## 1 Introduction  
Since the first employment of asbestos cement in the 1900, the use of synthetic fibers for the reinforcement of existing constructions has become a well established practice which finds different usages in civil engineering applications [1]. Particularly, continuous multi-filaments textile embedded within inorganic based matrix proved to be particularly effective to strengthen and rehabilitate concrete and masonry structures [2; 3; 4; 5]. These systems are known as Fabric Reinforcement Cementitious Matrix (FRCM) or Textile Reinforced Mortar (TRM) and present several advantages compared to traditional retrofitting techniques, such as high strength to weight ratio, corrosion resistance, easy and fast application, and low invasiveness [2; 3; 4; 5; 6]. Although fabrics are usually constituted by yarns made of dry filaments, different studies and commercial solutions propose the employment of fabric impregnated with polymeric coatings, usually epoxy resin or styrene-butadiene copolymer [7; 8; 9; 10]. The application of the coating has the double effect of enhancing the load bearing capacity of the reinforcement [8; 11; 12; 13; 14] and protecting the fibers from abrasion and chemical corrosion [9; 15; 16; 17; 18; 19], which is of particular significance for alkali-sensitive fibers, such as glass fibers. The increased mechanical performances of FRCM systems with coated fabrics is mainly attributed to the improved stress transfer capacity between the filaments [10; 11; 12; 13], which, in dry FRCM systems, is compromised by the poor penetration of the inorganic matrix within the filaments [11]. When a polymeric coating is applied, the load transfer mechanism between fabric and matrix changes [20]. In dry systems, the tensile behavior of the composite depends on the bond between filaments and matrix, while the bond between neighboring filaments is almost negligible [4; 11]. On the contrary, in pre-impregnated yarns, the fibers are embedded in the coating, which prevents the matrix to penetrate into the yarns. As a consequence, the stress-transfer between the fabric and matrix no longer depends on the ability of the latter to penetrate between the individual filaments, but on the interaction of the coating with the cementitious matrix. Experimental studies showed that, by applying a polymeric coating, the failure mechanism of the composite shifts from slippage of the filaments inside the yarn, to slippage of the yarns into the matrix and delamination at the fabric-matrix interface [8; 10]. This is due to difference in the chemical characteristics of organic coatings (hydrophobic) and inorganic matrix (hydrophilic), which can lead to a relatively poor bond of polymers with the cementitious matrices. In order to enhance the chemical interaction between these two components, some studies propose the application of inorganic coatings [21; 22; 23; 24; 25]. However, polymeric coatings present some characteristics that make them particularly suitable for industrial production. First of all, surface modification of fibers by application of sizings and coatings is a standard procedure, and industrial techniques for the production of coated fabrics are already on the market [26; 27]. Secondly, because of the great variety of polymeric coatings available, the specific characteristics of the fabric can be adjusted, for example, by providing a good flexibility which facilitate the application on the substrate. A promising, but still relatively unexplored technique to maintain the versatility of organic coatings for textile reinforcement, while enhancing their chemical compatibility with inorganic matrices, is the incorporation of inorganic nanofillers in the polymer [28; 29; 30]. Inorganic nanofiller, typically employed for the production of polymer nano-composite, includes: carbon nanoparticles, carbides, nanoclays, and nano-oxide, particularly silica (SiO\({}_{2}\)), alumina (Al\({}_{2}\)O\({}_{3}\)), and titania (TiO\({}_{2}\)) [31].