Experimental Characterization of Fabric-Reinforced Cementitious Matrix (FRCM) Systems Applied on Calcarenite Stone: Adoption of Non-Standard Setup for Double-Shear Bond Tests

The use of Fabric-Reinforced Cementitious Matrix (FRCM) systems is an innovative method for strengthening structures, particularly masonry, while addressing environmental and economic concerns. Despite their widespread use, characterizing FRCM composites poses challenges due to their complex mechanical behavior and considerable variability in properties. The available standardized testing methods exhibit some inconsistencies, underscoring the need for reliable characterization procedures. This paper presents an experimental study on the bond behavior between FRCM materials and calcarenite stone using a non-standard setup for double shear bond tests. Different FRCM systems are considered, varying the matrix composition and fabric nature. The experimental results are evaluated in terms of maximum stress, slip and data dispersion, alongside comparisons with double shear tests on larger samples and single-lap shear. These findings provide insights into how the mortar nature influences the stress-slip curves, strength, ductility and failure modes. The experimental study demonstrates the repeatability and robustness, particularly in terms of peak strength, of the non-standard setup configuration utilized in the study. The study highlights the importance of reliable characterization procedures for FRCM materials, especially in bond behavior assessments, emphasizing the need for further research to enhance our understanding of their application in structural reinforcement.