Freezing and Thawing Durability of FRCM Systems: Preliminary Study

The work focuses on investigating the influence of freeze-thaw cycles on the bonding behaviour of structural retrofit systems. To this scope, an extensive experimental programme has been planned in relation to direct shear tests carried out in displacement control on lap joints consisting of basalt and steel strips bonded to tuff units and clay bricks. The freeze-thaw ageing was carried out according to the Italian Guideline for the Identification, Qualification and Accep-tance of Fibre-Reinforced Composites (FRCM) with inorganic matrix to be used for structural strengthening. The experimental tests discussed in the next are a little part of a wider experimental campaign, aimed to develop sustainable mortars for structural repair/rehabilitation interventions. In fact, cement-free alkali-activated mortar seems to represent a reasonable alternative to the conglomerates currently used for repair/retrofitting applications, as they have lower stiffness than Portland cement mortars of the same strength class and can be produced from industrial by-products. The experimental programme is ongoing, and the first performed tests are presented in the paper; in addition to the said direct shear tests, results coming from direct tensile tests on FRCM systems are also discussed. It is highlighted that this experimental study is part of the STRIPES research project, funded by the PRIN-PNRR 2022 call.