A new biocomposite material mixing past and present to look toward the future

In the last decades interest of researchers in the field of vegetal fiber-based biocomposite materials to be used for structural strengthening has grown significantly. This interest is primarily driven by the plant fiber abundance, renewability, cost-effectiveness, historical-compatibility, and eco-friendly features. These positive aspects can be undermined by the variability of mechanical properties inherent in natural materials. Within this context, it seems interesting to consider the development of new biocomposite materials that involve the use of nanomaterials to enhance mechanical characteristics and to reduce material variability. This paper presents the preliminary results that will be used to assess the performance of biocomposites in structural strengthening of masonry structures, where the vegetal fibers are coated with nanomaterials. The base biocomposite is made of hydraulic lime mortar, enhanced with two different kind of fibers: Spanish broom and hemp fibers. Mechanical properties of these biocomposite materials are addressed experimentally by three-point bending tests and uniaxial compression tests. The results are compared to a reference material, made of classical hydraulic lime mortar, to investigate the best performances in the fiber- matrix bond. In particular, stress-strain curves are recorded to estimate maximum strength and strain together with a measure of fracture energy to assess the influence of natural fibers in the composite.