Stones are the basic and most important construction material used in building construction. Aggregate is a stone type that is used mostly in construction. It is used for preparing concrete. Other different types of stones are also used for decoration and construction. ( For stones classification visit this link – Click here).Characteristics of good building stones should satisfy the following:
Characteristics of good building stones
i) Appearance and color
ii) Porosity and absorption
v) Resistance to fire
vi) Electrical resistance
vii) Hardness and toughness
x) Dressing ( arrange in shape and size)
i) Appearance and color:
The stone which is to be employed(used) for decoration purposes, should have uniform color and should be free from clay. The stone should also have the ability to receive good polish.
ii) Porosity and absorption:
The pore present in the stone to a greater extent makes stone unsuitable for buildings Construction because during rain seeping into pores contains acid which destroys the stone. so, stones with fewer pores must be adopted.
The weight of good building stone should be high, as heavier stone can resist the force of a bigger magnitude.
The Compact stone can withstand the effect of external agencies effectively.
v) Resistance to fire:
Resistance against fire, the stone should be free from calcium carbonate(CaCo3) or oxide of iron and should have homogeneous Composition.
vi) Electrical resistance:
The electrical resistance of a stone decrease when it gets wet. Thus, to have a high electrical resistance stone must be non-absorbent like a stone.
vii) Hardness and toughness:
The stone must be hard and tough so that they may resist wear and tear hardness may be tested by Subtracting and toughness of the stone can be tested by subjecting to a hammering action.
Stones are used in the structures are usually subjected to compression, so the stone should have sufficient strength to scope (meet) with the requirement.
The stone is more durable in case it is compact, homogeneous and free from materials affected by dilute HCl and H2So4. It should have negligible water absorption.
x) Dressing ( arrange in shape and size) :
The art of shaping the stone is known as dressing. The stone should have uniform texture so that they may be easily dressed. if it is to hard finish will be poor and dressing will be uneconomical.
Cost is an important consideration in the selection of building stone. The subsequence cost of dressing of stone before it is placed directly in the structure should also be less.
The good stone must also be free from Quarry’s shape. The stone after Quarry and dressing should be left for a period of 6 to 12 months for proper seasoning before using in the construction work.
(# Quarrying of stone:
The act of taking out the stone from the natural rocks beds of various sizes is known as Quarrying of stone.
# Method of Quarrying:
i) Quarrying without blasting.
ii) Quarrying by blasting.
iii) Firing off a shot. )