When it is not possible to have any laboratory on the construction site. The quality check is performed with the help of some basic field tests. Although these tests are not very accurate, they provide some idea about the Quality of the cement
Testing of cement Can be Done by following two Method :
- Field Testing
- Laboratory Testing
Purity and quality of cement can be judged by applying the following rough and ready field tests:
Tests on Cement at Construction site
The following are the quality tests on cement at construction site:
- Color test
- Float test
- Date of packing
- Temperature test
- Presence Of Lumps
- Strength test
- Setting test
- Adulteration test
The colour of the cement should be greenish grey and it should be uniform in colour.
Take sample of cement from the bag and throw it in a bucket full of water, it should float for sometime before it sinks.
Date of packing
Check the date of packing of cement because strength of cement reduces with time, so it is important to check the manufacturing date of the cement. Generally, the cement should be used before 90 days from the date of manufacturing.
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.
Presence Of Lumps
Open the bag and take a look at the cement, There should not be any visible lumps. Thrust your hand into the cement bag, There should not be any lumps inside. Any bags contains such lumps it should be rejected.
A 25mm × 25mm × 200mm 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
A thick paste of cement with water is made on a piece of glass plate and it is kept under water for 24 hours. It should set and not crack.
Take a pinch of cement and feel (rub) between the fingers, It should give a smooth feeling and not a gritty feeling.
Type of Laboratory Test
- Fineness Test
- Consistency Test
- Setting Time Test
- Strength Test
- Soundness Test
- Heat of Hydration Test
- Tensile Strength Test
- Chemical Composition Test