Concrete is among the most essential construction materials and is commonly used in pavements, foundations, roads, bridges, walls, fences, and poles. By solidifying and hardening after mixing with water, concrete helps bind (strongly) other building materials. With several types of concrete to choose from, it is crucial to know which one best suits the construction you are working on.
The main types of concrete used in construction include plain concrete, high-density concrete, lightweight concrete, precast concrete, reinforced concrete, prestressed concrete, shotcrete, air-entrained concrete, self-consolidating concrete, and glass-reinforced concrete.
Read on as we break down all you need to know about the main types of concrete used in construction. Ready? Then let us get straight to business.
What Is Concrete?
Concrete is an important construction material used extensively in small, medium, or large constructions. As a composite material, concrete consists mainly of water, cement, and aggregate (sand, gravel, or rock).
When the above materials are mixed in good ratios, they usually form a stone-like paste that tends to harden over time, holding different parts of a structure.
Fresh concrete has several applications as it can be easily cast into rectangles, squares, circles, and several other shapes depending on the type of project. The importance of mixing cement, water, and aggregates in good ratios cannot be overstated. This is because the ratio of components used in making concrete determines its strength, workability, resistance to elements, and durability.
Generally, cement and lime are usually used as the binding materials, while sand acts as the fine aggregate. Crushed stones, clinkers, gravel, and broken bricks complete the composite by acting as coarse aggregates.
As technological advancements continue to influence construction techniques and procedures, so too does concrete evolve. Concrete classification is usually based on three factors: types of materials used in the creation, stress conditions, and the overall density. Below is an in-depth discussion of the main types of concrete used in construction.
1. Plain/Ordinary Concrete
Plain concrete is among the most commonly used concrete and is a great choice for pavements or other areas that do not need extremely high tensile strength. This concrete type uses the 1:2:4 mix design to mix cement, sand, and aggregates.
Although plain concrete has a satisfactory durability rating, it is not known to stand up too well to wind loading and vibrations, hence its use for light to medium construction.
2. Lightweight Concrete
Concrete that has a density of anything below 1920 Kg/m3 is classified as lightweight concrete. This type of concrete is known for its low thermal conductivity, which makes it great for protecting exposed steel structures.
Lightweight concrete is very flowable (due to its low density) and self-leveling, meaning it does not need too much work to be applied and distributed across the surface. Its lightweight nature makes it appropriate for use in constructing floor slabs, roofs, and window panels. The most commonly used aggregates in lightweight concrete include scoria, pumice, perlite, vermiculite, clays, and expanded shales.
3. High-Density Concrete
Also called heavyweight concrete, high-density concrete has the highest density of all types of concrete. This type of concrete usually has a density value of 3000-4000 Kg/m3, making it hard to mix and manipulate during construction.To prepare high-density concrete, construction engineers need to use crushed rocks as the composite’s coarse aggregates. The most commonly used coarse aggregate material in concrete is barytes, which boasts a solid 4.5 specific gravity.
Due to its density and solidity, high-density concrete is mostly used in large structures like atomic plants that produce potentially harmful radiations. The high-density concrete material will prevent the radiations from passing through the walls. This type of concrete is usually costly and requires expert mixing for it to hold its weight well.
4. Reinforced Concrete
Also known as reinforced cement concrete (RCC), this type of concrete usually features different-sized steel that acts as a reinforcement to increase the overall tensile strength. Therefore, in reinforced concrete, wires, cables, and steel rods are usually placed before the concrete sets.
By increasing tensile resistance, the steel reinforcements make the concrete stronger and more resistant to compressive forces. When making reinforced concrete, experts are usually keen to ensure there is a maximum bond between the reinforcement and the settling concrete.A successful bond between concrete and the steel reinforcements allows the resulting reinforced cement concrete to bear different types of stress and loads in small, medium, and heavy constructions. This makes RCC among the most important concrete types, especially since it can be used in a wide variety of projects without compromising on structural integrity.
5. Precast Concrete
As suggested by the name, precast concrete is usually prepared and cast off-site, usually in controlled factory environments. Precast concrete is commonly used in projects that require well-balanced ratios for the concrete to hold other members in place.
And to increase the concrete’s effectiveness during construction, precast concrete is usually made in factories with much attention given to the proportioning of the main ingredients of concrete. As a result, by the time the concrete arrives on site, the cement, water, and aggregates are usually professionally mixed to suit the exact construction requirements.
Precast concrete is commonly used for precast walls, beams, tunnels, columns, staircase units, poles, and concrete blocks. The main advantage of using this type of concrete is the speedy on-site assembly. Additionally, the preparation of the ingredients in controlled environments means the resulting concrete is usually of the highest quality.
