Characteristics Of Good Building Stones
- The stones should have a uniform texture, free from cavities, cracks and patches.
- The stones should not have visible stratification.
- The stones should not be dull in appearance.
- The stones should have fine compact structure for face work.
- Dark colour stones should not be used as it's colour fades with time.
- The stones should be strong and durable.
- The compressive strength of building stone should range between 60 to 200 N/sq. mm
- Heavyweight stones are used for stability of structures of damns, retaining walls, etc.
- Lightweight stones are used for arches, vaults, damns, etc.
- Hardness is determined by the Mohs Scale.
- Hardness is important for floors, pavements, aprons of bridges, etc.
- Toughness is the measure of impact which can be withstood by a stone.
- Tough stones should be used for vibratory and moving loads anticipation.
- Porosity is the property which depends on the mineral constituents, cooling time and structural formation.
- A porous stone usually disintegrates due to absorbed rainwater and later causes cracking.
Some Special Points:
- A good building stone should be free from Calcium Carbonate, Oxides of iron having different coefficients of thermal expansion.
- The stone should be well seasoned.
- Stone's resistance against wear and tear should be high.
- Stone should always be workable, i.e, cutting, dressing and bringing out in the desired shape and may not be uneconomical.
- The specific gravity of stones should range from 2.3 to 2.5.
*Source- Internet, Books and Self-Analysis