This Information Paper reports on long-term BRE studies of the durability of concrete made from crushed rock sources that at present are little used for this purpose. Such information is needed to assess the resource potential of these materials and to give specifiers and their clients confidence of lifetime performance in structures. After 20 years of unsheltered outdoor exposure, concretes made with crushed Jurassic limestone aggregates have performed well in resisting frost damage and protecting embedded metal. Also, the porosity of the aggregate reduces the expansive effect of alkali silica reactions. This IP considers a wide range of factors relating to maintaining overall quality in the built environment. It replaces IP2/86. 8 pages.