ABSTRACT
Gradual decrease in performance of a material or a structure. Any of the group of external factors, including weathering, biological, stress, incompatibility and use, that adversely affect the performance of building materials and components (Masters and Brandt, 1989). The sequence of chemical, mechanical or physical changes that lead to detrimental changes in one or more properties of building materials or components when exposed to one or a combination of degradation factors (Masters and Brandt, 1989). Mathematical function showing degradation with time (or age). Time-dependent mechanism leading to degradation. Service life used in the design of structures to take into account the timerelated scatter, and to provide a required safety against falling below the target service life.
