A lot of civil engineering projects like building construction and commercial construction use stone as a basic construction material. Due to their toughness and durability, stones are like high-end construction material. Whether it is a road, a building, a bridge, a retaining wall, or any kind of construction project – stones serve significant purposes.
There are various types of stones which are typically classified on the basis of their formation and origin. On the basis of geological classification, stones or rock used in construction are igneous rocks (basalt, diorite, granite, rhyolite), sedimentary rocks (lime stone, sandstone, and dolomite), and metamorphic rocks (quartzite, marble, slate, and gneiss).
Different factors such as compressive strength, crushing strength, hardness, impact value, and impermeability play a vital role in determining a particular type of stone to deliver a specific goal.
Some stones like granite and basalt are famous because of their enhanced strength and durability but at the same time other type of stones like gneiss are perfect for decorative applications. For massive construction projects like dams and bridge piers, we need stones with high compressive strength like sandstone, granite, and basalt.
So, it is important to know the purpose and pros of a specific type of stone to utilize it for the right type of application. For example, stone that is being used for road base in Austin Texas would need to be more durable than stone being used to landscape in Richmond Virginia
In this article, we are going to discuss few important stones used in civil engineering projects. We will walk you through their types, engineering applications, and structural aspects. At the end is the bonus for you! – we’ll discuss on how to choose the right type of stone for your construction project depending on the properties of a best stone.
So, let’s delve in:
Table of Contents
- 1. Granite
- 2. Slate
- 3. Sandstone
- 4. Limestone
- 5. Marble
- 6. Gneiss
- 7. Laterite
- 8. Basalt & Trap
- 9. Quartzite
- 10. Travertine
- 11. Alabaster
- 12. Chalk
- 13. Murum
- 14. Kankar
- How to choose the best type of stone for construction project?
Granite is an igneous rock. It is primarily composed of quartz, felspar, and mica. The color of granite depends on that of felspar present in it. It usually has grey, brown, green, and pink colors. It does not show any sign of strata which means it is difficult to split it into slabs.
Properties: Granite is an excellent stone when it comes to structural performance. The compressive strength of granite varies from 70 to 130 MPa (10,000 psi to 18,000 psi). The specific gravity of granite is around 2.64. Granite has a hardness of 6-7 on Mohs scale of hardness which means it is sufficiently hard. It offers good resistance against weathering.
Applications: Granite can be easily polished and worked and is commonly used for exterior facing of buildings. It is commonly used in houses and public buildings for flooring purposes. Granite is also processed into tiles and used in countertops. It is also frequently used in paving.
Slate is a metamorphic rock. Chemically it is an argillaceous rock i.e. it contains clay or alumina as main constituents. The color of slate stone is grey or dark blue. It has a stratified structure.
Properties: The compressive strength of slate varies from 60-70 Mpa (8700-11,000 psi). Its specific gravity is 2.8. On Mohs scale of hardness, it has a value of 5-6. Slate is a durable stone. It has good hardness and toughness index. It possesses good durability.
Applications: Slate, in form of tiles, is used as an excellent roof covering material. It has good insulating capability, moisture resistance, and wind resistance. Slate roofs can last for centuries. Slate tiles are also commonly used for interior and exterior flooring. It is also used in walkways, stairs, and wall cladding.
Sandstone is a sedimentary rock. It has a stratified structure. Chemically, it is a siliceous rock i.e. it contains silica as a main component. Its usual colors are white, brown, grey, and pink.
Properties: The compressive strength of sandstone varies from 30-40 Mpa (4000-6000 psi). Its specific gravity is between 2.6-2.9. On Mohs scale if hardness, sandstone has a value of 6-7. It is a sufficiently hard stone with good durability.
Applications: It is used in ashlar work, moldings, and carvings. It is also used for cladding facades and interior walls.
It is sedimentary rock of calcareous variety i.e. it contains lime or calcium carbonate as a main constituent. It is available in brown, yellow, and dark grey colors. It has a stratified structure.
Properties: The specific gravity of limestone is around 2.6. The compression strength of limestone is not good. On Mohs scale of hardness, it is rated between 3 and 4 which means it is not hard. It does not offer adequate resistance against weathering. It can be easily scratched and discolored.
Applications: Limestone can be used as masonry for walls. It is also used as load bearing stone for columns. It is extensively used in cement industry.
The biggest demerit of limestone lies in its foundational capability. Roads, dams, and other mega structures are avoided on limestone terrain. Limestone is a soluble rock and dissolves away under the action of water and forms caves. It is highly sensitive to changes in pH of water. Sinkholes are the most common example of foundation failure of limestone.
It is a metamorphic rock of calcareous variety. It contains lime or calcium carbonate as a main constituent. It is available in a variety of colors. The color of pure marble is white. However, impurities such as clay and iron oxides give it different colors. It is an unstratified rock.
Properties: The specific gravity of marble is around 2.7. It is a hard stone and takes very fine polish. Marble is quite sensitive to acid attack. It loses its shine rapidly when comes in contact with acid solution. Therefore, it requires good maintenance.
Applications: Marble is widely used as an ornamental stone. It gives an aesthetic look to structures. Marble tiles are used in flooring. Crushed marble is also used as construction aggregate. Furthermore, marble is used for important structures where appearance is of prime importance.
It is a sedimentary metamorphic rock. Chemically it is a siliceous rock with silica as chief constituent. It is majorly composed of quartz and felspar. Gneiss stones have a striped texture which can be straight, meandering, or a combination of both. It is available in a variety of colors.
Properties: The specific gravity of gneiss is between 2.5-2.7. It is easier to work with as compared to granite. On Mohs scale of hardness, it is rated between 5 and 6. It has adequate compressive strength and durability.
