3.2 Types of concrete

Concrete is a construction material made by mixing cement, water, and aggregates such as sand, blue metal, gravel, or crushed rocks. When mixed, the cement reacts with the water in a chemical process called “hydration”, which hardens the mixture into a strong, durable material over time. Concrete material is used in different elements of buildings.

The application of the concrete design in different elements results in different types of concrete, such as plain concrete, reinforced concrete, prestressed concrete, and precast concrete, where different requirements and considerations are required. AS3600 (concrete structures) outlined the consideration of the concrete works, including special concrete structures such as high-strength concrete and marine structures.

The composition material of plain concrete and reinforced concrete is similar, except that reinforced concrete is supported by steel bars (rebar) or steel mesh to increase the tension strength of the element. Figure 3.1 shows the placement of concrete material to be supported by the reinforcement.

In comparison, Figure 3.2 shows the placement of concrete without any reinforcement, representing plain concrete. The use of plain concrete is suitable when only compression of the concrete is required, such as in pavement and blinding. The use of reinforced concrete is where both tension and compression of the element are required, such as footings, slabs, columns and beams.