| Ultra-high-performance concrete (UHPC) is well known for its exceptional mechanical
properties, including high compressive strength and post-cracking tensile behavior. Although steel
fibers and normal steel transverse reinforcements have been used to improve the confinement of
UHPC, the possibilities for other confinement materials have not yet been investigated. This study
explores the confinement of UHPC using titanium alloy ties, which offer an exceptional strength-
to-weight ratio and corrosion resistance. Eight UHPC cylinders (8 in. × 16 in.) were cast; four of
them were confined with circular titanium hoops, and the remaining four were unreinforced to
serve as benchmarks. The percentage of transverse reinforcement in the confined specimens varied
from 1% to 4%. The specimens were tested under uniaxial compressive loading. The results were
investigated in terms of the stress-strain response, peak strength, peak strain, ultimate strength, and
ultimate strain. The results revealed that titanium alloy confinement can increase the peak
compressive stress of UHPC by approximately 53.37%. Based on experimental data, a novel
constitutive model for titanium alloy bars confined UHPC was proposed and compared with
existing models for concrete confined with low-strength or high-strength steel. The stress-strain
behavior of titanium-confined UHPC was well captured by the proposed model, which offers
precise peak and post-peak behavior predictions.
Keywords: Ultra-High Performance Concrete; Confinement; Titanium alloy bars; Seismic
Resiliency; Innovative materials; Stress-Strain Relationship |