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Research for Crack Generation and Propagation of Daejeon Granite under Stress Conditions
Econ. Environ. Geol. 2019 Dec;52(6):587-93
Published online December 31, 2019;  https://doi.org/10.9719/EEG.2019.52.6.587
Copyright © 2019 the Korean society of economic and environmental gelology.

Junghae Choi1*, Hye-jin Kim2 and Byung-gon Chae3

1Department of Earth Science Education, Kyungpook National University
2Kyungnam branch office, Human resources development service of Korea
3Policy and planning division, Korea Institute of Geoscience and Mineral Resources
Received September 17, 2019; Revised October 25, 2019; Accepted November 6, 2019.
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
 Abstract
This study were subjected to accelerated weathering test under freeze-thaw and pressure conditions to observe initiation and propagation of cracks using CLSM. Applied stress was set at 50 MPa, 55 MPa, 70 MPa for 3 samples each by using compressor and freeze-thaw experiment was conducted while samples maintained that condition. In freeze-thaw experiments, a temperature range was set to -20~40°C which was 1 cycle for 6 hours. The freeze-thaw cycle was composed of time which reached to set temperature for 1 hour and holding time for 2 hours. On the basis of this cycle, surface of samples was observed by CLSM after each 20 freeze-thaw cycle. From this research, according to increase freeze-thaw cycle, there were 7, 10, 19 each cracks and High pressured sample's accumulate length was longer than low pressured sample's. High pressured sample’s crack velocities were also faster than low pressured sample's which were calculated by accumulate length and freeze-thaw cycle.
Keywords : confocal laser scanning microscope, crack generation, crack propagation, freeze/thaw experiment, crack generation velocity

 

December 2019, 52 (6)