Stones And Its Properties

Explanation
A good building stone requires a crushing strength greater than 100 N/mm2. This is because the crushing strength of a stone determines its ability to withstand heavy loads and pressure without breaking or crumbling. Stones with a higher crushing strength are more durable and suitable for construction purposes as they can withstand the weight and stress exerted on them. Stones with a lower crushing strength may not be able to withstand the required load and can lead to structural failures. Therefore, a higher crushing strength is necessary for a good building stone.

Explanation
A good building stone should have a specific gravity greater than 2.7. Specific gravity is a measure of the density of a material compared to the density of water. A higher specific gravity indicates that the stone is denser and therefore more durable and strong, making it suitable for construction purposes. Stones with a lower specific gravity may be weaker and more prone to damage, making them unsuitable for building structures.

Explanation
Hardness is an important parameter considered in the construction of bridges because bridges are subjected to heavy loads and various environmental conditions. A bridge needs to be strong and durable to withstand these forces and maintain its structural integrity over time. Hardness is a measure of a material's resistance to deformation, and by using hard materials in the construction of bridges, they can effectively support the weight of vehicles and withstand external pressures such as wind, water, and seismic activity. Therefore, hardness is crucial in ensuring the safety and longevity of bridges.

Explanation
Granite is not suitable for ordinary building purposes because it is costly. This means that using granite for construction would be expensive and may not be cost-effective for most building projects.

Explanation
The percentage absorption by weight of a good stone should not exceed 0.6 after a certain number of hours. To ensure that the stone meets this requirement, it should be left for a longer period of time. The longer the stone is left, the more time it has to absorb water and reach its maximum absorption capacity. Therefore, the correct answer is 24 hours, as this is the longest duration provided and allows for the highest level of absorption.

Explanation
A good stone should have a toughness index that is higher than 19. This means that the stone should be able to withstand a significant amount of force or pressure without breaking or crumbling. Stones with a higher toughness index are more durable and can be used for various construction purposes, such as building walls or roads. A toughness index of 19 or higher ensures that the stone is strong enough to withstand the demands of these applications.

Explanation
A building stone should possess a crystalline structure because it provides strength and durability to the stone. Crystalline structure refers to the arrangement of atoms or molecules in a repeating pattern, which creates a solid and stable material. This structure helps the stone withstand external forces and prevents it from easily breaking or crumbling. Additionally, a crystalline structure allows the stone to have a uniform appearance and texture, making it more aesthetically pleasing for use in construction.

Explanation
Dressing of stone refers to the process of preparing the surface of a stone by removing any unevenness or irregularities to obtain a smooth and even surface. This process is commonly done to obtain plain edges or to shape the stone into the required size and shape. It involves techniques such as cutting, shaping, and polishing the stone to achieve the desired finish. Quarrying of stone involves extracting stone from a quarry, seasoning of stone refers to the process of drying freshly quarried stone to reduce moisture content, and blasting of stone involves using explosives to break larger pieces of stone.

Explanation
Stones with lighter shades of color are preferred because they don't spoil the appearance. Lighter shades of color tend to be more visually pleasing and can enhance the overall aesthetic of a space. Additionally, lighter colored stones are less likely to show dirt or stains, making them easier to maintain and keep clean.

Explanation
Granite is the best stone suited for construction of piers and abutments of a railway bridge. This is because granite is a strong and durable stone with high compressive strength, making it ideal for supporting heavy loads and withstanding the constant pressure and vibrations of a railway bridge. Additionally, granite has low porosity, which means it is less likely to absorb water and therefore less susceptible to damage from freeze-thaw cycles.