Abstract:
Fracture energy, non-destructive testing, some physical and mechanical tests and microstructural investigations were performed on 18-month 0.7 V%, 1.3 V% and 2.0 V% PVA fiber, glass fiber (GF) and steel fiber (SF) reinforced Ultra High Performance Concretes (UHPCs). Fracture test was performed on Single Edge Notched Beams (SENB) to investigate fracture energy, dissipated energy, flexural strength, crack resistance index (CRI), and flexibility index (FI) of UHPCs. Dynamic modulus of elasticity and damping ratios of the UHPCs were calculated by performing resonance frequency tests on the SENB samples by ASTM C215 standard. In addition, compressive strength, static modulus of elasticity, electrical resistivity, ultrasonic pulse velocity (UPV), Leeb hardness, Schmidt hammer, and density tests were also performed on the cylindrical samples. Field Emission Scanning Electron Microscopy (FE-SEM) and Energy Dispersive X-Ray (EDX) analyzes were performed to examine the interaction between the UHPC matrix and different fibers. Among all the mixtures, an exceptionally positive effect of SFs on the all mechanical properties of the UHPCs was observed. Dynamic test results showed that the increase in fiber ratio increased the damping ratio of UHPCs irrespective of fiber type. The UPV and electrical resistivity results offered promising results regarding the internal structure of UHPCs.
