Bond behaviour of seven-wire non-pretensioned plain strands embedded in high-performance concrete / Andrzej Seruga // W: Bond in Concrete : Bond, Anchorage, Detailing : 5th International Conference, Stuttgart, ... więcej

Bond behaviour of seven-wire non-pretensioned plain strands embedded in high-performance concrete / Andrzej Seruga // W: Bond in Concrete : Bond, Anchorage, Detailing : 5th International Conference, Stuttgart, Germany, 25th - 27th July 2022 : proceedings [Dokument elektroniczny] / eds. Jan Hofmann, Giovanni Plizzari. – Stuttgart : Institute of Construction Materials. University of Stuttgart : Materials Testing Institute. University of Stuttgart, 2022. – S. 464-476 : fot., tab., wykr. – Tryb dostępu: https://d-nb.info/1264911548/34. – Bibliogr. 3 poz., Abstr.

The bond of prestressing strands can vary with regard to the size of strand, the type of concrete mixture, the age and strength of concrete and many other factors. The bond level is significant for composite ... więcej

The bond of prestressing strands can vary with regard to the size of strand, the type of concrete mixture, the age and strength of concrete and many other factors. The bond level is significant for composite action between the concrete and steel, especially in the transfer zone of the pretensioned member. Tensioning force release can usually be performed when obtaining a minimal concrete compressive strength at the level of 40 MPa. Such a strength is required for a concrete maturity of twenty-four hours or less, which is not easy. With help comes the application of modern high-performance concrete (HPC) technology.
A research program to examine the bond of HPC on the concrete composition grade of C80/95 was designed. The concrete specimens with untensioned 7ɸ4 mm (12,9 mm dia.), 7ɸ5 mm (15,7 mm dia.) and 7ɸ6 mm (18,2 mm dia.) strands were precast in individual moulds. Six strandembedment lengths were tested: 40, 80, 120, 240, 330 and 460 mm. The main tests concerned measurements of slip between the strand and the concrete surface and were made with using an electronic extensometer attached to the free end of strand and concrete surface. The bond stressslip curves and bond strength versus free-end slip relationship was analysed. All specimens were tested in the laboratory of the Institute of Materials and Building Structures of Cracow University of Technology, Cracow, Poland.