Date:
EXPERIMENT NO-1
OBJECT: To determine the dimension and tolerance of brick.
APPARATUS REQUIRED: Tape
MATERIAL REQUIRED: Bricks – 20 nos.
THEORY: This test is performed to know the accuracy of the dimension of the bricks.
CLASSIFICATION OF BRICKS:
Sl.No. | Types of bricks | Properties | Use |
1. | First class bricks | i)These bricks are well burnt, having smooth and even surface ,with perfect rectangular shape and uniform reddish colour. ii) When struck with other brick, these give a metallic ringing sound. iii) They should not leave any mark when scratched by finger nail. iv) These should not absorb water more than 20% of its weight when immersed in water for 24 hours. v) When broken into two pieces these should show a uniform compact structure. | These are used for good structures such as outer walls and facing work when no plastering is done. These are also used in floors and reinforcement bricks slabs. Such bricks should be laid in rich mortar. |
2. | Second class bricks | i) These are not perfectly rectangular in shape and having rough surface, but are hard, slightly over-burnt and uniform in colour. ii) These give ringing sound when struck with each other. iii) Water absorption should not be more than 22% by weight, when immersed in water for 24 hours. | These are used for internal walls, not exposed to atmosphere; these are used in facing work, which should be plastered. These cannot be used for R.B. work. Such bricks may be laid in mud or lime mortar. |
3. | Third class or pila bricks | i) These bricks are not burnt properly in the kilns and may be slightly under/over-burnt; hence these are soft and can be easily broken. These are light red in colour, with yellowish tinge. ii) On striking, these do not give a ringing sound. iii) These should not absorb more than 25% of water by weight when placed in water for 24 hours. | These are used for inferior construction works, or at places where there is less rainfall or presence of dampness. |
4. | Jhama or over-burnt bricks. | Due to excess fusion and temperature bricks get over-burnt, loose their shape and get twisted. These bricks yet dark bluish in colour. | These are not used in building construction work. In the form of broken pieces, these may be used as road metal, also in foundations and floors as soling material. |
PROCEDURE:
1. Take twenty bricks out of the given samples.
2. Remove loose particles of clay and small projections from the bricks.
3. Arrange them on a level surface in contact with each other and in a straight line.
4. Measure the Overall length of the bricks laid by means of a steel tape.
5. The dimensions of 20 bricks should be within the following limits:
CLASS | LENGTH | WIDTH | HEIGHT |
Class A | 368 to 392 cm | 174 to 186 cm | 174 to186 cm |
Class B | 350 to 410 cm | 165 to 195 cm | 165 to 195 cm |
RESULT:
The following bricks belong to………..
Name
Roll No.
