Title:
Fiber Distribution in UHPC Beams: An Insight from 3D Micro-CT Scans on Shear Tests
Author(s):
Manuel Bermudez
Publication:
Web Session
Volume:
ws_S23_ManuelBermudez.pdf
Issue:
Appears on pages(s):
Keywords:
DOI:
Date:
4/2/2023
Abstract:
UHPC's inherent anisotropy has two effects on structural members: fiber orientation and fiber distribution. Both effects are impacted by the casting process and the flow pattern and have repercussions on the tensile response of the UHPC structural element. This study provides insight from micro-CT scans on shear tests of UHPC I-shaped beams with heights ranging from 300 to 1150 mm. The UHPC mix had 1.5% steel fibers and it was randomly poured into the beams. A qualitative analysis of the micro-CT images revealed that the issue of fiber orientation is significantly magnified by the fiber distribution as the beam depth increases. In structural elements subjected to shear loading with no structural redundancy, it is complex to depend on the tensile strength of UHPC as a predictor of shear strength. A shear design equation is proposed based on UHPC's compressive strength which has less variation associated with fiber distribution or orientation.