Types of Cement and Their Initial and Final Setting Time

In this blog, we are talk about setting time of cement and about the types and differences of Time of Cement. The initial & final time are used in cement to gain some strength purpose. And it enhance the beauty of your house or commercial building.

What Is Setting Time of Cement?

When we talk about the Initial and the final setting time of cement, about how much it takes time to lose its full softness and gain strength to resist the pressure.

Initial Setting Time of Cement

It is the time used elapsed between the moments that added the water into cement and to the time that the paste starts losing its softness.

Final Setting Time of Cement

It is the time used elapsed between the moment the water is added to the cement and the time when cement paste loses its flexibility completely and has reached sufficient firmness to resist certain pressure.

Basic Tests On Cement

The following tests are conducted on cement in the laboratory are as follows:

• Fineness Test of Cement
• Consistency Test of Cement
• Setting Time Test of Cement
• Soundness Test of Cement
• Heat of Hydration Test
• Specific Gravity Test of Cement
• Tensile Strength Test
• Chemical Composition Test

Significance of Initial and Final Setting Time of Cement

1. It is required that cement does not lose its flexibility too early or late. If cement set too early, have insufficient time for transportation or place concrete.
2. If cement set too late then there is a delay in construction work. Also, concrete will not get sufficient strength early and the formwork removal process delayed.
3. The proper setting time required for the thicken of cement paste to a defined consistency.
4. It is indirectly related to the chemical reaction of cement with water to form an aluminium–silicate compound.
5. Initial setting time is a valuable time to know for concrete transportation, placing, and curing.
6. Initial setting time also used to delay the process of hydration or hardening.
7. The final setting time used for the safe removal of scaffolding or form.
8. Factors of Affecting Initial and Final Setting Time of Cement
9. The fineness of cement, the presence of salts in sand, atmospheric conditions.

IS Code for Initial and Final Setting Time of Cement

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

Apparatus

Initial and Final Setting Time of Cement

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

2. Vicat Apparatus – Vicat apparatus should confirm to IS: 5513-1976.

3. Stopwatch

4. Gauging or Mixing Trowel

5. Glass Plate

6. Enamel tray

Test Procedure for Initial and Final Setting Time of Cement

Preparation of Test

1. Consistency of cement shall be evaluated before conducting a test to find out % of the water required by the weight of cement as normal consistency of cement (P).

2. Take about 400 gm of cement and add water about 0.85x P (P is % water needed for normal consistency of cement)

3. Mix water with cement quickly in a brief time about 3 min to 5 min. Start the stopwatch at the instance when water is added to the cement. Record this time (T1).

4. Now, fill this prepared cement paste in Vicat apparatus mould having a diameter of 80 mm and a height of 50 mm resting on non –porous glass plate. Properly fill and smooth off the top surface of mould and level it.

I. Procedure of Initial Setting Time of Cement

1. For deciding the first setting time of cement, place this mould filled with cement paste below the Vicat apparatus and fit the needle used for evaluating the initial setting time.

2. Lower the bottom of the needle such that it touches the top of cement paste filled in mould.

3. Remove the locking pin from the top and quick release the needle, allowing it to penetrate the cement paste.

4. At the beginning, the needle penetrates and touches the bottom of mould. Repeat this process, like quickly releasing the needle after every 2 minutes till the needle does not penetrate the cement paste for about 5 mm measured from the bottom of the mould.

5.  Note Time (T2) when needle does not penetrate 5 mm from the bottom of mould.

Initial and Final Setting Time of Cement

 II. Procedure of Initial Setting Time of Cement

1. For figuring out the final setting time of cement replace the needle with another needle having angular ring attachment.

2. Now, slightly release this needle on the surface of cement paste and see that it is making an impression of the ring on the surface or not. Not the time when need does not make an impression of the surface of cement paste. (T2)

Calculation of Initial and Final Time:

Initial setting time of cement = Time when needle does not penetrate 5 m 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)

Practical Calculations

Let 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

Time when water added to cement = 7:00 am

Time, when needle does not penetrate less than 5 mm from the bottom of mould = 7:45, am

Initial Setting Time of Cement = 7:45 am – 7:00 am = 45 min.

Time When angular ring needle does not make impression on the surface of cement paste = 12:00 pm

Final setting Time of Cement = 12:00 pm – 7:00 am = 5 hr = 300 min.

Standard Values of Initial and Final Setting Time for Various Cement

There are several types of cement used in the construction. It is Depending on the types of cement and mixture used during the manufacturing of cement with initial setting time and final setting time are differs for cement. There are standard–setting time for distinct types of cement is given below.