The late-life, in situ properties of concrete in nuclear power station structures

This paper describes an approach to predicting the late-life properties of concrete in nuclear power station (NPS) structures. Such data are needed to evaluate the performance of NPS structures under continued operation or when subjected to a short-term event leading to extreme conditions. A predictive model is described which uses as its starting point the 28-day compressive strength of the concrete, this being the measure used for quality control during construction. Other properties are derived using empirical relationships. Measurements of late-life properties are included together with results of tests on old concretes subjected to temperature excursion up to 150oC and loading at elevated temperatures. Non-destructive methods for evaluation of in situ properties and faults are also discussed. (27 references). (author)