Impregnated Carbon Fabric–Reinforced Cementitious Matrix Composite for Rehabilitation of the Finale Emilia Hospital Roofs: Case Study

In this paper, the mechanical performance of concrete beams strengthened by an impregnated carbon fabric–reinforced cementitious matrix (CFRCM) composite is investigated. The study is aimed at the rehabilitation of the Finale Emilia hospital roofs, which were severely damaged by the 2012 northern Italy earthquake. An 8-m-long concrete beam was taken from the building for reinforcement and testing in a beam test setup. The composite is designed to be externally applied to the existing thin clay tile layer bonded to the concrete beam intrados. Two lamination cycles, which differ by the way in which the partially organic adhesion promoter is applied to the fabric, are considered. It was found that impregnation through fabric immersion provides a 1.5-fold increase in the ultimate strength of the strengthened beam compared to expedited impregnation with a brush and that clay tiles make a very good supporting substrate, to the extent that cohesive fracture at the tile–concrete interface takes place on the verge of concrete failure near the hinge zone. Conversely, expedited impregnation of the carbon fabric with the adhesion promoter was unable to provide adequate fabric–matrix adhesion and led to delamination failure. Estimates of the adhesion strength, optimal bonded length, and of the composite, as well as of the concrete strain at failure, are provided.