How to check the quality of bricks for construction

It is a fact that people have many misconceptions about the blocks or bricks that are used for construction. They are often confused about choosing the right kind of bricks that are sturdy and durable. Some people believe that the bricks should be immersed in a tank filled with water while others say that it would affect the bonding between the bricks and the cement if they are soaked in water.

Bricks or building blocks are made by mixing clay, sand and iron oxide in water and then baking them in a kiln. Other than granting bricks their classic red colour, iron oxide does nothing to improve the quality of the blocks. However, there is no need to purchase them separately as most varieties of sand contain iron oxide. The blocks are baked in a kiln which is broken and opened a few days later. But, the kiln shouldn’t be opened unless it is cooled down naturally. It is said that the bricks would lose their sturdiness if the kiln is opened before it is cooled down. This is an important process that makes the bricks strong and durable. Clay is a major ingredient as it gives sturdiness to the bricks. However, building blocks cannot be made using just clay. All the ingredients have to be mixed in the correct ratio and baked in the kiln to make durable blocks.

There are some modern engineering tests to gauge the sturdiness of the bricks. However, the masons and construction workers use simple yet practical methods to test their durability. They take a block and knock on them using their knuckles. If the blocks make loud and clear sound, then they are of high quality. However, if they make a scattering sound, then those bricks won’t be used for construction.

Another test is to drop the block horizontally to the ground. It is said that a good quality brick won’t break even if it is dropped from six feet high. However, make sure that it is dropped horizontally. Besides, bricks that contain clay in the right ratio would have sharp corners and bright red colour.

Break a few blocks collected from various parts of the kiln. If they aren’t baked properly, you would find raw sand, in a yellow hue, inside the pieces. Before purchasing bricks in bulk orders, bring a few blocks home and immerse them in a bucket of water or in a pond. If the block doesn’t get soaked completely or the corners aren’t soft, then you could buy those blocks. A good quality block doesn’t get ruined if they are immersed in water.

As the blocks are baked in a kiln at high temperatures, they tend to absorb water. It would even absorb the water in the concrete mixture that is used for proofing. This might weaken the concrete and affect its quality. The bricks that are used for building the structure should be immersed in water or watered nicely using a hose. In engineering, this process is called pre-curing. Those who plan to build a house could even purchase bricks in advance and leave it outside in the rain for a year before the construction.

Even after the structure is built, it should be watered regularly for at least two more weeks. This would not only increase the durability of the bricks but make the concrete mixture sturdier too. This process is called post-curing. Without proper pre-curing and post-curing, the structure may not be sturdy enough.

(The writer is a civil engineer who has been working in India and the UAE for the last twenty-five years. He is also an expert in Vastu shastra. His WhattsApp number - + 971 50 731 0906.)