Non-destructive testing of concrete

The many methods for the non-destructive testing of concrete are reviewed. The methods are classified, though somewhat superficially, as surface methods, vibration and resonance methods, pulse propagation methods, radioactive methods and electrical and magnetic methods. The use of combinations of methods is seen as a significant development in the field. Other methods, some of which await exploitation, are discussed. It is concluded that unreasonable expectations for non-destructive test methods and a lack of trained technicians to apply them are the main reasons for their slow acceptance.