What is meant by plain concrete?

Plain concrete refers to a type of concrete that is composed solely of cement, aggregates (sand and gravel), and water without any form of reinforcement such as steel bars or fibers. This type of concrete relies entirely on its compressive strength, which is the ability of the material to withstand axial loads without collapsing.

The absence of reinforcement means that plain concrete is not designed to handle tensile stresses, which can lead to cracking and failures under tension or bending loads. It's commonly used in applications where the material is primarily subject to compressive forces, such as in foundations or simple slabs, where cracking can be managed through proper design considerations.

This concept is essential for understanding the different classifications and applications of concrete in construction, as the choice between plain and reinforced concrete significantly influences structural design and integrity.