Inovasi makmal (1)

INOVASI DALAM PENGAJARAN DAN PEMBELAJARAN

MAKMAL KEJURUTERAAN AWAM 2(C2003)

MAKMAL KONKRITPrepared by:

Noor Lida JusohKhadijah Murni Ismail

OBJECTIVE

To determine the slump of a sample from freshconcrete of given grade or proportions

TEST 1:SLUMP TEST

THEORY

Concrete is tested during its fresh and hardend state mainly to ensure that concrete mix satisfies the specification of works. In its fresh state, concrete is tested for its consistency so as to achive the desired workability. Workability is an important property in concrete since a workable mix will produce concrete, which can be well compacted, transported and placed without segregation. A well-compacted concrete will produce a good strength concrete. Unsupport concrete, when it is fresh, will flow to the sides and sinking in height will take place. This vertical settlement is known as slump. In this test fresh concrete is filled into a mould of specified shape and the settlement or slump is measured when the supporting mould is removed. Slump increases as water cement ratio increases and for different work different slump values are suitable.

TEST 1:SLUMP TEST

APPARATUS

1. Standard slump cone (100 mm top diameter x 200 mm 2. bottom diameter x 300 mm high)3. Small scoop4. Bullet-nosed rod5. (600 mm long x 16 mm diameter)6. Ruler7. Slump plate (500 mm x 500 mm)

MATERIAL 1. Cement

2.Fine aggregates 3.Course Aggregates 4.Water

TEST 1:SLUMP TEST

PROCEDURE PREPARATION OF CONCRETE MIX 1. Mix cement, fine and course aggregate in a mixer for 1

minute.2. Add in water and mix approximately for another 1 minute.3. When the mix is ready, proceed with the workability tets.4. Place the cone on a smooth, flat and clean surface.5. Fill the mould with 3 layers of concrete approximately of the

same thickness each6. Compact each layer of concrete by tamping it 25 times with

the standard steel rod.

7. Level the top surface of the concrete with a trowel.8. Lift the cone slowly vertically to allow concrete to subside.

TEST 1:SLUMP TEST

PROCEDURE

TEST 1:SLUMP TEST

SLUMP TEST

Measure the diffrence in level between the height of the mould and that of the higest of the subsided concrete. This diffrence in height in mm is taken as slump of concrete.

RESULT

TEST 1:SLUMP TEST

Propotion

Slump

0.6 0.8

1:2:4

1:1.5:3

DISCUSSION:1. Explain THREE (3) factor affecting concrete

workability2. Explain the importance of slump test in

concrete work3. Explain workability of the sample that you

have done 4.Give the definition of segregation and

bleeding in concrete mixture. 5. Sketch THREE (3) type of slump test.

TEST 1:SLUMP TEST

OBJECTIVE

The compressive strength is a measure ofthe concrete’s ability to resist loadswhich tend to crush it.

TEST 2:CUBE TEST

THEORY

The compression test shows the compressive strength of hardened concrete. The testing is done in a laboratory off-site. The only work done on-site is to make a concrete cube for compression test. The strength is measured in N/m2 and is commonly specified as a characteristic strength of concrete measured at 28 days after mixing. The compressive strength is a measure of the concrete’s ability to resist loads which tend to crush it.

TEST 2:CUBE TEST

APPARATUS : 1. Cube(150mm X 150mm)2. Small scoop3. Bullet-nosed rod 4. Steel float5. Steel plate

TEST 2:CUBE TEST

PROCEDURE :

1. Clean the cube mould and coat the inside lightly with form oil, then place on a clean, level and firm surface, i.e. the steel plate

2. Collect a sample3. Fill ¼ the volume of the mould with concrete then compact by

roping 25 times until four layer. Cube may also be compacted using a bulleted-nosed rod.

4. Fill the last layer to overflowing and rod 25 times into the top of the first layer, then top up the mould till overflowing.

5. Level off the top with the steel float and clean any concrete from around the mould.

6. Cap, clearly tag the cube and put it in a cool dry place to set for at least 24 hours.

7. After the mould is removed the cube is sent to the laboratory where it is cured and crushed to test compressive strength.

