## 1 Introduction  
In recent decades, significant improvements in the technologies and products available for the external strengthening and retrofitting of historical masonry structures and more recent structural elements have been developed. The first marketed family of products, Fiber Reinforced Polymer (FRP) composites, had fast and facile installation procedures, were lightweight, and showed good strengthening properties [1; 2]. Despite the indisputable advantages described above, FRPs soon revealed relevant drawbacks, such as, among other things, low compatibility with the stringent requirements implemented for protecting buildings that are part of cultural heritage, installation problems in the presence of wet surfaces, and low thermal and fire resistance [3; 4; 5]. Thus, a second generation of products, based on fabric embedded in an inorganic matrix (cement or lime-based mortars), was formulated. These are referred as Fabric-Reinforced Cemertitious Matrix composites (FRCM), Textile-Reinforced Mortars (TRM), Cemertitious Matrix-Grid (CMG), and Inorganic Matrix-Grid (IMG) composites [6]. Extensive experimental and theoretical research activities have been carried out and are still in progress to investigate and validate the mechanical behavior and bond properties of carbon fabric-cement-based mortar composite [3], polyparaphenylene benzobisoxazole (PBO) fabric-cement-based mortar composite [7; 8], glass grid-cement-based mortar composite [9], and unidirectional steel textile-cement-based/mineral-based mortar composite [10]. The general outcomes of these investigations confirmed that textile geometry, sand granulometry, mechanical properties of the constituent materials and their combination affect the load-bearing capacity, bond strength on substrate, and failure modes of FRCM composites. Furthermore, various experimental campaigns [11; 12] have pointed out that tensile and shear bond tests on FRCM composites are relevant in delivering reliable design methodologies. Several recent papers have investigated the performance of basalt FRCM composites for retrofit applications on masonry. [PERSON] et al. [13] tested different basalt-based FRCM configurations comprising readily available commercial systems. Basalt textiles with a yarn spacing of 25 mm and area weights of 220 or 350 g/m\({}^{2}\) were embedded in a one component mortar containing redispersable polymers or a natural hydraulic lime mortar, and basalt textiles with a yarn spacing 6 mm and an area weight of 250 g/m\({}^{2}\) were embedded in a two components mortar containing hydraulic lime, Eco-Pozzolan, special additives and synthetic polymers in water dispersion. Performance was evaluated in terms of both uniaxial tensile behavior and bond to masonry. The outcomes of the investigation revealed that the tensile tests were repeatable and reproducible in terms of peak stress, but matrix properties and fiber slippage caused some of them to fail in showing the expected trilinear behavior, whereas bond tests resulted in quite uniform peak stress. [PERSON] et al. [14] investigated the mechanical performances of a commercial basalt-FRCM system based on a basalt textile with an area weight of 400 g/m\({}^{2}\) and a yarn spacing of 8 mm embedded in a mineral-natural hydraulic lime mortar. Tensile tests and single-lap shear tests on masonry substrate were carried out to study the mechanical behavior and the bond properties of the composite. The tensile behavior of basalt-FRCM system was characterized by a tri-linear stress-strain response with failure occurring by sequential tensile failure of the fiber bundles. In single-lap shear tests, failure was characterized by the detachment of the fabric strips and external matrix layer. For more than seven decades now [15; 16; 17; 18], a broad family of binders, the alkali-activated materials, has been attracting systematic and increasing academic interest and has found large-scale applications in Eastern Europe and China [19; 20].