It is a fact that people have many misconceptions about the blocks or bricks that are used for construction. They are often confused when it comes to choosing the right type of bricks that are strong and durable. Some people believe that the bricks should be immersed in a tank full of water, while others say that it would affect the bond between the bricks and the cement if they are taken out of water.
Bricks or building blocks are made by mixing clay, sand and iron oxide with water and then firing them in a kiln. Other than giving the bricks their classic red color, iron oxide does nothing to improve the quality of the blocks. However, there is no need to buy them separately, as most varieties of sand contain iron oxide. The blocks are fired in an oven that is broken and opened a few days later. But, the oven should not be opened unless it cools down naturally. It is said that the bricks would lose their strength if the kiln is opened before it cools. This is an important process that makes bricks strong and durable. Clay is an important ingredient as it gives strength to the bricks. However, building blocks cannot be made from clay alone. All ingredients must be mixed in the correct ratio and baked in the oven to make durable blocks.
There are some modern engineering tests to measure the strength of bricks. However, masons and construction workers use simple but practical methods to test their durability. They take a block and poke them with their knuckles. If the blocks sound loud and clear, then they are of high quality. However, if they make a scattering sound, these bricks will not be used for construction.
Another test is to drop the block horizontally on the ground. It is said that a good quality brick will not crack even if dropped from a height of six feet. However, make sure it is dropped horizontally. Also, bricks containing clay in the right proportion would have sharp corners and a bright red color.
Break a few blocks collected from various parts of the furnace. If they are not baked properly, inside the pieces you will find raw, yellow sand. Before buying bricks in bulk orders, take a few blocks home and submerge them in a bucket of water or a pond. If the block does not soak completely or the corners are not soft, you can buy these blocks. A good quality block will not be ruined if submerged in water.
Because the blocks are fired in a kiln at high temperatures, they tend to absorb water. It would even absorb water from the concrete mix used for testing. This could weaken the concrete and affect its quality. The bricks used to build the structure should be dipped in water or hosed down well. In engineering, this process is called precure. Those planning to build a house could even buy bricks in advance and leave them out in the rain for a year before construction.
Even after the structure is built, it should be watered regularly for at least another two weeks. This would not only increase the durability of the bricks but also make the concrete mix more robust. This process is called post-curing. Without proper pre-curing and post-curing, the structure may not be strong enough.
(The writer is a civil engineer who has been working in India and UAE for the last twenty five years. He is also an expert in Vastu shastra. His WhatsApp number – + 971 50 731 0906 .)
