scholarly journals Performance of Cracked Ultra-High-Performance Fiber-Reinforced Concrete Exposed to Dry-Wet Cycles of Chlorides

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Longlong Niu ◽  
Shiping Zhang
Keyword(s):  
Reinforced Concrete ◽  
Flexural Strength ◽  
High Performance ◽  
Chloride Ion ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Self Healing ◽  
Fiber Reinforced ◽  
High Performance Fiber ◽  
Corrosion Of Steel

This paper presents an experimental study on the performance of cracked ultra-high-performance fiber-reinforced concrete (UHPC) exposed to dry-wet cycles of 3.5% NaCl solution under the temperature of 60°C. The results show that the wider the crack, the higher the corrosion degree of steel fibers embedded in UHPC, and the deeper the chloride ion diffusion on both sides of the crack. With the increase of dry-wet cycles, the flexural strength of precracked UHPC first decreases and then increases, and the lowest flexural strength was observed in 60 dry-wet cycles. Although self-healing is hard to cease the corrosion of steel fibers, it can relieve the corrosion of steel fibers and improve the flexural strength exposed to 100 dry-wet cycles.

scholarly journals Resistance of an Optimized Ultra-High Performance Fiber Reinforced Concrete to Projectile Impact

Buildings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 63
Author(s):  
Anna L. Mina ◽  
Michael F. Petrou ◽  
Konstantinos G. Trezos
Keyword(s):  
Reinforced Concrete ◽  
High Performance ◽  
High Performance Concrete ◽  
High Strength ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Fiber Reinforced ◽  
Depth Of Penetration ◽  
Projectile Impact ◽  
High Performance Fiber

The scope of this paper is to investigate the performance of ultra-high performance fiber reinforced concrete (UHPFRC) concrete slabs, under projectile impact. Mixture performance under impact loading was examined using bullets with 7.62 mm diameter and initial velocity 800 m/s. The UHPFRC, used in this study, consists of a combination of steel fibers of two lengths: 6 mm and 13 mm with the same diameter of 0.16 mm. Six composition mixtures were tested, four UHPFRC, one ultra-high performance concrete (UHPC), without steel fibers, and high strength concrete (HSC). Slabs with thicknesses of 15, 30, 50, and 70 mm were produced and subjected to real shotgun fire in the field. Penetration depth, material volume loss, and crater diameter were measured and analyzed. The test results show that the mixture with a combination of 3% 6 mm and 3% of 13 mm length of steel fibers exhibited the best resistance to projectile impact and only the slabs with 15 mm thickness had perforation. Empirical models that predict the depth of penetration were compared with the experimental results. This material can be used as an overlay to buildings or to construct small precast structures.

Relationship between Fiber Orientation and Flexural Strength in Ultra-High-Performance Fiber-Reinforced Concrete Panels

2014 ◽  
Vol 629-630 ◽  
pp. 71-78 ◽  
Author(s):  
Bo Zhou ◽  
Yuichi Uchida
Keyword(s):  
Reinforced Concrete ◽  
Flexural Strength ◽  
Fiber Orientation ◽  
High Performance ◽  
Fiber Reinforced Concrete ◽  
Bending Test ◽  
Fiber Reinforced ◽  
Three Point Bending ◽  
Concrete Panels ◽  
High Performance Fiber

In this study, the influence of fiber orientation on the flexural strength of ultra-high-performance fiber-reinforced concrete (UHPFRC) was examined. To this end, a circular UHPFRC panel measuring φ1,200 × 50 mm was cast from its center, and test specimens measuring 50 × 50 × 200 mm with 10 mm notches for three-point bending tests were cut from it with angles of 0, 30, 60 and 90° between the specimen axis and the radial direction of the panel. After the bending test, fiber orientation on the ruptured surfaces of the specimens was observed. The flexural strengths of the specimens cut at angles of 60, 30 and 0° were 80, 40 and 10% of that for the specimen cut at an angle of 90°. It was also found that the flexural strength of specimens cut from a rectangular panel cast from its center point depended on their original positions and orientation within the panel. Similar fiber orientation characteristics were found in the circular and rectangular panels.

scholarly journals Flexural behaviour of ultra-high-performance fiber-reinforced concrete at high strain rates

2021 ◽  
Vol 63 (3) ◽  
pp. 40-45
Author(s):  
Tri Thuong Ngo ◽  
◽  
Van Hai Hoang ◽  
Keyword(s):  
Reinforced Concrete ◽  
Flexural Strength ◽  
Strain Rate ◽  
Volume Content ◽  
High Performance ◽  
Fiber Reinforced Concrete ◽  
Fiber Reinforced ◽  
Fiber Volume ◽  
High Performance Fiber ◽  
Flexural Resistance

In this study, the flexural resistance of ultra-high-performance fiber-reinforced concrete (UHPFRCs) containing different fiber volume content, under static and dynamic flexural loading was investigated. Thirty-six specimens of UHPFRCs, size 0.5x0.5x210 (mm), reinforced with 0.5%, and 1.5% volume of smooth steel fiber (d=0.2 mm, l=19 mm) were cast and tested by three-point bending test, under the static load (strain rate 1.67x10-5 s-1) and high acceleration load (strain rate up to 210 s-1). Experimental results show that the flexural strength of UHPFRCs increases significantly when the fiber reinforcement content increases. In addition, as the loading speed increases, the flexural resistance of the material also increases. The flexural strength of UHPFRC material reinforced with 0.5 and 1.5% of fiber volume content was 17.7 and 30.0 MPa at static loads, increased to 23.6 and 51.92 MPa at a loading rates of 110 s-1 and 28.86 and 61.04 MPa at loading rate of 210 s-1.

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