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Study on the effect of dynamic flexural load on the electrical resistivity of concrete

Zhu Huasheng, Zeng Xiaohui, Lan Xuli, Yang Jiangfan, Long Guangcheng, Xie Youjun

Archives of Civil and Mechanical Engineering

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2023

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Vol. 23, no. 3

art. no. e176, 2023

EN

The electrical resistivity is an important property for the structure concrete of metro track. In this work, the effect of dynamic flexural load on the electrical resistivity of concrete was investigated. Results show that the electrical resistivity of concrete first rapidly decreased and then slowly decreased with loading cycles; The higher the stress level and loading frequency, the greater the attenuation of concrete resistivity, the maximum value reached 33%. Acoustic emission test showed that the electrical resistivity is related to the damage of concrete. According to the theory of concrete fatigue damage, a new model was proposed to characterize the relationship between the dynamic damage of concrete and the electrical resistivity, R2 > 0.98. This work provides insight into development of the theory of electrical conductivity in concrete, and novel strategy for the dynamic damage monitoring of concrete.

2

Creep model of cement and asphalt (CA) mortar based on micro‑meso structure

Zhu Huasheng, Zeng Xiaohui, Lan Xuli, Long Guangcheng, Xie Youjun

Archives of Civil and Mechanical Engineering

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2023

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Vol. 23, no. 1

art. no. e10, 2023

EN

CA mortar, as a filling layer, has been widely used in slab ballastless track. Since the creep deformation directly determines the track regularity and the train ride comfort, we investigated the effect of various stress levels on CA mortar creep. Results showed that the creep strain of CA mortar increased by 10 times when the stress level increased from 10%σp to 40%σp . Furthermore, it was first discovered that creep of CA mortar was attributed to the organic-inorganic interface slip and the propagation of microcracks. This work proposed a new CA mortar creep model based on the micro-meso structure characteristics, and its accuracy of prediction was much higher than previous models, R2 > 0.93.

3

Dynamic splitting tensile behaviour and statistical scaling law of hybrid basalt-polypropylene fibre-reinforced concrete

Fu Qiang, Zhao Xu, Zhang Zhaorui, Peng Gang, Zeng Xiaohui, Niu Ditao

Archives of Civil and Mechanical Engineering

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2021

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Vol. 21, no. 4

123--144

EN

The dynamic splitting tensile behaviour of hybrid basalt‒polypropylene fibre-reinforced concrete (HBPRC) was investigated, and the reinforcing mechanism of the fibres was explored. The results indicate that the dynamic splitting tensile strength and dynamic energy dissipation capacity of HBPRC increased with strain rate. The effects of fibre type and content on the strain rate sensitivity of dynamic splitting tensile strength were consistent with that of dynamic dissipation energy. Furthermore, the dynamic splitting tensile strength of concrete was improved by adding appropriate content of basalt fibre (BF) and polypropylene fibre (PF), and the improving effect of hybrid BF and PF was the most significant. Excess fibres reduced the dynamic splitting tensile strength at low strain rates but improved it at high strain rates. The addition of fibres improved the dynamic dissipation energy and the impact resistance of concrete. With an increase in the strain rate, the pull-out lengths of BF and PF decreased gradually. When using hybrid BF and PF, the failure morphology of BF did not change considerably, although PF underwent more severe damage. Based on the weakest-link theory, a calculation model for the statistical scaling law of dynamic splitting tensile strength considering the strain rate effect was established.