Removable/Reversible Solutions for the FRP-Confinement of Historical Masonry Columns

The retrofitting of historical masonry is often limited by strict rules of reversibility and aesthetical impacts. In this scenario, the use of fibers reinforced polymers (FRPs) is generally forbidden because of the epoxy-based matrix is glued on the substrate, even if their effectiveness is largely proved. Since the reversibility of the intervention is one of the most relevant aspects in the field of cultural Heritage, further research aiming to the optimal compromise between safety and conservation is still needed. The present research aims to experimentally demonstrate two methods oriented to the removability of the FRP-confinement of masonry columns. The first consists of a liquid adhesion-inhibitor applied by brush before the hand lay-up installation of the FRP-wrapping. Alternatively, a MylarTM layer placed between the substrate and the FRP-jacket was experienced to fully-eliminate the bond between jackets and core substrate. Pure compression tests were performed in order to check the mechanical effectiveness of the proposed techniques. After testing the FRP-jacket was removed in order to observe the substrate conditions in terms of detachment of material and/or discoloration. The main results are herein discussed demonstrating the validity of the proposals for two different types of masonry (i.e. tuff and limestone).