lab 3 report construction material

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Construction Materials

Laboratory Report 3 Lab Concrete Mix Design

ZAMAN UNIVERSITY

2013-‐2014

Professor: Bun Kim Ngun

Student’s Name: Mengheng LIM

Experiment from 5th to 19th of January 2014

Laboratory Report 3 Concrete Mix Design Based on ACI Standard

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Content

Page

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

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

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

IV. Procedures: .......................................................................................................... 6

V. Data ....................................................................................................................... 12

VI. Calculation ......................................................................................................... 13

VII. Conclusion ......................................................................................................... 14

VIII. References ......................................................................................................... 15


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Lab Concrete Mix Design

I. Objective of the experiment:

The aim of this experiment is to design the concrete with 30MPa strength for 28days

by using the ACI standard. Moreover, we will also be able to conduct the compression

strength for 3 days 7 days and 28 days and compare the different. Further more we

also can find its bulk density of concrete. This experiment will also let us know about

the availability uses of the American Standard to the structure in Cambodia, as we do

not have the same compositions such as Aggregates or Cement.

II. Introduction

• The American Concrete Institute (ACI) is a leading authority and resource worldwide

for the development and distribution of consensus-based standards, technical

resources, educational programs, and proven expertise for individuals and

organizations involved in concrete design, construction, and materials, who share a

commitment to pursuing the best use of concrete.

• Base on the ACI standard we are going to use we will design the concrete with

30MPa strength after 28 days. And this concrete can be use as the mass concrete,

beam or column.

• The strength of concrete is increasing day by day after mixing and has a higher rate if

we place those in the high moisture contain.

• There are some limitation of the size of the coarse aggregate to have its maximum

size of 20mm and the dry-rod weight of coarse aggregate of 1600kg/m3. It also should

have the moisture absorption of 2% for coarse aggregate and 1.5% for fine aggregate.

Furthermore, the fineness modulus of sand should be 2.7.

• In order to make 1m3 of concrete using this design we need

o Cement = 360kg

o Fine Aggregate = 804kg

o Coarse Aggregate = 1028kg

o Water Cement Ratio = 0.54 0.55 0.56 (based on the slump test)

o Slump = 75-100 mm


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III. Materials and Tools

Ø FOR SLUMP TEST

a. Sample: Volume of Slump Cone

Small diameter (d) 0.1m

Large diameter (D) 0.2m

Height (H) 0.3m

Volume (V) 0.0055m3

• Waste factor of 40% due to the small volume of concrete but big equipment,

which result in a big waste of concrete compare to amount that we need • So the total volume needed for the slump test is 1.4V = 0.0077m3

• The water cement ratio of 0.54

For 1 m3 (kg) For 0.0077 m3 (kg)

Cement 360 2.77

Fine Aggregate 804 6.19

Coarse Aggregate 1024 7.88

Water (W/C = 0.55) 194.4 1.50

b. Apparatus: 1) Balance with 0.1g precise

2) Slump Cone (d=10cm, D=20cm, Height=30cm)

3) Metal Plate

4) Tamper

5) Portable Concrete Mixer

6) Ruler

7) Metal Tray and metal shovel


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Ø FOR THE COMPLETE CONCRETE MIX

c. Sample: Volume of CUBE mold

Each side (L) 0.15m

Volume (V) 0.003375m3

Volume for 9 molds 9V = 0.030375m3

Waste factor of 15%

So the total volume needed for the slump test is 1.15x9V = 0.035m3

The water cement ratio of 0.56

For 1 m3 (kg) For 0.035 m3 (kg)

Cement 360 12.6

Fine Aggregate 804 28.14

Coarse Aggregate 1024 35.84

Water 201.6 7.05

d. Apparatus: 1) Balance with 0.1g precise

2) Portable Concrete Mixer

3) Metal Pan Container

4) Tamper

5) Trowel

6) Hummer

7) Metal Shovel

8) Lubricant oil

9) Brush

10) Towel

Ø FOR COMPRESSIVE STRENGTH TEST

e. Sample: Concrete block after mixing

f. Apparatus

Compressive strength testing machine


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Balance with 0.1g precise Metal Tray

Towel

Small Metal Shovel

Hummer Trowel

Fine Aggregate Coarse Aggregate Cement


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Portable Concrete Mixer

Compression Machine with monitor

Cone, Metal Plate and tamper

Cubic Molds Cylindrical Container with brush

Lubricant Oil


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IV. Procedures:

To determine the slump test

1. Use the balance to measure the 6.19kg of fine aggregate, 7.88kg of coarse

aggregate then place into different metal trays.

