should make a semi logarithmic plot of particle size versus percent finer, using the graph on the data sheet. If less than 12 percent passes the No. 200 sieve, compute CU and Cc and show on the graph. Preparation Dried Sample + Tray

1192.81

(g) Tray (g) Dried Sample (g)

692.66 500.15

KNS 2591 CIVIL ENGINEERING LABORATORY 3 FACULTY OF ENGINEERING UNIVERSITI MALAYSIA SARAWAK

CALCULATION : C = ( Total mass sample before sieve-Total mass sample after sieve )12 = ( 500.15-500.09 )12

= 0.005 g

BS Test Sieve

Mass Retained (g)

Corrected Mass (g)

% Retained

% Passing

Max Load (g)

14 mm 10 mm 6.3 mm

4.15 13.28 31.93

4.155 13.285 31.935

0.83 2.66 6.39

99.17 96.51 90.12

1500 1000 750

3.35 mm 1.18 mm 600 μm 425 μm 300 μm 212 μm 150μm 63 μm mass passing 63 μm Total

40.68 60.60 70.44 52.80 69.81 45.88 50.45 49.46 10.61

40.685 60.605 70.445 52.805 69.815 45.885 50.455 49.465 10.615

8.13 12.12 14.08 10.56 13.96 9.17 10.09 9.89 2.12

500.09

500.15

100.00

81.99 69.87 55.79 45.23 31.27 22.10 12.01 2.12 0

400 100 75 75 50 50 40 25

Notes : % Retained = Corrected Mass Retainedml x 100 C = Mass Retained/Total Mass Sample Corrected Mass = Mass Retained + C % Passing = 100 - Σ % Retained

KNS 2591 CIVIL ENGINEERING LABORATORY 3 FACULTY OF ENGINEERING UNIVERSITI MALAYSIA SARAWAK

Thus, the graph of particle size (mm) versus percent finer is plotted as shown below.

Coefficient of Uniformity Cu This is the indicator of the spread of the range of the grain sizes and is defined as Cu =

D60 D10

Cu = 0.70 mm 0.15 mm Cu = 4.67 Coefficient of Curvature Cc This is the measure of the shape of curve between D60 and D10 grain sizes, defined as( D30 ) 2 Cc = ( D10 × D60 )

Cc =

(0.29 mm)2 (0.70 mm x 0.15 mm)

Cc = 0.80

KNS 2591 CIVIL ENGINEERING LABORATORY 3 FACULTY OF ENGINEERING UNIVERSITI MALAYSIA SARAWAK

DISCUSSION :

Sieve analysis is one type of mechanical analysis which determines the size range of particles present in a soil, expressed as a percentage of the total dry weight or mass. Sieve analysis consists of shaking the soil sample through a set of sieves that have progressively smaller openings. The results of sieve analysis are generally expressed as the percentage of total weight of soil that passed through different sieve. From the results, the total mass sample after sieving is smaller than the total mass before sieving where 0.06 g of soil is missing. This is probably because the small particles of soil is missing during the sieves are being vibrated.

Therefore, the total mass is corrected by adding the mass retained with the corrected mass of soil.

CONCLUSION :

The objective to determine the grain-size distribution of soil by sieve analysis is achieved. The soil tested is sandier as 13.96% of soil is retained in the 300μm sieve.

KNS 2591 CIVIL ENGINEERING LABORATORY 3 FACULTY OF ENGINEERING UNIVERSITI MALAYSIA SARAWAK

HYDROMETER ANALYSIS

THEORY : The method covers the quantitative determination of the particle size distribution in a soil from the coarse sand size to the clay size.

OBJECTIVE : The objective of the test is to determine the grain-size distribution of soil by hydrometer method.

RESULTS / ANALYSIS :

Table 1 Hydrometer Test Data

1

2

3

4

5

6

7

8

9

10

Date

Time of readin g

Elapse d Time (min)

Temp. (ToC)

Readin g Rh’

Rh’+ Cm = Rh

Effectiv e Depth HR (mm)

Particle Diamet er D (mm)

Rh’R’ o =Rd

Percenta ge finer than D

K(%)

KNS 2591 CIVIL ENGINEERING LABORATORY 3 FACULTY OF ENGINEERING UNIVERSITI MALAYSIA SARAWAK

• t is the elapsed time from the start of sedimentation (min) • T ,the temperature of the suspension at that time (°C) • Rh is the hydrometer reading at the upper rim of the meniscus, consisting of the decimal part only with the decimal point moved three places to the right • For example, a hydrometer reading of 1.0325 would be recorded as an R,, value of 32.5 • Cm is the meniscus correction • HR is the effective depth (mm) corresponding to Rh obtained from the calibration curve

• D is the equivalent particle diameter • Ro is the hydrometer reading at the upper rim of the meniscus in the dispersant solution (mm) • K is the percentage by mass of particles less than D • Rd is the modified hydrometer reading 1. The true hydrometer reading Rh (mm) is calculated, from the equation: Rh = Rh’ + Cm Where C is the meniscus correction and R’h is the observed hydrometer reading. Enter the values in column 6 of Table 1. 2. The effective depth, HR (mm) is obtained, at which the density of the suspension is measured, corresponding to the reading, Rh, from the hydrometer scale calibration curve, either by reading off from the curve or by calculation from its equation. The value of HR isentered in column 7 of Table1. 3. The equivalent particle diameter, D (mm) is calculated, from equation

where, η is the dynamic viscosity of water at the test temperature (m.Pa.s) shown in Table 2 HR is the effective depth at which the density of the suspension is measured (mm); ρs is the particle density (Mg/m3); t is the elapsed time (min); 0.005531 is a constant. Record the value of D, calculated from each set of readings, as shown in column 8 in Table 1.

