Author: haroonkhan

Autoclaved calcium silicate bricks are popularly known as sand–lime bricks. These bricks are made from a mixture of 95% of sand and 5% of lime (CaO) by weight. These bricks are hard, strong and are uniform in colour and texture. It presents a smooth and soft surface and hence may not be suitable for plastering.…

These bricks are made by pressing the clay to a high pressure of about 40 kg/sq.cm. They are directly burnt without drying. A special type of oil is used in the process which gives a glazed surface. The glazed surface may get peeled off when exposed to weather. These bricks are of a regular shape,…

Refractory bricks, also called Refractory Fire Bricks, are prepared from fire clay in the same manner as ordinary bricks. Refractory bricks contain about 30% alumina and 70% silica. After drying, they are burnt in kilns at high temperature ranging from 1400–1900°C. These bricks are yellowish white in colour. As the fire bricks can resist high…

There are different kinds of bricks which differ from the conventional building bricks with respect to their shape, specifications and special purpose for which they are made. Those bricks are discussed in the subsequent sections. Bull-nosed Bricks A brick moulded with a rounded angle is termed as the bull nose. It is used for rounded…

In this test a brick is broken, and the broken surfaces are examined for the structure. It should be uniformly burnt, homogeneous in structure, compact and free from any defects such as holes, lumps, etc.

Two bricks are struck against each other slightly. A good brick has a clear ringing sound, and the bricks should not get break.

The hardness of a brick surface is determined by making a scratch on the surface of a brick with the help of a finger nail. If no impression is left on the surface of the brick, the brick is considered to be hard.

Twenty bricks are taken at random and their dimensions, length, width and depth are measured. Variations in dimensions generally allowed up to ± 3% for class one and ± 8% for other classes.

The presence of soluble salts causes efflorescence on the surface of the brick. Here also five test samples of bricks are taken at random. The brick is placed in a dish with 2.5 cm immersed in distilled water. The brick is allowed to absorb the water fully, and then the water evaporates through it. When…

For the test, five bricks are taken at random from the lot. They are dried in an oven at 110–115°C till they attain constant weight. Generally it takes 48 hours. Bricks are then cooled at room temperature, which generally takes 4–6 hours and are then weighed. Let the weight of a dry brick be W1. Bricks…