For determination of setting time of hydrated lime.
IS: 6932(Part 11)-1983-Method of tests for Building Lime (Determination of setting time of hydrated lime)
Equipment & Apparatus
- Burette (50 ml)
- Enamel tray
- Vicat apparatus
Preparation of sample
Lime putty is prepared by thoroughly mixing the 500 gm hydrated lime with an equal mass of clean water and kept for soaking for 24 hours.
- The vicat mould “E” is filled with this paste, the mould resting upon a non porous plate. After filling the mould the top surface is leveled.
- Initial Setting Time: The test block is placed under the rod bearing the needle “C” . The needle is lowered gently to contact with the surface of the test block and then released quickly, allowing it to penetrate into the test block.
- This procedure is repeated until the needle fails to pierce the test block by 5±0.5 mm measured from the bottom of the mould.
- The period elapsing between the time when water is added to the lime and the time at which the needle fails to pierce the test block by 5±0.5 mm is the initial setting time.
- Final Setting time: The needle “C” is replaced by the needle with an annular attachment “F“.
- The lime is considered as finally set when, upon applying the needle gently to the surface of test block, the needle makes an impression on the surface of test block while the attachment fails to do so shall be the final setting time.
The results of initial and final setting time is to be reported to the nearest five minutes
Safety & Precautions
- Use hand gloves while removing containers from oven after switching off the oven.
- Thoroughly clean & dry the container before testing.
- Use apron & safety shoes at the time of testing.
- The apparatus should remain free from vibrations during the test.
- The initial needle is not bent & is fixed vertically straight in to the movable rod.
- The needles & the plunger should be kept free from the adhering cement.
- Equipment should be cleaned thoroughly before testing & after testing.
- Needle should be kept in their respective place after being cleaned & greased.
- Test should be carried out at 270C & 65 ± 5% relative humidity.
- Petroleum jelly should be applied to the mould.
- Bearing should be oiled periodically.