Reinforcing Potential of Mineral-Impregnated PBO Fibre Yarns in a Sustainable Blended Matrix

Textile Reinforced Concrete (TRC) is now a key technology for the structural rehabilitation of deteriorated concrete structures, as well as for novel, versatile and highly customisable thin structures with optimised raw material utilisation. In order to fully exploit the excellent strength and modulus of high-performance fibres, like PBO, a uniform impregnation of the yarns is generally applied to achieve optimum stress transfer from the inorganic matrix to the load-bearing reinforcements. Mineral impregnation techniques for high-tenacity multifilament textiles are gaining increasing popularity over their polymeric counterparts mainly due to their enhanced thermal stability and good potential for reducing environmental impact. This paper presents and discusses the pull-out behaviour of PBO yarns embedded in a newly developed limestone calcined clay cement (LC³) mortar. Emphasis is placed on the bond properties of two grades of PBO fibres through pull-out tests. It is shown that the mineral impregnation plays a crucial role, not only in improving the mechanical response in terms of bond, but also in overcoming the differences in stiffness and properties of the PBO fibres, allowing the use lower grade fibres without compromising the overall performance of the composite.