Testing for SG and WA of Fine Aggregate

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Construction Materials

Laboratory Report 1 Testing for Specific Gravity and Water Absorption of Fine Aggregate

ZAMAN UNIVERSITY

2013-‐2014

Professor: Bun Kim Ngun

Student’s Name: Mengheng LIM

Experiment on 23rd of November 2013


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Content

Page

I. Objective of the experiment: ................................................................................. 2

II. Introduction ........................................................................................................... 2

III. Materials and Tools ............................................................................................ 3

IV. Procedures: .......................................................................................................... 4

V. Data ......................................................................................................................... 5

VI. Calculation ........................................................................................................... 6

VII. Conclusion ........................................................................................................... 8

VIII. References ......................................................................................................... 10


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Testing for Specific Gravity

and Water Absorption of Fine Aggregate

I. Objective of the experiment:

In this experiment we want to find the specific gravity and water absorption of fine

aggregates which has been place in water for 24h and after it has been dry up in the

oven. For this experiment, we based on the ASTM C128 standard method and carries

out three different separate tests for more accurate result. This experiment will also

helped us to determine and discuss about the different values due to the errors and

some other factors that has been affected during the process.

II. Introduction

• Specific Gravity is the characteristic that mostly used for calculation for

volume occupied by the aggregate in various mixtures that contain aggregate

such as Portland cement concrete, bituminous concrete, and other mixtures that

are proportioned or analyzed on an absolute volume basis.

• Water Absorption values are widely for calculation of the proportional different

mass of an aggregate as the water is absorbed in the pore spaces within the

constituent particles, compared with dry condition, when it is deemed that the

aggregate has been in contact with water long enough to satisfy most of the

absorption potential.

• These two values are very important to engineers when building structures high

humidity atmosphere and the place where there are a huge different in humidity

daily or monthly. It helps engineer to determine the correct amount of the fine

aggregate during the mixture process so that they can get the better quality for

their concrete. Moreover, before the structures have been finished, this values

must be take into account for calculate the total weight and expansion of the

structures when there are different in humidity in the atmosphere.


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III. Materials and Tools

a. Sample:

• Fine Aggregate: it must be place in the tap water for at least 24h to

make sure that all of its pores has been filled with water. 1kg of fine

aggregate (weight before place in the tap water) is needed to carry out

3 separate tests.

b. Apparatus:

1) Balance with 0.1g precise

2) 250ml volumetric flasks and funnel

3) Conical mold and Tamper

4) Metal pans

5) Drying oven

6) Heat gun

7) Small metal shovel


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IV. Procedures:

1. Use the metal shovel to take out the sand from the wet sand container and place it

on a metal pan about 1.5 inner-volume of conical mold.

2. Use heat gun to dry the surface of the wet fine aggregate to get saturated-surface-

dry aggregate (SSD) and also mix during drying

ü Make sure that it is not too hot as we need only its surface to dry

3. Then use the Conical mold to test whether the fine aggregate surface it dry or not.

Place the Conical mold on the metal pan then put the aggregate inside with small

pressure until it is full. Use tamper to drop on the top of the mold 25 times with

the height 5mm above the mold. Finally, remove take the mold up vertically and

slowly. Then if the aggregate remain in the shape, it means that the aggregate still

has a wet surface, but if the top aggregate has been fallen down a bit, then it can

be used as the saturated surface dry sample.

4. Use the balance to weight SSD about 200g ±10g and mark as S

5. Then put SSD into the 250ml volume metric flask with the help of funnel. Then

put the water inside and shake it gently until there is no bubble coming out which

mean there is no space between each particle. Add more water to the 250ml notice

line.

6. Clean out any wet water outside the volume metric flask and then use the balance

to measure its weight get mark as C

7. Take out those aggregate and place it into the metal pan, use additional water to

help removing aggregate particles. After that, pour the water out of the metal pan

as much as possible.

