PSI - Issue 64

Alamgir Khan et al. / Procedia Structural Integrity 64 (2024) 539–548 Alamgir khan / Structural Integrity Procedia 00 (2019) 000–000

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Furthermore, the cooperative effect of MWNT/NCB demonstrates promising performance at both normal and elevated temperatures.

(b)

(a)

NCB surface damages

MWCNT

NCB

MWCNT surface damage

Fig.6 SEM iamge of MWCNT/NCB composite fillers (a) at normal temperature and (b) elevated temperature (400 ºC)

Conclusion In this study, CAC-based MWCNT/NCB conductive composite fillers were investigated at normal and elevated temperatures (200 °C and 400ºC). Based on the findings of the present study, the following conclusions were drawn: • At room temperature, the addition of MWNCT/NCB improves the compressive strength and decreases the electrical resistivity. The electrical resistivity of CNCB2 significantly decreased with increasing MWCNT/NCB content and was observed to have 9.6×10 4 Ω. cm electrical resistivity and good piezoresistivity sensitivity under cyclic compression loading. At 200 °C, the strengths of the CAC control and CNCB1-CNCB2 reached a peak owing to the further hydration of anhydrous CAC and silica fume. CNCB2 observed 9. 7×10 4 Ω. cm electrical resistivity, excellent piezoresistivity and peak FCR response. • Upon further exposure to 400 °C, CNCB1 and CNCB2 exhibited a decline in compressive strength due to high porosity, matrix, and MWCNT/NCB surface damage. However, CNB2 exhibited good piezoresistivity and a stable and fully reversible FCR response after exposure to 400 °C. In conclusion, the incorporation of CAC as binder to improve thermal properties, prevent spalling at elevated temperature and MWNCT/NCB as conductive composite is a promising method for enhancing their resistance to elevated temperatures, resulting in the development of smart intrinsic sensor for structural health monitoring (SHM). Acknowledgements The authors would like to acknowledge financial support from the National Natural Science Foundation of China (No. U2106220, No. 52178197, and No. 51902068). References [1] Y. Liu, Y.J.M. Bao, 2023. Automatic interpretation of strain distributions measured from distributed fiber optic sensors for crack monitoring. Journal of Measurement 211, 112629. [2] A. Davis, M. Mirsayar, D.J.C. Hartl, B. (2021). A novel structural health monitoring approach in concrete structures using embedded magnetic shape memory alloy components. Journal of Construction and Building Materials 311, 125212. [3] E. Cheilakou, N. Tsopelas, A. Anastasopoulos, D. Kourousis, D. Rychkov, R. Gerhard, B. Frankenstein, A.