Construction Materials and Their Properties
Expert-defined terms from the Advanced Certificate in Tunnel Drainage Engineering course at London School of Business and Administration. Free to read, free to share, paired with a globally recognised certification pathway.
**Aggregate** #
**Aggregate**
* Aggregate is a granular material, such as crushed stone, gravel, or sand, that… #
It is a crucial component of concrete, asphalt, and other construction materials. Aggregate is chosen for its size, shape, and durability, and it must be clean and free of impurities.
**Asphalt** #
**Asphalt**
* Asphalt is a mixture of bitumen, aggregate, and filler that is used to pave ro… #
It is applied in a hot liquid state and then cools and hardens to form a durable surface. There are several types of asphalt, including hot mix asphalt, warm mix asphalt, and cold mix asphalt, which are distinguished by their production temperature.
**Bitumen** #
**Bitumen**
* Bitumen is a sticky, black, and highly viscous liquid or semi #
solid form of petroleum. It is used as a binder in asphalt, tar, and pitch. Bitumen is produced naturally or as a residue from the distillation of crude oil. It is characterized by its high resistance to water and its ability to withstand extreme temperatures.
**Cement** #
**Cement**
* Cement is a fine powder that is used as a binding agent in construction materi… #
It is made by heating a mixture of limestone, clay, and sand to a high temperature, then grinding it into a fine powder. Cement is mixed with water and aggregate to form concrete, mortar, or stucco.
**Concrete** #
**Concrete**
* Concrete is a construction material made from cement, water, and aggregate #
It is a versatile and durable material that is used in a wide range of applications, from foundations and walls to bridges and buildings. Concrete can be poured on site or precast in a factory. It can also be reinforced with steel to increase its strength and durability.
**Fly Ash** #
**Fly Ash**
* Fly ash is a fine powder that is produced as a byproduct of coal #
fired power plants. It is a pozzolan, which means that it has the ability to react with calcium hydroxide in the presence of water to form compounds with cementitious properties. Fly ash is often used as a partial replacement for cement in concrete, as it can improve the workability, durability, and strength of the mixture.
**Geotextile** #
**Geotextile**
* Geotextiles are permeable fabrics that are used in civil engineering and const… #
They are made from natural or synthetic fibers and are used to separate, filter, reinforce, protect, or drain soils and other materials. Geotextiles are classified into two main categories: nonwoven and woven. Nonwoven geotextiles are made by bonding fibers together, while woven geotextiles are made by weaving fibers together. Geogrids are a type of geotextile that are made from high-strength polymers and are used to reinforce soils and other materials.
**Grout** #
**Grout**
* Grout is a mixture of cement, water, and sometimes sand or other additives tha… #
It is a low-strength material that is pumped or poured into place and then allowed to harden. Grout is used to seal cracks, anchor bolts, or fill gaps between concrete slabs.
**Mortar** #
**Mortar**
* Mortar is a mixture of cement, water, and sand that is used to bond masonry un… #
It is also used to fill joints between units and to provide a smooth surface for plastering or painting. Mortar is made by mixing cement, water, and sand in the right proportions to achieve the desired consistency and strength.
**Reinforced Concrete** #
**Reinforced Concrete**
* Reinforced concrete is a composite material made of concrete and steel reinfor… #
The steel reinforcement, often in the form of rebar, is placed in the concrete before it hardens, and it is used to increase the strength and ductility of the concrete. Reinforced concrete is used in a wide range of applications, from buildings and bridges to dams and tunnels.
**Rock** #
**Rock**
* Rock is a natural material that is composed of minerals and is formed from the… #
Rocks are classified into three main types: igneous, sedimentary, and metamorphic. Igneous rocks are formed from the solidification of magma, sedimentary rocks are formed from the accumulation of sediments, and metamorphic rocks are formed from the transformation of existing rocks under high pressure and temperature.
**Soil** #
**Soil**
* Soil is a natural material that is composed of minerals, organic matter, water… #
It is the upper layer of the Earth's crust and is formed from the weathering of rock and the decomposition of organic matter. Soil is classified into several types, based on its texture, structure, and other properties. The most common classification is based on the particle size distribution, and it distinguishes between clay, silt, sand, and gravel.
**Steel** #
**Steel**
* Steel is a metal alloy that is made of iron and carbon #
It is a strong and durable material that is used in a wide range of applications, from construction and transportation to machinery and appliances. Steel is characterized by its high strength, ductility, and resistance to corrosion. It is available in various forms, such as reinforcing steel, rebar, and structural steel.
**Tunnel Lining** #
**Tunnel Lining**
* Tunnel lining is the inner surface of a tunnel that supports the ground and pr… #
It is typically made of concrete, steel, or a combination of both. There are several types of tunnel lining, such as segmental lining, cast-in-place lining, and sprayed concrete lining. Segmental lining is made of precast concrete segments that are assembled and installed in the tunnel. Cast-in-place lining is made of concrete that is poured and cured in place. Sprayed concrete lining is made of concrete that is sprayed onto the tunnel surface.
**Waterproofing** #
**Waterproofing**
* Waterproofing is the process of preventing water from entering a structure or… #
It is an important aspect of tunnel drainage engineering, as it ensures the stability and durability of the tunnel. There are several waterproofing methods, such as using a bentonite layer, applying a membrane, or installing a drainage layer. Bentonite is a type of clay that swells when it comes into contact with water and forms a tight seal. Membranes are flexible materials that are placed on the tunnel surface and prevent water from passing through. Drainage layers are layers of granular material that are placed between the tunnel lining and the surrounding soil and collect and remove water from the tunnel.