研究目的
To study the influence of surrounding rock temperature on mechanical property and pore structure of concrete for shotcrete use in a hot-dry environment of high-temperature geothermal tunnel.
研究成果
The 40 (cid:1)C hot-dry environment is conducive to enhance the mechanical properties of concrete and optimize its pore structure at the age of 1d. However, the hot-dry environments after 7 days will deteriorate the mechanical properties and pore structure of concrete, and the higher the temperature, the more obvious the deterioration. There is a significant correlation between curing temperature and porosity of capillary pores, median pore diameter, average pore diameter and fractal dimension.
研究不足
The study focuses on the hot-dry environment and does not consider the effects of humidity or other environmental factors. The temperature range is limited to 40 (cid:1)C to 100 (cid:1)C.
1:Experimental Design and Method Selection:
The surrounding rock temperature was divided into four grades (40 (cid:1)C, 60 (cid:1)C, 80 (cid:1)C and 100 (cid:1)C) to simulate the hot-dry environment. The mechanical properties and pore structure characteristics of concrete were studied by mechanical and mercury intrusion porosimetry (MIP) tests.
2:Sample Selection and Data Sources:
Concrete for shotcrete use with a strength grade of C25 was selected. The mix proportion was designed based on literature.
3:List of Experimental Equipment and Materials:
Constant temperature ovens for simulating hot-dry environments, standard curing room, hydraulic pressure tester, hydraulic universal test machine, Micromeritics Autopore IV 9500 porosimeter.
4:Experimental Procedures and Operational Workflow:
Specimens were prepared and cured in different environments. Mechanical tests and MIP tests were carried out at specified ages.
5:Data Analysis Methods:
Fractal dimension of pore structure was calculated through the fractal model based on thermodynamic method. Bivariate correlation analysis was conducted on the curing temperature and the pore structure parameters.
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