Granite, limestone and marble are used as construction materials. Cement, which is made from limestone, is used to make concrete. But reinforced concrete has better properties for construction work than concrete alone.

Granite, limestone and marble

The materials used in the construction industry include:

• aluminium and iron - metals obtained from ores
• brick - made from clay
• glass - made from sand
• cement and concrete - made using limestone
• granite, limestone and marble - rocks mined or quarried from the ground

Granite is much harder than marble, which is much harder than limestone.

Granite, limestone and marble are used as construction materials. Cement, which is made from limestone, is used to make concrete. But reinforced concrete has better properties for construction work than concrete alone.

Granite, limestone and marble

The materials used in the construction industry include:

• aluminium and iron - metals obtained from ores
• brick - made from clay
• glass - made from sand
• cement and concrete - made using limestone
• granite, limestone and marble - rocks mined or quarried from the ground

Granite is much harder than marble, which is much harder than limestone.

Metal carbonates such as calcium carbonate break down when heated strongly. This is called thermal decomposition. Here are the equations for the thermal decomposition of calcium carbonate:

calcium carbonate  calcium oxide + carbon dioxide

Other metal carbonates decompose in the same way. Here are the equations for the thermal decomposition of copper carbonate:

copper carbonate  copper oxide + carbon dioxide

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.

Granite, marble and limestone

Granite, marble and limestone are examples of the three different types of rock.

name of rocktype of rockhow it is formed granite igneous from molten rock that's cooled and solidified marble metamorphic by the action of high temperatures and pressures on limestone limestone sedimentary from layers of the compressed remains of sea creatures

Reinforced concrete

Reinforced concrete is a composite material made from concrete and steel. It is a better construction material than concrete alone because:

• concrete is hard and strong when squashed, but weak when stretched
• steel is flexible and strong when stretched

The composite material combines the best properties of both materials, so that it is hard and strong when squashed or stretched. This makes it useful for building bridges