ABSTRACT
Durability of a material may be defined as the ability to exist for a long time without significant deterioration, by resisting the environmental effects which result in some changes in the properties of the material with time. Service life and durability are usually considered as equivalent terms. Under given conditions of use, if the properties deteriorate to such an extent that safety or economy outrules further use, the material is considered to reach the end of its service life (Mehta and Monteiro, 2006). Durability is not only significant from the safety, economy and technical points of view. Ecologically, materials with longer service lives mean better conservation of natural resources.
