Local bond-slip behavior and mechanisms of steel fiber-UHPC matrix interface modified by nano-engineering
Wang, X. Ma, X. Li, L. Wu, Q. Qiu, L. Han, B.
Wang, X.
Ma, X.
Li, L.
Wu, Q.
Qiu, L.
Han, B.
Publication Date
2026-03
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© 2026 The Authors. This is the Author Accepted Manuscript of the article distributed under the Creative Commons CC-BY license (https://creativecommons.org/licenses/by/4.0) in accordance with the University of Bradford Rights Retention Policy.
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openAccess
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2025-11-28
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Abstract
The bond performance at the interface between steel fibers and the ultra-high-performance concrete (UHPC) matrix plays a critical role in determining the mechanical behavior of UHPC. While nano-engineering presents promising strategies to strengthen this interface, the localized bond-slip behavior of steel fibers in nano-engineered UHPC is not fully understood, owing to complex microstructural features and pronounced stress heterogeneity along the interface resulting from the fiber-matrix modulus disparity. Combining pull-out tests, microstructural characterizations, theoretical modeling, and numerical simulations, this study elucidates two distinct mechanisms responsible for bond enhancement induced by nanofillers: the interface nano-modification effect and the transition zone nano-modification effect. The relative scale between nanofillers and steel fibers governs the enrichment or dilution of nanofillers at the interface, thereby affecting the modification efficacy within the transition zone. These mechanisms collectively contribute to a notable improvement in interfacial bond strength, reaching a peak value of 11.73 MPa—exceeding all previously reported results. The derived bond-slip constitutive models, grounded in these mechanistic insights, indicate that although nano-engineering can substantially improve the strength and durability of UHPC, it also leads to a reduction in ductility.
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Accepted manuscript
Citation
Wang X, Ma X, Ashour A, et al (2026) Local bond-slip behavior and mechanisms of steel fiber-UHPC matrix interface modified by nano-engineering. Cement and Concrete Composites. 167: 106421.
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Article