Setting Time Of Cement | Final Setting Time Of Cement

Initial and Final setting time of cement

Initial Setting Time Of Cement :

It means, time elapsed between when the water is added into the cement & when the cement paste begins to lose its fluidity.

It may also be defined as, the time when water is added into the cement & the Vicat square needle penetrating to a depth of 33-35 mm from the top (5 to 7 mm from the bottom) of the Vicat Apparatus’s mould.

Final Setting Time (FST) of Cement :

The FST means the interval between when water is added or mixed into the cement & when the cement paste has totally lost its fluidity.

Apparatus required for the Initial and Final Setting Time of Cement are :

1. Balance – The permissible variation at a load of 1000 g shall be ± 1.0 g.

2. Vicat Apparatus – It should be confirm to IS 5513-1976.

3. Stop Watch

4. Mixing Trowel

5. Glass Plate

6. Enamel tray.

Test Procedure for Initial & Final Setting Time of Cement :

Preparation of Test

1. First of all we perform test of Consistency of cement, before conducting a test to find out % of the water required by the weight of cement as normal consistency of cement (P).

2. For this test, we have to take about 400 gm of cement & then add water about 0.85x P (P is % water required for normal consistency of cement)

3. Now Mix water with cement in 3-5 min. Now, Start the stopwatch at the instance when water is added to the cement. Record this time (T1).

4. Now we have to fill this prepared cement paste in a Vicat apparatus mould having a diameter of 80 mm & height of 50 mm resting on a non–porous glass plate.

5. Then, we have to Properly fill & smooth off the top surface of mould and level it.

I. Procedure of Initial Setting Time of Cement

1. For determining the IST of cement, we have to filled this mould with cement paste below the Vicat apparatus.

2.Now we have to fit the needle which we have to used for testing the initial setting time.

3. Our next step will be to Lower the bottom of the needle such that it just touches the top of cement paste filled in mould.

4. Then we have to Remove the locking pin from the top & quickly release the needle, we have to just allowing it to penetrate into the cement paste.

5. You will observe at staring, the needle penetrates & touches the bottom of mould.

6. We have to Repeat this process quickly releasing the needle after every 2 minutes till the needle fails to penetrate the cement paste for about 5 mm measured from the bottom of the mould.

5. We have to Note Time (T2) when needle fails to penetrate 5 mm from the bottom of mould.

II. Procedure of Final Setting Time of Cement

1. For determining the Final setting time of cement, we have to just replace the needle with another needle having an angular ring attachment.

2. After that we have to slightly release this needle on the surface of the cement paste.

3. Then we have to observe whether it is making an impression of the ring on the surface or not. Not the time when need fails to make an impression on the surface of cement paste. (T2).

Calculation of Initial and Final Time

Initial setting time of cement = Time when needle fails to penetrate 5 mm from the bottom of mould.(T2) – The time when added to cement (T1)

Final setting time of cement = Time when angular need ring impression stop on cement paste (T3) – Time when water added to cement (T1)

IS Code for Initial & Final Setting Time of Cement :

As Per IS: 4031 (Part 5) – 1988. The initial and final setting time of cement is calculated using the VICAT apparatus conforming to IS: 5513 – 1976.

Here are the sample Practical Calculations :

Suppose, Consistency of cement (P) = 30% and Weight of cement = 400 kg

Water to be added in cement = (0.85 x P ) x 400 = (0.85 x 30%) x 400 = 102 ml

The time when water added to cement = 7:00 am

Time, when needle fails to penetrate less than 5 mm from the bottom of mould = 9 : 00am

Initial Setting Time of Cement = 9 : 00am – 9 : 45 am = 45 min.

Time When angular ring needle fails to make impression on the surface of cement paste = 2 : 00 pm

Final setting Time of Cement : 5 hr - 300 min.

Standard Values of IST & FST for Various Cement :

In construction industry, there are various types of cement used which depends on the types of cementas well as the admixture used in the manufacturing of cement.

Due to these reasons, setting time may varies for different cement. The standard–setting time for different types of cement is given below.

Name of Cement	Ref. IS Code	Initial Setting Time(min)	Final Setting Time(Max)
OPC (33)	IS: 269	30	600
OPC (43)	IS: 8112	30	600
OPC (53)	IS: 12269	30	600
SRC	IS: 12330	30	600
PPC	IS 1489.P1	30	600
RHPC	IS: 8041	30	600
PSC	IS: 455	30	600
High Alumina	IS: 6452	30	600
Super Sulphate	IS: 6909	30	600
Low Heat	IS: 12600	60	600
Masonry Cement	IS: 3466	90	1440
IRS – T -40	Railway	60	600

Here is the video of Initial and Final Setting time of cement :

FAQs:

Initial Setting of Cement

It means, the time elapsed between when the water is added into the cement & when the cement paste begins to lose its fluidity. It should be less than 30 min for OPC cement.

Final Setting Time of Cement

It is the time elapsed between the moment the water is added to the cement & the time when the cement paste loses its plasticity completely & should be able to resist certain definite pressure. It should not be more than 600 min for OPC cement.

Initial and Final Setting Time of OPC Cement?

For OPC, the Minimum setting initial setting is 30 min and the maximum final setting time is 600 min.

What is the Initial setting time of Portland Pozzolona cement (PPC) ?

The Minimum initial setting time of PPC cement is 30 min.