To better understand how concrete behaves under fire conditions, an experimental program coupled with numerical modeling (using theories of heat and mass transfer) is implemented to measure and predict pore pressures in concrete under extreme temperatures. In intense fire conditions, the low permeability of concrete inhibits internal flow of steam (generated by the heating) and thus causes an increase in pore pressure that may then lead to spalling. Spalling of concrete under thermal loading due to pore pressure buildup is highly dependent upon the intensity and duration of heat input. Therefore, pore pressures measured experimentally or predicted from heat and mass transfer numerical models produce varied results depending on the characteristics of thermal loading. Many individuals regard the ASTM E119 thermal loading profile as the standard for determining the durability of structural members in fire conditions, however, this standard may not represent the worst-case scenario for the structure.;In this study, pore pressure and temperature are experimentally measured in various concrete mixtures under extreme thermal loading conditions (more severe than those specified in ASTM E119). A numerical model is then implemented for each of the mixtures to predict pore pressure and temperature distributions over time. Because the numerical model accounts for mass transport, the ability of gases and liquids to migrate through concrete is first quantified through experimental measurement of gas and water permeability to generate input data for the numerical model. The behavior of concrete subjected to severe thermal loading conditions is then better understood through experimental measurement and numerical prediction of internal temperature and pressure data.
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