What is the initial setting time of Portland-Pozzolana Cement when tested by the Vicat apparatus method as described in IS 4031 (Part 5):1988?

Explanation:

• As per IS 4031 (Part 5): 1988, which outlines the procedure for determining the initial setting time of cement using the Vicat apparatus, the initial setting time for Portland-Pozzolana Cement should not be less than 30 minutes.
• This standard defines the time it takes for the cement paste to lose its plasticity and begin to set, and for Portland-Pozzolana Cement, it is specified as 30 minutes or more

 Additional Information The Vicat Apparatus is an essential tool used for determining the setting times (initial and final) of cement, and it also measures the consistency of the cement paste. It is widely used in accordance with standards like IS 4031 (Part 5): 1988 to ensure the quality of cement used in construction.

Components of Vicat Apparatus:

1. Frame: The apparatus is typically mounted on a metal or wooden frame that holds all the components together.

2. Plunger: The most important part is the Vicat needle or plunger (a metal rod with a pointed end), which is used to test the consistency and setting times of cement.

3. Scale: A vertical scale attached to the apparatus that allows accurate measurement of the needle's penetration depth.

4. Needle Holder: The needle is fixed to a holder, which is part of a movable system that ensures precise downward movement.

5. Base Plate: A flat surface where the cement paste is placed for testing.

6. Initial and Final Setting Time Needle: There are two different needles for testing:

   • Initial Setting Time Needle: A needle with a 1-mm sqaurearea used for the initial setting time.

   • Final Setting Time Needle: A thicker needle, typically with a 5-mm diameter, used for the final setting time.