Long-term Losses of Prestress in Precast Members Cast from HPC

Paper deals with results of experimental program which is focused on the monitoring of prestress losses in experimental beams cast from normal concrete C40/50 and high performance concrete C70/85. All beams were subjected to the same prestress force initiated by four pre-tensioned strands. Experimental beams were equipped by elastomagnetic sensors which were embedded on the strands for measuring of prestressing forces. Concrete strains were measured by sensitive strain gauges embedded in the beams. Beams were placed outside the facility in order to simulate similar weather conditions as precast girders used for construction of concrete bridges have. Obtained results of measurements were compared to theoretical values predicted by three different rheological models introduced in Eurocode 2 a Model Code 2010.