Common Building Stones (Types Of Stones Used For Building & Civil Engineering Constructions)
Stones are commonly used for building constructions. The importance of stones in civil engineering cannot be overemphasized. They are used in road construction, commercial buildings, residential buildings, etc.
The following are some of the common stones used in building construction:
- Basalt & Trap
- Sand Stone
Basalt & Trap: The structure of this type of stones is medium to fine grained and compact. Their colour varies from dark grey to black. Fractures and joints are common. Their weight varies from 18kN/m3 to 29kN/m^3. The compressive strength varies from 200 to 350N/mm2. They are used as road metals and aggregates for concrete. They are igneous rocks and are also used for rubble masonry works for bridge piers, dams and river walls. They are also used for pavement construction.
Granite: These are also igneous in nature. Their colour varies from light gray to pink. They have crystalline structure and are fine to coarse grained. These rocks are hard and durable, and take polish well. They have a specific gravity of between 2.6 -2.7 and compressive strength between 100 to 250N/mm^2. They are used as kerbs and pedestals, and for the construction of river walls, bridge piers, dams and other civil engineering works. They are also commonly used for monumental and institutional building works. Polished granites are used as cladding for columns and walls and as table tops. Generally, granites are used as coarse aggregates in concrete.
Gravel: Gravel is a versatile and widely used material in construction. It is typically made up of small, rounded stones that are sorted by size, composition, color, or shape. Gravel is often used as a base material for roads, driveways, and foundations. It can also be used as fill material or pipe bedding, providing superior drainage.
In some concrete mixes, gravel is added to increase volume and strengthen the concrete. Gravel can also be used as an alternative to concrete for driveways, walkways, and low-traffic roads.
Gravel is sorted and sold based on its size or “grade,” which is typically determined by screening. During the screening process, crushed stone is sifted through grates of varying sizes so that it can be sorted and shipped off. Another critical characteristic of this material is its shape. Rounded stones and rocks with jagged edges behave differently when compressed or under lateral pressure, making some mixtures more suitable than others for foundations.
Gravel is an essential building material that has many applications in construction. Its versatility makes it an attractive option for builders looking for a cost-effective and durable solution.
Sand Stone: These stone types are sedimentary in nature hence, they are stratified. They consist of quartz and feldspar. They exist in various colours such as grey, white, red, brown, buff, yellow and dark grey. The specific gravity varies from 1.85 to 2.7 and compressive strength varies from 20 to 170N/mm^2. Its porosity varies from 5 t0 25 per cent. Weathering of rocks renders it unsuitable for building. It is desirable to use sandstones in combination with silica cement for heavy structures, if necessary. Sandstones are used for masonry works, for dams, river walls and bridge piers.
Laterite: Laterite is metamorphic in nature. It has a porous and spongy structure. It may have a brownish, greyish, yellowish or reddish colour. Its specific gravity is 1.85 and the compressive strength varies from 1.9 to 2.3 N/mm^2. Laterite has high iron oxide content. It is easily quarried in blocks. This rock type can gain strength when properly seasoned. When used as building stone, it should be plastered on the outer surface.
Slate: This is a metamorphic rock. It is composed of quartz, clay minerals and mica. It has fine grained structure. Slate splits along the planes of original bedding easily. Its specific gravity is 2.6 to 2.7 and the compressive strength varies from 100 to 200 N/mm^2. The colour varies from dark grey, greenish grey, purple grey to black. Slate can be used as slabs, roofing tiles, pavements, etc.
Marble: Marble is a metamorphic rock which can take good polish. Available in different pleasing colours like pink and white, it has a specific gravity of 2.65 and a compressive strength of 70-75 N/mm^2. It is used for facing and ornamental works. Marble has a variety of uses in building such as, it can be used for columns, steps, flooring and other such uses in construction.
Quartzite: They are metamorphic rocks. The structure is fine grained to coarse, and often granular and banded. It is the chief constituent with feldspar and mica in small quantities. With a specific gravity from 2.55 to 2.65, its crushing strength varies from 50 to 300 N/mm2. They are used as building blocks and slabs. They are also used as coarse aggregates in concrete. They are available in different colours like yellow, grey and white.
Gneiss: Gneiss is a metamorphic rock. It has fine to coarse grains. They also commonly have alternative dark and white bands. Other varieties include purple, pink, dark grey, greenish grey, and light grey. They are not often preferred for construction purposes due to deleterious properties, but may be used for minor constructions. Hard varieties may however, be used for construction of buildings. It has a specific gravity of 2.5 to 3.0 and a crushing strength of 50 to 200 N/mm^2.