Ultra‐high performance concrete under direct tension: Investigation of a hybrid of steel and synthetic fibers

Abstract

Ultra‐high performance concrete (UHPC) offers superior tensile properties in comparison to normal and high‐strength concrete. This is known to largely depend on the fibers included in the UHPC mixtures. Among the available types of fiber, steel fibers have been commonly used in the current practice. However, given the price and availability issues associated with steel fibers, there has been growing interest in benefiting from synthetic fibers in UHPC. This was the motivation for the current study to investigate the potential of five synthetic fibers by evaluating how the tensile properties of the UHPC mixtures made with a hybrid of steel and synthetic fibers are influenced under direct tension. The synthetic fibers of choice consisted of nylon, polypropylene, polyvinyl alcohol, alkali‐resistant glass, and carbon fibers. By using a dog bone test setup, the main tensile properties of the developed mixtures (i.e., direct tensile strength, elastic modulus, and stress–strain relationship) were systematically determined. The results extracted from direct tension tests were then further processed in conjunction with digital image correlation analyses to investigate the formation and propagation of cracks, as well as the post‐cracking response. The original findings reported from this study are expected to pave the way to broaden the fiber types that can be considered for the structural applications of UHPC, especially where high tensile stresses/strains are anticipated.

Experimental study and optimal design of UHPC T‐shaped beam

“…6,[8][9][10][11] Additionally, its exceptional tensile strength, flexural strength, and crack resistance, rendering it highly resilient in demanding structural applications. 12 By virtue of its exceptional properties, UHPC offers multiple advantages in construction. Its extraordinary mechanical properties and durability contribute to the construction of high-performance, long-lasting structures, thereby enhancing the overall sustainability and resilience of our built environment.…”

Strain rate sensitivity of strain‐hardening fiber‐reinforced concrete subjected to dynamic direct tensile loading

“…Strain-hardening fiber-reinforced concretes (SHFRCs) including high-performance fiber-reinforced concrete (HPFRC) and ultra-high-performance fiber-reinforced concrete (UHPFRC) have been demonstrated to exhibit superior tensile resistance with high tensile strength, ductility, and energy absorption capacity even under high strain rate loading owing to their unique strain hardening behavior. [1][2][3][4][5][6][7][8] These superior properties make SHFRCs promising for various structures including bridges, gas tanks, offshore structures, nuclear reactor containment shields, heavy-duty runways, defense shelter, crash barriers, and more, which are exposed to extreme loading conditions such as earthquakes, impacts and blasts. 9 Currently, SHFRCs have been applied to real-life bridge structures such as the 33-m Mars Hill Road bridge in US, the 36.4-m-span Akakura Onsen Yukemuri Bridge in Japan, the 60-m single-span Sherbrooke pedestrian bridge in Canada, the Seonyu footbridge in South of Korea, the Saint Pierre La Cour bridge in France, Kampung-Linsum bridge in Malaysia, etc.…”