Applications: Gneiss is a good option for street paving. It is also used in kitchen or bathroom countertops. Gneiss is a good option for facade cladding.
Laterite is a sandy claystone having high percentage of iron oxide. Chemically, it is an argillaceous rock. It has a porous and cellular structure. Its color varies from light to dark red.
Properties: The specific gravity of laterite varies from 2-2.2. It has low compressive strength somewhere around 2-3 Mpa. It is not suitable for load bearing applications.
Applications: Laterite blocks are suitable as building stones. Nodular laterite is stronger and proves to be a good road metal.
8. Basalt & Trap
Basalt is an igneous rock. It has a dark appearance and its color varies from dark grey to black. It has a fine grained texture.
Properties: The specific gravity of basalt is around 2.7. It has good compressive strength and offers great resistance to weathering. Furthermore, basalt has satisfactory fire resistance and adequate acoustic insulation. It is also resistant to chemically active environment.
Applications: Basalt is regularly used in street paving. It is used as crushed aggregate for construction projects. Crushed basalt is used for road base, asphalt pavement, concrete aggregate, and railway ballast.
Being resistant to staining and scratches, quartzite is an ideal choice for kitchen countertops. It goes parallel to granite but in some applications, quartzite stands out. It is also best for floor tiles, walls, and stairs where you have high foot traffic. You might have seen railway ballast taking vibration of a railcar; it is mostly made with quartzite.
Although, this stone doesn’t fit in the field of heavy construction, but it is ideal for interior decorative applications in building construction. Although it is bit pricey but it is readily available in array of colors like yellow, gray, and white.
Because of its eye-catching shades and colors upon polish, travertine is an ideal choice for interior ornamental decorations. Although it is quite porous and is not ideal for heavy construction; but still it is perfect for flooring, wall cladding, vanity tops, stands, basins, and facades.
The stone has properties that make polishing pretty simple and easy. So, the stone is a best alternative for some other high-end types. If you’re interested in exploring some eye-catching designs, here’s a lead.
It is a stone famous for translucency (semitransparency). It offers clarity and clearness in its applications. During medieval period, builders used this stone in tombs, effigies, altars, and other religious ornamental applications. However, it is not a tough stone and can easily disintegrate when exposed to heavy rainfall or strong winds.
Some architects prefer it for use in windows or skylights. See Alabaster windows. Anyhow, you can crave different shapes from this stone as it is soft. But whatever application you’re using it in, it is best to have some surface protection to avoid disintegration.
You might doubt chalk because it’s porous or not durable but there’re still houses standing while being made with chalk as the main construction material. Chalk can be cut into brick or wattle and use as blocks or alternatively, it is can also be used as mortar in construction.
It is pure white in color and is a type of sedimentary rocks. It can also be used in manufacturing of Portland cement, and putty work.
Murum is famous for its deep brown and red color. It is a type of metamorphic rock that has laterite stone as a composition rock. It is ideal for ornamental applications like garden wall, or fancy garden paths. In its fine form, we can use it for plinth filling, backfilling of trenches, footing, pits, or even in road pavement. But make sure it doesn’t contain any organic matter. You can easily compact it and create hard surface. It is a suitable type of soil for construction.
It has a blue grey fracture texture that is mainly used for producing hydraulic lime. It can also be used as an alternate to stabilize compressed earth. It has close properties to cement and fat time. In geological terms, it is detrital or residual rolled type of rock.
How to choose the best type of stone for construction project?
Now that you’re through different types of stones in construction, it’s the time to pick one right for your project depending on the properties your project demands.
Here’re some requirements of a good construction stone:
Strength of the Building Stone
In construction projects, we utilize stone either for load carrying or for ornamental purpose. If you’re using stone as main construction material or there’s a need to use it for supporting load, the stone must be of high strength. High quality stones are bit expensive but they are able to withstand compressive loads. You can check the compressive strength of the stone to be in the range 60 to 200 N/mm2.
A stone being used in areas exposed to elements like rain, wind, and sun must be durable. Strong and durable stones have solid texture and their chemical composition makes them tuff. A close-grained and crystalline stone with dense structures can resist deterioration because of wind and rain.
Hardness and Toughness
A hard and tough stone won’t undergo any scratches if you scrap with surface with sharp object.While using stones in high traffic areas like floors, tiles, bridge aprons, and road; make sure the stone has considerable hardness and toughness. Mohr’s scale of hardness can help determine toughness and hardness before using in construction work.
Specific gravity is a relative term indicating the density of a stone. For applications on heavy-duty projects like dam and retaining wall; make sure you check the specific gravity to be on the higher side. Such a stone is likely to withstand weight and loads.
Porosity and Absorption
For construction applications where stones are exposed to elements, make sure the stone is non-porous. Such a stones are generally tougher and resistant to disintegration upon exposure to heavy rains or wind. Porous stones that absorb water can easily disintegrate.
Seasoning and Dressing
Stones require seasoning period of months after quarrying. But it differs a lot among different types of stones. So, make sure the stone you’re using have been placed inside shade without walls so it can dry under the impact of air circulation.
The versatility of stone in terms of shade, color, and tint make appearance a critical property of stone. So, make sure you choose a stone type that complements the design and color of your project. We recommend opting light shades as dark stones tend to fade overtime under the impact of light and harsh sun. Here’re some decorative ideas for stone used in construction.
Stones are durable and adaptable for use in construction but at the same time they have hefty price tag. So, it is advisable to select a type of stone that goes along your budge requirements.
Fire-resistance is a critical property for using it in construction projects. Fire resistant stones don’t have oxides of iron or calcium carbonate and have different thermal expansion coefficients.
Try to choose a stone with homogeneous structure as they are generally compact and hard. Open-texture and non-crystalline stones are porous and can easily disintegrate.
Further read: Physical Classification of Rocks [With EXAMPLES]