Requirements of Good Building Stones
Here described requirements of good building stones:
- Strength: The stone should be capable to resist the load coming on it. Ordinarily it is not of primary concern since all stones are with good strength. Though in case of large structure, it can be necessary to verify the strength.
- Durability: selected Stones should be capable of resisting adverse effects of natural forces like, rain, wind and heat.
- Hardness: The stone utilized in floors and pavements should be capable to resist abrasive forces which are caused by movement of people and materials over them.
- Toughness: Building stones should be tough sufficient to sustain stresses developed due to vibrations. The vibrations can be raised due to the machinery mounted over them or loads moving over them.Stone aggregates used in the road constructions should be tough.
- Specific Gravity: Heavier variety of stones should be used for the construction of retaining walls, dams, docks and harbors. The particular gravity of good building stone is between the range 2.4 and 2.8.
- Porosity and Absorption: Building stone should not be porous. If it is porous rain water will enters into the pour and reacts with stone and crumbles it. The freezing of water in pores occurs and it results into the disintegration of the stone in higher altitudes.
- Dressing: Giving required shape to the stone is known dressing. It should be simple to dress so that the cost of dressing is reduced. Yet the care should be taken so that, It is not be at the cost of the required strength and the durability.
- Appearance: In case of the stones to be utilized for face works, where appearance is a primary requirement, its ability and color to receive polish is an important factor.
- Seasoning: Good stones should be free from the quarry sap. Laterite stones should not be utilized for 6 to 12 months after quarrying. They are permitted to get rid of quarry sap by the action of nature. This procedure of removing quarry sap is known seasoning.
- Cost: Cost is an essential consideration in choosing a building material. Closeness of the quarry to building site brings down the price of transportation and therefore the cost of stones comes down.
On the other hand it may be noted that not a single stone may satisfy all the requirements of a good building stones, as one requirement can oppose another. For instance, durability and strength requirement contradicts ease of dressing requirement. Therefore it is necessary that site engineer looks into the properties needed for the intended work and choose the stone.