Análisis del comportamiento frente acciones cíclicas de muros de mampostería reforzados con materiales compuestos de matriz inorgánica y tejidos de fibras vegetales

Abstract

In order to pursue sustainable objectives in the construction industry, a new composite material using vegetal fabric coated with resin and embedded into mortar was developed, characterized and applied on masonry walls. In this study, fabrics of different types of vegetal fibres (flax, hemp, sisal, and cotton) coated with resins were manufactured, and with them, FRCM (Fabric Reinforced Cementitious Matrix) specimens were produced for tensile tests and bonding tests with masonry units. Once characterized the FRCM of vegetal fibers specimens, two types of fibres were chosen to reinforce masonry walls. Results showed an excellent interaction between vegetal fibres and mortar matrix. The coating with resins improved the mechanical properties of the yarns and avoided the typical slipping failures in FRCM composites. For strengthening masonry walls, hemp and cotton FRCM were chosen. Hemp FRCM was the composite that reached the highest mechanical strength, whereas cotton FRCM had the greatest elongation capacity and multicracking response. These strengthening systems increased significantly the shear strength and the ability to dissipate energy from the unreinforced masonry walls, showing even better efficiency than glass FRCM strengthened walls (also tested in this study) under cyclic loading. In addition, the use of a greater volume of fibres in the case of the FRCM of vegetal fibres allowed reducing the volume of cementitious matrix to be used (0.5 and 5%, contrasted with glass-FRCM), which reduced the specific weight of the FRCM. In addition, analytical and numerical models were proposed for the analysis of FRCM and wall specimens manufactured and tested in this study. Their experimental results adjusted the parameter of analytical and numerical models. These models were effective calculation tools to reproduce FRCM specimens and masonry walls reinforced with FRCM behavior, where the connection between mesh-mortar and mortar-masonry is good enough to avoid failures due to mesh sliding and mortar debonding. In general, this thesis represents a great step in the topic of the use of vegetable fibers within cementitious matrices. Well, from the low density, low cost and sustainability that represent vegetal fibres it was possible to develop a composites with greater sustainability and efficiency (in contrast with the synthetic fibers FRCM used in this study), able to improve the mechanical performance of masonry walls subjected to cyclic loading.