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Selection of Building Materials

• Different Materials

Different Materials

A)  Sand:

• Should be free from –   Clay, Dirt, Mica & Shales etc.

B)  Brick:

• Shape should be proper.
• Corners should be sharp, not broken.
• Color should be uniform.
• Ringing sound in collision.
• Water absorption not more than 15%, etc.

C)  Steel Reinforcement:

• Free from – rust, cracks, piping, oils, grease.
• Strength in proportion with concrete.

D)  Aggregate:

• Should be solid, cubical and free from dirt.
• Do not contain clay, mud or dirt particles.
• Should be graded (small to large), not single size.

E)  Water:

• Drinkable water is best one.
• Waste water from industries may be harmful.
• Should be free from clay, oil and grease.
• Maximum water decrease strength & durability.

F)  Cement:

• Only high grade of cement can not increase the strength of concrete.
• Grade of cement should be just higher the grade of concrete.
• Higher grade of cement produces more heat of hydration and cracks.
• Quantity of cement can not increase strength, water-cement ratio should be decreased.
• Quantity of cement can not be saved using higher grade, while water-cement ratio not decreased. But it can not be done without admixture for required workability.

Note:

• You can replace switch, bulb, finishing, but not the structure (cement, sand & aggregate). The cost of structure is only 30-40% of total cost.
• For the good quality of construction you have to pay only 10-12% more cost than you think.
• After addition of water, concrete and/or mortar should be placed at position within 3 hrs, not whole day.
• More water cannot give the best compaction, but giver porous & weak concrete.

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