The chemical and physical properties of building materials

Building components are produced in different dimensions and forms. A block is traditionally defined as a building stone that can be lifted with two hands, whilst a brick can be lifted with one. Two people are needed to carry a building board. A new category has now become common: large building elements that can only be moved and positioned by machines. Each group of materials and components creates its own particular form of working.

Properties of materials are chemical and physical. Chemistry describes a substance's elemental content and composition, whilst physics gives a picture of its form and structure. For example, as far as chemistry is concerned it does not matter whether limestone is in powder or boulder form; in both cases, the material's chemical composition is calcium carbonate. In the same way, physical properties such as insulation value or strength are independent of chemical composition.

In conventional building it is primarily the physical properties that are considered, and it is almost entirely these properties that decide what materials can and should be used. Exceptions, where the chemical properties are also taken into consideration, occur where the material will be exposed to various chemicals. Determining the material's reaction to moisture, oxygen or gases will include chemical analysis. This is much more important nowadays with increased air pollution, which contains various highly reactive aggressive pollutants.

An ecological evaluation of the production of building materials requires a knowledge of which substances are involved in the manufacturing process and how these react with each other. This gives a picture of the possible pollutants within the material, and what the ecological risks are when the material is dumped in the natural environment. Increased attention to the quality of indoor climates also creates a greater need for chemical analyses. In many cases problems are caused by emissions from materials in the building. How these react with the mucous membranes is also a question of chemistry. It has been shown that certain materials react with each other, and can thus affect each other's durability, decay and pollution potential.

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