Uses Of Limestone
Limestone is a type of rock, mainly composed of calcium carbonate. Limestone is quarried (dug out of the ground) and used as a building material. It is also used in the manufacture of cement, mortar and concrete. Reactions with acids

Carbonates react with acids to produce carbon dioxide, a salt and water. For example:

calcium carbonate + hydrochloric acid → carbon dioxide + calcium chloride + water

CaCO3 + 2HCl → CO2 + CaCl2 + H2O

Since limestone is mostly calcium carbonate, it is damaged by acid rain. Sodium carbonate, magnesium carbonate, zinc carbonate and copper carbonate also react with acids: they fizz when in contact with acids, and the carbon dioxide released can be detected using limewater.

Calcium hydroxide

When limestone is heated strongly, the calcium carbonate it contains decomposes to form calcium oxide. This reacts with water to form calcium hydroxide, which is an alkali. Calcium hydroxide is used to neutralise excess acidity, for example, in lakes and soils affected by acid rain.

Cement, mortar and concrete

Cement is made by heating powdered limestone with clay. Cement is an ingredient in mortar and concrete:

mortar, used to join bricks together, is made by mixing cement with sand and water
concrete is made by mixing cement with sand, water and aggregate (crushed rock)

Advantages and disadvantages of various building materials

Limestone, cement and mortar slowly react with carbon dioxide dissolved in rainwater and wear away. This damages walls made from limestone, and leaves gaps between bricks in buildings. These gaps must be filled in or ‘pointed’. Pollution from burning fossil fuels makes the rain more acidic than it should be, and this acid rain makes these problems worse.

Concrete is easily formed into different shapes before it sets hard. It is strong when squashed, but weak when bent or stretched. However, concrete can be made much stronger by reinforcing it with steel. Some people think that concrete buildings and bridges are unattractive.

Quarrying

You need to be able to evaluate some of the effects of the limestone industry.

The main advantages and disadvantages of the limestone industry AdvantagesDisadvantagesLimestone is a valuable natural resource, used to make things such as glass and concrete.Limestone quarries are visible from long distances and may permanently disfigure the local environment.Limestone quarrying provides employment opportunities that support the local economy in towns around the quarry.Quarrying is a heavy industry that creates noise and heavy traffic, which damages people's quality of life.

	Created by catherine gaskell almost 11 years ago

Note on Limestone and Building materials, created by catherine gaskell on 05/06/2013.

Limestone and Building materials