Enhancement of fabric–mortar interfacial adhesion by particle decoration: insights from pull-off measurements

Abstract

Polymer-impregnated carbon fabric is used as an alternative to metallic reinforcement bars in cementitious materials, which is then termed textile-reinforced concrete (TRC). In this study, the bond strength between the cement-based matrix and the fabric was enhanced by decorating the polymer (an epoxy) coating the carbon fabric with hydrophilic micron-size particles (cement or silica) or nanocarbons (functionalized carbon nanotubes or graphene oxide). Cement powder decoration led to a 25% increase in the bond strength (measured by a pull-off test) and a 30% improvement in the mechanical properties of the composite. At the micron scale, the decoration resulted in the formation of a 100-μm thick interlayer between the decorated fabric and the cement-based matrix. Unexpectedly, exposure of the cement-decorated samples to a NaCl environment (as in off-shore constructions) resulted in enhanced bond strength due to the growth of salt crystals at the fabric–matrix interface.