Articles

UHPC Fiber Orientation using Electrochemical Impedance Spectroscopy: A Pilot Study

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Abstract

This is an accepted article with a DOI pre-assigned that is not yet published.

Fiber orientation in ultra-high performance concrete (UHPC) is a critical factor that relates to both material- and structural-level behavior. Many techniques have been studied to quantify fiber orientation including but not limited to computer vision-aided image analysis, computerized tomography (CT) scanning, and electromagnetic methods. This presentation will discuss a pilot study on the application of electrochemical impedance spectroscopy (EIS) to determine fiber orientation in UHPC-class materials. EIS is a multi-frequency measurement of a material’s resistive and dielectric properties that can be measured using the traditional 4-electrode configuration as in a resistivity measurement. In application to UHPC, EIS has been shown to be dependent on distribution and orientation metallic fibers. However, further work is required to interpret the results towards quantifiable descriptors of both. A series of prismatic beam samples were created with different fiber volume fractions. Different casting methods were employed to create random and aligned fiber orientations. EIS was measured on specimens that were subsequently subjected to 4-point bending to assess tensile resistance. Additionally, a limited parametric study was completed using a commercially available multiphysics modeling platform. This aimed to determine how different parameters such as fiber orientation and fiber volume fraction influence the impedance response. The presentation will provide an overview of this work and its preliminary findings.

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