Service-Life Prediction (ACI 365.1R-00)

Description

Service-life concepts for buildings and structures date back to when early builders found that certain materials and designs lasted longer than others (Davey 1961). Throughout history, service-life predictions of structures, equipment, and other components were generally qualitative and empirical. The understanding of the mechanisms and kinetics of many degradation processes of concrete has formed a basis for making quantitative predictions of the service life of struc-tures and components made of concrete. In addition to actualor potential structural collapse, many other factors can gov-ern the service life of a concrete structure. For example, ex-cessive operating costs can lead to a structure’s replacement.

This document reports on these service-life factors, for both new and existing concrete structures and components. The terms “durability” and “service life” are often errone-ously interchanged. The distinction between the two terms is evident when their definitions, as given in ASTM E 632, arecompared:Durability is the capability of maintaining the serviceabil-ity of a product, component, assembly, or construction overa specified time. Serviceability is viewed as the capacity ofthe above to perform the function(s) for which they are de-signed and constructed. Service life (of building component or material) is the pe-riod of time after installation (or in the case of concrete, placement) during which all the properties exceed the mini-mum acceptable values when routinely maintained. Three types of service life have been defined (Sommerville 1986).