TECHNICAL NOTE Tensile Strength of Rock Under Elevated Temperatures V. Vishal • S. P. Pradhan • T. N. Singh Received: 12 April 2011 / Accepted: 16 August 2011 / Published online: 8 September 2011 Ó Springer Science+Business Media B.V. 2011 Abstract Rock strength affects the behaviour of rocks differently under different conditions such as temperature, time, pressure, presence of fluids, rock mass characteristics and stress history of rock in a natural environment. It is not always easy to replicate such conditions of undisturbed rock in a laboratory scale. Hence, it is imperative to study the rock behaviour with respect to every such condition which the rock experiences since its time of formation. Temperature is one of the key parameters which influence the rock throughout its history, ranging from the conditions of formation, experience of depth (loading/unloading) or deformational and metamor- phic history. Also, increase in rock temperature; say due to the thermal stress changes like disposal of spent nuclear fuels affects the strength of the surrounding rock. In this work, the effects of temperature on the tensile strength of rock have been studied. The results obtained were interesting as the strength of rock is found to increase considerably up to a particular temperature after which it starts falling by as much as 70% around 250°C. Keywords Tensile strength  Temperature  Rock behaviour  Khondalite  Eastern Ghats 1 Introduction The tensile strength of rock is very critical for any design within the rock for long term stability because rock fails much earlier under tensile stresses as compared to other stresses. Most disposal of spent fuel has been proposed all over the world mainly in hard rock terrain either of igneous or metamorphic origin due to its compactness, low porosity and permeability as well as favorable thermo-hydro-mechanical environment. When these spent fuels are buried within the rock mass, they initiate heat dissipation in surrounding barriers and possibility of thermal expansion and heat transfer to the surrounding environment. Very limited works have been done to understand the tensile strength of rocks under elevated temperatures. Several research- ers have attempted to study the thermo-mechanical behaviour of rocks either in granitic, carbonate rocks or sandstones (Heuze 1983; Dwivedi et al. 2008; Singh et al. 2007; Yavuz et al. 2010; Yasar et al. 2010). However, khondalitic rocks of meta- morphic origin have not attracted the study under these conditions; which can be a good host rock for the safe house of spent fuel. In the present investigation, khondalitic rocks from southern India were collected from the site at various depths. 48 samples of diameter to thickness ratio 1:1.25 were prepared to test the rock under tensile loading at various temperature ranges (ISRM 1978; ASTM 1988). V. Vishal (&)  S. P. Pradhan  T. N. Singh Department of Earth Sciences, Indian Institute of Technology Bombay, Mumbai 400076, India e-mail: v.vishal@iitb.ac.in 123 Geotech Geol Eng (2011) 29:1127–1133 DOI 10.1007/s10706-011-9440-y