TEST 2:CUBE TEST

RESULT

TEST 2:CUBE TEST

Water cement

ratio(w/c)

Test date Age of cube

Weight of cube

Max.load

Compression strength(kN/m2)

Compression strength

(Mpa)

0.4

0.5

0.6

0.7

0.8

DISCUSSION

1. Explain THREE (3) factor affecting concrete strength

2. Explain the important of cube test in construction

3. Why cube test must be done make on 7 and 28 days

4. Why the inside of the cube must be cleaned and coated with form oil?

5. Why concrete cube must be curing.

TEST 2:CUBE TEST

OBJECTIVE

To determine the suitable mixture for coarse aggregate and fine aggregate used in concrete.

TEST 3:SIEVE ANALYSIS TEST

THEORY

Fine aggregate is the sand and coarse aggregate is the broken stone used in concrete. Mixed aggregate is the combination of coarse aggregate and fine aggregate used in concrete. Proportion of different sizes of aggregates are used in a concrete mix. Grading of particle size distribution is determined by sieve analysis. This graded aggregate contain material finer than 5 mm classify as fine aggregate. A graded aggregate is one which is made up of stone or particles of different sizes, ranging from large to small. Fine aggregate particles fill the voids in between the coarse aggregate when compacted in concrete mix.


APPARATUS

1. Sieve Shaker2. Sieve (Coarse aggregate)3. Sieve ( Fine aggregate) MATERIAL

1. Sand ( Fine aggregate)2. Broken stone (Coarse aggregate)


PROCEDURE

COARSE AGGREGATE GRADED ( NOMINAL SIZE 20mm)

1. Bring the material to the dry condition before weighing and sieving, this may be achieved either by drying at room temperature or by heating at a temperature not exceeding 110°C

2. Check that the test sieve are dry and clean before use

3. Weight 2 kg the material which pass 20 mm sieve

4. Weight each sieve and pan before use


PROCEDURE


5. Place the sieve to form a nest of sieves, the large size being on top of lower size sieve size. Place the receiving pan at the bottom. Fix this nest of sieves in a sieve shaker.

6. Place an amount of material on the top sieve.

7. Now cover the top sieve and operate the sieve shaker for 10 minute


PROCEDURE


8. Weight the material retained on each sieve.

9. Weight the material on each sieve by minus result at number 8 with number 4

10. The total weight at the final must be nearly 2kg. ( different not less than 1% ) . If not, repeat the procedure above.


PROCEDURE

FINE AGGREGATE GRADED ( NOMINAL SIZE 5mm)

1. Bring the material to the dry condition before weighing and sieving, this may be achieved either by drying at room temperature or by heating at a temperature not exceeding 110°C

2. Check that the test sieve are dry and clean before use

3. Weight 2 kg the material which pass 5 mm sieve

4. Weight each sieve and pan before use


PROCEDURE


5. Place the sieve to form a nest of sieves, the large size being on top of lower size sieve size. Place the receiving pan at the bottom. Fix this nest of sieves in a sieve shaker.

6. Place an amount of material on the top sieve.

7. Now cover the top sieve and operate the sieve shaker for 10 minute


PROCEDURE


8. Weight the material retained on each sieve.

9. Weight the material on each sieve by minus result at number 8 with number 4

10. The total weight at the final must be nearly 2kg. ( different not less than 1% ) . If not, repeat the procedure above.


RESULT


BS. Test Sieve Size

(mm)

Mass of sieve(g)

Mass of sieve + mass retained on

each sieve

Mass retained on each sieve

(g)

Mass passing on each sieve

(g)

Percentage passing (%)

DISCUSSION1. Why the fixed rate of coarse aggregate and

fine aggregate are not suitable for all concrete mixture

2. What is the important in grading aggregate3. State THREE (3) factor that effecting the

result4. Give THREE (3) main feature aggregate

required5. Differentiate between crushed and uncrushed

aggregate


OBJECTIVE

To determine the workability of a sample from fresh concrete of given grade or proportions

TEST 4:COMPACTING FACTOR TEST

THEORY Concrete is tested during it fresh and hardened

state mainly to ensure that concrete mix satifies the specification of work.In its fresh state, concrete is tested for its consistency so as to achieve the desired workability. Workability is an importang property in concrete since a workable mix will produce concrete, which can be well compacted, transported and placed without segregation. A well-compacted concrete will produce a good strength concrete.


