This report provides a literature review of existing research and summary of BRE work; identifies the appropriate UK Codes relating to HAC concrete; assesses deterioration mechanisms in identified critical environments; provides information on the nature and prevalence of long-term durability issues; assesses the implications for structural adequacy. The principal objectives of the research project on pre-cast HAC concrete were to provide a basis for predicting the risk of deterioration through corrosion of reinforcement and chemical attack; to establish the nature and prevalence of durability issues in buildings and assess the implications for structural adequacy. 55 pages.