LAB Report - Hydrometer TEST ( Group 1) - EC110 4B PDF

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SOIL ENGINEERING LABORATORY ECG263 MARCH – JULY 2021 LECTURER

: IR. AMMINUDIN BIN AB LATIF

TITLE OF EXPERIMENT

: HYDROMETER TEST

DATE OF TESTING

: 2/4/2021

GROUP

: EC110 4B (GROUP 1)

GROUP MEMBERS 1. A’IN NUR ASYQIN BINTI MOHD ANUAR (2019220582) 2. MOHAMMAD AZHAD UKAIL BIN MAT NASIR (2019647054) 3. MUHAMMAD AMIRUL THAQIF BIN NORMAN (2019291846) 4. NUR ALYA ATHIRAH BINTI MUHAMAD FARIT (2019220294) LEVEL OF OPENESS : 1 CO-PO

Description

CO3

Perform teamwork skills in task related to soil engineering Function effectively as an individual, and as a member in diverse technical teams.

PO9

CONTENT / CRITERIA

AFFECTIVE DOMAIN

MARK

INTRODUCTION

A1

2

OBJECTIVE(S)

A2

4

PROCEDURE & METHODOLOGY

A3

2

RESULTS & ANALYSIS

A3

4

DISCUSSION

A4

4

CONCLUSION

A5

4

TOTAL MARKS

20

1. INTRODUCTION Level 1 laboratory activity refers to condition where the problem and ways & means are guided and given to the students. The answers to the task, on the other hand, are left to the students to solve using their collective imagination and ingenuity. The exercise is intended to gradually introduce and instil autonomous learning among students, preparing them for the far more difficult job of open-ended laboratory tasks. In this laboratory we will be exposed to the usage of hydrometer test to determine and evaluate the particle size distribution of a given soil sample. For soil samples containing finegrained particles, a wet sieving procedure is first carried out and test is conducted to determine the combined clay/silt fraction percentage. The combined clay or silt fraction is determined from the weight difference and expressed as a percentage of the total sub-sample weight. The test is in accordance to BS 1377-2:1990 test 9.2. The soil hydrometer test is the best way to determine the particle size distribution of fine-grained soils like clay and silt. All geotechnical laboratories are familiar with this sedimentation procedure. It is because the hydrometer is a device that uses the notion of buoyancy to determine the relative density of liquids. One or more scales, such as specific gravity, are usually calibrated and graded.

2. OBJECTIVE The objective of this lab is to determine the grain size distribution of a soil sample for fine soil.

3. PROCEDURE & METHODOLOGY

1. The fine soil from the bottom pan of the sieve set was taken, and was placed into a beaker, and 125 mL of the dispersing agent (sodium hexametaphosphate (40 g/L)) solution was added. The mixture was stirred until the soil is thoroughly wet. Let the soil soak for at least ten minutes. 2. While the soil is soaking, 125mL of dispersing agent was added into the control cylinder and it was filled with distilled water to the mark. The reading at the top of the meniscus formed by the hydrometer stem and the control solution was taken. A reading less than zero is recorded as a negative (-) correction and a reading between zero and sixty is recorded as a positive (+) correction. This reading is called the zero correction. The meniscus correction is the difference between the top of the meniscus and the level of the solution in the control jar (Usually about +1). The control cylinder was shaken in such a way that the contents are mixed thoroughly. The hydrometer and thermometer were inserted into the control cylinder and the zero correction and temperature were noted respectively. 3. The soil slurry was transferred into a mixer by adding more distilled water, if necessary, until mixing cup is at least half full. Then, the solution was mixed for a period of two minutes. 4. Immediately the soil slurry was transferred into the empty sedimentation cylinder. The distilled water was added up to the mark. 5. The open end of the cylinder was covered with a stopper and it was secured with the palm of our hand. Then, the cylinder was turned upside down and back upright for a period of one minute. (The cylinder should be inverted approximately 30 times during the minute.) 6. The cylinder was set down and the time was recorded. Then, the stopper was removed from the cylinder. After an elapsed time of one minute and forty seconds, very slowly and carefully the hydrometer was inserted for the first reading. (Note: It should take about ten seconds to insert or remove the hydrometer to minimize any disturbance, and the release of the hydrometer should be made as close to the reading depth as possible to avoid excessive bobbing).

7. The reading was taken by observing the top of the meniscus formed by the suspension and the hydrometer stem. The hydrometer was removed slowly and placed back into the control cylinder. Very gently spin it in control cylinder to remove any particles that may have adhered. 8. The hydrometer readings were taken after elapsed time of 2 and 5, 8, 15, 30, 60 minutes and 24 hours.

