Choice of Bricks:
The bricks manufactured in Sri Lanka often suffer from the deficiencies of poor quality and dimensional in accuracies, as the manufacturers do not adhere to the relevant standards. Hence it is important to select dependable suppliers for the supply.
The testing of bricks is a very important point in this regard and a point often considered by the consultants.
# In laboratory conditions the bricks can be tested for strength, absorption of water.
# In the site the physically testing can be done by tapping two bricks, dropping on another brick.
#When a randomly selected brick is dropped on to another brick from a height of 1.2m the brick at the ground level should not break. Thus a breaking is an indication of low strength.
# The degree of burning of the bricks should be tested as most of the properties like strength, dimensional stability, wet strength, and water absorption are affected by the burning process.
The simplest possible way is to find the degree burning inspection of cross section of a broken brick.
- If the burning is partial, the color of the cross section is not uniform and it will be possible to see partially burnt core, which would have a pale color than the outer crust. (Shown in figure) Such bricks would absorb higher quantity of water especially from the mortar.
- The over burnt bricks can be identified from the dark patches due to burning and these should be avoided as they would form quite weaker bonds.
Also when two bricks are tapped together a good ringing sound indicates a well-burnt brick with optimum water content.
# The surface texture of a brick is an indication of the quality controlling at the manufacturing stage. Brick manufactured from raw materials of poor quality has defects like lumps, cracks, and cavities sand particles on
the surface. A uniform smooth surface texture is an indication of the attention paid at the manufacturing stage. A non-uniform colored surface is another indication of poor quality control.