ABSTRACT
Engineering structures can be classified according to their purpose, and the requirements of the soil on which, in which, adjacent to which or from which the structure is constructed can be specified. This would form the basis of an application - orientated approach to classification. A second approach is a material-orientated approach to classification, according to which both the physical properties and the local environment should be considered before the material can be classified as suitable for a particular purpose. Examples of the two approaches are given. It is clear that the material approach is most complex, and yet it follows the paths of thought that an engineer would need to follow and it thus provides the basis of a knowledge-based system for design.
