Hello,
I will talk about steel, but I think the same procedure can be applied also for concrete:
Like most materials, steel expands when the surrounding temperature increases. Each material has a different response to the heat, which is characterized by its thermal expansion coefficient. The thermal expansion coefficient represents the amount that the material expands per each degree increase. The procedure for measuring it can be described as follows:
1. Take a long steel specimen. Measure the length of it and its temperature. Let the initial length be L0 and the initial temperature be T0.
2. Heat the specimen until the temperature increases to T1. The change in temperature is thus DT=T1-T0
3. Measure again the length of the the heated specimen (It should be longer than the initial length). Let the final length be denoted as L1. The length difference is DL=L1-L0
Note that the length difference is very small and you will need special increments in order to measure it accurately! The longer the bar, the better and more accurately you can measure the length difference.
4. It is DL=a*DT*L0, where a is the cofficient of thermal expansion of steel, and thus the thermal coefficient can be calculated as: a=DL/(DT*L0)
For steel, it is: a = around [10 to 13] * 10^(-6) per oC. Note that this is not an exact value, as the phenomenon is NOT linear and the value of a depends on the initial temperature T0.
Hello,
I will talk about steel, but I think the same procedure can be applied also for concrete:
Like most materials, steel expands when the surrounding temperature increases. Each material has a different response to the heat, which is characterized by its thermal expansion coefficient. The thermal expansion coefficient represents the amount that the material expands per each degree increase. The procedure for measuring it can be described as follows:
1. Take a long steel specimen. Measure the length of it and its temperature. Let the initial length be L0 and the initial temperature be T0.
2. Heat the specimen until the temperature increases to T1. The change in temperature is thus DT=T1-T0
3. Measure again the length of the the heated specimen (It should be longer than the initial length). Let the final length be denoted as L1. The length difference is DL=L1-L0
Note that the length difference is very small and you will need special increments in order to measure it accurately! The longer the bar, the better and more accurately you can measure the length difference.
4. It is DL=a*DT*L0, where a is the cofficient of thermal expansion of steel, and thus the thermal coefficient can be calculated as: a=DL/(DT*L0)
For steel, it is: a = around [10 to 13] * 10^(-6) per oC. Note that this is not an exact value, as the phenomenon is NOT linear and the value of a depends on the initial temperature T0.
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