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论文类型：期刊论文

发表时间：2022-06-29

发表刊物：Fuhe Cailiao Xuebao/Acta Materiae Compositae Sinica

卷号：38

期号：7

页面范围：2348-2358

ISSN号：1000-3851

摘要：The macro steel fiber and nano carbon black as conductive materials were added into the concrete to make smart concrete. A new type of concrete beam with double layers combined with the smart concrete and plain concrete was produced. In addition, the effect of the steel fiber content and the depth of the steel fiber-nano carbon black/concrete smart layer on the post-crack toughness and self-monitoring performance were studied in this paper. In order to monitor the concrete crack, four-probe method was used to measure the electrical resistance of the specimens. The results show that the toughness of the concrete beams is increased with the increasing of fiber content and the depth of the smart concrete layer. The crack self-monitoring of the concrete can be realized by analyzing the characteristics of the fraction change in resistance-time ( ρ FCR- t ) curve. Furthermore, the ρ FCR value is nearby zero before cracking, then a significant increase of ρ FCR can be found after the crack appearing. If more than one crack happens on the smart concrete beam due to the deflection hardening behavior, new turning points where the slope of ρ FCR- t curve changes can be observed. Additionally, the self sensing behavior decreases with the increasing of the steel fiber content and the depth of the smart concrete layer. The ρ FCR value of the specimen increases rapidly after crack happening, after that it increases slowly gradually. However, the fractional change in resistance value at a certain crack width ( ω COD) decreases with the increasing of the fiber content and the height of the smart concrete layer. The proposed first order exponential decay function fits well with the ρ FCR- ω COD curves. © 2021, Editorial Office of Acta Materiae Compositae Sinica. All right reserved.

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