The final setting time of cement refers to the time elapsed between the addition of water to cement and the point at which a 1 mm needle creates an indentation on the paste inside the mould, while a 5 mm attachment does not create any impression. This test is crucial in determining the strength gain rate of cement over time.
Procedure to Find Final Setting Time of Cement
Apparatus Required
To conduct experiments in cement testing, certain apparatus and tools are required. These include Vicat’s apparatus, a balance, a measuring cylinder, a stopwatch, a glass plate, an enamel tray, and a trowel.
Vicat’s apparatus is a device that is used to determine the setting time of cement. A balance is needed to accurately measure the mass of the cement samples being tested. A measuring cylinder is used to measure the volume of water required for the test. A stopwatch is used to time the setting of the cement.
In addition, a glass plate and an enamel tray are required to hold the cement samples during the experiment. Finally, a trowel is used to mix the cement and water together to form a paste.
Together, these apparatus and tools enable accurate and precise testing of cement properties, which is important for ensuring the quality and performance of cement in various applications.
Test Procedure
Before beginning the test procedure to determine the amount of water required to give cement paste normal consistency, a consistency test must be conducted. This involves taking 400 g of cement and mixing it with 0.85P of water by weight of cement to form a neat cement paste. The gauging time should be kept between 3 to 5 minutes, and the time should be recorded (T1) when the water is added to the cement.
Next, the Vicat mould should be filled with the cement paste prepared earlier. The mould should be completely filled and the surface of the paste should be smoothed off to make it level with the top of the mould. This cement block is referred to as the test block.
To determine the final setting time, the needle of the Vicat’s apparatus should be replaced with the needle that has an annular attachment. The cement is considered finally set when the final setting needle makes an impression on the surface of the test block while the attachment fails to do so. This time should be recorded as T2.
Fig 1: Vicat’s Apparatus used for determination of Final setting time of cement
Observations
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Calculations
Final Setting Time=T2-T1
Result
The initial setting time of the given sample of cement= _____ min
Precautions
To ensure accurate results during the final setting time test, several necessary precautions must be taken. Firstly, it is essential to release the final setting time needles gently to prevent any disturbance that could affect the test results. Additionally, the experiment should be conducted in an area free from any vibration or other disturbances to minimize any external factors that could impact the outcome of the test.
Moreover, it is crucial to clean the needles every time they are used to avoid any contamination or interference in the test. The position of the mould should also be shifted slightly after each penetration to avoid repeating the same spot, which could lead to erroneous results. Finally, the test should be carried out under the specified environmental conditions to ensure consistency in the testing procedure and eliminate any potential variables that could affect the test results. Overall, by following these precautions, accurate and reliable final setting time test results can be achieved.
Standard Specification of Setting Time for Different Type of Cement
The setting time of cement can vary depending on the admixtures added during the manufacturing process. The standard setting times for different types of cement are listed in accordance with the IS 4031 and IS 269 standards.
Table-1: Final Setting Time for Different Type of Cement
| Cement Type | Final Setting Time, min (max.) |
| OPC(33) | 600 |
| OPC(43) | 600 |
| OPC(53) | 600 |
| SRC | 600 |
| PPC | 600 |
| RHPC | 600 |
| PSC | 600 |
| High alumina | 600 |
| Super sulphated | 600 |
| Low heat | 600 |
| Masonry cement | 1440 |
| IRS-T-40 | 600 |