Plasticity in construction

The term 'plasticity' refers to the degree to which as material has the characteristic of being easily shaped, moulded or formed. More specifically in terms of material science and building physics it relates to the terms plastic region and plastic deformation - where a material is unable to retain elasticity (return to its original shape), or as such has the ability to undergo permanent deformation in response to forces being applied. It is the middle stage of the characteristic behaviour of materials under stress and strain from forces being applied, the first stage being elasticity and the last stage being fracture or failure.

It is important to note that plasticity refers to a materials characteristics rather than being a reference to a particular type of material, such as plastic.

For example, natural clay has the characteristic of plasticity because it can be moulded into any shape, but also wood can have the characteristic of plasticity, where timber beams for example over years become permanently bowed but retain their strength and do not reach fracture point.

Plastics may also posses plasticity as a characteristic when they are heated and moulded into for example building components.

The level that a material can sustain plastic deformation under tensile force is referred to as ductility, whilst a material's ability to deform plastically without failing under compressive stresses is referred to as malleability.

A material that has a very small plastic region and potentially elastic region also is referred to as brittle.