PSI - Issue 28

Angeliki-Eirini Dimou et al. / Procedia Structural Integrity 28 (2020) 1679–1685 Author name / Structural Integrity Procedia 00 (2019) 000–000

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The exact amount of rGO and ultrasonic energy to be applied in the future step is of utmost importance to produce the cementitious composites. Gao et al. (2019) showed that the mechanical properties of such composites with incorporated GO and carbon nanotubes vary greatly, depending on the different amounts of sonication energy, because of the change in particle size distribution and the affected microstructure. As shown, large amounts of sonication energy affect the electrical properties of rGO dispersion. Taking all these elements into account and the aforementioned literature review, the cementitious composites in the future step will be produced with a concentration of 0.15 wt% rGO sonicated at a sonication energy of about 60 kJ.

250000

250000

rGO_0.075 dispersion

rGO_0.05 dispersion

5 kJ

5 kJ

200000

200000

60 kJ

15 kJ

15 kJ

150000

150000

30 kJ

60 kJ

30 kJ

100000

100000

90 kJ

50000

50000

90 kJ

Electrical Impedance |Z| [Ohm]

0.1 1 10 100 1000 10000 100000 0

0

Electrical Impedance - |Z| [Ohm]

1

10 100 1000 10000 100000

Frequency [Hz]

Frequency [Hz]

(a)

(b)

250000

250000

rGO_0.10 dispersion

rGO_0.15 dispersion

200000

200000

5 kJ

15 kJ

15 kJ

150000

150000

30 kJ

30 kJ

100000

60 kJ

60 kJ

100000

90 kJ

90 kJ

50000

50000

5 kJ

Electrical Impedance |Z| [Ohm]

Electrical Impedance |Z| [Ohm]

0.1 1 10 100 1000 10000 100000 0

0.1 1 10 100 1000 10000 100000 0

Frequency [Hz]

Frequency [Hz]

(c)

(d)

250000

250000

rGO_0.20 dispersion

rGO_0.25 dispersion

200000

200000

60 kJ

150000

150000

30 kJ

90 kJ

15 kJ

60 kJ

100000

100000

90 kJ

50000

50000

5 kJ 15 kJ

30 kJ

5 kJ

Electrical Impedance |Z| [Ohm]

0.1 1 10 100 1000 10000 100000 0

0.1 1 10 100 1000 10000 100000 0

Electrical Impedance |Z| [Ohm]

Frequency [Hz]

Frequency [Hz]

(e) (f) Fig. 4. Electrical impedance measurements of all investigated rGO dispersions and for different sonication energies (kJ).