ü Make sure that both aggregate are not in the very wet condition

ü Fine aggregate should not contain a lot of dust

ü Coarse aggregate should have a good gradation, the very flat shape

must be remove

2. Take the Water Cement Ratio of 0.54 and weight 1.5kg of tap water then place

into another tray.

3. Then using the balance to measure 2.77kg of cement and place it into tray.

ü Make sure cement is the last for the measurement because the longer

you place outside the package; more moisture will affect quality of

cement.

4. Prepare for the slump cone on the metal plate and bring it near to the portable

mixer as possible

ü Try to fine the any place that is more horizontal as possible to avoid

any incline for water to loss in great amount.

ü The nearly to the portable mixer, the less concrete we loss and

keeping time for the reaction of cement and water

5. Go to the portable concrete mixer and set the angle for the opening, which lead

you to make a better mix.

ü Make sure it is not too high, it will not mix well with this small

amount, and not too low, to prevent the mixer split out any particle.

6. Bring all the tray near the mixer, then pour the fine and coarse aggregate first into

the mixer, wait until it is homogenous

ü Manually use the trowel to help the mixer

7. Then pour the cement into the mixer, and also manually use your hand to help it

mix for more homogenous.

8. Then pour the water into the mixer, and also manually help to mix with trowel to

make it more homogenous.

9. Then use the trowel to get the concrete into metal tray


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ü Do not need to make sure that the all the concrete is transfer from the

mixer into the tray for the first time. Someone should try to collect all

the remaining concrete and put on anther tray.

10. One person stands on the hand for each side of the cone and make sure it is very

close to the metal plate as possible.

11. Use trowel to transfer the concrete into the cone, when it reach to one-third height

of the cone, use tamper to hit it 25 times.

ü Tamper inside all around the cone and in the middle to make sure it

has less pores.

12. Continue pour the concrete inside the cone until reach two third of the height and

full, use tamper to hit each 25 times. Use the trowel to take the concrete to fill up

if it is not full after tamper.

13. Then take out the cone carefully, slowly and importantly vertically. And place that

cone near the concrete.

14. Use the tamper place on the cone, and use the ruler to measure the length that the

concrete from the top of the concrete to the tamper.

15. Confirm that slump with the limitation of 75 mm to 100mm.

16. If is it less, use more water cement ratio to increase the slump. If it is more, use

less water to decrease the slump. Then repeat the process again to check.

17. If it is falling within this limit, we can use the ratio of water cement to mix for the

future concrete mix design.


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Procedure for complete concrete mixing

1. Prepare at least 9 molds near to the mixer and make sure it has been set up by

already screw to keep it shape.

2. Use the hummer to break any small concrete remain and clear it out.

3. Use the towel to clean inside the mold to remove any dust.

4. Pour the lubricant oil into the cylindrical container and use the brush to brush the

oil everywhere inside the mold

ü This will prevent concrete to stick to the mold permanently and easy

to remove after one day.

5. Use the balance to measure the 28.14kg of fine aggregate, 35.84kg of coarse

aggregate then place into different metal trays.

ü Caution of the limitation of the balance: our balance can measure only

15kg before tare only, so we can weight the fine aggregate 2 times and

3 time for coarse aggregate.

6. Take the Water Cement Ratio of 0.56 and weight 7.05kg of tap water then place

into another tray.

7. Then using the balance to measure 12.6kg of cement and place it into tray.

8. Go to the portable concrete mixer and set the angle for the opening, which lead

you to make a better mix.

9. Bring all the tray near the mixer, then pour the fine and coarse aggregate first into

the mixer, wait until it is homogenous also manually use your hand to help to

make it faster and better result

10. Then pour the cement into the mixer, and also manually use your hand to help it

mix for more homogenous.

11. Then pour the water into the mixer, and also manually help to mix with trowel to

make it more homogenous

12. Use trowel to transfer the concrete into the cone, when it reach to one-third height

of the cone, use tamper to hit it 25 times.

