On measuring techniques of pore pressure in concrete at elevated temperature
On measuring techniques of pore pressure in concrete at elevated temperature
Entrapment of water vapor pressure is a major reason leading to explosive spalling of concrete subjected to elevated temperature. However, the measurement techniques for pore pressure inside concrete specimens were not consistent from different studies. This paper presents an extensive review of pore pressure measurement techniques first. Three main differences (viz., medium to transfer pore pressure, type of pressure gage head, and placement of thermocouples) were found in previous studies. An experimental program comprising twelve pore pressure gages was designed to evaluate effectiveness of all the combinations of factors by conducting one-dimensional heating test of concrete slabs. The test results showed that heat transfer properties and temperature measurements were not influenced by the different measurement techniques. Filling steel tubes with rods or leaving the tubes empty would impair build-up of vapor pressure. On the contrary, filling it with silicon oil will create extra hydraulic pressure due to thermal expansion of the oil itself. The use of sintered metal as a gage head could compensate additional pressure by introducing free volume and collect pore pressure evenly. Placing thermocouples outside the steel tube would not compromise accuracy of temperature measurement and the complexity of the measurement system could be greatly reduced. At last, two requirements are proposed for correctly measuring vapor pressure: (1) expansion of oil must be compensated by free volume; (2) free volume should not interfere with moisture accumulation and vapor pressure build-up.
LI, Ye
86d13351-982d-46c3-9347-22794f647f86
Zhang, Dong
c6477a48-e211-494a-8e8d-78571aa845c2
TAN, Kang Hai
d6b202e6-50ba-4236-961a-c9be0cb46e5c
17 August 2020
LI, Ye
86d13351-982d-46c3-9347-22794f647f86
Zhang, Dong
c6477a48-e211-494a-8e8d-78571aa845c2
TAN, Kang Hai
d6b202e6-50ba-4236-961a-c9be0cb46e5c
LI, Ye, Zhang, Dong and TAN, Kang Hai
(2020)
On measuring techniques of pore pressure in concrete at elevated temperature.
Cement and Concrete Composites, 114.
(doi:10.1016/j.cemconcomp.2020.103737).
Abstract
Entrapment of water vapor pressure is a major reason leading to explosive spalling of concrete subjected to elevated temperature. However, the measurement techniques for pore pressure inside concrete specimens were not consistent from different studies. This paper presents an extensive review of pore pressure measurement techniques first. Three main differences (viz., medium to transfer pore pressure, type of pressure gage head, and placement of thermocouples) were found in previous studies. An experimental program comprising twelve pore pressure gages was designed to evaluate effectiveness of all the combinations of factors by conducting one-dimensional heating test of concrete slabs. The test results showed that heat transfer properties and temperature measurements were not influenced by the different measurement techniques. Filling steel tubes with rods or leaving the tubes empty would impair build-up of vapor pressure. On the contrary, filling it with silicon oil will create extra hydraulic pressure due to thermal expansion of the oil itself. The use of sintered metal as a gage head could compensate additional pressure by introducing free volume and collect pore pressure evenly. Placing thermocouples outside the steel tube would not compromise accuracy of temperature measurement and the complexity of the measurement system could be greatly reduced. At last, two requirements are proposed for correctly measuring vapor pressure: (1) expansion of oil must be compensated by free volume; (2) free volume should not interfere with moisture accumulation and vapor pressure build-up.
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e-pub ahead of print date: 3 August 2020
Published date: 17 August 2020
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Local EPrints ID: 497283
URI: http://eprints.soton.ac.uk/id/eprint/497283
PURE UUID: 2d152c9b-f965-4574-819f-4fb0b7f4cfe0
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Date deposited: 17 Jan 2025 17:42
Last modified: 18 Jan 2025 03:23
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Author:
Ye LI
Author:
Dong Zhang
Author:
Kang Hai TAN
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