A preliminary investigation of energy consumption in fracture of ultra-high performance concrete
•The toughness of the UHPC was over 200 times as much as that of the matrix.•The newly-formed surface area was quantitatively examined by X-ray CT.•Matrix cracking of UHPC consumes an energy of 16.78 J per unit surface area.•An exponential relation is found between fiber pullout energy and embedded...
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Veröffentlicht in: | Construction & building materials 2020-03, Vol.237, p.117634, Article 117634 |
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Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | •The toughness of the UHPC was over 200 times as much as that of the matrix.•The newly-formed surface area was quantitatively examined by X-ray CT.•Matrix cracking of UHPC consumes an energy of 16.78 J per unit surface area.•An exponential relation is found between fiber pullout energy and embedded length.•Energy consumed by fiber pullout is much higher than that by matrix cracking.
The increased strength has induced an increased brittleness of modern concrete, and the addition of fibers has been proved to be an effective measure to conquer this challenge. While the toughening mechanisms of fibers have been well understood, the relative contribution of each mechanism to the overall toughness is unclear. In this study, the notched UHPC specimens with various fiber contents are characterized using three-point bending tests. Furthermore, the X-ray computed tomography imaging analysis and fiber pullout test are performed to determine the relative energy consumed by matrix cracking and fiber pullout during fracture of the UHPC. The results show that with fiber addition of 1% and 2%, the toughness of the UHPC is about 230 and 290 times as much as that of the UHPC matrix without fiber, respectively. Meanwhile, the energy consumed by multiple cracking is much less than that consumed by fiber pullout. With fiber content of 1% and 2%, multiple cracking accounts for 2% and 2.7% of the input energy, respectively, while fiber pullout contributes to about 50% and 70% of the overall toughness, respectively. |
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ISSN: | 0950-0618 1879-0526 |
DOI: | 10.1016/j.conbuildmat.2019.117634 |