6. Prestressed Concrete
Prestressed concrete is commonly used in heavy construction projects due to its ability to withstand large loads and tensions. This type of concrete allows for the placement of predetermined engineering stresses on the primary members to help counteract the potential stresses that are likely to occur after loading.
Therefore, prestressed concrete works by combining the high compressive strength of concrete and steel’s high tensile strength. By prestressing the concrete before use in construction, construction engineers are guaranteed that the concrete will hold its weight well and consequently neutralize the resulting forces.
Prestressed concrete is commonly used in piles, floor beams, water tanks, bridges, runways, and railway sleepers, among other heavy types of construction.Some of the advantages of using prestressed concrete include:
- Enhanced compressive strength of the resulting concrete
- Prestressed concrete is vital in reducing the risk of tension cracks in the lower sections of load-bearing beams
- Prestressed concrete also helps to increase overall resistance to shear, thus eliminating the need for stirrups
- Ideal for projects with heavy dead loads such as long-span roofs, bridges, and other heavy constructions
7. Air-Entrained Concrete
Air-entrained concrete is a unique form of concrete containing microscopic air bubbles that vary in size depending on preparation type. The air bubbles perform the role of creating expansion chambers to allow water to expand when freezing, consequently relieving the concrete’s internal pressure.
To entrain the air, concrete specialists add foaming agents like alcohols, fatty acids, and resins during the concrete mixing process. However, for the job to be successful, engineering supervision is necessary to ensure the air-entrained concrete is well mixed.
The use of air-entrained concrete is common in environments prone to heavy snow and subsequent freeze-thaw cycles. Therefore, structures that use air-entrained concrete are more resistant to deterioration resulting from freezing and thawing, scaling, and abrasion.
8. Rapid Hardening Concrete
Rapid hardening concrete, also known as rapid-set concrete, is ideal for projects with short durations. This type of concrete has a solid reputation for setting fast and is highly resistant to low temperatures, which makes it ideal for use at any time, regardless of the season.
The significantly reduced hardening time allows the concrete to bond various members in little time, which allows for the completion of projects in good time.
Although unique due to its properties and features, this type of concrete is ideal for specific uses only during cold weather and in small repairs that need to be completed fast. Using rapid hardening concrete as the main concrete in large projects is ill-advised as it will almost certainly compromise the building or bridge’s overall structural integrity.
9. Glass Concrete
Glass concrete uses recycled glass as the aggregate, which allows the resulting structure to have a shiny, classy appearance that enhances its overall aesthetic appeal. Besides enhancing the beauty of a structure, glass concrete is also known to provide improved thermal insulation compared to other types.
This type of concrete is mostly used in construction projects that place extra focus on the final appearance. You will mostly find glass concrete used on decorative facades and large format slabs. The embedded glass’s shiny or colored appearance gives the slab or exterior cladding a shiny, colorful appearance.
10. Asphalt Concrete
Commonly known as blacktop or asphalt, this type of concrete is usually used on roads, highways, sidewalks, parking lots, and airport runways. Asphalt concrete results from the combination of asphalt and aggregates, which allows for fast hardening without compromising on strength.
Asphalt concrete is great when used in areas with great dynamic loads due to its skid resistance, workability, durability, stability, permeability, and flexibility. However, asphalt concrete must be well-mixed to withstand automobile and human loads.
11. Shotcrete Concrete
Shotcrete concrete is prepared in a similar fashion to normal concrete. However, the main difference between shotcrete and other forms of concrete is the mode of application.
Shotcrete is usually placed using nozzles as they allow for high-pressure releases. The use of nozzles to set up the concrete means the concrete will begin compacting immediately when sprayed on the surface.
This type of concrete is ideal for small repairs of wood, steel, or concrete structures and cannot be used as a structure’s primary concrete. Shotcrete concrete is also ideal when working on hard to access areas since the nozzle will allow construction workers to shoot the concrete at otherwise difficult angles.
12. Pumped Concrete
Pumped concrete is usually used when working on high rise buildings, especially the hard-to-access upper floors. This type of concrete is usually very workable and can be easily conveyed to the upper floors via a pipe.The pipe is often a rigid or flexible hose that carefully discharges the mixed concrete to the target areas on the hard-to-reach floor.
The use of pumped concrete is not solely limited to high-rise buildings. The concrete can also be used in construction projects like bridges and roadways and small-scale construction projects like swimming pools. Pumped concrete can also come in handy when looking to create extremely flat floors on horizontal construction projects.
