Title: High Performance Fiber Reinforced Cement Composites with Innovative Slip Hardending Twisted Steel Fibers
Author(s): Dong joo Kim, Antoine E. Naaman, and Sherif El-Tawil
Appears on pages(s): 119-126
Keywords: strain hardening; slip hardening; pullout mechanism; strain rate sensitivity; twisted fiber; equivalent bond strength; effect of matrix strength; tensile tests; bending tests
This paper provides a brief summary of the performance of an innovative slip hardening twisted steel fiber in comparison with other fibers including straight steel smooth fiber, high strength steel hooked fiber, SPECTRA (high molecular weight polyethylene) fiber and PVA fiber. First the pull-out of a single fiber is compared under static loading conditions, and slip rate-sensitivity is evaluated. The unique large slip capacity of T-fiber during pullout is based on its untwisting fiber pullout mechanism, which leads to high equivalent bond strength and composites with high ductility. Due to this large slip capacity a smaller amount of T-fibers is needed to obtain strain hardening tensile behavior of fiber reinforced cementitious composites. Second, the performance of different composites using T-fibers and other fibers subjected to tensile and flexural loadings is described and compared. Third, strain rate effect on the behavior of composites reinforced with different types and amounts of fibers is presented to clarify the potential application of HPFRCC for seismic, impact and blast loadings.