The First-class Bricks-
As the name suggests, the first-class bricks are of standard size and shape as compared to the others. They have a high strength so as to meet the desirable properties of the good bricks. They are burnt in kilns and on submerging them in water for 24 hours, they absorb 15% self-weight. These bricks have reddish-brown color. Most commonly, these are used for the permanent and the superior construction work.
The Second-class Bricks:
These brick’s quality is lower than the first-class bricks. They are ground-moulded and are non-uniform in shape. Burnt in kilns, they consist of rough, uneven faces or maybe hairline cracks. Moreover, they absorb 22% of their weight when immersed in the water for 24 hours. These bricks are used in the construction of the walls that are plastered later.
The Third-class Bricks:
These types of bricks are low in strength and don’t meet the standards of the good bricks. They are burnt in clamps. Such bricks have distorted edges, thus they are irregular in shape. In the addition, they absorb 25% of the self-weight when submerged for 24 hours in the water. These are used to build temporary structures.
The Fourth-class Bricks:
These bricks are over-burnt and are dark in color with an irregular shape. Due to the complex nature, these bricks may possess strength higher than the first-class bricks in various cases. This renders its use as the aggregate for concrete to construct floors, foundations, roads, etc.