Dundee University believes it could be the world centre of concrete expertise within five years, in the wake of a planned Pounds 500,000 expansion backed by Scottish Enterprise Tayside. Dundee's concrete technology unit, founded in 1989, currently has seven staff, and now plans to recruit another 14 new researchers. It aims in particular to boost its work on "green concrete" - the term given to sustainable construction involving the recycling of waste materials such as demolition rubble and incinerator ashes into concrete.