Building Stones || Classification of Rocks

 In many places, as in hilly regions, stones are more freely available than clay bricks. They occur naturally and need not be manufactured so that stone masonry becomes cheaper than brick work. From early days, even before the bricks were invented by the humans, stones were used to build dwellings. Old roads with heavy traffic were also paved with stones. In addition, man learnt to build beautiful monuments with natural stones. They were used for ornamental work in important structures like temples and places of assembly. Stones are more permanent than most of other natural building materials like wood. Most of the prehistoric monuments that remain even today are made of stones. Stones were preferred before the advent of concrete for heavy engineering constructions like bridge piers, harbour walls, seaside walls, and they are still used for facing work, for tall buildings. In many situations, as in foundations of ordinary buildings which are liable to be flooded, the stonework is used instead of brickwork. Submerged bricks usually breakdown with time but the stonework remains stable. Today, stones form an important source of aggregates (both coarse and fine) for concrete.

CLASSIFICATION OF ROCKS :- 

The stones used for masonry construction must be hard, durable, tough and sound. It must be free from weathered soft patches of material, cracks and other defects which may reduce its strength and durability. Stones for building purposes must be obtained by quarrying from solid massive rocks and not by breaking boulders. 

The major classifications of the rocks are discussed here: 

 Geological Classification :-

• Igneous rocks.
• Sedimentary rocks 
• Metamorphic rocks

 Physical classification :-

• Stratified rocks 
• Unstratified rocks
• Foliated rocks

 Chemical classification :-

• Silicious-consisting of quartz. sand, etc.
• Argilacious-consisting of clay minerals.
• Calcarious--consisting of carbonate of lime