The terms "material" and "building material" are used in the building trade to describe materials from which building components and constructions are made. The generic term "building materials" refers to numerous substances that are assigned to various groups on the basis of their chemical structure. The building materials most commonly used in Germany can be divided into the following categories:Concrete
Concrete is divided into normal concrete and lightweight concrete. Normal concrete is a mixture of cement and the aggregates sand and gravel. It does not have any cavities and usually has high compressive strength. Normal concrete with steel bars added to it is called reinforced concrete.
Lightweight concrete differs from normal concrete on account of the substances it contains. It is normally mixed with pumice and expanded clay and has considerably lower compressive strength. A special version is porous concrete. It is made by adding gas-producing substances, which give the concrete a porous structure during the hardening process. Concrete is best worked on with a rotary hammer because you do not have to apply any pressure to the machine.