The strength of brick masonry depends upon the strength of bricks used in the masonry construction. The strength of bricks depends upon the nature of soil used for making and the method adopted for molding and burning of bricks. since the nature of soil varies from region to region, the average strength of bricks varies from as low as 30kg/sq cm to 150 kg /sq cm the basic compressive stress are different crushing strength.
The strength of a single brick masonry unit varies widely, depending on its ingredients and manufacturing method. The permissible compressive stress in brick masonry depends upon the following factors:
- Type and strength of brick.
- Mortar strength and elasticity.
- Size and shape of masonry construction.
- Bricklayer workmanship.
- The method used to lay brick.
- Brick uniformity
There are many checks that can be applied to see the quality of bricks used on the site. Normally the bricks are tested for Compressive strength, water absorption, dimensional tolerances and efflorescence. However at small construction sites the quality of bricks can be assessed based on following, which is prevalent in many sites.
- Visual check – Bricks should be well burnt and of uniform size and color.
- Striking of two bricks together should produce a metallic ringing sound.
- It should have surface so hard that can’t be scratched by the fingernails.
- A good brick should not break if dropped in standing position from one metre above ground level.
- A good brick shouldn’t absorb moisture of more than 15-20% by weight, when soaked in water.