Epoxy Resins for Interphase Strengthening of Textile-Reinforced Composites for Structural Applications

In the field of structural retrofitting and building rehabilitation, inorganic matrix textile-reinforced composite materials offer many interesting advantages, such as resistance to high temperatures and aggressive environments, water vapor permeability, compatibility with traditional supports and reversibility of intervention. Yet, mechanical performance of the reinforcing system strongly depends on the bond quality at the fabric-to-matrix interphase, which is usually unsatisfactory. Indeed, hydration products of the inorganic binder are incapable of penetrating among the multifilament yarn, thus allowing for the so-called telescopic failure. Therein, inner filaments (the core) slide over outer filaments (the sleeve). This failure mode occurs inconsistently and, although imparting ductility, prevents exploitation of the reinforcing potential of the fabric. In this chapter, we discuss a landscape of coating techniques intended to promote fabric-to-matrix adhesion. Design parameters for the coating, such as formulation, viscosity and thickness, alongside an investigation of the system thermal stability, are discussed based on recent advances in the field.