Relationship between fiber orientation/distribution and post-cracking behaviour in ultra-high-performance fiber-reinforced concrete (UHPFRC)

The relationship between fiber orientation/distribution and post-cracking behaviour in ultra-high-performance fiber-reinforced concrete (UHPFRC) was quantitatively evaluated. A circular UHPFRC panel was cast from its center and prismatic specimens were cut at angles of 0, 30, 60 and 90 degrees between the specimen axis and the radial direction of the panel. The post-cracking behaviour was assessed with three-poiht bending tests, and fiber orientation/distribution throughout the panel was then evaluated using image analysis and 3D visualization of fiber orientation based on X-ray computed tomography (CT) data. The post-cracking flexural strengths of the specimens cut at angles of 60, 30 and 0 degrees were 80, 40 and 10% of that for the specimens cut at an angle of 90 degrees, indicating perfect linear dependence on the contribution of fibers near the fracture surfaces. Two rectangular UHPFRC panels with a 1:2 width/length ratio were cast, and similar fiber orientation characteristics were found for the circular and rectangular panels. (C) 2017 Elsevier Ltd. All rights reserved.