All of us have dropped drinking glasses and mugs before and seen them break into many pieces on the floor.

This begs the question: how can such brittle materials be used in engineering?

Ceramics have been used in civil structures for centuries. They are used in many ancient structures that have survived to the present day – the great pyramid of Giza, the great Wall of China. These structures show that ceramics are very resistant to corrosion and wear, and can be used in many applications, even though they may be brittle.

What is a ceramic?

Materials that are classed as ceramics are non-metallic. They are primarily oxides, but can also be carbides, nitrides, borides, and silicides. They can be single compounds or mixtures of several different compounds.

Clay ceramics and stone have traditionally been used as structural materials. More recently, these ceramics have been replaced by concrete which is a complex ceramic composite.

Ceramics have also been developed to be used in electronic, computer, communication, biomedical and aerospace applications.

Ceramics and glasses have a wide range of mechanical and physical properties, but most are hard and brittle. Ceramics contain flaws caused by processing and preparation. These flaws make ceramics brittle materials and often result in premature failure. The flaws are variable in size and number, leading to variable mechanical behaviour.

There are many common ceramics that are used in civil structures. Some of the earliest building materials were ceramics. Stone is a ceramic, as are bricks, and tiles.

Bricks, and tiles are typically made from clay. Clay is a complex mixture of silicates. We will discuss silicates in more detail in a later section.

Stone and bricks are ideal for use as building materials as they are very strong in compression. The reason for the large compressive strength of ceramics lies in their atomic structure.