Concrete Laboratory

7/27/2019 Concrete Laboratory

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CONCRETE TECHNOLOGY

CC203

CIVIL ENGINEERING DEPARTMENT

POLYTECHNIC OF SULTAN AZLAN SHAH

B

Group Name

CONCRETE LABORATORY

..Laboratory / Workshops Name

EN. ANUAR BIN WAHAB

Lecturers Name

2..

Number of Practical

MORTAR

..

Title of Practical

Lecturers Comment

.

.

..

..

Mark :______________%

4/7/2013..

Date & Time of Practical

11/4/2013

.Due Date

No. Matrix of Group Members :

15DKA12F108415DKA12F104115DKA12F1113

.

.


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CONCRETE LABORATORY


SULTAN AZLAN SHAH POLYTECHNIC

EXPERIMENT : 3

TITLE : MORTAR TEST

INTRODUCTION : Mortar may be defined as a paste formed by mixing water, a fine

aggregate and a binding material in a specified proportion. Thisexperiment to see the strength of mortar.

OBJECTIVE : To determine the compressive strength of 1:2 cement and mortar cubes

after 7 days curing.

THEORY : The compressive strength of cement mortar is determine in order to

verify whether the cement conforms to the standards specifications ( BS 12:1971)and whether it will be able to develop the required compressive strength of

concrete.

APPARATUS : 1. Universal testing machine or compression testing machine as per BS

1881 :part 4:1970.

: 2. Cubes mould (150 X 150 X 150) mm

: 3. Vibrating machine as per BS 12:1971

: 4. Sand

: 5. Measuring

: 6. Trowel


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PICTURE APPARATUS

Cube mould

sand

SAFETY AND HEALTH

When everyone in the workshop must wear shirts and shoes workshop workshops.

When to do a job you need to wear gloves when working. Use the tools in the workshop right way. Sure that no one in front of you when doing a job. Do not interfere with a friend when being worked.

PROCEDURE

Mix proportions, mixing and curing of specimens.

1. Calculate the material required. The material for each cube shall be mixed separately andthe quantities of cement and standard and shall be as follows :

i. Cement :2500 gii. Standard :6000 g

iii. Water cement ratio :0.6


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2. Place on a nonporous plate or china dish a mixture of cement and standard sand in theproportion of 1:2 by weight and mix dry with a trowel for one minute and then with water

until the mixture is of uniform colour. The percentage of water to be used shall be water

cement ratio 0.6. the time of mixing (gauging) shall be in any mixing not less than 3

minutes and if the time taken to obtain a uniform colour exceeds 4 minutes, the mixture

shall be rejected and the operation is repeated with the fresh quantity of cement, sand

and water.

3. Place the assembled mould on the table of the vibrating machine and firmly hold it inposition by means of a suitable clamp. Securely attach a hopper shall not be removed

until completion of the vibrating period.

4. Immediately after mixing of mortar in the hopper of the mortar as explained above, fillthe entire quantity the cube mould and compact by vibration. The period of vibration

shall be 2 minutes at the specified

12000 + 400 vibrations perminutes.

5. Remove the mould from the machine and keep it at temperature of 27 + 2 in anatmosphere for at least 90% relative humidity for 24hour after completion of vibrations.

6. At the end of this period, remove the cube from the mould and mark for identificationand immediately submerge in clean and fresh water and keep there until taken out just

prior to breacking. The water in which the cube are submerge shall be renewed after

every 7 days and shall be maintained at the temperatus of 27+2. Keeping the cubes

wet till they are placed in machine for testing.

TESTING & RESULT

Remove any projecting fins and wipe surface water off the cube specimens. The compressive

strength shall be the average of the strength of three cubes for each period respectively.

Cube 7days

Maximum load in KN Strength

Cube1 99.9 KN 4.44 N/MM

Cube2 88.9 KN 3.95 N/MM


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QUESTION

1. How the cement can affect the strength of concrete ?Cavitation in concrete

There are many cavities, power will be reduced. Hollow can occur depending on the water and

cement as well as the amount of water loss from the concrete.

The ratio of water and cement content

An increase in the ratio of water and cement content resulted in an increase in the degree ofcavitation on the concrete drying the same. With this cause can reduce the compressive strength

of concrete.

2. Why do you need to know the strength of concrete?To identify the actual concrete strength at a certain age, for safety reasons to continue the work

next.

To know the actual concrete strength of various grades of concrete types that can be used incertain structures.


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CONCRETE LABORATORY


SULTAN AZLAN SHAH POLYTECHNIC

EXPERIMENT : 3

TITLE : CEMENT SET TIME

INTRODUCTION : This experiment aimed to cement good quality or not, as well as

hydration. Fresh cement between 0-45 minutes, if it's 45 minutes past the

mean cement quality still further, this is only the initial setting time.

setting end time, it takes a relatively long time 3-10 hours, To see the mark

on the cement surface without the cutter of the Vikat apparatus.

THEORY : The time form 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 cell around each particles of cement.

INITIAL SETTING TIME

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

measured quantities of gypsum defined 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.

FINAL SETTING TIME

This refer to completion of setting which correspond to the peak temperature in

the cement paste. The sifening cement paste increases as the volume of the cell

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.


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APPARATUS :

1. Vicats apparatus with initial setting time needle and final setting time needle.2.

Weighing balance accurate up to 0.1 gm.3. Non porous plate (Glass or Metal).

4. Stop watch.5. Spatula.6. Trowel of about 210 gm weight.7. Measuring cylinder 250 ml capacity.

PICTURE APPARATUS

SAFETY AND HEALTH

When everyone in the workshop must wear shirts and shoes workshop workshops. When to do a job you need to wear gloves when working. Use the tools in the workshop right way. Sure that no one in front of you when doing a job. Do not interfere with a friend when being worked.

MATERIAL

1. Water2. Portland cement

PROCEDURE

A. DETERMINE THE INITIAL SETTING TIME OF CEMENT.

1. Mix 400 g of cement with % of water obtained from the standard consistencey test forcement.

2. Leave the mixed cement for 45 minutes before testing it .3. Place specimen ring under Vicat apparatus and lock needle No.2(1 mm) on surface of

paste to test the initial setting time of cement. Set indicator scale to zero.


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4. Release weighted needle and record the penetration in mm.5. Repeat processes in different points of the mixture surface.

B.

DETERMINE THE FINAL SETTING TIME OF CEMENT.

1. Final setting time of cement tested using needle No.3(5 mm) and placed in moisturesurrounding. Test done by placing the needle on the mixed cement surface. After the final

setting time, the point of the needle will leave a mark on the cement surface. This

procedures are done after 10 hours the cement mixture prepared.

RESULT

Test A

Moisture content for standard consistency mixture : 26 %

: 104 ml

Test B

Initial setting time of cement : 195 %

Final setting time of cement : 3-10 hour

QUESTION

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

LESS

Cement will dry quickly and result in an impact cracking.

MORE

It takes time to harden and cause separation between water and cement.

2. State the significance of determining the initial and final setting times.


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Initial setting time

To determine the quality of cement or not.

Final setting time

To see the mark on the cement surface without the cutter of the Vikat apparatus.

Concrete Laboratory

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