Bonding and anchoring of a CFRP reinforced render for the external strengthening of old masonry buildings

Abstract

This paper presents part of the results of an experimental study undertaken to develop a structural strengthening technique for old masonry buildings. The technique consisted of external reinforcement with a CFRP (Carbon Fibre Reinforced Polymer) reinforced render.CFRP reinforced render is an innovative seismic structural strengthening material for the structural masonry walls of old buildings. It consists of a non-cementitious mortar reinforced with a carbon fibre mesh and is applied to one or both wall faces (preferably by shotcreting). The reinforced render material was developed to improve the mechanical capabilities of masonry walls subjected to “in-plane” and “out-of-plane” seismic loads. Similarly to other widely known composite materials (e.g., reinforced concrete) the composite behaviour of the reinforced masonry relies on both the anchoring as well as on the adhesion of the reinforcing material to the masonry substrate. These aspects are the main objectives of the presented experimental work.The tests carried out in this study included the mechanical characterisation of all the materials involved, specifically of the mechanical behaviour of the reinforced composite render material, and finally focused on the bonding characteristics between CFRP reinforced render strips and masonry substrates, as well as the anchoring solution for the ends of the strips. The present experimental work is part of a research project to develop an innovative seismic strengthening technique for load-bearing masonry wall buildings.