Thermomechanical Analysis of Different Types of Sandstone at Elevated Temperature

Excerpt

Many centuries ago, humans used to build their houses using wood, but due to natural hazards such as fire, humans have now shifted to the concept of building their houses and monuments using rock materials such as concrete, sandstone, bricks, etc. Managing fires or extinguishing them in time, the change in the physical properties of stone building materials at elevated temperature, and the variation in the strength and deformation of stone building materials with change in temperature remain debatable issues. Understanding the effect of fire on stone building materials such as sandstones would be helpful to evaluate whether fire-damaged monuments can be strengthened or should be demolished, or whether damaged parts should be replaced. For centuries, sandstone has been used not only in India but all over the world for several purposes. Wide-scale application of sandstone can be seen in different monuments, temples, and buildings in India, i.e., the Red Forts of Delhi and Agra, places and buildings in Fatehpur Sikri, Kota, Jaipur, Jodhpur, Buddhist Rameswaram temples in south India, the Indian parliament house, the presidential house, the supreme court building, etc. Globally, the White House in the USA is made of Aquia Sandstone, and Ayres rock (Uluru) in Australia, the world’s largest monolithic sacred site, is made of kosic sandstone (Allison and Bristow 1999; Allison and Goudie 1994; BRE 1945; Hajpal 1999, 2002a, b; Chakrabarti 1993; Chakrabarti et al. 1996; Dorn 2003; Fitzner et al. 2003; Goudie et al. 1992; Alm 1985). In particular, India has witnessed several fire incidents recently (Gorton Castle, Shimla 2014; Connaught Place, Delhi 2014; Surat, Gujarat 2014). Hence, the effect of temperature on the strength and deformation behavior of stone building materials such as sandstones needs to be studied in detail before construction of any monuments using these materials. Under the influence of high temperatures but below the melting point of sandstone, its microstructure rearranges, new microcracks develop, and preexisting ones become widespread and widen. Meanwhile, various physical and mineralogical changes take place in the rock matrix. After cooling down to air-dried temperature, thermally induced changes become permanent in some of the sandstone matrix. The effect of temperature on the physical and mechanical properties of rock has become an important area of study in the rock mechanics field. Over the last few years, various investigations have been carried out in this field to determine the complex behavior of rock under thermomechanical (TM) coupling (Alshayea et al. 2000; Hudson et al. 2005; Cheng and Arson 2014; Heuze 1983; Jaeger et al. 2007; Tian et al. 2012). That work measured the variation of physicomechanical parameters such as the modulus of rock deformation, Poisson ratio, tensile strength, compressive strength, cohesion, internal friction angle, viscosity, thermal expansion coefficients, etc. with temperature (Brede 1993; Xu et al. 2008; Somerton 1992; Dwivedi et al. 2008). …