Dr Ian Sims is a Director of RSK Environment Ltd in the UK, where he is responsible for Materials Consultancy and Expert Witness Services. He graduated in geology at London University in 1972 and then undertook research in concrete technology, including AAR in the British Isles, being awarded a PhD in 1977. Ian joined Sandberg LLP in 1975 and gained wide experience with construction geomaterials. In 1996, he moved to STATS Limited, which joined RSK Group PLC in 2008. He has specialised for over 40 years in concrete, its constituents and all aspects of AAR. Between 1988 and 2014, Ian was Secretary of the RILEM Technical Committees on AAR and awarded RILEM Fellowship. As a Fellow of the Geological Society, he was Secretary for four sequential Engineering Group working parties, producing report-books on Aggregates, Stone and Clay materials and construction in Hot Deserts. Ian received the Society's Engineering Group Award and later the Coke Medal. He has served on many other committees, including chairing the editorial panel for ICE's journal 'Construction Materials' and currently chairing the BSI committee on Aggregates. Ian's publications include 'Concrete Petrography: a handbook of investigative techniques', now in its second edition.

Alan Poole followed a research and teaching career in the petrology of civil engineering materials at Queen Mary, University of London. Throughout his later career he has been much involved with investigation of materials problems associated with concrete and related materials for government and major civil engineering organisations. One particular area of expertise is alkali-aggregate reaction in concrete, a costly and world-wide problem. He was a member of the international committee for the organisation of a series of major 'ICAAR conferences' on alkali-aggregate reaction until 2000 and chaired the two held in the UK (1976 & 1992). As a result of consultancy interests he has gained a wide experience in the investigation of civil engineering material failures of all sorts and has contributed chapters in a number of technical books and journals including co-authoring the recently published 'Concrete Petrography' which deals with all aspects of the investigation of concrete deterioration. He acts as secretary to the Geological Societies Applied Petrography Group and is also a member of British Standards Institution committees concerned with concretes and aggregates.