PSI - Issue 42

Available online at www.sciencedirect.com Structural Int gri y Procedia 00 (2019) 000 – 000 Structural Integrity Procedia 00 (2019) 000 – 000 Available online at www.sciencedirect.com ^ĐŝĞŶĐĞ ŝƌĞĐƚ Available online at www.sciencedirect.com ^ĐŝĞŶĐĞ ŝƌĞĐƚ

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Procedia Structural Integrity 42 (2022) 1700–1707

© 2022 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the scientific committee of the 23 European Conference on Fracture – ECF23 Abstract The present work investigates experimentally the improvement of fracture toughness and electrical conductivity in the hardened cementitious matrix after the addition of graphene nanoplatelets (GnPs), at four different concentrations varying between 0.05 wt% and 0.4 wt% per cement. The experimental investigation is conducted through flexural and electrical impedance spectroscopy (EIS) tests on prismatic specimens. The study is oriented towards establishing a correlation between the electrical response of the nanocomposites under alternate current and the exhibited fracture toughness values ( K Ic ). The flexural test results show that the incorporation of the GnPs in the matrix can increase the average K Ic values and can decrease the average resistivity ( ρ ) when compared with the reference matrix. The maximum increase in K Ic (+ 29 %), and the decrease in ρ (- 68 %) were found in the mixture with the lowest amount (0.05 wt%) of GnPs. Moreover, the comparison of the ρ values and the K Ic values, as a function of the GnPs concentration, reveals a reverse relation between the two parameters ( K Ic and ρ ). The functional correlation between these parameters was also confirmed by linear regression analysis, resulting from the experimental data fitting. The analysis provides evidence that EIS can be used as a non-destructive tool to assess the fracture toughness of cementitious nanocomposites. © 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) er-review under responsibility of 23 European Conference on Fracture - ECF23 Keywords: Fracture toughness; Cementitious nanocomposites; Electrical impedance a Research Unit of Advanced Materials, Department of Financial Engineering, University of the Aegean, Chios, Greece, b Department of Chemistry, School of Science and Technology, International Hellenic University, St. Luke 654 04, Kavala, Greece c ADVISE S.A., 17, Gymnasiarchou Madia str., Chios, 821 32, Greece d Laboratory of Testing and Materials, Department of Mechanics, National Technical University of Athens, Athens, 15780, Greece Abstract The present work investigates experimentally the improvement of fracture toughness and electrical conductivity in the hardened cementitious matrix after the addition of graphene nanoplatelets (GnPs), at four different concentrations varying between 0.05 wt% and 0.4 wt% per cement. The experimental investigation is conducted through flexural and electrical impedance spectroscopy (EIS) tests on prismatic specimens. The study is oriented towards establishing a correlation between the electrical response of the nanocomposites under alternate current and the exhibited fracture toughness values ( K Ic ). The flexural test results show that the incorporation of the GnPs in the matrix can increase the average K Ic values and can decrease the average resistivity ( ρ ) when compared with the reference matrix. The maximum increase in K Ic (+ 29 %), and the decrease in ρ (- 68 %) were found in the mixture with the lowest amount (0.05 wt%) of GnPs. Moreover, the comparison of the ρ values and the K Ic values, as a function of the GnPs concentration, reveals a reverse relation between the two parameters ( K Ic and ρ ). The functional correlation between these parameters was also confirmed by linear regression analysis, resulting from the experimental data fitting. The analysis provides evidence that EIS can be used as a non-destructive tool to assess the fracture toughness of cementitious nanocomposites. © 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of 23 European Conference on Fracture - ECF23 Keywords: Fracture toughness; Cementitious nanocomposites; Electrical impedance 23 European Conference on Fracture - ECF23 Evaluation of fracture toughness in graphene-based cementitious nanocomposites via electrical impedance E. Tziviloglou a , Z.S. Metaxa b , G. Maistros c , S.K. Kourkoulis d , N.D. Alexopoulos a * a Research Unit of Advanced Materials, Department of Financial Engineering, University of the Aegean, Chios, Greece, b Department of Chemistry, School of Science and Technology, International Hellenic University, St. Luke 654 04, Kavala, Greece c ADVISE S.A., 17, Gymnasiarchou Madia str., Chios, 821 32, Greece d Laboratory of Testing and Materials, Department of Mechanics, National Technical University of Athens, Athens, 15780, Greece 23 European Conference on Fracture - ECF23 Evaluation of fracture toughness in graphene-based cementitious nanocomposites via electrical impedance E. Tziviloglou a , Z.S. Metaxa b , G. Maistros c , S.K. Kourkoulis d , N.D. Alexopoulos a *

* Corresponding author. Tel.: +30-22710-35464 E-mail address: nalexop@aegean.gr * Corresponding author. Tel.: +30-22710-35464 E-mail address: nalexop@aegean.gr

2452-3216 © 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of 23 European Conference on Fracture - ECF23 2452-3216 © 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of 23 European Conference on Fracture - ECF23

2452-3216 © 2022 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the scientific committee of the 23 European Conference on Fracture – ECF23 10.1016/j.prostr.2022.12.214