INITIAL AND FINAL SETTING TIME
We need to calculate the initial and final setting time as per IS: 4031 (Part 5) – 1988. To do so we need Vicat apparatus conforming to IS: 5513 – 1976, Balance, whose permissible variation at a load of 1000g should be +1.0g, Gauging trowel conforming to IS: 10086 – 1982.
Procedure to determine initial and final setting time of cement
i) Prepare a cement paste by gauging the cement with 0.85 times the water required to give a paste of standard consistency.
ii) Start a stop-watch, the moment water is added to the cement.
iii) Fill the Vicat mould completely with the cement paste gauged as above, the mould resting on a non-porous plate and smooth off the surface of the paste making it level with the top of the mould. The cement block thus prepared in the mould is the test block.
A) INITIAL SETTING TIME
Place the test block under the rod bearing the needle. Lower the needle gently in order to make contact with the surface of the cement paste and release quickly, allowing it to penetrate the test block. Repeat the procedure till the needle fails to pierce the test block to a point 5.0 ± 0.5mm measured from the bottom of the mould.The time period elapsing between the time, water is added to the cement and the time, the needle fails to pierce the test block by 5.0 ± 0.5mm measured from the bottom of the mould, is the initial setting time.
B) FINAL SETTING TIME
Replace the above needle by the one with an annular attachment. The cement should be considered as finally set when, upon applying the needle gently to the surface of the test block, the needle makes an impression therein, while the attachment fails to do so. The period elapsing between the time, water is added to the cement and the time, the needle makes an impression on the surface of the test block, while the attachment fails to do so, is the final setting time.
If you have a query, you can ask a question here.
SOME DEFINE INITIAL SETTING TIME AS 20 MINUTES,SOME SAY 40 MINUTE AND SOME OF THE VIEW 2 HOUR ,WANA CALRIFICATION PLZ
for opc minimum 30min,maximum 45min
to refer M.S shetty book
how will calculate the yield of concrete
thanks alot
initial time must not be less than 45 min…and final time not more than 10 hours
Dear MR. Fahad and MR. Kundi
as per BIs requirement initial setting time for cement is MINIMUM 30 minutes and final setting time is 600 minutes
final setting time is MAXimum 600 minutes
The initial setting time is 45minutes while the final setting time should not be more than 10hours
normally for OPC final setting time should not be exeed 10 hrs, while for GGBS it will exeed….
what is the importance of knowing the initial and final setting of cement?
for insuring to get the required strength and then further work progress may occur.
What is the reasons for having standard consistency high and low respectively?
very short and effective
why we are taking 0.85 times the water required to give a paste of standard consistency for initial setting time….
its very useful for my first civil project
As per gernal intial and final setting time depend upon the climate and soarse of aggregate
so educative. can u post the importance of initial and final setting time for cement
Thank u,very much
what is the maximum time for the use of m50 concrete at site
because sometimes miller may take 2 hours to deliever the concrete due to heavy traffic
Hi Manikandan,
This is actually fingure method for yield of concrete
For example for M20(1:1.5:3)
2/3(1X.035+1.5X0.035+3X0.035)=?
0.035 is your Volume of 50Kg of Cement
Dear sir, my question is how much time maximum time required for placing the freshly mixed concrete at site and give me IS code reference .
how is the rate of setting of portland cement controlled in manufacturing process?
hello mam/sir
i would like to know why the initial setting time should be adequately large?