Experimental investigations and analytical models on Composite Reinforced Mortar (CRM) systems for masonry strengthening: a state-of-the-art review

Composite Reinforced Mortar (CRM) is an emerging technique for strengthening masonry structures, based on the use of a pre-cured FRP mesh embedded within an inorganic matrix. Although CRM systems can be certified within the European Union, specific design codes are still lacking, and the available guidance remains fragmented. This paper provides an overview of experimental investigations carried out on CRM constituent materials to test mechanical properties and durability, and on structural members strengthened with CRM, such as masonry walls subjected to in-plane and out-of-plane actions, vaulted elements, and crowning beams. Existing analytical models for predicting the capacity of masonry elements retrofitted with CRM are reviewed and critically discussed in the light of experimental evidence. The shake table tests conducted to investigate the seismic behaviour of masonry structures strengthened with CRM are also described. Furthermore, the potential use of CRM for integrated energy-structural retrofitting solutions is examined, together with low-impact strategies suitable for fair-faced masonry applications and architectural heritage.