Variation of wave velocity and thermal conductivity of concrete after high-temperature treatment

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• 作者：Qiang Sun ; Jishi Geng ; Weiqiang Zhang ; Chao Lü
• 关键词：Wave velocity ; Thermal conductivity ; Crack width ; Thermal reaction
• 刊名：Environmental Earth Sciences
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：76
• 期：2
• 全文大小：
• 刊物类别：Earth and Environmental Science
• 刊物主题：Geology; Hydrology/Water Resources; Geochemistry; Environmental Science and Engineering; Terrestrial Pollution; Biogeosciences;
• 出版者：Springer Berlin Heidelberg
• ISSN：1866-6299
• 卷排序：76

文摘

This paper studies the variation of mass, density, wave velocity and thermal conductivity of concrete after high-temperature heat treatment. The range of temperature to which the concrete specimens are exposed is 25–900 °C, in a heating furnace. The results are summarized as follows: three temperature ranges (20–300 °C, 300–600 °C and above 600 °C) corresponding to the moisture vaporization (i.e., adhered water, combined water or crystal water), decomposition of some minerals (i.e., Ca-hydroxide, Mg-hydroxide) and Ca-carbonate are obviously evident. The physical properties of concrete specimens change most significantly within the temperature range above 300 °C, which may be attributed to the transformation of concrete minerals. Moreover, within the temperature range of 300–900 °C, especially between 400 and 600 °C, the concrete structure has significant chemical changes basing on the variations of surface features, ultimately making the number and width of cracks and mass loss level increased, as well as the wave velocity and thermal conductivity changed.