Effect of Fiber Type and Fiber Hybrids on Strain-Hardening and Multiple Cracking Properties of the Ultra-High Performance Cementitious Composites under Uniaxial Loads

Five series of strain hardening ultra-high performance cementitious composites (SHUHPCC) incorporated with different types of fibers and hybrid fibers were produced. Three types of fibers (steel fiber, polyvinyl alcohol fiber and polyethylene fiber) were used as mono or hybrid reinforcement in SHUHPCC with the same volume fraction of 2%. The primary strengths, strain hardening and multiple cracking behaviors of hybrid fiber reinforced SHUHPCC under the uniaxial tensile are investigated. Test results show that the SHUHPCC containing PE fibers exhibited higher strain hardening capacity and lower first cracking strength than composites reinforced with mono PVA fiber or mono steel fiber. The composites containing PVA fibers or steel fibers have higher tensile strength and first cracking strength than the composite reinforced by mono PE fiber. Hybridization reinforcement with different fibers is able to make up defects of mono fiber reinforcement for SHUHPCC. The change laws of tensile strength and uniaxial compression strength of SHUHPCC with mono PE fiber and mono PVA fiber are opposite to each other.