EFFECT OF THE HEAT TREATMENT ON THE PHYSICAL AND MECHANICAL PROPERTIES OF BILASPUR SANDSTONE

Abstract

In rock engineering, at high temperatures, the properties of the rock are important for safety and structure design assessment. High temperatures or fires alter the physical-mechanical properties of sandstone commonly used in monuments. The heat resistance depends on the cementing mineral type, the cement amount and the grain size. The objective is to determine the changes in the physical-mechanical properties of sandstones exposed to high temperatures. The physical-mechanical properties of sandstones include colour, volume, mass, density, tensile strength, compressive strength, modulus of elasticity, stress-strain response and Poisson's ratio. All samples were obtained from the river bed of Sutlej from the district Bilaspur, Himachal Pradesh. All prepared specimens were heated at 6 different temperatures, 25, 100, 300, 400, 500 and 700 ℃. The specimens were heated-up to different temperatures at an increasing rate of 1 ℃/min, then held for 24 hours and then cooled down at a decreasing rate of 1 ℃/min to room temperature. The Brazilian disc and Uniaxial compressive strength tests were performed to investigate the stress-strain behaviour, tensile strength, uniaxial compressive strength, and elastic modulus. Results show that the specific sandstone has the maximum tensile strength at 100 ℃, maximum uniaxial compressive strength at 300 ℃ and maximum elastic modulus at 300 ℃. It is noticed that the failure pattern is changed slightly from brittle to ductile above 400 ℃. The maximum strength depends on the evaporation of moisture content, fill up of micro-cracks due to compressive load and the cementing minerals in the sandstones. The specimens fail due to the micro-crack development and expansion at high temperatures. Results show that this study will be beneficial to understand the relationship between the Physical-mechanical behaviour of sandstones and with thermal effect. The study can be useful in designing and restoring structures such as monuments after fire, geothermal energy, deep mining and nuclear waste disposal.