An Experimental Study on FRCM-to-Calcarenite Stone Bond Trough Double Shear Pulling Tests

In the last decades, Fabric Reinforced Cementitious Matrix (FRCM) composites have gained popularity among the retrofitting techniques for historical buildings. Their growing success mainly relies on the use of the inorganic matrix that promotes improved compatibility with the stone or clay masonry substrate. However, several issues arise from the mechanical characterisation of these composite materials due to numerous variables involved in the problem such as test set-up adopted, mortar type, fibre treatment and substrate. The proposed experimental study aims to investigate on the shear bond behaviour of different types of FRCM, consisting of a combination of cement or lime-based mortar matrix and a glass or basalt fibre grid. For the scope, an easy and handy innovative set-up is proposed for double shear bond tests in order to overcome some of the drawbacks related to the test configuration. The outcomes from traditional measurement systems are complemented with the use of the contactless Digital lmage Correlation (DIC) technique in order to deduce more detailed experimental information on the mechanical behaviour of the FRCM systems. The experimental results were then used to validate an already proposed numerical model, with the aim of comparing the experimental and numerical global response curves and trying to estimate the unknown parameters required for modelling. The outcomes may contribute to the advancement of the knowledge on the mechanical behaviour of FRCM composites for structural retrofitting applications by a deep study of their constitutive characterization.