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Construction materials

Cement and concrete

Concrete is made by mixing together:

  • cement - made by heating powdered limestone and clay together
  • gravel - crushed rocks
  • sand
  • water

A chemical reaction occurs in the mixture and it eventually sets hard.

Reinforced concrete

Concrete is often reinforced with steel. A steel support is made by joining steel bars or cables together. This is then usually surrounded by a mould. Concrete is poured into the mould, where it fills the gaps in the steel support and sets hard. Reinforced concrete is an example of a composite material.

Back to Rocks and metals index

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