Effect of Fiber Orientation Distribution on Flexural Properties of UHPC

doi:10.16552/j.cnki.issn1001-1625.2025.0562

Abstract

Abstract: To investigate the influence of steel fiber orientation on the flexural performance of ultra-high performance concrete (UHPC), an electromagnetic coil was developed to generate a uniform magnetic field, and the characteristics of its internal field distribution were analyzed. Directional steel fiber UHPC was prepared using magnetic field-induced alignment. The fiber orientation was quantitatively evaluated using CT scanning and 3D image reconstruction. Four-point bending tests were conducted on UHPC with different fiber volume fractions (0%, 0.5%, 1.0%, 1.5% and 2.0%) and fiber lengths (10, 13, 16 and 20 mm) for fiber orientation distribution and randomly distribution. Additionally, the effects of different parameters on load-deflection behavior, flexural strength, and toughness were investigated. The results indicate that after magnetic field induction, the fibers are predominantly aligned along the target direction, achieving a fiber orientation coefficient of up to 0.882 or greater. The flexural strength and toughness of directional steel fiber UHPC increase by 68.6%～125.7% and 68.2%～325.1%, respectively. The optimal strengthening effect is observed at a fiber length of 13 mm and a volume fraction of 1.5%. Compared with randomly distribution fiber UHPC, under equivalent flexural strength, the fiber content in directional steel fiber UHPC is reduced by more than 50%.

Key words: UHPC, directional steel fiber, flexural strength, flexural toughness, magnetic field, orientation coefficient

CLC Number:

TQ172
TU528

ZOU Hua, LI Shuichang, LAO Jiakun, LIU Ping. Effect of Fiber Orientation Distribution on Flexural Properties of UHPC[J]. BULLETIN OF THE CHINESE CERAMIC SOCIETY, 2025, 44(12): 4359-4367.

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