Articles

An Evaluation of the Placement and Fiber Orientation Factors based on Existing UHPC Codes and Standards

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Abstract

In various infrastructure applications, ultra-high-performance concrete (UHPC) has been investigated widely for its exceptional structural and durability qualities. Although UHPC structures have proved structural stability at the structural level, fiber dispersion and fiber orientation due to casting procedure and construction processes remain concerns. Fiber orientation and structural performance of UHPC members are strongly influenced by the casting flow direction of freshly mixed UHPC, formwork geometry, rebar arrangement, casting device, and rheology of the mixtures. Different professional organizations across various countries have released UHPC design codes and guidelines, and each addressed fiber orientation in a distinctive way. An extensive review of the influence of various factors on fiber orientation in structural elements is presented in this article. A review of existing structural design guidelines for UHPC and steel fiber-reinforced concrete materials from France, Germany, Japan, South Korea, Canada, Switzerland, Australia, and the United States was conducted. The method used to account for fiber orientation and dispersion was discussed. The effect of undesirable fiber orientation was compensated by different design reduction factors introduced by several design codes. Additionally, this paper discusses the underlying rationale for these design factors. The paper concludes by making recommendations to design professionals and suggesting future research directions.

Keywords: fiber orientation, design code, placement, casting

How to Cite:

Islam, M. & Zhang, Q., (2023) “An Evaluation of the Placement and Fiber Orientation Factors based on Existing UHPC Codes and Standards”, International Interactive Symposium on Ultra-High Performance Concrete 3(1): 73. doi: https://doi.org/10.21838/uhpc.16686

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