The Use of Fiber-Reinforced Concrete in Structural Retrofitting

The NTC 2018, in Section 11.1, allows the use of fiber-reinforced concrete (FRC) for structural applications, pro-vided that it is accompanied by a "Certificate of Technical Evaluation" (CVT) issued by the President of the Higher Council of Pub-lic Works, based on guidelines approved by the same President. In January 2019, the Higher Council of Public Works published the "Guidelines for the Identification, Qualification, Technical Evaluation Certification, and Acceptance Control of Fiber Reinforced Concrete (FRC)" and, subsequently, in May 2022, the "Guidelines for the Design, Implementation, Control, and Testing of Struc-tural Elements in Fiber Reinforced Concrete with Steel or Polymer Fibers," which provide the procedures for the identification, qualification, and control of fiber-reinforced concrete, as well as the procedures for the design, execution, and control when using FRC for the construction of new structural elements and the strengthening of existing reinforced concrete structures respectively. In 2020, research began at the Italian Institute for Concrete and at TEKNA CHEM SPA to develop and produce a fiber-reinforced ce-mentitious product with extremely high toughness and hardening potential. In 2023, TEKNA CHEM SPA received the CVT for AETERNUM HTE, certifying a ductility class of 14d and hardening characteristics. Based on this, a numerical-experimental cam-paign has been started at the Mediterranea University of Reggio Calabria, in collaboration with the TEKNA CHEM Point of Reggio Calabria. The study focuses on structural retrofitting, including the use of FRC exoskeletons. The aim is to validate the applicabil-ity, toughness class, and performance of certain FRC products used in the retrofitting of existing structures and the construction of new structures, and to evaluate and estimate the effects of degradation on the products' durability once in place. This paper descri-bes the programmed experimental investigation campaign and presents the first experimental results along with some numerical applications.