March 6, 2021
A civil engineer knows how to check the quality of cement. But, do you know that? You may think how much necessary it is to know for you. Let me explain that.
Think you are going to build a property by investing your all earnings of life. Now say, the structure is how much important to you? You also have to know the strength and longevity of that structure depends on many factors and the cement is notable of them. Now think, knowing the quality of cement is how much important. It’s ok that the engineer you’ve hired will check the quality of all elements but it’s better you can check them yourself, doesn’t it?
Well, you may read many instructions from different laboratories but you might not understand their all terminology. That is why the way might be difficult a little for you. But here we are going to tell you the way that you can easily understand.
Before discussing the matter of how to check the quality of cement before construction you need to know something. Yes, you have to know, what is cement before understanding the quality?
Cement is nothing but a powdery substance that makes concrete after mixing with sand, gravel, and water. Usually, cement is made by the chemical combination of aluminum, silicon, calcium, iron, and some other ingredients. The purity and ratio of those ingredients and the making process determine the quality of the cement that is going to be made.
Don’t worry we will not finish the content until we can make you understand how to check the quality of cement before construction. So, let’s concentrate on the core matter of this guide. Just keep reading.
Ensuring the quality of cement is necessary to confirm before construction. What will you do if you can’t check the quality after making the construction? So, follow the following tips and know the quality of the cement that is being used in your dream construction.
This is a very simple matter but it signifies a lot. The age of the cement is directly proportional to the strength. Use the cement as early as possible from the manufacturing date you will have optimum strength from it. Nothing matters to the age of the strength. It decreases its strength over time eventually. It doesn’t mean you must have to use it within one to two days but not more than one or a couple of months. The following chart shows the strength reduction. Just have a look.
Just think you will get almost 50% of the whole strength if you use the cement that was manufacture 1 year back. Definitely, you don’t want to have it. So, be careful about the packaging date.
The color also matters. First of all look for what is the color of the cement? And then check if the color is uniform everywhere or not? The color of the cement indicates the composition of the cement. That means it tells about the proportion of different elements and the amount of clay.
Whatever, an ideal color of good quality cement is grey which also consists of the shade of light greenish color! You also have to look the color is uniform and same everywhere.
Cement is a powdery substance that we’ve said before. It is also important to know how fine your cement is! The finer the cement, the stronger the bond! It contains the smallest particles which react with water to form concrete. If the particles smallest, they will have the largest number of contacting points to form the strongest bond.
The test is done by the Blaine air permeability apparatus. Here the specific surface area of the air permeability is measured. The specific area is measured either square centimeter divided by gram (sq. cm/g) or square meter divided by kilogram (sq. meter/kg). It is tasted by throwing a fixed quantity of air through the compacted sample of cement. If you just have the device you can easily test the fineness of your cement.
A lump on the cement is not a good sign. Usually, the cement doesn’t have any lump at the time of packaging. It will be made over time. If the cement absorbs moisture, it will lead to form lump. Moisture is the enemy of cement until it is used. The cement also forms the lump even it reacts with a drop of water. If you store the cement in a place where the air contains much vapor, the whole bag can be concreted. After that, it will be useless. We also advise not to use the cement that has lump inside.
You can also check the quality of the cement just by your two fingers. It is a very simple technique but gives you significant information. Just take a pinch of cement by your two fingers. Then start rubbing. As the cement is powdery, you will feel smooth. You won’t find here any harsh ingredients if the cement is of good quality. If you feel rough then you have to understand the cement contains sand or other harsh elements which indicates impurity.
All you need to do this test is a bucket and water. Take a little water in the bucket. Then take some quantity of cement in your hand and then throw the cement on the water. Now wait for some time and see what happens. If the cement is of very good quality the cement floats on the water for some time. The time is about 10 to 20/30 seconds. But if it has any impurities it sinks immediately and accumulates at the bottom of the bucket. On the other hand, some impurities may float in the water for a long time. Now check the cement and have the idea what quality cement that is!
You may ask how you can check the shape of cement as it is powdery! Well, you can also check the quality by observing the shape under water. For this, mix some water with cement and make a paste. Then give a specific shape of that paste. Ensure the paste has at least one sharp edge. After that immerse the cement paste under the water and look for the shape after the paste is cemented. The shape will never be changed if the cement is ideal and of good quality.
Can you tell me, what is the temperature of cement after packaging? You should test this before using every bag of cement at the construction site. Open the bag and just insert your hand into the cement. If it doesn’t absorb any moisture then you feel cool. Yes, the clean and dry cement bag is always cool. The temperature increases after getting moisture inside the bag. Don’t use the bag if you feel warm before using it.
We are talking all about the cement to ensure good strength. After all, we want to ensure a stronger structure that will last long. We can also test the strength of the cement in an easy way. You have to make a piece of cement block of dimension 200mm in length, 25mm width, and 25mm of depth. Then immerse the block under water for 7 days. Then place the block 15cm apart and load with 34kg. Then your cement is of good quality the block can withstand the weight. But you will see the sign of failure if you’ve used low-quality cement.
Sometimes you might not check the manufacturing or packaging date of the cement. The cement bag is traveled from one place to another place and the manufacturing date might be scratched off. At that time you can check the specific gravity. The specific gravity doesn’t only indicate the age of the cement it also tells the overall quality. The specific gravity of ideal cement always stays between 3.1 to 3.6 g/cc.
If you want to ensure the best quality you have another option to test. You may also know the chemical composition of the cement that it is made of. Usually, the cement has many ingredients but should match with the following percentage of different elements.
How many of us check the quality of the cement at the construction site? More important how many people know these techniques. Forget everything about the past when you didn’t know how to check the quality of cement before construction. But at this time it is clear to you and you can easily check the quality. Now decide, will you go for using cement without checking the quality of it again?