Table of Contents
(IS:4031 2019 METHODS OF PHYSICAL TESTS FOR HYDRAULIC CEMENT (PART 5) Determination of Initial Setting Time and Final setting Time of Cement Paste)
Initial Setting Time of Cement:
The initial setting time of cement is defined as the time from mixing water to cement to the state of paste when it starts losing plasticity.
Final Setting Time of Cement:
The final l setting time of cement is defined as the time from mixing water to cement to the state of paste when it loses complete Plasticity and becomes firm to displacement under defined pressure.
The setting times of concrete affects the workability duration of the freshly nixed concrete. Once this workability period is assessed, the production – transportation- placement of concrete can be planned for concrete operations.
The parts of Vicat Apparatus ( IS: 5513) with plunger of 10 mm diameter, are shown below
Test Procedure for Initial and Final Setting Time of Cement
Preparation of Test:
Find out % of the water required by the weight of cement for normal / standard consistency of cement (Let it be P gm or percent).
Take about 400 gm of cement and add water about 85 percent of water that was required for normal consistency.
Mix water with cement quickly in a short time about 3 min to 5 min. Start the stopwatch at the instance when water added to the cement. Record this time (T1).
Now, fill Vicat apparatus mould with the paste.
Procedure of Initial Setting Time:
Place the mould in Vicat apparatus in such a way that the needle just touches the surface Release the needle and note down the penetration. Go on repeating the test at interval of two minutes till the pentation is upto 5 mm from bottom. Let it happen after time T2
The difference in the two time readings, T1 and T2 in minutes Is initial setting time in
Procedure of Final Setting Time:
For determining the final setting time of cement replace the needle with another needle having annular space.
On releasing the needle makes impression on the surface. Go on repeating the process.
Note the time when the needle makes no impression on the surface. Let it be T3.
Final setting time of cement = (T3) –T1) in minutes
Test Format for Initial final Setting Times For cement
Setting Times of different Grade of cement