Toughness measurement - The need to think again

The first part of the paper reviews a number of concurrent developments which have taken place in recent years in the concrete research area. The developments include the commercial development of FRC materials, the proposals for evaluating the enhanced performance of FRC materials, the development of high performance (high strength/brittle) concretes, the application of fracture mechanics to concrete together with the revolution in testing machines with the introduction of closed-loop testing. The limitations of current standards and guidelines for evaluating the toughness of FRC materials are also reviewed and proposals for overcoming these limitations are advanced. It is proposed that notched beams, subjected to three-point loading, rather than unnotched beams subjected to four-point loading should be used for toughness measurement and that the deformation of the beams should be measured directly from the specimen rather than through the testing machine.