Contribution of Fiber Alignment on Flexural Properties of UHPC and Prediction using the Composite Theory
This paper investigates the effect of fiber alignment on the flexural properties of ultra-high performance concrete (UHPC) made with different steel fiber lengths (6, 13, and 20 mm) and volumes (1%, 2%, and 3%). Fiber alignment of prismatic samples was secured using a flow-induced casting method. Test results indicated that prismatic samples cast using the flow-induced method can enable 35% greater fiber orientation compared to those prepared using a conventional casting method that results in random fiber orientation. Such improvement in fiber orientation led to 60% and 80% higher flexural strength and toughness, respectively. At a fiber volume of 2%, the increase in fiber length from 6 to 20 mm can result in 45% and 195% greater flexural strength and toughness, respectively, for samples with flow-induced fiber alignment. With the increase in fiber volume from 1% to 3% for 13-mm long fibers, such enhancements were 55% and 40%, respectively. Similar flexural properties can be obtained for UHPC made with 1% of the longer fibers when the flow-induced casting method is employed compared to those prepared using the conventional casting method at 3% of the shorter fibers. The flexural-to-tensile strength ratio of UHPC increased with the increase in fiber length, volume, and orientation. For a given fiber length and volume, the flexural-to-tensile strength ratio increased linearly with the increase in fiber orientation. When the variations in flexural-to-tensile strength ratios are considered as a function of fiber length, volume, and orientation, flexural strength of UHPC can be predicted with a maximum spread of 15% using the Composite Theory.
H. Huang et al., "Contribution of Fiber Alignment on Flexural Properties of UHPC and Prediction using the Composite Theory," Cement and Concrete Composites, vol. 118, Elsevier, Apr 2021.
The definitive version is available at https://doi.org/10.1016/j.cemconcomp.2021.103971
Civil, Architectural and Environmental Engineering
Keywords and Phrases
Composite theory; Fiber alignment; Fiber length; Flexural properties; UHPC
International Standard Serial Number (ISSN)
Article - Journal
© 2020 Elsevier, All rights reserved.
01 Apr 2021