Degradation, the chemical/physical response of building and con-
struction materials exposed to in-service environments, must be
predicted prior to their installation in structures if materials are to
be effectively selected, used and maintained. These assessments of
materials degradation require that methods be available to aid
prediction of service life. The objectives of building materials science
are a) to charac- terize and categorize materials, b) to predict,
preferably in a mathematical sense, material or component response
including expected service life, and c) to make improvements in material
response through improvements in design, formulation, processing or
specification. For building and construction materials, continued
progress has been made towards objective (a), but little progress has
been made towards objectives (b) and (c). Of these, the mathematical
prediction of service life appears to be of greater importance, because,
if general approaches or models having application to a wide range of
building and construction materials can be identi- fied, then the
categorization, selection, use and improvement of materials can proceed
in a systematic manner. Researchers in advanced technologies, such as
aerospace, nuclear, electronics and medicine, have apparently been more
successful than researchers in building and construction technology in
responding to the need for reliable predictions of service life.