Introduction to Building Material Part 1 ( Stone Masonry )

STONEMASONRY

The stones are derived from rocks which form the earth’s crust and have no definite shape or chemical composition but are two or more minerals.

Also Read: 18mm-thick-cement-plaster

Stones are classified in the following three groups:

Geological classification:

a)  Igneous rocks: The igneous rocks are formed by the cooling of magma or lava. These are strong & durable. It has a crystalline glossy and fused texture.

b)  Sedimentary rocks: These rocks are formed due to the gradual deposition of materials like sand, clay, etc. These rocks are also called stratified because these rocks are formed in layers.

c)   Metamorphic rocks: These rocks are formed due to the alternation of the original structure under the heat and pressure.

SL No.	Rocks		Examples
1	Igneous rock		Granite, Basalt, Dolerite, Gabbro, Andesite, Dolomite, Trap, Pegmatite etc.
2	Sedimentary rocks		Gravel, Sand, Lime, Shales, Gypsum,Lignite etc.
3	Metamorphic rocks	Marble, Slate, Quartz etc.

Physical classification of rocks:

a)  Stratified rocks: The stratified rocks are those rocks which exhibit distinct layers which can be separated.

b)  Unstratified rocks: The unstratified rocks are those which do not show any sign of strata and cannot be easily split into slabs.

c)   Foliated rocks: They have the tendency to split in a definite direction.

Gabbro

Sl.No	Rocks	Example
1	Stratified rocks	Sandstone, Limestone, Slate
2	Unstratified rocks	Granite, Trap, Marble
3	Foliated rocks	Gneiss, Schist

Chemical classification of rocks:-

a)  Siliceous rock: In these rocks, silica is the main constituent.

b)  Argillaceous rocks: In these rocks, clay is the main constituent.

c)   Calcareous rocks: In these rocks, lime or calcium carbonate( CaCO₃ ) is the main constituent.

Sl No.	Rocks	Example
1	Siliceous rock	Granite, Sandstone, Quartzite
2	Argillaceous rock	Slates, Laterite, Clay, Mudstone
3	Calcareous rock	Limestone, Marble

 The classification of sedimentary rocks :

Rocks	Example
Mechanical	The conglomerate, Breccia, Sandstone, Siltstone, Mudstone, Shale, etc.
Chemical	Limestone, Dolostone, Evaporties etc.
Organic	Coal, Chert

The classification of igneous rocks:

Rocks	Example
Intrusive(plutonic)	Gabbro, Diorite, Granodionrite, Granite etc.
Extrusive(volcanic)	Basalt, Andersite, Dacite, Rhyosite etc.

Shale

The classification of metamorphic rocks:

Rocks	Example
Foliated	Slate, Schist, Gneiss, etc
Non- Foiliated	Quartzite, Marble, etc.

Our Youtube Channel: Specialised Civil