Interfacial Bonding of Nano-modified Cementitious Composites Incorporating Basalt Pellets to Normal Concrete

Interfacial bonding between precast normal concrete (NC) and cast-in-place high-performance fiber-reinforced cementitious composites (HPFRCC) has received significant attention in recent years, for applications such shear key fillers in bridge deck joints. Novel HPFRCC has been recently developed at the University of Manitoba. These composites include various constituents (cement, slag, nano-silica) and reinforced with fiber systems (single and hybrid) including polyvinyl alcohol (micro-PVA) and basalt fiber pellets (macro-BFP). BFP is a novel class of basalt fibers, where basalt fiber strands are coated by a polymeric resin with textured surface micro-grooves. In this study, the interfacial shear bond adhesion and coefficient of friction between the NC and HPFRCC were evaluated using bi-shear test and slant shear test, with an inclination angle of 33.7º with the vertical. The results showed that nano-silica had a significant effect at improving the interfacial bonding strength and coefficient of friction with NC. The addition of 1% micro-PVA fibers to macro-BFP (hybrid system) in the nano-modified composites led to a noticeable improvement in their interfacial bonding and coefficient of friction with NC, which suggests their promising use for future field applications.