Bricks
Brick is obtained by casting fine clay into a block, which is dried and then burnt. It is the oldest building block to replace stone. The manufacture of bricks began by hand casting, sun drying and burning in clamps. There has been a considerable amount of technological development with better knowledge about raw material properties, better machinery and better techniques of moulding, drying and burning.
The size of the bricks is 90 mm × 90 mm × 90 mm and 190 mm × 90 mm × 40 mm. With mortar joints, the sizes of these bricks are taken to be 200 mm × 100 mm × 100 mm and 200 mm × 100 mm × 50 mm. Although the old size of 8*3′′/4× 4*1′′/2× 2*5”/8 masonry sizing of 9″×41′′2×3″ is still commonly used in India Is.
Types of bricks
Bricks can be broadly classified as:
(i) Manufacture of bricks
(ii) paving bricks
(iii) Fire Bricks
(iv) Special bricks.
(i) Building Bricks: These bricks are used for the construction of walls.
(ii) Paving bricks: These are vitrified bricks and are used as pavers.
(iii) Fire Bricks: These bricks are specially made to withstand the temperature of the furnace. Silica bricks belong to this category.
(iv) Special Bricks: These bricks differ from the commonly used building bricks in respect of their size and purpose for which they are made. A list of some such bricks is given below:
(a) Bricks of special shape
(b) facing bricks
(c) perforated building bricks
(d) hollow bricks of burnt clay
(e) sewer bricks
(f) Acid resistant bricks.
(a) Special shaped bricks: Special shaped bricks are manufactured to meet the requirements of different situations. Some of them are shown in Fig.
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Fig. Special shaped bricks
(b) Front Bricks: These bricks are used in the Maori exterior. Once these bricks are rendered, plastering is not required. The standard size of these bricks is 190 × 90 × 90 mm or 190 × 90 × 40 mm.
(c) Perforated Building Bricks: These bricks are manufactured with a perforation area of 30 to 45 percent. The area of each perforation should not exceed 500 mm2. The perforation should be distributed evenly over the surface. They are manufactured in sizes of 190 × 190 × 90 mm and 290 × 90 × 90 mm.
(d) Burn not clay hollow bricks: Fig. shows a burnt clay hollow brick. These are light in weight. These are used for the construction of partition walls. They provide good thermal insulation to buildings. They are manufactured in sizes of 190 × 190 × 90 mm, 290 × 90 × 90 mm and 290 × 140 × 90 mm. The thickness of any shell shall not be less than 11 mm and the thickness of any web shall not be less than 8 mm.
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| Fig. hollow bricks |
(e) Sewer Bricks: These bricks are used for construction of sewage lines. They are made up of surface soil, fire clay, or a combination thereof. They are manufactured in sizes of 190 × 90 × 90 mm and 190 × 90 × 40 mm. The average strength of these bricks should be at least 17.5 N/mm2. Water absorption should not exceed 10 percent.
(f) Acid resistant bricks: These bricks are used for floors which are prone to acid attack, lining of chambers in chemical plants, lining of sewers carrying industrial effluents etc. These bricks are made of shale of suitable composition with clay or less lime. and iron materials, flint or sand and vitrified at high temperature in ceramic kiln.