What is ordinary concrete, plain concrete, low strength concrete, high strength concrete and free flow concrete?

Ordinary concrete, also known as normal weight concrete, is a type of concrete that is made using a combination of cement, water, aggregate (typically gravel and sand), and air. It is referred to as “ordinary” or “normal weight” because it has a typical unit weight of around 2,400 to 2,800 kg/m3, which is the weight of the solid ingredients used to make the concrete.

Ordinary concrete is a versatile and widely used building material that can be used for a variety of applications, including foundations, walls, beams, columns, slabs, pavements, and sidewalks. It is relatively low-cost and easy to work with, making it an attractive option for many construction projects. However, it also has some limitations, such as relatively low strength and limited durability in certain harsh environments, which may require the use of specialized concrete mixtures for specific applications.

Plain concrete

Plain concrete, also known as plain cement concrete (PCC), is a type of concrete that is made using only cement, water, and aggregates (typically sand and gravel). Unlike conventional concrete, it does not contain any reinforcement such as steel bars or mesh, and relies solely on the compressive strength of the concrete to resist structural loads.

Plain concrete is used in a variety of applications, including foundations, sidewalks, curbs, gutters, and paving. It is also often used as a base layer for other types of concrete structures, such as reinforced concrete.

Due to its lack of reinforcement, plain concrete is typically not as strong as reinforced concrete and is only used in low-stress applications where the loads it will be subjected to are not significant. It is also more susceptible to cracking and other types of damage, which may require repairs or replacement over time.

Despite these limitations, plain concrete is still a commonly used building material due to its low cost, ease of construction, and versatility. However, careful consideration should be given to the suitability of plain concrete for specific applications, as well as to the design and construction practices used to ensure its quality and durability.

Low strength concrete

Low strength concrete refers to a type of concrete with a compressive strength that is lower than the typical range for normal weight concrete, which is typically in the range of 20 to 60 MPa (2,000 to 6,000 psi). Concrete with a compressive strength less than 20 MPa is considered to be low strength concrete.

Low strength concrete is used in a variety of applications where the loads it will be subjected to are not significant, such as in non-structural elements like sidewalks, curbs, gutters, and paving. It is also used as a base layer for other types of concrete structures, such as reinforced concrete.

Low strength concrete is typically made using a lower amount of cement and/or a lower water-cement ratio than normal weight concrete, resulting in a lower compressive strength. It is also often made using lower-quality aggregate materials, which may be lighter and less dense than the aggregate used in normal weight concrete.

Despite its lower strength, low strength concrete is still a commonly used building material due to its low cost, ease of construction, and versatility. However, care must be taken to ensure that it is used appropriately in applications where it is suitable and that adequate quality control measures are in place to ensure its quality and durability.

High strength concrete

High strength concrete is a type of concrete with a compressive strength that is higher than the typical range for normal weight concrete, which is typically in the range of 20 to 60 MPa (2,000 to 6,000 psi). Concrete with a compressive strength greater than 60 MPa is considered to be high strength concrete.

High strength concrete is used in a variety of applications where the loads it will be subjected to are significant and where a higher level of strength is required, such as in bridges, high-rise buildings, and other large structures. It is also used in specialized applications where high strength is necessary, such as in nuclear power plants and other critical infrastructure.

High strength concrete is typically made using a higher amount of cement and/or a lower water-cement ratio than normal weight concrete, resulting in a higher compressive strength. It is also often made using higher-quality aggregate materials, which may be denser and stronger than the aggregate used in normal weight concrete.

To achieve high strength, specialized concrete mixtures are used, which may include the use of high-performance cement, supplementary cementing materials (such as fly ash or slag), and/or chemical admixtures that alter the setting time, workability, or other properties of the concrete.

While high strength concrete has many advantages, it can also be more expensive and more difficult to work with than normal weight concrete. Careful consideration should be given to the suitability of high strength concrete for specific applications, as well as to the design and construction practices used to ensure its quality and durability.

Free Flow concrete

Free-flow concrete, also known as self-compacting concrete, is a type of concrete that is designed to flow and spread under its own weight, without the need for manual compaction or vibration. This is achieved by using specialized mixtures of concrete that have a high level of workability, or fluidity, that allows the concrete to spread and fill even complex-shaped forms or molds.

Free-flow concrete is characterized by its ability to flow and fill small voids, crevices, and corners in a structure without segregation, bleeding, or loss of cohesiveness. This makes it ideal for use in applications where traditional concrete might be difficult to place, such as in heavily reinforced structures or in forms with intricate shapes.

Free-flow concrete is typically made using a combination of high-performance cement, supplementary cementing materials (such as fly ash or slag), fine aggregates, and chemical admixtures that alter the rheology (flow properties) of the concrete.

While free-flow concrete has many advantages, such as improved efficiency and reduced labor costs, it can also be more expensive and more difficult to produce than traditional concrete. Careful consideration should be given to the suitability of free-flow concrete for specific applications, as well as to the design and construction practices used to ensure its quality and durability.