8. Fill that empty flask with only tap water again and then use balance to measure

the weight and mark as B

9. Place the aggregate in the metal pan into the drying oven for 24H with the

constant temperature of 115oC to get the oven-dry aggregate

10. Use balance to weight the oven-dry aggregate and mark as A

v Repeat this process for 3 times


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V. Data

A: Oven-dry weight

B: Weight of empty flask filled with tap water

C: Weight of flask with aggregate filled with tap water

S: Weight of saturated surface dry aggregate

1st Experiment

A1 197.3g

B1 342.8g

C1 465.8g

S1 200.8g

2nd Experiment

A2 193.6g

B2 345.3g

C2 468.3g

S2 200.2g

3rd Experiment

A3 196.2g

B3 353.8g

C3 479.0g

S3 201.4g


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VI. Calculation

Specific Gravity of Saturated Surface Dry Fine Aggregate

SSG(SSD) =B+S -C�

Specific Gravity of Oven Dry Fine Aggregate

ASG(OD) =B+S -C

Water Absorption of Fine Aggregate

S - AWA (%) = ×100A

First Experiment

200.8( )342.8 200.8 465

2.5809.8

SG SSD = =+ −

197.3( )342.8 200.8 465.8

2.5359SG OD = =+ −

200.8 197.3(%) 100 1.77%197.3

WA − = × =

Second Experiment

200.2( ) 2.5932345.3 200.2 468.3

SG SSD = =+ −

193.6( )345.3 200.2 468.3

2.5077SG OD = =+ −

200.2 193.6(%) 100 3.41%193.6

WA − = × =

Third Experiment

201.4( ) 2.6430353.8 201.4 479.0

SG SSD = =+ −

196.2( )353.8 201.4 479.0

2.5748SG OD = =+ −

201.4 196.2(%) 100 2.65%196.2

WA − = × =


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Average Result:

2.5809

2.5359 2.507

2.5932 2.6430( ) 2.60573

( ) 2.53943

1.77 3.41 2.6

7 2.57

5(%)

48

2.61%3

avg

avg

avg

SG SSD

SG OD

WA

+

+ +

+= =

= =

+ + = =

Standard Deviation:

( )

( )

(%)

SG SSD

SG OD

WA

δδδ

= 0.0268

= 0.0275

= 0.6701

The table shows the overall summary of the result:

1st Experiment

2nd Experiment

3rd Experiment

Average Standard Deviation

SG (SSD) 2.5809 2.5932 2.6430 2.6057 0.0268

SG (OD) 2.5359 2.5077 2.5748 2.5394 0.0275

WA (%) 1.77% 3.41% 2.65% 2.61% 0.6701


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VII. Conclusion

According to the result from our experiments,

The average of Specific Gravity of Saturated Surface Dry Fine Aggregate is 2.6057.

The average of Specific Gravity of Oven Dry Fine Aggregate is 2.5394.

The water absorption rate of the fine aggregate is 1.77%, 3.41%, 2.65%

Discussion: Although the result of SG of SSD and OD for each experiments are close to each

other’s, but there are a huge different in result of Water Absorption and has the

standard deviation up to 0.67. So the overall result of this experiment should not be

trusted or used this result for practical purpose. The experiment went wrong might be

due to:

• The sample fine aggregate that we used as the sample is not pure fine aggregate,

but there are some dust (diameter < 75µm) that mixed with aggregate.

• The sample was continuously lose during the process, which we cannot make sure

that all of the sample will be transferred from one container to another container

and also amount of sample lose for each experiment is not the same.

• Furthermore, at the stage of Saturated Surface Dry (SSD), the drying surface rate

of the three samples are not the same.

• On the other hand, there are also other factors that affect our experiments such as

eye-level error during the volume of water in the volumetric flask.

The test is recommended for carry out the new experiment and might also have to

improve the efficiency but trying to minimize above factors that affect the result. Some

improvement methods are:

• Wash the sample to remove all dust (diameter < 75µm) before use. It can be used

the sieving method with the sieve number 200.

• Minimize the loss of the sample while trying to transfer from one container to

another container.

• Use Pycnometer instead of volumetric flask as it can decrease the eye level error

and also decrease the rate of transferring the sample from volumetric flask to other

container.


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• Make sure that there should not be a big different rate of SSD, by each time try to

measure the amount of wet aggregate taken out and time to dry to be similar.

More importantly make sure the level of distribution of sample in the conical

mold process should be the same or similar. And do not place the sample without

any covering of cloth is it is not being used or pause in any cases.


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VIII. References

1. “Basic Construction Materials” by Theodore Marotta, John C. Coffey, Cynthia

LaFleur-Brown, Christine LaPlante. 8th Ed. Pearson 2010.

2. ASTM C0128-04A Test Method for Density, Relative Density (Specific Gravity), and

Absorption of Fine Aggregate

3. FINE AGGREGATE DENSITY TESTING, WHATIS THE RIGHT WAY TO DO

IT? By Chris Rogers and Tom Dziedziejko

Testing for SG and WA of Fine Aggregate

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