The investigation of changes in the physical and mechanical properties of saraftepe tephrites (Trabzon,Turkey) with temperature

In this study, the changes in engineering properties with high temperatures and critical temperature values and their effective alteration times were determined on tephrite samples taken from a raw material quarry in Sarraftepe, 10 km south of Trabzon city. The samples were heatened for 2 hours at temperatures between 200-1200 oC, and cooled at room temperature and in water in order to apply a thermal shock. One-dimensional compression tests, ultrasonic wave speed tests and specific gravity tests were conducted to determine the changes in engineering properties of the samples and mass losses at each temperature increment were calculated. Physical and mechanical properties suffered at each increment, with 65% and 80% loss in one-dimensional compression strength, 64% and 73% loss in compressional wave velocity values were determined on samples which exposed 1000 oC and cooled at air and in water, respectively. The mass loss values of the samples which were cooled at room temperatures reached 7%, and 7.4%-7.7% increase were determined in specific gravity values. According to the test results, the 60% of total loss at one-dimensional compression strength and approximately 55% of total decrease in compressional wave velocity were happened before 600 oC mark. This temperature was also the effective temperature of the change in specific gravity, as a significant increase in the specific gravity values of the samples were observed after this temperature. In order to investigate the effect of exposure time on the engineering properties of the samples at critical temperatures, the samples were exposed to critical temperatures for 30, 60, 90, and 120 minutes, and a significant decrase in one-dimensional compressive strength values of the samples were determined after 60 minute mark.