Nano-modified Slag-based Cementitious Composites Reinforced with Multi-scale Fiber Systems

This study responds to the need for improving the overall performance of concrete infrastructure to achieve longer service life, fewer cycles of repair, and reduced life-cycle costs. Hence, novel high-performance fiber-reinforced cementitious composites were developed using various types of nano-materials and fibers. The composites developed in this study comprised high content (50%) slag by mass of the base binder (700 kg/m3) as well as nano-silica or nano-crystalline cellulose (produced in Canada). In addition, nano-fibrillated cellulose (NFC), produced in Canada, and a novel form of basalt fiber strands enclosed by polymeric resins called basalt fiber pellets (BFP), representing nano-/micro- and macro-fibers, respectively, were incorporated in the composites. The composites were assessed in terms of early- and late-age compressive strength, flexural performance, and resistance to freezing and thawing cycles. Generally, the BFP reduced the compressive strength of the composites, but the co-existence of nano-materials and NFC alleviated this trend. Furthermore, all nano-modified composites with multi-scale fibers showed notable improvement in terms of flexural performance (post-cracking behavior, residual strength, and toughness) and resistance to frost action. Thus, they can be used in a suite of infrastructural applications requiring high ductility in cold regions.