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A platform for research: civil engineering, architecture and urbanism
Comparative flexural behavior of ultra-high-performance concrete reinforced with hybrid straight steel fibers
HighlightsHybrid of long and medium-length fibers improves flexural performance of UHPC.Fiber reinforcing index higher than 0.5 is required for deflection-hardening behavior.Negative synergy values are obtained for hybrid use of straight steel fibers.Fiber hybridization obviously influences fiber bridging behavior in UHPC.Hybrid use of fibers leads to a lower complementary energy than that of long fibers.
AbstractThis study investigates the implications of fiber hybridization on the flexural behavior of ultra-high-performance concrete (UHPC). To do this, we considered three straight steel fibers with different lengths, lf, of 13mm (short), 19.5mm (medium-length), and 30mm (long) at various volume fractions. Test results indicated that the hybrid use of long and medium-length fibers effectively improved the flexural performance in terms of post-cracking strength, deflection capacity, toughness, and cracking behavior, whereas the hybrid use of long and short fibers generally decreased the performance. To verify this observation, a micromechanical analysis was performed for obtaining the fiber bridging curve, which most significantly influences the post-cracking properties. The hybrid use of long and short (or medium-length) fibers provided negative synergy values in toughness due to several detrimental effects. The complementary energy in the fiber bridging curve increased with an increase in the fiber length, so that an increase in the proportion of short (or medium-length) fiber clearly decreased the complementary energy. Based on a proposed equation for the relationship between the normalized modulus of rupture and the fiber reinforcing index, we found that it is possible to produce deflection-hardening behavior of UHPC with straight steel fibers when the fiber reinforcing index is higher than 0.5.
Comparative flexural behavior of ultra-high-performance concrete reinforced with hybrid straight steel fibers
HighlightsHybrid of long and medium-length fibers improves flexural performance of UHPC.Fiber reinforcing index higher than 0.5 is required for deflection-hardening behavior.Negative synergy values are obtained for hybrid use of straight steel fibers.Fiber hybridization obviously influences fiber bridging behavior in UHPC.Hybrid use of fibers leads to a lower complementary energy than that of long fibers.
AbstractThis study investigates the implications of fiber hybridization on the flexural behavior of ultra-high-performance concrete (UHPC). To do this, we considered three straight steel fibers with different lengths, lf, of 13mm (short), 19.5mm (medium-length), and 30mm (long) at various volume fractions. Test results indicated that the hybrid use of long and medium-length fibers effectively improved the flexural performance in terms of post-cracking strength, deflection capacity, toughness, and cracking behavior, whereas the hybrid use of long and short fibers generally decreased the performance. To verify this observation, a micromechanical analysis was performed for obtaining the fiber bridging curve, which most significantly influences the post-cracking properties. The hybrid use of long and short (or medium-length) fibers provided negative synergy values in toughness due to several detrimental effects. The complementary energy in the fiber bridging curve increased with an increase in the fiber length, so that an increase in the proportion of short (or medium-length) fiber clearly decreased the complementary energy. Based on a proposed equation for the relationship between the normalized modulus of rupture and the fiber reinforcing index, we found that it is possible to produce deflection-hardening behavior of UHPC with straight steel fibers when the fiber reinforcing index is higher than 0.5.
Comparative flexural behavior of ultra-high-performance concrete reinforced with hybrid straight steel fibers
Yoo, Doo-Yeol (author) / Kim, Sung-Wook (author) / Park, Jung-Jun (author)
Construction and Building Materials ; 132 ; 219-229
2016-11-22
11 pages
Article (Journal)
Electronic Resource
English
| British Library Online Contents | 2017
| British Library Online Contents | 2011