Issue 50

K. Kaklis et alii, Frattura ed Integrità Strutturale, 50 (2019) 395-406; DOI: 10.3221/IGF-ESIS.50.33 395 Focused on the research activities of the Greek Society of Experimental Mechanics of Materials A simplified damage evolution relationship and deformation characteristics of a pozzolanic lime mortar when subjected to unloading-reloading cycles in the pre-peak region Kostas Kaklis School of Mineral Resources Engineering, Technical University of Crete, Chania 73100, Greece kaklis@mred.tuc.gr, https://orcid.org/0000-0003-2722-5915 Zach Agioutantis Department of Mining Engineering, University of Kentucky, Lexington, Kentucky 40506, USA zach.agioutantis@uky.edu, https://orcid.org/0000-0002-9799-4114 Stelios Mavrigiannakis School of Mineral Resources Engineering, Technical University of Crete, Chania 73100, Greece smaurig@mred.tuc.gr, https://orcid.org/0000-0002-6409-6043 Pagona Maravelaki-Kalaitzaki School of Architectural Engineering, Technical University of Crete, Chania 73100, Greece nmaravel@elci.tuc.gr , https://orcid.org/0000-0002-8776-6695 A BSTRACT . Two series of uniaxial and triaxial compression tests including unloading-reloading cycles were performed under different confining press- ures, in order to study the stress-strain and the deformation behavior of a pozzolanic lime mortar subjected to cyclic loading. Each test included a cyclic loading sequence using five loops in the pre-peak region. The experi- mental results showed that the specimens exhibit a strain-softening behavior for uniaxial and low pressure triaxial tests and a strain-hardening behavior for higher triaxial compression tests. The mortar specimens subjected to triaxial compressive cyclic loading at higher confining pressures failed along a single or conjugate shear planes accompanied by considerable lateral ex- pansion. The marked Young’s modulus degradation behavior in the pre- peak region is related to damage that occurs in each specimen. K EYWORDS . Pozzolanic lime mortar; Cyclic loading; Plastic strain; Young’s modulus degradation; Damage evolution. Citation: Kaklis K., Agioutantis Z., Mavri- giannakis S., Maravelaki-Kalaitzaki P., A simplified damage evolution relationship and deformation characteristics of a pozzolanic lime mortar when subjected to unloading-re- loading cycles in the pre-peak region, Frattura ed Integrità Strutturale, 50 (2019) 395-406. Received: 22.01.2019 Accepted: 25.05.2019 Published: 01.10.2019 Copyright: © 2019 This is an open access article under the terms of the CC-BY 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. I NTRODUCTION he authors have previously investigated and published the mechanical properties of a pozzolanic lime mortar, which consists of carbonate sand, hydrated lime and metakaolin (ML) [1]. Pozzolanic mortars have multiple appli- T