A rebar is a steel bar or mesh of steel wires used as a tension device in reinforced concrete and reinforced masonry structures to strengthen and hold the concrete in tension. Its applications are many and its use is vital in the construction of almost every modern building. Rebars are used for the following purposes in construction.
To reinforce masonry:
Using steel bars in masonry provides the same benefits as it does for reinforced concrete. In addition, when encased in cement, the steel bars add to the fire resistance of a structure. In general, reinforcing bars made from high-carbon steel are often used in masonry because the higher carbon content makes them more resistant to corrosion. For easy cutting of rebars, an Electric rebar cutter is used normally.
To strengthen the structure:
The main reason for using rebar is to strengthen the materials of construction (concrete or masonry). Reinforce concrete with rebar, and it becomes a much more durable building material. While steel is actually a weaker material than concrete, the rebar is embedded in a matrix of concrete which transfers the load. This increases the compression strength of the matrix and makes it more resistant to tensile stresses or tearing apart.
To provide tensile strength:
Rebar is used to providing tensile strength in concrete structures such as road and bridge decks, sidewalks, and slabs. These structures must be built with proper reinforcing materials otherwise there may not be enough tensile strength to hold the structure together against the tremendous pressures of live load and traffic. Tensile strength is the key to rebar being used as a reinforcement material. Rebars are made of strong steel and are formed into longitudinal bars which are bent by rebar bender. They provide the tensile strength needed to make a normal concrete slab or beam function as designed.
To provide compressive strength:
Rebar can also be used to increase the compressive strength of concrete structures. Because steel has a higher modulus (ratio of stress to strain) than most other metals, any material made with rebar tends to resist deformation better.
As such, when you place two pieces of ordinary concrete together, you are creating what is known as a composite material, where the properties of both materials working together will be greater than each material acting independently. Because concrete has poor compressive strength, it requires reinforcement with steel to achieve any significant strength in compression.
To provide crack control:
Rebar can also be used to control cracks in concrete structures. Simply put, a crack is a discontinuity in a structure that allows movement to occur along the surface of the structure.
These movements can cause the entire structure to crumble and fail. Sometimes it is possible to control these cracks by using different types of reinforcement such as mechanical fasteners or properly applied cementitious materials. However, when these techniques are not enough the only solution may be to use steel bars in order to prevent further crack propagation.
To reduce shrinkage and temperature cracking:
In some locations, there are climate conditions that cause the concrete to shrink as it dries. In other areas, ground movement from freezing or flooding can also cause cracks to develop in a structure. When this happens, reinforcing steel bars can help control the cracks by acting as anchors for either small or large cracks. When they function in this way, the rebar is called a confining bar.