There is often talk of industrial gas growth spurred on by infrastructure development, but a recent first in China is literally an example of gases deployed in groundwork.
China experienced its first successful attempt of using liquid nitrogen to cool a large mass of concrete in the construction of the foundations of the Waisha River Bridge in Shantou, Guangdong, in Southern China in July (2014).
Concrete cooling by liquid nitrogen has been practiced for years in western countries. The heat generated during the curing of concrete can lead to a temperature of 93ºC – if this heat is not quickly neutralised, it can have detrimental effects on the strength of the concrete and can even lead to cracking.
As explained by a researcher at the technical centre of the Second Harbour Engineering Company (SHEC), a subsidiary of the China Communications Construction Company, water with a pipe running in the concrete mass is usually used for concrete coolingneeds in the country. However, the hydration heat generated by such a large mass cannot be easily removed by this traditional method to control the temperature of the concrete at 28ºC, with an ambient temperature of 35ºC.
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