Ingredients of Good Brick Earth and brick requirements

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Brick Information in Detail:

Bricks are the basic material used for wall construction and can be mold into required shape and size. Ingredients used in first class bricks are:-

    • Silica— A good brick earth should contain 50% to 60%. It imparts uniform shape to the brick. It prevents raw bricks from warping, cracking and shrinking. In excess destroys cohesion between particles, hence does not imparts plasticity.
    • Alumina— It is the chief ingredient and should contain 20 to 30 %. It imparts plasticity to brick earth for easy molding. In excess imparts warping, cracking and shrinking.{ both the components i.e. Silica and Alumina helps each other.}
    • Lime— Quantity of lime should not exceed 5%. It should be finely powdered to prevent shrinkage and flaking of bricks. For making raw bricks sand alone is in-fusible so we use lime for slight fuse at kiln temperature (i.e we can say that sand alone is infusible, but it slightly fuses at kiln temperature in presence of lime.), because fused sand used as a hard cementing material.
    • Oxide of Iron— About 5 to 6% is desirable in good brick earth. It helps lime to fuse sand. It imparts red color to the bricks. In excess it make bricks blackish and bluish. In less quantity it make bricks yellowish.
    • Magnesia—A small quantity imparts yellow tint color to bricks and decreases shrinkage. In excess it leads to decay of bricks.

When you are on field you observed all these brick requirements and you must perform all these for better understanding.

Let’s start

    • outer surface must be even having sharp edges and compact structure with uniform shape and standard size.
    • the brick should be well burnt in kilns and must be free from cracks, flaws and nodules.
    • must have deep red  and cherry color.
    • Brick strength must be 105 kg/cm2.
    • should not make impression on brick surface when scratched with finger nail on the field.
    • it should be free from organic matter, stones, acids and salts.
    • must produce metallic ringing sound when two randomly selected bricks struck with each other.
    • should not absorb water more than 20% of its self dry weight when immersed for 24 hours.
    • must resist atmospheric effects.
Brick defects are as follows:-
    • bloating: the presence of swollen mass at the surface due to excess in carbonaceous and sulphur content.
    • lamination: the presence of lamina due to air entrapment in clay, when molded clay and sand mixed with another mold then two layers were formed with entrapped air.
    • Chuffs: A deformed shape was obtained by falling of rainwater on a hot brick.
    • Black core: due to improper burning i.e. lack of oxygen for carbon and sulphur oxidation within clay.
    • porosity: the presence of voids i.e small empty pockets.
    • nodules: a small swelling at the surface of the brick.

 Thanks for Visiting:)


Arbaj Demrot is the founder of VideRime Online Learning, a leading engineering website. He did his BE Civil and M.Tech Structure from RGPV University, Bhopal and has been working as an Assistant Professor in a reputed college.

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