But for the pumped concrete to flow up the pipe and into the required areas, only fine aggregates are used. Using fine aggregates ensures that the concrete flows freely to the designated areas.
As the name suggests, limecrete is concrete that utilizes lime in place of cement. More often than not, limecrete uses lightweight aggregates like sharp sand and glass fiber and is mainly used to construct domes, vaults, and floors.
This type of concrete is easy to clean and highly renewable, features that make it environmentally friendly. Limecrete can also come in handy when constructing floors with radiant floor heating.
14. Fiber-Reinforced Concrete
This type of concrete uses fibers to increase flexibility, tensile strength, and resilience, among other positive qualities that allow for effective load-bearing. The fibers are usually made from different materials like glass, steel, polymer, carbon, and even coconut fiber.
And since some fibers are known to react with cement, it is crucial to take extra care when mixing. Fiber-reinforced concrete is mostly used in industrial floors, airports, and pavements in bridges. The presence of fiber improves the concrete’s resistance to cracks, making it ideal for high-traffic areas.
Advantages of Using Concrete
As one of the most commonly used building materials, concrete has a wide range of uses that vary depending on the project type. Below are some of the main advantages of using concrete in construction.
Concrete Is Highly Economical
Concrete’s major ingredients like water, cement, and aggregates are usually easily available and at pocket-friendly prices. Generally, concrete is easier to obtain when compared to other construction materials like steel and polymers.
Concrete Is Castable Into Various Shapes and Sizes
Due to its liquid state, fresh concrete is highly flowable (depending on the mixing ratio). The concrete resulting can be poured into various configurations or formworks, depending on the project’s scope. However, concrete’s ability to be manipulated into different shapes and sizes makes it one of the most convenient building materials.
Concrete Has Great Water Resistance Characteristics
Although dissolved chemicals in water like chlorides and sulfates can induce gradual corrosion in different concrete types, well-mixed concrete is better at resisting corrosion than steel and wood. This explains why concrete is commonly used in submerged applications like dams, canals, pipelines, linings, and waterfront structures.
Concrete Can Resist High Temperatures
Compared to wood and steel, concrete has better heat-resistance properties. This is because the main binder in concrete, calcium silicate hydrate (C-S-H), can withstand high temperatures of up to 910°C (1670°F).
Concrete is a poor conductor of heat, a feature that allows it to store a significant amount of heat from the immediate environment. Moreover, concrete can withstand up to 6 hours of heat, which gives rescuers enough time to act in case of fire emergencies. Concrete’s solid fire resistance properties have seen it used to fireproof steel in constructions.
Concrete Is Environmentally Friendly
Did you know that concrete can recycle various industrial wastes and use them as substitutes for aggregate or cement? Some of the commonly used materials include fly ash, waste glass, slag, or even ground vehicle tires.
Concrete’s ability to reuse waste material helps to conserve the environment, thus promoting green construction.
Concrete stands out due to its wide application methodologies. A construction worker can hand apply, pour, spray, grout, or pump concrete to the target areas.
Moreover, concrete types like shotcrete do not take long to dry and solidify, which makes concrete versatile for a host of construction projects.
There Are Several Types of Concrete
As observed throughout the article, there is a wide range of concrete. The availability of different types of concrete ensures that structural integrity is not compromised during construction. This is because there is concrete for light projects, concrete for heavy projects, and even concrete for small repairs.
Concrete Is Low Maintenance
Unlike other building materials that require regular painting and coating as protection against weathering, concrete structures do not need too much maintenance. Regular coating replacement is enough to keep concrete strong and durable for several years, making it ideal for large construction projects.
Concrete is a highly convenient construction material due to its availability in different forms. From high-density concrete to light concrete, precast concrete, prestressed concrete, and even glass concrete, there is a wide variety of concrete types to choose from.
The best concrete is one that compliments the design of the structure under construction. Therefore, it is important to consider the properties of a particular concrete type before using it in construction. Heavy construction projects will require strong and durable concrete with high tensile and compression resistance properties.
- Wikipedia: Composite Material
- Wikipedia: Thermal Conductivity
- Wikipedia: Vermiculite
- Civil Engineering: Why Stirrups Are Used In Beam And Column Construction?
- Designing Buildings: Types Of Concrete
- DIY Network: How Does Radiant Floor Heating Work?
- Civil Digital: 10 Advantages Of Concrete as Construction Material
- Pro Crew Schedule: Concrete In Construction
- Wikipedia: Asphalt Concrete
- Mo Civil Engineering: Shotcrete Concrete