The impact of high temperature on compressive strength and density of two types of granites from India

摘要

Physical properties of rocks have significant engineering value. Compressive strength and density of rocks are used in many rock mechanics related studies pertaining to civil and mining activities, stability of the excavations and estimation of the support required. In addition, rocks like granite are used as a building material and are encountered in many civil and infrastructure projects. However, these properties vary with increase or decrease in their temperature. A host of data exists on heat treatment of different rocks. In order to augment such studies and to further the know-how in this discipline, a comprehensive analysis of 56 samples of two types of granites from India was taken up in this study. The tests for compressive strength and density with increase in temperature from 35°C to 600°C were devised and conducted. The results revealed that the behaviour of two groups of the granite varied in a noticeable range on a linear scale. A reduction of 45 to 49 in strength from room temperature to 600'C in the two types of granites points to the loss of strength with increasing temperature. A reduction of 4.3 to 6.3 in density of the samples on heating can be considered to be mild. The rearrangement of grains, loss of water content initially and increase in volume on further heating are considered to be the major reasons for reduction of such physical properties in a linear manner. Colour changes have also observed in the heating process which needs to be explained in future.