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A platform for research: civil engineering, architecture and urbanism
Variations of Physical and Mechanical Properties of Heated Granite After Rapid Cooling with Liquid Nitrogen
Abstract To determine the effect of liquid nitrogen ($ LN_{2} $) cooling on the damage of heated rock, we conducted a series of physical and mechanical tests on Shandong granite samples. These granites were first slowly heated to the target temperatures (25~600 °C) and held for 10 h, followed by rapid cooling with a coolant. Three coolants were used and compared in our experiment: air, water and $ LN_{2} $. Physical properties and mechanical properties were tested after thermal treatments. Microstructural changes were also observed using scanning electron microscope and optical microscope. According to experimental results, permeability of the heated granites increases significantly after $ LN_{2} $-cooling, while density, P-wave velocity, strength and elastic modulus reduce. As heating temperature rises, changes in these properties become more pronounced. Compared to air-cooling and water-cooling, $ LN_{2} $-cooling induces greater changes in the physical and mechanical properties at any target temperature. This indicates that $ LN_{2} $-cooling can damage the heated rocks more remarkably than the other two cooling treatments. According to microscopic analysis, inter-granular cracking is the primary failure mode during thermal treatment, and most of the inter-granular cracks distribute at the boundaries of quartz. Our results in this paper are of great value for understanding the characteristics of thermal damage induced by rapid cooling.
Variations of Physical and Mechanical Properties of Heated Granite After Rapid Cooling with Liquid Nitrogen
Abstract To determine the effect of liquid nitrogen ($ LN_{2} $) cooling on the damage of heated rock, we conducted a series of physical and mechanical tests on Shandong granite samples. These granites were first slowly heated to the target temperatures (25~600 °C) and held for 10 h, followed by rapid cooling with a coolant. Three coolants were used and compared in our experiment: air, water and $ LN_{2} $. Physical properties and mechanical properties were tested after thermal treatments. Microstructural changes were also observed using scanning electron microscope and optical microscope. According to experimental results, permeability of the heated granites increases significantly after $ LN_{2} $-cooling, while density, P-wave velocity, strength and elastic modulus reduce. As heating temperature rises, changes in these properties become more pronounced. Compared to air-cooling and water-cooling, $ LN_{2} $-cooling induces greater changes in the physical and mechanical properties at any target temperature. This indicates that $ LN_{2} $-cooling can damage the heated rocks more remarkably than the other two cooling treatments. According to microscopic analysis, inter-granular cracking is the primary failure mode during thermal treatment, and most of the inter-granular cracks distribute at the boundaries of quartz. Our results in this paper are of great value for understanding the characteristics of thermal damage induced by rapid cooling.
Variations of Physical and Mechanical Properties of Heated Granite After Rapid Cooling with Liquid Nitrogen
Wu, Xiaoguang (author) / Huang, Zhongwei (author) / Song, Hengyu (author) / Zhang, Shikun (author) / Cheng, Zhen (author) / Li, Ran (author) / Wen, Haitao (author) / Huang, Pengpeng (author) / Dai, Xianwei (author)
2019
Article (Journal)
English
Local classification TIB:
560/4815/6545
BKL:
38.58
Geomechanik
/
56.20
Ingenieurgeologie, Bodenmechanik