Work

Fiber distribution and its influencing mechanism on properties in sprayed ultra-high performance concrete

Year: 2025

Type: article

Abstract: A fiber-reinforced sprayed ultra-high performance concrete (SUHPC) with high consistency and suitable sprayed thickness was developed in this paper. Fiber distribution of SUHPC after pumping and spraying is the intrinsic mechanism for the changes in strength and toughness, especially with its high consistency, high fiber content, no coarse aggregate are completely different from conventional shotcrete. Therby a series of studies were performed including rheological behaviours, mechanical properties, and its influencing mechanism. Results showed that the field sprayed thickness of SUHPC achieved about 30 mm when it has a flow resistance of 164.7% of casted UHPC. More bubbles were entrapped during spraying, the partially unbroken bubbles were easily trapped in the fresh matrix and transformed into irregular coarse pores (≥25 μm) with a low sphericity and a 55.2% increase in porosity, which will partially weaken the strength and toughness of SUHPC, with a compressive strength of 112.6 MPa, 18.7% lower than that of UHPC. Additionally, the fiber orientation in SUHPC was more parallel to the sprayed surface after spraying, mainly concentrated in 75 ° to 85 °, and the fiber lap rate was also improved by 28.2% because of its approximate two-dimensional distribution, beneficial to improve the tensile toughness of SUHPC as a repair reinforcement layer. As the fiber content decreased, the consistency of fresh concrete, porosity and strength all shown a reduction, and the fibers became more parallel to the sprayed surface. Overall, the short straight steel fiber is preferred by SUHPC and its content should not be less than 78 kg/m3. This study will provide theoretical support for the development of specifications and guidelines on SUHPC.

Source: Case Studies in Construction Materials

DOI: 10.1016/j.cscm.2025.e04361

Authors: Jinyang Cui, Shuguang Li, Wenwei Li, Zhen He, Huamei Yang, Kailai Zhang

Institutions: China Three Gorges Corporation (China), Wuhan University

Language: English

Topic: Innovative concrete reinforcement materials

Subfield: Civil and Structural Engineering

Field: Engineering

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $2,660

Funders: China Three Gorges Corporation, National Natural Science Foundation of China