Experimental analysis on adhesion of nfrcm systems applied to masonry structures

Nowadays, structural strengthening is a prevalent topic of numerous research projects, above all if the materials used are sustainable, eco-friendly or green. In fact, the application of sustainable composite materials as structural strengthening represents the most innovative technique in the civil field. This paper is focused on the use of alternative fibers to produce structural reinforcement based on sustainable resources. Specifically, vegetable and volcanic fibers were utilized to manufacture NFRCM (Natural Fibers Reinforced Cementitious Matrix) systems. The results obtained by the authors from previous experimental investigations highlight significant structural performance of the strengthened masonry elements using natural fibers (vegetal, mineral). A suitable strengthening system for masonry structures shows a similar stiffness, for mechanical compatibility, with the substrate, exhibiting enough tensile capacity. The FRCM systems ensure advantages such as easiness of application, low invasiveness and reduced intervention time, respect at common composite materialsbased on synthetic fibers, with a lower cost, better fire resistance, higher compatibility with existing structures and breathable surface. In this paper, in order to analyze the innovative strengthening technique, an experimental investigation was carried out in the Materials and Structures Engineering Laboratory of Civil Department of University of Calabria. In particular, tensile and pull-out tests were carried out on sustainable composite materials and strengthening system, using flax and basalt fibers and common clay bricks typical of the Mediterranean area.