How does concrete crack?

Concrete is a building material made from a mixture of Portland cement, sand and water. It is used to construct floors, foundations and walkways in a variety of commercial and residential structures. Though this material is known for its strength and durability, concrete suffers damage because of high levels of abuse or improper installation. Concrete typically shows damage in the form of cracks, which can range from light surface fractures to holes that are large enough to make a structure unusable.