Long-term behavior of concrete slabs prestressed with CFRP rebars subjected to four-point bending

The present study investigates behavior of concrete slabs prestressed with carbon-fiber-reinforced polymers (CFRP) subjected to four-point bending. The main experimental set comprised 10 identical 4.5 m long specimens from which 8 were subjected to quasi-static loading until failure. The remaining two specimens were exposed to sustained loading with duration of 1 and 7 years, and subsequently were loaded until failure. The main objective of this study is to analyze the long-term behavior in order to assess the assumption of several authors that no significant creep or stress relaxation occurs in CFRP prestressed rebars. To achieve that, the experimental data were compared to the results of a complex finite element model in which the CFRP is modeled by a linear elastic material (without creep) which allowed us to confirm the initial hypothesis that no considerable creep or stress relaxation occurs in the prestressed CFRP rebars.