Dimensions of Bricks And Interlocking Of Bricks Used For Construction Of Walls
Brick masonry is made of brick units bonded together with mortar. Two essential components of brick masonry are
- Bricks
- Mortar
- Bricks:-
General properties of bricks:-
- Colour:- Colour should be uniform and bright.
- Size:- Bricks should of standard sizes laid by the BIS (Bureau of Indian Standards).
- Textures:- They should possess fine, dense and uniform texture.
- Soundness:- When two bricks are struck together metallic sound should be emitted and when brick is hit by hammer ringing sound should be emitted.
- Hardness:- Bricks should not have any impressions or scratches when the brick is being laid or after dried in the sun.
- Water absorption:- To test the water absorption of bricks, take a bucket of water free from dirt and other saline deposits and immerse the brick in the water for 24 hours. After the completion of time take the brick outside of the bucket and weight the brick. By taking the initial weight of the brick and water absorbed brick we can calculate the water absorption of the bricks. Bricks with water absorption less than 15% is considered has first class bricks, 20% has second class bricks and 25% has third class bricks.
- Efflorescence:- Bricks which are confined to BIS should not show white patches when soaked in water for a day and allowed to dry in shade. White patches on bricks show the presence of saline deposits like sulphate, magnesium and potassium.
- Thermal conductivity:- Bricks laid by following Indian standards should have low thermal conductivity, So that building built with them are free from noise pollutions and cool in summer and hot in winter.
Clay burnt bricks |
Types of bricks: There are two types of bricks according to the Indian standard specification codes
- Modular bricks and
- Non- modular bricks
Modular bricks:- Modular brick conform to the size specified by the bureau of Indian standard institution. Bricks which is of same shape, size and colour as laid by the BIS is known as modular bricks or standard bricks.
The size of the BIS laid bricks are 20 cm X 10 cm X 10 cm with the inclusion of mortar thickness, the actual size is 19 cm X 9 cm X 9 cm
According to the quality, masonry bricks are classified into three classes
a) First class bricks
b) Second class bricks
c) Third class bricks
a) First class bricks:-
First class bricks are those which are strictly confined to BIS, bricks should have plan surface, sharp edges and size with tolerance in dimensions +-3% ( size 19 cm X 9 cm X 9 cm). Uniform in colour i.e red or brown, Machine moulded and should possess high crushing strength not less than 10.7 N/mm2. Efflorescene should be NIL and water absorption should be less than 15% of whole water poured in the tub during immersion of brick in water. These are free from saline deposits.
b) Second class bricks:-
Second class bricks are less confined to BIS, This bricks possess same properties but Slightly different from the first class bricks. This bricks possess slightly uneven surface and edges with tolerances + -8% but the second class bricks have the standard size and bricks are hand moulded with crushing strength not less than 7 N/mm2. Due to the hand moulding this bricks will have little efflorescence and water absorption is less than 20%. They are fully burnt and ringing sound is emitted when two bricks are struck together.
c) Third class bricks:-
Third class bricks are those which are manufactured in special shapes and sizes to be used for giving architectural shapes. Such bricks are used for copings, cornice, and string courses, sloping walls. these are hand moulded and are over burnt or under burnt and non-uniform colour and efflorescence is more and have 25% water absorption
Fly ash bricks |
- Mortar
Following types of mortars may be used in brick masonry:
- Cement mortar
- Cement lime mortar
- Lime mortat
- Lime surkhi(Lime and sand) mortat
- Mud mortar
Definition of Mortar
Mortar is a homogeneous mixture, produced by uniform mixing of a binder with sand and water to make a paste of required ratio and used to bind bricks.
Mortar is a homogeneous mixture, produced by uniform mixing of a binder with sand and water to make a paste of required ratio and used to bind bricks.
The ingredients of mortar are cement like lime or combination of lime and cement (portland pozzolana cement) and lime pozzolana where sand is used as a filter along with binders to reduce shrinkage characteristics of the mortar.
Consistency of mortar is found by the formula
Lime mortar is prepared from hydraulic and semi-hydraulic limes .
Cement mortar is prepared from cement sand and water mixing ratio and should be used with half an hour from the mortar is mixed.
Very informative article.Clearly explains all the properties of bricks in details.Worth reading.
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