Table of Contents
In this article, we will discuss how to check the quality of cement.
Cement may be prescribed as a material with adhesive and cohesive properties which make it capable of bonding mineral fragments into a compact whole.
For constructional uses, the definition of the word cement is restricted to the bonding materials utilized with stones, sand, bricks, building blocks, etc.
The principal components of this type of cement are made of lime so in building and civil engineering we are concerned with calcareous cement.
The cement of interest in the making of concrete has the property of setting and interest underwater under a chemical reaction with it and is therefore called hydraulic cement.
1. How to Check the Quality of Cement?
Here are the factors that need to be observed to know and check the quality of cement as follows:
a. Packing Date
The manufacturer’s date should be observed on the cement bag. It is necessary because the strength of cement declines with age.
Cement may be defined as a very fine powder that absorbs moistness from the air fast. A tiny quantity of moisture is constantly available in the air, and when the cement bag absorbs this moistness, the initial setting occurs, and the cement slowly fails its strength.
| Age of cement | Percentage of Strength reduction |
|---|---|
| 3 months | 20% to 30% |
| 6 months | 30% to 40% |
| 12 months | 40% to 50% |
From the above table, you can notice that the strength of cement loses its strength over a span of time.
2. Colour of Cement
The colour of cement should be uniform. An ideal colour of cement is grey with a light greenish shade. The cement colour gives an indication of excess clay or lime.
3. Check for lumps
Lumps are created due to the existence of moistness in cement. Cement experiences a chemical reaction when it is in contact with atmospheric moistness this process is defined as hydration. Due to which lumps of cement paste are seen. Cement evolves ineffective once it is hydrated with moisture (liquid form or vapour form).
4. Rubbing Test
Always grab a bit of cement on your fingers and rub it within your fingers, it should be smooth while rubbing. If it is rough, which means that cement is mixed with sand.
5. Float test of cement
Bring a handful of cement and put it in water, a good quality cement should always sink and not float on water.
6. Hand insertion
Keep[ your hand in the cement bag. It must provide you with a cool sensation. It means that no hydration reaction took place in the cement bag, the cement can be used.
7. Shape Test of Cement
Bring 100g of cement and prepare a stiff paste by putting in some water. Then make a cement cake having sharp edges and put it on a glass plate. Submerge this plate in the bucket containing water on it. Watch that the shape shouldn’t get damaged during settling. Good cement should be capable to form and attain strength in water.
8. Strength Test
Prepare a block of cement 2.5 cm x 2.5 cm and 20 cm long. Submerge the cement block in water for a period of 7 days. Put the submerged concrete block on supports 1500 cm apart and then provide a load with a weight of 340 N. The block which is prepared of good cement should not display any sign of failure.
9. Specific Gravity of Cement
Discovering the specific gravity of cement is of the supreme matter if cement is kept for more than three months in a store. Good quality cement must have a specific gravity (Sg) of around 3.1-3.6gm/cc.
| Read Also: Grades of Cement Mortar |
