Experimental investigation on flexural and ductile behaviors of rebar‐reinforced ultra‐high‐performance concrete beams

Abstract

This paper experimentally investigated the flexural and ductile behaviors of ultra-high-performance concrete (UHPC) beams. The failure modes, deflection, ductility, concrete strain, and reinforcement strain were tested using eight UHPC rectangular beams. The experimental parameters were the reinforcement ratio, the reinforcement diameter, and the UHPC cover thickness. The experimental results showed that all specimens exhibited flexural failure characterized by the yielding of steel rebars, multiple micro-cracks, one localized macro-crack, and slight crushing of UHPC. It was concluded that increasing the reinforcement ratio significantly enhanced the stiffness, flexural capacity, and ductility of the rebar-reinforced UHPC beams, whereas showed little effect on their cracking load. Meanwhile, both the reinforcement diameter and UHPC cover thickness in the range investigated here had little influence on the flexural performance of UHPC beams in the elastic stage and crack development stage, whereas exhibited different influences in the yield stage. Besides, increasing the reinforcement ratio was in favor of presenting the deflectionhardening behavior, while the reinforcement diameter and UHPC cover thickness had little influence on the deflection-hardening behavior. The analytical models were established to predict the yielding load, peak load, and ultimate load of rebar-reinforced UHPC beams, and the predictions showed good agreement with the experimental results in this study. Also, the steel reinforcement could show a dominant role in the bearing capacity by increasing the reinforcement ratio. A post-yielding capacity factor λ was proposed, which could Discussion on this paper must be submitted within two months of the print publication. The discussion will then be published in print, along with the authors' closure, if any, approximately nine months after the print publication.

Experimental Study on the Structural Ductility of UHPC Beams under Flexure

“…That is, the ductility of reinforced UHPC is affected by the fiber content represented by the tensile resistance of UHPC, reinforcement ratio, and strain-hardening capacity of the reinforcement. This remark was further supported by the experimental investigation carried out by Qiu et al (2022).…”

Tensile and flexural tests on ultrahigh performance concrete grouted sleeve connection

“…30,31 Also, steel fibers enhance the bond strength between rebar and UHPC, and their contribution to bond strength increases with fiber content increasing. 32,33 The proposed new UHPC grouted sleeve connection is depicted in Figure 1b. This connection is similar to the typical grouted sleeve connection (Figure 1a), and the fluid UHPC fills the sleeve before the projected rebars were inserted.…”

“…In particular, well‐mixed steel fibers improve the tensile strength of UHPC, reduce the initiation of cracks, restrain the propagation of cracks, and improve ductility 30,31 . Also, steel fibers enhance the bond strength between rebar and UHPC, and their contribution to bond strength increases with fiber content increasing 32,33 . The proposed new UHPC grouted sleeve connection is depicted in Figure 1b.…”

Experimental study and optimal design of UHPC T‐shaped beam

“…7 Foremost among these characteristics is UHPC's outstanding compressive strength, which typically exceeds 150 MPa. 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.…”

“…Comprising a precise combination of cement, fine aggregates, silica fume, quartz flour, high‐range water reducers, and steel fibers, UHPC harnesses the unique properties of each component to achieve remarkable results 7 . Foremost among these characteristics is UHPC's outstanding compressive strength, which typically exceeds 150 MPa 6,8–11 . Additionally, its exceptional tensile strength, flexural strength, and crack resistance, rendering it highly resilient in demanding structural applications 12 .…”