Properties and Quarrying of Good Building Stones

Building stones are fundamental materials in construction, providing structural integrity and aesthetic appeal. Understanding the properties of good building stones and the quarrying process is crucial for ensuring the longevity and durability of structures. This guide delves into the essential characteristics of quality building stones, the methods of stone quarrying, and the factors contributing to stone deterioration.

Properties and Quarrying of Good Building Stones

Properties of Good Building Stones

1. Appearance
• Good and uniform color.
• Dark-colored stones are more susceptible to weathering.
2. Crushing Strength
• Minimum 100 MPa.
3. Durability
• High durability is essential.
4. Hardness
• If the hardness coefficient is less than 14, the stone is not suitable for roadwork.
• Minimum hardness coefficient for roadwork is 17.
5. Wear
• Wear by Attrition Test should be less than 3%.
6. Resistance to Fire
• Stones should have good resistance to fire.
7. Specific Gravity
• Should be greater than 2.7.
8. Water Absorption
• Should be less than 0.6%.
9. Texture
• Should be free from cracks and cavities.
10. Toughness Index
• Determined by Impact Test.
• High toughness: >19
• Moderate toughness: 13-19
• Not tough: <13
11. Weathering Resistance
• Stones should be sufficiently resistant to weathering.
• Should be well-seasoned and facilitate dressing.

Stone Quarrying Process

1. Hand Tools
• Basic method for small-scale extraction.
2. Channeling Machine
• Operated by steam or electricity.
3. Blasting
• Most commonly used method for large-scale production.

Dressing of Stones

Purpose:

• To increase strength and durability.
• To obtain a desirable appearance.
• To ease transportation and handling.
• To suit the requirements of stone masonry.

Deterioration of Stones

1. Alternate Drying and Wetting
2. Frost Action
3. Movement of Water/Chemicals
4. Vegetation or Organic Growth

Frequently Asked Questions

1. What is the minimum crushing strength required for a good building stone?
• The minimum crushing strength required is 100 MPa.
2. Why is the hardness coefficient important for building stones?
• The hardness coefficient determines the stone's suitability for roadwork. Stones with a hardness coefficient less than 14 are not suitable for roadwork.
3. What is the acceptable water absorption rate for building stones?
• The water absorption rate should be less than 0.6%.
4. How is the toughness index of a stone determined?
• The toughness index is determined by the Impact Test. Stones with a toughness index greater than 19 are considered highly tough.
5. What are the common methods of stone quarrying?
• Common methods include using hand tools, channeling machines, and blasting.

Conclusion

Selecting the right building stone is crucial for the durability and aesthetic appeal of any construction project. By understanding the properties of good building stones and the quarrying process, you can ensure the longevity and strength of your structures. Keep in mind the factors that contribute to stone deterioration and take preventive measures to maintain the integrity of your building materials.