There are many types of stones such as basalt, marble, limestone, sandstone, quartzite, limestone, slate, gneiss, leiteite, and granite that can be used as building materials. The stones used in the construction of buildings must be solid, durable and tough, and must be free from soft patches of materials, cracks and other defects that are responsible for reducing strength and durability. Stones for construction purposes are obtained by quarrying from massive hard rocks. What are the stones used in buildings?
Each type of stone is suitable for different construction applications based on its characteristics. For example, certain types such as basalt and granite have superior properties such as high compressive strength and durability, and are therefore used in major construction works. However, there are stones that make their properties (such as low pressure strength and the presence of harmful substances in their components) suitable for minor construction work such as gneiss so the stones are used as building materials and also for decorative purposes.
Basalt stone, also known as traps, is commonly used in road construction as a sum of concrete production and rubble construction works for bridge piers, river walls, and dams. The structure of the basalt stone is medium to fine grained and compact.
The compressive strength of this stone type ranges from 200 MPa to 350Mpa, and its weight ranges between 18 KN / m3 to 29KN / m3. Basalt has good weather resistance, is not affected by moisture, and is very difficult to wear in precise shapes. Basalt changes color from dark gray to black.
The application of granite in the construction of buildings includes sidewalks for bridges, retaining walls, dams, curbs, stone pillars, coarse aggregate in concrete, railway patience, moisture-proof and exterior wall cladding, and massive uses. The granite structure is crystalline, it is strong and largely durable, and its compressive strength ranges from 100MPa to 250MPa. It also has low absorbance value, less porosity, good frost resistance and weathering but has weak fire resistance. It takes good polish, and the color varies from light gray to pink. Polished granite can be used as table coverings, columns and walls cladding.
Sandstones with silica cement are used in the construction of heavy structures. It is also used in construction works, dams, piers, and river walls. It consists of quartz and feldspar and is found in different colors such as white, gray, red, orange, brown, yellow and dark gray. The compressive strength ranges from 20MPa to 170MPa, and gravity ranges from 1.85 to 2.7. It should be known that wrinkled sandstone makes it unsuitable for building construction.
Slate shows great contrast to the buildings properties that depend on the thickness of the panels and the color of the rock. It is used as roofing tiles, slabs, and sidewalks. It consists of quartz, mica and clay minerals. Panel compression strength varies from 100MPa to 200MPa, and can be dark gray, greenish gray, violet gray to black. The slate structure is well-liked and its specific attractiveness is 2.6 to 2.7.
All limestone is not useful for building buildings. The unwanted species is rich in mud or is very soft and practically unsuitable for construction work. However, dense and small types free from cavities and fissures can be easily worn and polished well.
Limestone is used for floors, ceilings and sidewalks and as a basic cement material. Limestone should be avoided as a facing stone in areas where air is polluted by industrial gases and also in coastal areas where salty winds can attack it.
Laterite is used as a building block, but the exterior needs to be coated. It contains a high content of iron oxide and can be easily cut into blocks. Laterite occurs in smooth and hard varieties, and the compressive strength of the poor ranges from 1.9MPa to 2.3 MPa, the color of Laterite may be brown, red, yellow, brown and gray.
It is used for facades and ornamental works in columns, floors and steps. Marble compressive strength ranges from 70MPa to 75MPa marble stones are very strong and uniform in texture and less porous and pick up great paint. It can be easily cut and carved into various shapes. Marble is available in different colors such as white and pink.
This type of stone is used for simple construction because the presence of harmful substances in its components makes it undesirable for building buildings. However, hard types of gneiss can be used in construction work. The compressive strength ranges from 50MPa to 200MPa. It is good for coarse grains, light gray, pink, purple, greenish gray and dark gray.
It is used as building blocks, slabs, and concrete aggregates. The quartzite structure is good for baking cereals and most of them are granules and brands, mainly consisting of feldspar and mica in small quantities. Crushing strength ranges from 50MPa to 300MPa and is available in different colors such as white, gray and yellow.
It is used for paving, garden paths and yards. The specific gravity is 1.68 and the compressive strength ranges from 80-120 MPa. The stone has holes engraved and basin in its surface which means it has a porous surface and a consistent texture. They can be polished smooth and shiny, and come in a variety of colors from gray to coral red.
It is an important property to be considered when a stone is used for flooring and pavement. The coefficient of hardness is to be found by conducting a test on a standard specimen in Dorys testing machine.
The process of removing moisture from pores is called seasoning. The best way of seasoning is to allow it to the action of nature for 6 to 12 months. This is very much required in the case of laterite stones.
1. Strength : The stone should be able to resist the load coming on it. Ordinarily this is not of primary concern since all stones are having good strength. However in case of a large structure, it may be necessary to check the strength.
4. Toughness:Building stones should be tough enough to sustain stresses developed due to vibrations. The vibrations may be due to the machinery mounted over them or due to the loads moving over them.The stone aggregates used in the road construction should be tough.
6. Porosity and Absorption:Building stone should not be porous. If it is porous rainwater enters the pour and reacts with stone and crumbles it.In higher altitudes, the freezing of water in pores takes place and it results in the disintegration of the stone.
7. Dressing: Giving the required shape to the stone is called dressing. It should be easy to dress so that the cost of dressing is reduced. However the care should be taken so that, this is not at the cost of the required strength and the durability.
9. Seasoning:Good stones should be free from the quarry sap. Laterite stones should not be used for 6 to 12 months after quarrying.They are allowed to get rid of quarry sap by the action of nature. This process of removing quarry sap is called seasoning.
10. Cost:Cost is an important consideration in selecting a building material. The proximity of the quarry to the building site brings down the cost of transportation and hence the cost of stones comes down.
Stoneis a heterogeneous substance characterized by wide ranges of mineral composition, texture, and structure. Consequently, the physical and chemicalproperties, i. e., the durability, are extremely variable.