Physical Properties of Sandstones After High Temperature Treatment

Under the influence of high temperatures below the rock melting point, rock micro-structures change significantly (Dwivedi et al. 2008), new micro-cracks are developed, and pre-existing ones extended/widened (Den’gina et al. 1994). Meanwhile, various physical and mineralogical changes take place in the rock matrix. After cooling down to room temperature, thermal-induced changes are irreversible to some extent. Hence, rock physical properties from a macroscopic point of view are temperature-history dependent as they rely on the maximum temperature experienced. Knowledge on this issue is a key factor for successful implementation of modern geotechnical engineering projects, such as nuclear waste storage (Sundberg et al. 2009), underground coal gasification (Roddy and Younger 2010), geological CO2 storage (Rutqvist et al. 2002), geothermal heat extraction (Zhao 2000) and stability analysis of constructions in rocks after exposure to fire (Zhan and Cai 2007). Sandstone is a common sedimentary rock, having broad applications in geotechnical engineering. Therefore, the research on the thermo-physical properties of sandstones is extremely meaningful on a wide range. In this manuscript, an extensive review of international literature, especially of Chinese publications not considered in the English-speaking scientific community so far, covers physical properties such as bulk density, porosity, permeability and compressional wave velocity of sandstones after high temperature treatment. The considered sandstones along with their characteristics are listed in Table 1. The testing procedures of thermal treatment in the references reviewed in this manuscript are identical, taking into account heating the samples at a certain rate and under atmospheric pressure conditions in a furnace until a predetermined temperature is reached. The maximum temperature is maintained for a period (several hours), and then cooled down in the furnace or at ambient conditions. The detailed testing parameters for each reference reviewed are summarized in Table 2.