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Stones are derived from the rocks which are naturally occurred as the portion of earth’s crust. Each rock has a different chemical composition and exhibits different properties. Some of these rocks are widely used in the construction industry. Some commonly used building stones along with their properties and uses are explained in this article.
Commonly Used Building Stones
Following are the commonly used building stones.
- Basalt and trap
Granite is an igneous rock which is formed by the solidification of magma at a considerable depth from the earth’s surface. It is hard and durable. It is available in different colors. The color of granite varies according to the amount of feldspar in it. It can be polished nicely.
The compressive strength of granite is about 75 to 130 MPa. Its specific gravity lies between 2.63 to 2.75. Its density is about 26 to 27 KN/m3.
Granite is used for large engineering projects such as the construction of bridge abutments, dams, offshore structures, etc. It is also used for constructing steps, walls, flooring, etc.
2. Basalt and trap
Basalt and trap are also igneous rocks. These stones are also called as green stones or white stones or blue basalt. They are hard and tough. It is difficult to work with this kind of rocks. The specific gravity of basalt and trap varies from 2.6 to 3.0. They are having a high compressive strength of 150 to 190 MPa.
Basalt and trap used as railway ballast, aggregate in concrete, pavement material, etc. Yellow and red-colored basalt and trap are used to construct decorative features in structures.
Syenite is also an igneous rock which is hard and durable like granite. The structure of syenite is coarse-grained and its crushing strength varies from 90 to 150 MPa. It is available in different colors but typically they are light in color.
Crushed syenite is commonly used as aggregate in pavement construction and concrete making. It is also used for external facings of building walls etc.
Limestone belongs to sedimentary rocks which are formed by the deposition of particles of weathering. It contains calcium carbonate in huge proportion. It is soft and easily workable. The compressive strength of limestone is about 55 MPa and specific gravity lies between 2.0 to 2.75.
Limestone is used to manufacture lime and cement. It is also used for flooring, roofing, etc.
Chalk is a sedimentary rock and it contains pure lime in it. It is very soft and easily can be converted into powdered form. It is generally white in color and contains a porous structure.
powdered chalk is used for manufacturing lime putty and also used as a pigment in Portland cement.
Sandstone is a sedimentary rock and consists of different minerals like quartz, feldspar, silica, etc. in it. The hardness of sandstone depends upon the proportion of minerals in it. However, it is easily workable and also available in different colors. The specific gravity of sandstone lies between 2.65 and 2.95. Its compressive strength is about 65 MPa and with a density of 20 to 22 KN/m3.
It is used as material for roofing, paving, columns, facing works and ornamental carvings, etc.
Caliche also called as Kankar falls under the sedimentary category of rocks. It is the impure form of limestone. It is porous in structure and irregular in shape. Its hardness varies from soft to hard.
Caliche or kankar is used as aggregate in pavement construction. It is also used to prepare hydraulic lime.
Marble belongs to the metamorphic category of rocks and it is formed when limestone is subjected to excessive heat and pressure. This process of forming is called metamorphism. Marble is hard and compact in nature. It occurs in different colors and also it can take a good polish. Its compressive strength is about 70 Mpa. The specific gravity of marble is about 2.65.
Marble is used for flooring, facing works, steps, etc. It can be carved into required shape easily hence, it is used for decorative and ornamental works of structures.
Slate is a metamorphic rock which is formed by the metamorphic action of shale under low pressure and heat conditions. It is hard and brittle. It consists of foliated texture and generally black in color. It can be split into thin slabs along its natural foliated planes. Its crushing strength ranges from 75 to 210 Mpa with a specific gravity of 2.89.
Slate is used for floorings, roofing works, partitions, damp proof courses, etc.
Quartzite also belongs metamorphic category which is formed by the metamorphism of sandstone under high pressure and temperature. It is of crystalline structure with a granular texture. It is hard and brittle. It is not easily workable. Its compressive strength is about 115 MPa.
Quartzite is used as road aggregate, concrete aggregate, etc. it is also used to construct retaining walls, rubble masonry, stone pitching, etc.
Laterite also belongs to the metamorphic category. It is porous and spongy in its structure. It is soft and workable hence quarrying of laterite is easy. It has low crushing strength which is about 1.8 to 3.0 MPa. When it is decomposed it turns into moorum which is widely used for road construction.
Laterite is used for rough stone masonry works, pavement construction works, etc.
Gneiss is another metamorphic rock formed by the metamorphosis of granite. It consists of foliated structure hence it can be split into thin slabs along its bedding planes. It is strong and durable. Its crushing strength varies from 206 MPa to 370 MPa with a specific gravity of 2.69.
Crushed gneiss used for pavement construction, rough stone masonry works, stone pitching, etc.