How to find out the quality of Cement on site
What is cement
A cement is a binder, a very important substance that is used for construction that sets, hardens, and adheres to other materials that bind them together.
Role of Cement
Cement acts as the primary glue in construction projects. Cement is the key ingredient in concrete. If we consider by volume it usually makes up to 10 percent to 15 percent of concrete as a binder with 20 percent and 75 percent aggregates which can be a combination of sand, gravel, and crushed stones.
Cement makes up the paste that binds aggregates together in the mixing of concrete. It hardens through a process called hydration. During hydration the cement and water harden for years, so, technically speaking, the concrete gets even stronger over time.
The main part is mixing the cement with as little water as possible without comprising the flexibility of the wet cement.
Steps to determine the quality of Cement
It is very hard to determine the quality of the cement. In this article detailed information is given about how to detect the quality of cement. The following test are conducted on site to detect the quality of cement
1. Check the Manufacturing date or Date of Packaging
As per IS specifications cement should be re tested, if it is stored within three months. Many types of research reveal that the strength of the cement reduces as time goes on.So before opening the cement bag, one must check the following information i.e date of Packaging and Manufacturing date.
Checklist before opening the Cement Bag
- 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.
- We must check grade and type of cement printed on a cement bag. On the cement bag front side there should be mentioned OPC 53 in words also. For example ‘Ordinary Portland Cement, 53 Grade ’ordinary Portland Cement, 53-S Grade whichever is applicable.
- 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 about the product.
D.MRP (maximum retails price) Check is also important check on a cement bag. The supplier or manufacturer can fool us by selling the cement bag for price more than MRP. Therefore verifying the MRP before buying the cement bag will help the consumer to avoid any kinds of frauds.
- On Standard brand of Cement, there is printed ‘Use no Hooks’ or symbol on cement bag.
F.Check there should be a batch/control unit number in terms of the week; month and year of packing must be printed on the cement bag. It is secure to use a cement bag which is recently packed, usually less than 3 months.
2. Check the color of the cement
One must always check the uniformity and color of the cement. The color of the cement should be grey or light greenish shade.
3. Lump Test
The Cement must be free from small lumps. There should not be any hard lumps in the cement such lumps are formed due to absorption of moisture from the atmosphere. If any bag found to have such type of lumps should be rejected.
4. Test the cement by rubbing
The cement should feel smooth between fingers while rubbing. If it felt rough, it indicates adulteration with sand. It should always feel smooth, not gritty. This type of test is also known as Adulteration Test.
5. Water Sinking Test
This test is done with water. The test consists of throwing some cement in a bucket full of water.The cement particles should float for some time before sinking.If the cement particles doest not float , it indicates that the quality of cement is not good. Immediately the cement should be sent for rejection.
6. Temperature Test of Cement
This is a simple test for Hydration,To conduct the hydration test one should inset the hands inside the cement.If the cement gives a cool feeling then it means that the cement is of excellent quality.However, if it gives a warm feeling that means the cement is hydrated which isnt good.
7. Setting Test.
Cement can also be termed as Hydraulic Cement as it sets under water. For testing the quality of cement Take 100 gm of cement and prepare a paste out of it by adding some water. Make the paste a little bit stiff.The next step is to prepare a cement cake with sharp edges which one needs to place on a glass platter. Now immerse this plate in a water bucket. Examine the shape it shouldn’t get disturbed while it is settling down in the water. Cement which possess good quality attains strength and settles down under water.
8. Smell Test
Smell a little bit of cement.If it has an earthy smell , then the cement consist of excess amount of pounded clay and silt. Immediately one should reject the cement.
9. Strength Test
A cement block of size 25 mm ×25 mm and 200 mm long is prepared and it is immersed for 7 days in water. After that, it is placed on supports 15cm apart and it is loaded with a weight of about 34 kg. The Cement block should not show signs of failure.
10 Specific Gravity test
Specific Gravity of cement is the ratio of the density or mass of cement to the density or mass of a reference substance.
The volume is constant both in state density or mass. The specific gravity value of portland cement is generally around 3.15 while the specific gravity value of portland-blast-furnace-slag and portland-pozzolan cement may have specific gravities near 2.90.
Uses of Cement
Cement is a multifunctional product. The functionalities of cement are mentioned below
- The cement slurry is used for filling cracks in concrete structures.
- Cement mortar is used for masonry work, plastering and pointing.
- Cement concrete is used for the construction of various structures like buildings, bridges. water tanks, tunnels, docks, harbors, etc.
- Cement is used to manufacture lamp posts, telephone posts, railway sleepers, piles, etc.
- For manufacturing cement pipes, garden seats, dust bins, flower pots, etc. cement is commonly used.
- It is useful for the construction of roads, footpaths, courts for various sports, etc.
This article has provided a brief outline about the functionalities and different test conducted to detect the quality of cement. It is very important to follow the correct method and to use appropriate serviced equipment. For construction professionals, it is very important to know the steps and detect the right quality of Cement. If there are errors or failures in the Construction site, it will incur a huge loss to the Construction organization. Testing of Cement is essential to ensure compliance with the specification. High-performance building materials is very much required in construction companies as it enhances resilience including critical infrastructure protection. Thus to create a high-performance building once should always determine the quality of cement as it plays a vital role in the construction project