Performance of Fiber Reinforced Materials: Historic Perspective and Glance in the Future

Ideally high performance fiber reinforced concrete should have enhanced modulus of elasticity, higher bend over point, sustained strain hardening response characterized by sequential multiple cracking with controlled crack widths. Conventional fiber reinforced concrete primarily alters the post peak response and can constrain macro cracks. Strain hardening response can be obtained by controlling processing (extrusion, pultrusion, spraying chopped fiber and cement slurry), volume, type and geometry of fibers (e.g. textile) and rheology of matrix (self-consolidating concrete (SCC), ultra-high performance concrete (UHPC)). Use of nanofibers such as carbon nanotubes (CNT) and carbon nanofibers (CNF) fundamentally alters the nano structure of calcium silicate hydrate (C-S-H) gel. Reinforcing concrete with CNT can enhance modulus of elasticity, enhance toughness, reduce autogenous shrinkage and delay corrosion of steel bar reinforcement. Modeling and characterizing interfaces at multiscale is critical in development of high performance fiber reinforced concrete.