13. Continue pour the concrete inside the cone until reach two third of the height and

full, use tamper to hit each 25 times. Use the trowel to take the concrete to fill up

if it is not full after tamper.

14. Use the hummer to hit every side of the mold as the help to reduce any

honeycomb and also to make it smoother.


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15. Keep it as in the room condition for one day and then remove the mold to get the

concrete block.

16. Place those concrete blocks into the water tank to improve it strength.


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To test the compression strength of the concrete

1. Take out 3 concrete blocks from the water tank and place it on the towel.

2. Use the towel to dry the outside surface.

3. Then weight each of concrete blocks and record that as W1 W2 W3.

4. Turn on the compression machine by pressing the Power button on the controller,

and also turn on PC and the monitor.

5. On the controller, press Screw mandrel Lift to lift it up, and remove the wood

sticks out.

6. Then on the PC, launch its program and then input the detail of the concrete block:

Test Number; Number of Day; Design strength = 28MPa; Speed of Compression

to 3Mpa/s

7. Place the concrete block in the middle and then press Screw mandrel down until

the it touch the block.

8. Then on the PC click Tare to make its initial as zero then click Run, and on the

controller click Start.

9. While it continuously compress, the Strength vs. Time graph is generated on the

monitor and with the strength on that current moment.

10. Once the concrete reach its maximum strength, it will automatically stop further

compress to the concrete. We can notice that it will stop after we can hear some

breaking sound on the concrete.

11. Then on the controller press Screw mandrel Lift to remove the concrete block

then use the towel to clean any remaining broken concrete both on the bottom and

the top surface.

Repeat this process for 3 times.


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V. Data

Table 1: Concrete Compressive strength result after 7 days

Sample 1 Sample 2 Sample 3

Weight (g) 7876.7 7966.8 7899.6

Load (kN) 605.4 666.4 649.4

Compressive Strength (MPa) 26.3 29.6 28.3

Table 2: Concrete Compressive strength result after 14 days


Weight (g) 7891.9 7909.0 8000.9

Load (kN) 760.8 761.2 752.6

Compressive Strength (MPa) 33.8 33.8 33.4


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VI. Calculation

Bulk Density

Bulk Density =W

V �

Table 1: Bulk Density result after 7 days


Weight (kg) 7.8767 7.9668 7.8996

Volume (m3) 0.003375 0.003375 0.003375

Bulk Density (kg/m3) 2333.83 2360.53 2340.62

Table 2: Bulk Density result after 14 days


Weight (kg) 7.8919 7.9090 8.0009

Volume (m3) 0.003375 0.003375 0.003375

Bulk Density 2338.34 2343.40 2370.63


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VII. Conclusion

According to the result from our experiment; we notice that low compressive strength

of the concrete after 7 days is 26.3 MPa, which mean that it is very close to the

strength that we design. Moreover, others two concrete blocks already give us the

strength more than 28 MPa. On the other hand, the compressive strength after 14 days

is more than 33 MPa. So it means that it is reached to the desired strength when we

design. And also the bulk density does not have a great different for immersing the

concrete in the water in longer period.

Discussion: As we have observe from this experiment, each materials use can produce different

number of result, such as slump does not fix to have the same ratio for Water Cement

Ratio. It will vary due to he moisture contain of aggregates.

On the other hand, the ways we make the use of ready mix concrete also affect the

strength of the concrete. For example, if we wait too long before it is transfer to the

side, the slump will reduce which mean it has a higher chance for concrete to have

honeycomb. Furthermore, when we use tamper instead of vibrator, we also can notices

that we will have a huge different rate of pore for each of the concrete blocks. So this

test can be improve by using vibrator.

After the test we have conduct the concrete mixing to get the concrete blocks for at

least 14 days, we can conclude that we pass the mix design to get the strength

requirement. So it means that the ACI Standard that is produced by The American

Concrete Institute can also be applied to the concrete mix design in Cambodia.

However, this standard can be confirmed to work well in the lab work test, but not in

the real construction side. The reason for that is the lack of responsible for each step of

the procedure, especially the ratio of the sample used.


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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. ACI Standard for 28MPa Concrete Mixed Design.

lab 3 report construction material

Documents

concrete design

strength of concrete

mass concrete

1m3 of concrete

best use of concrete

bulk density of concrete

aci standard page

o coarse aggregate