Field Tests of Cement for Civil Engineers_सीमेंट के फील्ड टेस्ट
Channel: Engineers at Site
Date: 09/04/2021

Field Tests of Cement for Civil Engineers
Cement, one of the most important building materials, is a binding agent that sets and hardens to adhere to building units such as stones, bricks, tiles, etc. 
Cement generally refers to a very fine powdery substance chiefly made up of limestone (calcium), sand or clay (silicon), bauxite (aluminum) and iron ore, and may include shells, chalk, marl, shale, clay, blast furnace slag, slate. The raw ingredients are processed in cement manufacturing plants and heated to form a rock-hard substance, which is then ground into a fine powder to be sold. 
Cement mixed with water causes a chemical reaction and forms a paste that sets and hardens to bind individual structures of building materials.

 Date of Manufacturing: As the strength of cement reduces with age, the date of manufacturing of cement bags should be checked.
 Cement Color: The color of cement should be uniform. It should be typical cement color i.e. gray color with a light greenish shade.
 Whether Hard Lumps are Formed: Cement should be free from hard lumps. Such lumps are formed by the absorption of moisture from the atmosphere.
 Temperature Inside Cement Bag: If the hand is plunged into a bag of cement, it should be cool inside the cement bag. If hydration reaction takes place inside the bag, it will become warm.
 Smoothness Test: When cement is touched or rubbed in between fingers, it should give a smooth feeling. If it felt rough, it indicates adulteration with sand.
 Water Sinking Test: If a small quantity of cement is thrown into the water, it should float some time before finally sinking.
 The smell of Cement Paste: A thin paste of cement with water should feel sticky between the fingers. If the cement contains too much-pounded clay and silt as an adulterant, the paste will give an earthy smell.
 Glass Plate Test: A thick paste of cement with water is made on a piece of a glass plate and it is kept under water for 24 hours. It should set and not crack.
 Block Test: A 25mm × 25mm × 200mm (1”×1”×8”) block of cement with water is made. The block is then immersed in water for three days. After removing, it is supported 150mm apart and a weight of 15kg uniformly placed over it. If it shows no sign of failure the cement is good.