20.500.12556/DiRROS-19612 Large ring test for evaluation of restrained shrinkage cracking calibration and experimental trial The durability of shotcrete tunnel linings is significantly affected by restrained shrinkage cracking. Given the unique characteristics of shotcrete applied in tunnel linings, especially when dealing with accelerated shotcrete containing reinforcement fibres, it is necessary to upscale the ring test commonly used. This paper presents a comprehensive experiment using large ring tests with cast concrete to investigate the impact of upscaling ring test geometry. The two ring specimens demonstrated comparable cracking age (22 days) and strain measured in the steel ring, suggesting that consistent results can be obtained through the proposed instrumentation, calibration, and correction methods. Moreover, the estimated induced tensile stresses of the concrete rings (2.8 and 2.7 MPa) are slightly lower than the predicted tensile strength (3.3 MPa) at the age of cracking, which indicates that some driving forces contributing to restrained shrinkage cracking were not indicated in the strain gauge readings. Furthermore, the study identified multi-crack formation and additional potential causes for crack initiation, which include self-restraint due to the moisture gradient in the vertical direction, deflection of the concrete ring caused by its self-weight, and friction on the contact surface of the support. Therefore, optimising the geometry of the ring specimens and the apparatus is imperative to minimise additional driving forces and unmeasurable restraints for crack initiation, especially when employing the stress rate method to assess cracking potential. concrete restrained shrinkage tunnel lining large ring test beton ovirano krčenje tunelske obloge test z velikim obročem true false true Hindawi Publishing Corporation Angleški jezik Slovenski jezik © 2024 Zhongyu Xu et al. Neznano 2024-07-22 14:30:37 2024-07-22 14:44:48 2024-07-25 14:42:12 0000-00-00 00:00:00 2024 0 0 Nasl. z nasl. zaslona; Opis vira z dne 16. 7. 2024; str. 1-18 Issue 1 Vol. 2024 5. Apr. 2024 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 2024-04-05 620.1/.2 1687-8094 10.1155/2024/6698625 201974787 https://onlinelibrary.wiley.com/doi/epdf/10.1155/2024/6698625 1 725a7d35-4815-11ef-b487-001a4af901a5 https://dirros.openscience.si/Dokument.php?lang=slv&id=27108 RAZ_Xu_Zhongyu_2024.pdf RAZ_Xu_Zhongyu_2024.pdf 1 47C1B0B57ADEE90630EFD9D0F233CF25 3365476e0214e686a6003d0501e9ca9b6c04ae4e2ff03f99a5979c9dc6ab6fe0 9a39c40c-4816-11ef-b487-001a4af901a5 https://dirros.openscience.si/Dokument.php?lang=slv&id=27112 Zavod za gradbeništvo Slovenije 0 0 0