APPARATUS

1. Two conical hoppers and cylinder2. Weighing machine

MATERIAL

1. Fresh concrete.


PROCEDURE

PREPARATION OF CONCRETE MIX

1. mix cement, fine and course aggregate in a mixer for 1 minute.

2. add in water and mix approximately for another 1 minute. when the mix is ready, proceed with the workability tets.


PROCEDURE

COMPACTING FACTOR TEST.

1. Clean thoroughly all inside surfaces of hoppers to reduce friction.

2. Each hopper has hinged door (trap door) at the bottom. Make sure that this door is close before commencing the test.

3. Fill up the upper hopper with concrete to the brim.


PROCEDURE


4. Release the door to let the concrete falls into the lower hopper.

5. Release the door of the second hopper to let the concrete falls into the cylinder.

6. Cut off excess concrete from the top of the cylinder by sliding it across with two floats.


PROCEDURE


7. Determine the net weight of the concrete. This weight is known as “ weight of partially compacted concrete”.

8. Empty the cylinder and refill it with the conrete from the same sample in three layers. Tamp each layer 25 times with the standard steel rod.


PROCEDURE


9. Level off the top surface of the cylinder and weight it to the nearest 10mg. This weight is known as “weight of fully compacted concrete”.

10. Calculate the compacting factor of concrete


DISCUSSION

1. What is the meaning of workability

2. Why compacting factor test has to be done quickly after the conrete is mixed

3. What is the factor influence concrete workability

4. Define the compacting factor


OBJECTIVE

To determine initial setting and final setting time of cement.

TEST 5:CEMENT SET TIME

THEORY

The time from the addition of water to the initial and final setting stage are know as setting time. Setting refer to changes of the cement paste from fluid to rigid. The setting process is accompanied by the temperature changes, hydration resolves in the formation of the sea around each particles of cement.


THEORY

The means of controlling the rate at which cement stiffened is by intergrading measured quantities of gypsum

(a) initial setting timedefined has the beginning of the noticeable stiffening in the cement paste and correspond to the rapid rise in temperature. This normally takes about 45-175 minutes.

(b) Final setting timeThis refer to completion of setting which correspond to the peak temperature in the cement paste. The stiffening cement paste increases as the volume of the sel increases and the stage at which this is complete, the final hardening process begins. It normally takes between 3 hours to 10 hours for this to happen.


APPARATUS

1. Vicat's apparatus with initial setting time needle and final setting time needle.

2. Weighing balance accurate up to 0.1gm.3. Non porous plate (Glass or Metal)4. Stop watch5. Spatula.6. Trowel of about 210gm weight .7. Measuring cylinder. 250ml capacity8. Enamel trough Cube(150mm X 150mm)


PROCEDURE

1. Mix 500 g of cement with the percentage of water required for normal consistency as described above. (The specimen used for the normal consistency test can be used.)

2. After moulding cement paste into the test ring, place specimen in moist room for 30 minutes.


PROCEDURE

3. Place specimen ring under Vicat apparatus and lock needle on surface of paste. Set indicator scale to zero.

4. Release weighted needles and record the penetration in mm after 30 seconds.

5. Repeat process every fifteen minutes until initial set is achieved.


PROCEDURE

6. Repeat processes every hour until final set is achieved.

7. Clean the cube mould and coat the inside lightly with form oil, then place on a clean, level and firm surface, i.e. the steel plate

8. Collect a sample


PROCEDURE

9. Fill ¼ the volume of the mould with concrete then compact by roding 25 times until four layer. Cube may also be compacted using a bulleted-nosed rod.

10. Fill the last layer to overflowing and rod 25 times into the top of the first layer, then top up the mould till overflowing.

11. Level off the top with the steel float and clean any concrete from around the mould.


PROCEDURE

12.Cap, clearly tag the cube and put it in a cool dry place to set for at least 24 hours.

13. After the mould is removed the cube is sent to the laboratory where it is cured and crushed to test compressive strength.


DISCUSSION

1. Which two factors mainly influence setting time of cement?

2. Discuss briefly the significance of determining the initial and final setting times.

3. What is the effect on setting time of cement if water added is less or more than 85% of normal constituency of cement ?


Inovasi makmal (1)

Business

Transcript of Inovasi makmal (1)