INITIAL AND FINAL SETTING TIMES OF CEMENT

 

INITIAL AND FINAL SETTING TIMES OF CEMENT

(IS: 269- 1989 and IS: 4031- 1988 part 5)

 

AIM:  To determine the initial and final setting times for the given sample of cement.

 

APPARATUS:

 Vicat apparatus (conforming to IS: 5513-1976) with attachments, balance, weights, gauging trowel.

 

INTRODUCTION:

In the construction industry work, we all deal with concrete, mortar it requires time to mix, transport, and place. In this time cement is in property of the plastic state and known as setting time. The initial setting time is defined as when the cement starts to set in his position i.e the moment that water added to the cement and time it's losing its plasticity. Now the final setting time defines as when the cement get starts Harding means it starts taking some external force when it is placed in mould. The initial setting time for cement is 30minutes and for the final setting time, it is about 10 hrs after placing cement in mould.          

PROCEDURE:

Preparation of Test Block:

1.      Take a fresh cement to weigh it 300gm in the pan. and with cement weight 0.85 times the water required. This water is from standard consistency results should be taken.

2.         Used portable or drinking water for making cement paste.

3.      The paste will be checked in the way and under the conditions recommended in the assurance of consistency of standard cement paste.

4.          Now set the stop watch in start mode

5.     Fill the mould with the cement paste gauged as above the mould resting on a nonporous plate.

6.        The cement block thus prepared in the mould is the test block. Finally, fill the mould to top-level and the proper surface of mould should be prepared.

 

DETERMINATION OF INITIAL SETTING TIME:

1.        Spot the test blocks restricted in the mould and lay it on the non-permeable plate, under the bar bearing introductory setting needle, bring down the needle tenderly in contact with the outside of the test block and rapidly discharge, permitting it to infiltrate into the test block.

2.         In the beginning, the needle will completely pierce the test block.

3.        Rehash this technique until the needle, when acquired contact with the test block and delivered as depicted above, neglects to puncture the square to a guide 5 toward 7 mm estimated from the base of the form will be the underlying setting time.

 

DETERMINATION OF FINAL SETTING TIME:

1.       Supplant the needle of the Vicat Appartus by the needle with an annular attachment.

2.       The cement will be considered as at long last set when, after applying the needle delicately to the outside of the test block, the needle establishes a connection consequently, while the connection neglects to do as such.

3.         The time frame passed between when water is added to the cement and the time at which the needle establishes a connection with the outside of the test block while the connection neglects to do so will be the final setting time.

 

PRECAUTIONS:

 Clean machines will be utilized for checking. All the devices will be liberated from vibration during the test. The temperature of the water and that of the test room, at the hour of checking, will be 27 0C + 20 C. Care will be taken to keep the needle straight.

 

OBSERVATIONS:

Time in minutes :
Height in mm fails to penetrate

 

 

RESULT:      Initial setting time for the given sample of cement =

 

Final setting time for the given sample of cement =

 

 

 

COMMENTS: