3 Types of Reinforced Concrete to Know About in 2023

Reinforced concrete is a versatile and widely used construction material that has transformed the way we build structures. It is a composite material made of concrete and reinforcement, typically steel bars or mesh, that enhances its strength and durability. In this article, we will delve into the three main types of reinforced concrete, exploring their unique characteristics, applications, and benefits.

1. Understanding Reinforced Concrete

Reinforced concrete is a combination of concrete and reinforcement materials, working together to create a stronger and more reliable building material. By incorporating steel reinforcement, concrete gains improved tensile strength, enabling it to withstand bending and cracking forces. This synergistic blend of materials has made reinforced concrete the material of choice for various construction projects.

1.1 What is Concrete?

Concrete is a composite material composed of three main components: cement, aggregates (such as sand and gravel), and water. When these ingredients are mixed together, they form a paste that hardens over time, resulting in a durable and solid structure. Concrete has been used in construction for centuries due to its versatility, affordability, and long-lasting properties.

1.2 What is Reinforcement?

Reinforcement, in the context of reinforced concrete, refers to the materials used to strengthen the concrete and provide additional tensile strength. Steel is commonly used as reinforcement due to its high strength and compatibility with concrete. Reinforcing steel bars or mesh are strategically placed within the concrete to counteract tensile forces and enhance the overall performance of the structure.

• History of Reinforced Concrete

Fibers have been used for concrete reinforcement since prehistoric times though technology has improved significantly, as is applicable to other fields. At an early age, straw and mortar were used for producing mud bricks, and horsehair was used for their reinforcement. As fiber technology developed, cement was reinforced by asbestos fibers in the early twentieth century.

• Glass Fiber Reinforced Concrete (GFRC)

GFRC has been successfully used for the last 25 years for concrete reinforcement, in addition to steel. GFRC is manufactured into big panels with a simple configuration or into intricate shapes by using special techniques. Originally, GFRC components were anchored directly with the buildings by the use of metal studs. It was revealed that GFRC shifts considerably due to which the direct anchors are being replaced by slip anchors. Several structures use GFRC for dissimilar faces like ceramic tiles, bricks, and architectural purposes.

• Steel Fiber Reinforced Concrete (SFRC)

Steel fiber reinforced concrete is a composite material that can be sprayed. It consists of hydraulic cement with steel fibers that are dispersed randomly and possess a rectangular cross-section. The steel fibers reinforce concrete by withstanding tensile cracking. The flexural strength of fiber-reinforced concrete is greater than the un-reinforced concrete. Reinforcement of concrete by steel fibers is isotropic in nature that improves the resistance to fracture, disintegration, and fatigue. It is able to withstand light and heavy loads.

• Engineered Cementitious Composite (ECC)

A fiber-reinforced concrete has been developed recently that is called Engineered Cementitious Composite (ECC). It is claimed that this concrete is 40 % lighter than normal concrete, resistance to cracking exceeds 500 times, and strain hardening exceeds several percent strain. Thus, the ductility is significantly greater than normal concrete. It is also known as bendable concrete since it can easily be molded and shaped. It can self-repair minor cracks by the reaction with carbon dioxide and rainwater, making the concrete stronger.

2. Plain Reinforced Concrete

Plain reinforced concrete, also known as simply reinforced concrete, is the most basic type of reinforced concrete. In this type, the reinforcement is placed only in areas where tensile stresses occur, while the remaining sections of the structure are composed of plain concrete.

2.1 Advantages of Plain Reinforced Concrete

Plain reinforced concrete offers several advantages, including:

• Cost-effectiveness: Since reinforcement is only added where necessary, the overall material and labor costs are reduced compared to other types of reinforced concrete.
• Flexibility: The absence of reinforcement in non-essential areas allows for easier modifications or alterations during construction or renovations.
• Simplicity: Plain reinforced concrete is relatively straightforward to design and construct, making it suitable for a wide range of applications.

2.2 Applications of Plain Reinforced Concrete

Plain reinforced concrete finds extensive use in various construction projects, such as:

1. Slabs: Plain reinforced concrete slabs are commonly employed in flooring systems for residential, commercial, and industrial buildings.
2. Foundations: The simplicity and cost-effectiveness of plain reinforced concrete make it ideal for building foundations.
3. Walls: Reinforced concrete walls can be constructed using a combination of plain and reinforced concrete, depending on the specific requirements of the structure.
4. Beams: Beams made of plain reinforced concrete are often utilized to support heavy loads and distribute them evenly across a structure.

3. Pre-Stressed Reinforced Concrete

Pre-stressed reinforced concrete is a type of reinforced concrete in which the steel reinforcement is placed under compression before the concrete is cast. This compression counteracts the tensile forces that the concrete will experience during use, resulting in a stronger and more resilient material.

3.1 Advantages of Pre-Stressed Reinforced Concrete

Pre-stressed reinforced concrete offers several advantages over other types of reinforced concrete:

• Increased Strength: Pre-stressing the reinforcement provides higher overall strength, allowing for longer spans and reduced structural thickness.
• Improved Durability: The compression in the reinforcement minimizes cracking and deformation, enhancing the durability and lifespan of the structure.
• Design Flexibility: Pre-stressed concrete allows for more creative and innovative designs due to its improved load-carrying capacity and reduced structural weight.

3.2 Applications of Pre-Stressed Reinforced Concrete

Pre-stressed reinforced concrete is commonly used in various structural elements, including:

1. Bridges: Pre-stressed concrete is particularly well-suited for bridge construction, as it enables the creation of long-span structures with high load-bearing capacity.
2. Beams and Slabs: Pre-stressed beams and slabs are employed in buildings and parking structures, allowing for larger column-free spaces.
3. Liquid Storage Tanks: The high strength and durability of pre-stressed reinforced concrete make it an excellent choice for liquid storage tanks, such as water reservoirs and silos.
4. Railway Sleepers: Pre-stressed concrete sleepers are used in railway tracks to ensure stability and resistance to heavy loads.

4. Fiber-Reinforced Concrete

Fiber-reinforced concrete (FRC) is a type of reinforced concrete that incorporates fibers into the mix to enhance its properties. The fibers, typically made of steel, glass, synthetic materials, or natural fibers, serve as reinforcement and improve the concrete’s resistance to cracking and impact.

4.1 Advantages of Fiber-Reinforced Concrete

Fiber-reinforced concrete offers numerous advantages in construction:

• Increased Toughness: The addition of fibers improves the concrete’s toughness, making it more resistant to cracking and impact.
• Enhanced Durability: Fiber reinforcement enhances the durability and longevity of the concrete, reducing the need for frequent repairs or replacements.
• Improved Ductility: FRC exhibits improved ductility, allowing it to deform without catastrophic failure under excessive loads or seismic events.

4.2 Applications of Fiber-Reinforced Concrete

Fiber-reinforced concrete finds applications in various construction scenarios, including:

1. Industrial Floors: FRC is commonly used in industrial settings where heavy equipment and traffic are present, as it can withstand high loads and resist cracking.
2. Pavements: Fiber-reinforced concrete pavements are employed in road construction to increase durability and minimize cracking caused by traffic and environmental factors.
3. Tunnels: Fiber-reinforced concrete is utilized in tunnel construction to enhance structural integrity and resistance against ground movements.
4. Precast Concrete Products: FRC is also used in the manufacturing of precast concrete products such as pipes, manholes, and retaining walls, providing improved strength and durability.

FAQs

Q1: What are the key differences between plain reinforced concrete and pre-stressed reinforced concrete?

A1: The key difference lies in the approach to reinforcement. Plain reinforced concrete only reinforces areas where tensile stresses occur, while pre-stressed reinforced concrete pre-compresses the reinforcement to counteract tensile forces. Pre-stressed concrete offers increased strength and durability compared to plain reinforced concrete.

Q2: Is fiber-reinforced concrete more expensive than plain reinforced concrete?

A2: Fiber-reinforced concrete may have a slightly higher upfront cost due to the addition of fibers. However, considering its enhanced durability and reduced maintenance requirements, it can prove to be cost-effective in the long run.

Q3: Can fiber-reinforced concrete be used in residential construction?

A3: Yes, fiber-reinforced concrete is suitable for residential construction. It offers benefits such as improved crack resistance and enhanced durability, making it an excellent choice for various applications, including foundations, slabs, and walls.