PSI - Issue 28

Available online at www.sciencedirect.com Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2019) 000–000

www.elsevier.com/locate/procedia

ScienceDirect

Procedia Structural Integrity 28 (2020) 502–510

© 2020 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 European Structural Integrity Society (ESIS) ExCo Abstract The time evolution of the electric signals emitted during uniaxial compression of prismatic cement mortar specimens is investigated in this study. The electric signals are recorded in the form of very weak electric currents, and their analysis is achieved in terms of the Pressure Stimulated Currents technique. The study is focused on the quantification of the role of the specimens’ age, i.e., the time interval between the production of the specimens and the implementation of the tests, on the intensity of these electric signals. In this context, four classes of specimens were tested, including specimens of ages equal to 3, 14, 28 and 90 days. It was concluded that for early ages the Pressure Stimulated Currents are quite stronger in comparison with those of mature specimens. There were no detectable differences between the specimens of ages 28 and 90 days, neither concerning the electric activity nor the mechanical response. Moreover, it was indicated that during loading, the electric activity is strongly intensified only after the mechanical response of the specimens abandons linearity, independently of the specimens’ age. Finally, it was concluded that the time evolution of the electric activity provides indicators that can be considered as pre-failure warnings, i.e., signals of upcoming fracture. © 2020 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 European Structural Integrity Society (ESIS) ExCo Keywords: Structural Health Monitoring; Novel sensing techniques; Pressure Stimulated Currents; Early age cement mortar; Compression 1st Virtual European Conference on Fracture Monitoring the mechanical response of early aged cement-mortar specimens using the Pressure Stimulated Currents technique Dimos Triantis a , Ilias Stavrakas a , Antonios Kyriazopoulos a , Ermioni D. Pasiou b , Stavros K. Kourkoulis b, * a Department of Electrical and Electronics Engineering, Electronic Devices and Materials Laboratory, University of West Attica, 250 Thivon Avenue, 122 44, Athens, Greece b Department of Mechanics, School of Applied Mathematical and Physical Sciences, National Technical University of Athens, 5 Heroes of Polytechnion Avenue, Theocaris Bld., Zografou Campus, 157 73 Athens, Greece

* Corresponding author. Tel.: +30 210 7721263; fax: +30 210 7721302. E-mail address: stakkour@central.ntua.gr

2452-3216 © 2020 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 European Structural Integrity Society (ESIS) ExCo

2452-3216 © 2020 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 European Structural Integrity Society (ESIS) ExCo 10.1016/j.prostr.2020.10.059