KNS 2591 CIVIL ENGINEERING LABORATORY 3 FACULTY OF ENGINEERING

UNIVERSITI MALAYSIA SARAWAK

4. The modified hydrometer reading, Rd,is calculated from the equation: Rd = R,, - Ro where; R'o is the hydrometer reading at the upper rim of the meniscus in the dispersant solution. The value of Rd is entered as shown in column 9 of Table 1. 5. The percentage by mass, K is calculated, of particles smaller than corresponding equivalent particle diameter, D (mm), from the equation;

Where, m is the mass of the dry soil used (g) The value K is entered corresponding to each value of D as shown in column 10 of Table 1.

KNS 2591 CIVIL ENGINEERING LABORATORY 3 FACULTY OF ENGINEERING UNIVERSITI MALAYSIA SARAWAK

Hydrometer Calibration and Sample Data

Weight of hydrometer = 70.0 g Volume of hydrometer, Vh = 70.0 ml L = 241.0 mm N = 10.0 mm h = 158.0 mm

Hydrometer No.

1

Meniscus Correction

Cm

0.5 mm

Reading in dispersant

Ro

0.5 mm

Calibration equation HR = 193.7 – 3.85 Rh Dry mass of soil

M

50.08 gram

Particle density

Ρs

2.70

Mg/m3

measured/assumed Viscosity of water at

Η

0.891

m.Pa.s

25oC

Calibration of Hydrometer

Scale mark

Reading

(g/cm3)

Rh

Distance from

d+N=H

HR

(mm)

lowest mark d (mm) 1.030 1.025 1.020 1.015 1.010 1.005 1.000 0.995

30 25 20 15 10 5 0 -5

12.6 18.5 37.0 56.0 75.0 94.0 114.1 133.0

22.6 28.5 47.0 66.0 85.0 104.0 124.1 143.0

92.2 98.1 116.6 135.6 154.6 173.6 193.7 212.6

KNS 2591 CIVIL ENGINEERING LABORATORY 3 FACULTY OF ENGINEERING UNIVERSITI MALAYSIA SARAWAK

Data Collection and Calculation

1

2

3

4

5

6

7

8

9

10

D ate

Time of

Elapse d

Temp .

Readin g

readin g

Time

(T˚C)

Rh’

Rh’ + Cm = Rh

(min)

Effectiv e

Particle

Rh’-

Depth

Diamete r

R’o = Rd

HR

D (mm)

Percenta ge finer than D

(mm)

K (%) 9/8

1 0/8

9.00a m 9.02a m 9.04a m 9.06a m 9.08a m 9.16a m 9.30a m 10.00a m 9.00a m

0

25

13.0

13.5

141.73

-

12.5

39.64

2

25

10.0

10.5

153.28

0.0351

9.5

30.13

4

25

6.5

7.0

166.75

0.0259

6.0

19.03

6

25

1.5

2.0

186.00

0.0223

1.0

3.17

8

25

-1.5

-1.0

197.55

0.0199

-2.0

-6.34

16

25

-2.5

-2.0

201.40

0.0142

-3.0

-9.51

30

25

-3.5

-3.0

205.25

0.0105

-4.0

-12.69

60

25

-4.0

-3.5

207.18

0.0074

-4.5

-14.27

1440

25

-4.5

-4.0

209.10

0.0015

-5.0

-15.86

CALCULATION : Formula used:

Particle size,

D = 0.005531

ηH t ( ρ s − 1) t

Percentage finer, K=

100ρ s Rd m( ρ s − 1)

KNS 2591 CIVIL ENGINEERING LABORATORY 3 FACULTY OF ENGINEERING UNIVERSITI MALAYSIA SARAWAK

Thus, the graph of effective depth, HR versus reading, Rh is plotted as below.

From the graph above, the equation of the line is HR = 193.7 – 3.85 Rh. Thus, the graph of percentage finer (%) versus particle diameter (mm) is plotted as shown below.

KNS 2591 CIVIL ENGINEERING LABORATORY 3 FACULTY OF ENGINEERING UNIVERSITI MALAYSIA SARAWAK

DISCUSSION :

Hydrometer analysis is one of the mechanical analysis to determine the size range of particles present in a soil. Hydrometer analysis is based on the principle of sedimentation of soil grains in water. When a soil specimen is dispersed in water, the particles settle at different velocities, depending on their shape, size and weight. Hydrometer analysis takes longer time due to the waiting for the sediments of smaller soils particles. Some errors such as defects on equipment and parallax error (personal error during taking reading) may occur during experiment and these will affect the result of the experiment After the soil sample gone through the procedures of this Hydrometer Analysis, data is taken for plotting the grain size distribution graph. From the graph, we can see that this soil sample is considered as poorly graded.

CONCLUSION : The objective to determine the grain-size distribution of soil by hydrometer method is achieved. The sample of soil in this laboratory test is poorly graded.