4. ANALYSIS AND ENTERPETATION OF DATA Particle Size Distribution – Hydrometer test

Initial mass of dry soil used (g) = BS Sieve Mass of opening size Sieve / pan only (mm) (g)

1 000 Mass of Sieve / pan and soil (g)

Test Sedimentation by the hydrometer method method Cumulative Mass of soils Corrected percentage mass retained Percentage passing retained (g) retained (%) (g) (%)

5

0.00

3.35

0.00

0.0

0.0

5.00

5.00

0.5

99.5

2

10.00

10.00

1.0

98.5

1.18

20.00

20.00

2.0

96.5

0.6

60.00

60.00

6.0

90.5

0.425

50.00

50.00

5.0

85.5

0.3

70.00

70.00

7.0

78.5

0.212

100.00

100.00

10.0

68.5

0.15

130.00

130.00

13.0

55.5

270.00

270.00

27.0

28.5

285.00

285.00

28.5

1000

100

0.063 Soil Passing 63 µm Total

Soil Mechanics Laboratory, Universiti Teknologi MARA Pahang

Soil Description

Light Grey Silty SAND

Test method

Sedimentation by hydrometer method

Calibration and Sample Data

Pretreatment for Organic Matter

Hydrometer No.

Pretreatted with

Meniscus Correction, Cm

0.250

Initial dry mass of soil, mօ (g)

Reading in Dispersant, Rօ’

1.250

Dry mass after pretreatment, m (g)

Calibration Equation, Hr

204.479 - 4.046 Rh

Pretreatment loss, mօ – m (g)

% of soil passes 0.063 mm sieve

Percentage loss (%)

Dry mass of soil used, m (g)

600.00

Particle Density of soil, ρs (Mg/m3)

2.65

Water Temperature, T (օC)

27

Viscosity of water, η (mPa.s)

0.852

Equivalent particle diameter (mm) η𝐻𝑟

𝐷 = 0.005531 √(𝜌 𝑠 −1)𝑡 % Finer than D 100𝜌𝑠 𝐾={ 𝑚(𝜌 𝑠 − 1)

} 𝑅𝑑

Rh’= Cm + Rh

Effective depth, Hr (mm)

Particle diameter, D (mm)

Rh ’ + Rօ ’ = Rd

% finer than D, K (%)

29.25

87.145

0.052

30.50

8.16

Date

Time

Elapsed Time, t (min)

1 Jan

8.30 am

0.5

27

29.00

1.0

27

23.00

23.25

111.421

0.042

24.50

6.55

3.0

27

16.00

16.25

139.743

0.027

17.50

4.68

4.0

27

14.00

14.25

147.835

0.024

15.50

4.15

8.0

27

12.00

12.25

155.927

0.017

13.50

3.61

15.0

27

10.00

10.25

164.019

0.013

11.50

3.08

30.0

27

8.00

8.25

172.111

0.0095

9.50

2.54

60.0

27

6.00

6.25

180.203

0.0069

7.50

2.01

120.0

27

4.00

4.25

188.295

0.0050

5.50

1.47

240.0

27

3.00

3.25

192.341

0.0035

4.50

1.20

640.0

27

2.50

2.75

194.364

0.0022

4.00

1.07

1440.0

27

2.00

2.25

196.387

0.0015

3.50

0.94

2 Jan

8.30 am

Temp., T (օC)

Reading, Rh

Tested by:

Check by:

Approved by:

90 80 70

% Finer

60 50 40 30 20 10 0 0

0.01

0.02

0.03

Particle diameter, D (mm

0.04

0.05

0.06

5. DISCUSSION

Based on the experiment, students can apply the basic knowledge about hydrometer test that used in order to determine the specific gravity of density of the suspension. The hydrometer test is commonly used to determine the soil's moisture content. The fine particle's grain size is between 0.065mm and D (particle diameter) > 1m. The sample was given by the students in order to test the grain size distribution. We took the fine soils from the sieve set's bottom pan and placed it in a beaker with 125mL of the dispersion agent (sodium hex metaphosphate (40g/L)) in this wet sieving experiment. It is important to use the right amount of sodium hex metaphosphate solution. To prevent the solution from clumping together. If only a small amount of sodium hex metaphosphate is applied, it will be wasteful. When the mixture was whirled in a circular manner, the soil was completely soaked. Allow 10 minutes for the mixture to soak. After the soil had soaked, we filled the control cylinder with distilled water to the mark and applied 125 of dispersion agent. We obtained a reading at the top of the meniscus with the hydrometer stem and the control solution. From the calibration equation, effective hydrometer depth, H and the value of K¹ have been obtained. Equivalent particle diameter has been calculated by using this formula:

Value of D (mm) is given. Modified hydrometer has been calculated by using formula Rd = R’h – R’0. (R’0 = hydrometer reading in the dispersant solution). Percent finer have been calculated by using the formula below:

m = weight of the soil sample in grams Adjusted percentage passing has been calculated the grain size curve D versus the adjusted percent finer have been plotted on the semi logarithmic sheet.

6. CONCLUSION

From the experiment, we have conclude that the experiment have successfully done as we have achieved the objective of this experiment which is determining the grain size distribution of fine soil sample. The percentage of finer than D and the equivalent particle diameter effective depth were determined. A hydrometer test can be used to estimate the percentage of finer particles. As a result, the particle will get finer proportionately with time. The temperature must stay constant during the test, which is room temperature (27 degree). The better the dirt for construction, the finer it is. It is critical to have finer soil, but it is equally critical to obtain coarser aggregate. Because of the decreased fineness, the concrete will be easier to finish. It is not suited for use in construction....