## 1 Introduction
They highlighted that the fibers could be surface-treated, and their content could be optimized to define a suitable material for restoration. [PERSON] et al. [9] investigated the flexural behavior of natural hydraulic lime mortars reinforced with natural cane fibers for brick manufacturing and use in sustainable construction. Results indicated improvements in post-cracking flexural strength compared to unreinforced mortars, along with increased ductility. [PERSON] et al. [12] examined quasi-static responses to compression, shear, and flexure of hydraulic lime mortars reinforced with polypropylene microfribers, noting improvements in flexural toughness but increased weakness in mode I fracture. The same authors [13] also analyzed the dynamic response to impact loading in flexure, finding higher sensitivity in the lime mortar reinforced with fibers compared to Portland cement mortar and concrete reinforced with fibers. The main application of said mortars was to repair stone masonry structures of historical importance in Canada subjected to varying degrees of seismicity. [PERSON] et al. [14] investigated the mechanical behavior in quasi-static and dynamic regimes of hydraulic lime mortars reinforced with polypropylene microfribers in various quantities. They explained the improvement in quasi-static flexural strength and toughness with increasing fiber content, highlighting the material's sensitivity to the deformation velocity in dynamic flexural testing. Recently, [PERSON] et al. [15] studied lime mortars reinforced with polyvinyl alcohol (PVA) fibers, analyzing their behavior in flexure, compression, and indirect tensile strength. The findings showed that both flexural strength and fracture energy increased with fiber content, as did tensile and compressive strengths, but at different rates. They concluded that the newly proposed mortar presented appropriate properties for the strengthening of masonry structures, especially for intervention in cultural heritage buildings. The research on lime concretes is limited, as stated above. A chapter called \"Lime Concretes with Ad Hoc Performances\" authored by [PERSON] and [PERSON] can be found in the book \"Building Engineering Facing the Challenges of the 21 st Century\" [16]. In this work, the authors use \"limecrete\" to refer to lime concretes and present several cases involvingthe design of mortars and concretes for restoration works and new buildings. Additionally, [PERSON] et al. [17] designed hydraulic lime concretes to restore the Rosello church in Lerida, Spain. Besides these works, there are several papers focused on adding lime to different concretes [18; 19; 20; 21; 22; 23]. However, these are not specifically designed for restoration purposes but rather for the benefits of using lime due to sustainability and economic reasons. The findings on fiber-reinforced lime concrete are extremely scant despite the potential advantages, such as increased ductility and toughness. Furthermore, for specific applications related to both the conservation and rehabilitation of historical heritage, as well as its use in new construction, achieving compatibility requirements may not align with the desire for high compressive strength (typically defined as 6-7 MPa) [8]. Consequently, it becomes necessary to analyze the dynamic fracture behavior of this type of low-strength concrete [24; 25; 26] as opposed to that of higher-strength natural hydraulic lime concretes, whose application field is not as focused on heritage restoration and conservation. Therefore, building upon this scientific literature, this paper aims to investigate the behavior of low-strength hydraulic lime concrete reinforced with polyvinyl alcohol fibers under various loading conditions. The hydraulic lime concrete matrix was designed using an innovative methodology recently developed by the authors of this work [27].