HOW TO CHECK CEMENT QUALITY
Cement is one of the most important materials used in construction. The strength of a structure depends upon several factors, cement quality is one of them. To achieve the desired strength of concrete and to increase the longevity of structure good quality cement should always be used.
So it is important to check the quality of cement before using. In our previous article, we have already discussed the different types of cement and their uses in construction. Today we will discuss how to check the quality of cement at site.
It is not easy to check all properties of cement on the site but there exist some preliminary field tests which can give us a rough idea about the quality of cement.
Below mentioned tests are the simple tests which you can perform easily on site to find out the quality of cement with no apparatus. These preliminary tests include checking the properties of cement which affect the Cement strength and quality.
To check the quality of cement we need to pass some easy tests which are described below:
- DATE OF PACKING:
The strength of cement decreases with time. First of all, check the manufacturing date in the bag before using. Generally, cement should be used before 90 days from the manufacturing date. The percentage of strength loss of cement is given in the below table.
The below table gives details about the percentage of strength loss for different time intervals.
| Age of cement | Percentage of Cement Strength reduction |
| 3 months | 20%-30% |
| 6 months | 30%-40% |
| 12 months | 40%-50% |
From the above table, it is clear that strength of cement loses its strength over a period of time.
- CEMENT COLOR:
The cement should be uniform in color. Good quality cement should have gray color with greenish shade.
The color of the cement is light or grey, greenish shade, and it should be uniform within a bag. The cement color shows a sign of excess of clay or lime and a burning degree.
- CHECK FOR LUMPS:
Lumps are formed due to the presence of moisture in cement. Cement undergoes a chemical reaction when it is reacted with the atmospheric moisture this process is termed as hydration. Moisture is a big enemy for cement. Cement becomes useless once it is hydrated with water (liquid form or vapour form)
- RUBBING TEST:
Cement should feel smooth while rubbing in between fingers. If it gives a rough feeling that means cement is mixed with sand.
5 TEMPERATURE TEST:
Simply insert your hand into the cement bag, it should give cool feeling if its quality is good. Otherwise, you may feel warm because of hydration reaction.
- FLOAT TEST:
Take some amount of cement and throw it in water. The cement should float for sometimes before it sinks in the water.
- SETTING TEST:
Make a thick cement paste with water and immerse it in water for 24 hours. It should be set and should not develop cracks.
- STRENGTH TEST:
Prepare a cement block of 25 mm x 25 mm and 200 mm in length. Now submerge it in water for 7 days. Now place it on supports 15 cm apart and load it with 34 kg weight. Block made from good cement will not show any signs of failure.
Points to Check on a Cement Bag Before Buying
1. Check Manufacturer Name and Trademark
On a cement bag, you have to check the manufacturer’s name and its registered trademark. If the name and trademark are not properly printed or there is any spelling mistake, then the cement bag may be duplicated.
2. IS Mark
We must check the ISI mark printed in black color on the cement bags. The ISI mark ensures about quality of cement that meets the requirements as per Indian standards or that the cement packed in the bag has fulfilled every requirement of the specifications.
3. Cement Grade
We must check the grade and type of cement printed on a cement bag. On the cement bag’s front side there should be mentioned OPC 53 words also.
For example ‘Ordinary Portland Cement, 53 Grade ’Ordinary Portland Cement, 53-S Grade whichever is applicable.
4. Cement Brand Name
Specified brand name of Cement bag. It is important to check cement is of a reputable brand. We must also verify the delivery sheet provided by the brand, to know the technical details of the product.
5. MRP of Cement Bag
MRP (maximum retail price) Check is also important to check on a cement bag. The supplier or manufacturer can fool us by selling the cement bag for a price more than MRP.
Therefore verifying the MRP before buying the cement bag will help the consumer to avoid any kind of fraud.
6. Use No Hooks
On the Standard brand of Cement, there is a printed ‘Use no Hooks’ or symbol on the cement bag.
7. Batch/Control Unit Number
Check there should be batch/control unit numbers in terms of the week; the month and year of packing must be printed on the cement bag.
It is secure to use a cement bag that is recently packed, usually less than 3 months.
8. Additive Details
Check if the type and percentage of performance improver are added and if added must be printed on the cement bag.
9. Reference IS Code
Reference IS code number should be printed on the cement bag. For example, if you have ordered OPC 53 grade cement, then “IS-12269-1987” should be printed on the cement bag.