Durmeková T., Ružička P. & Mudrochová B., 2017: Laboratory study of changes in Paleogene sandstones from Slovakia exposed to high temperatures. Acta Geologica Slovaca, 9, 1, 63–73.

Laboratory study of changes in Paleogene sandstones from Slovakia exposed to high temperatures

Tatiana Durmeková¹, Peter Ružička² & Barbora Mudrochová¹

¹Department of Engineering Geology, Faculty of Natural Sciences, Comenius University in Bratislava, Ilkovičova 6, 842 15 Bratislava, Slovakia; durmekova@fns.uniba.sk
²Department of Mineralogy and Petrology, Faculty of Natural Sciences, Comenius University in Bratislava, Ilkovičova 6, 842 15 Bratislava, Slovakia; ruzicka@fns.uniba.sk

Abstract

Two types of Paleogene sandstone with different initial porosity and strength were studied after their exposure to high temperatures. Cylindrical rock specimens were heated for six hours in a muffle furnace at 400, 600, 800 and 1000°C, and subsequently, cool samples were tested to determine their uniaxial compressive strength, water absorption and ultrasonic wave velocity. In addition to visual changes in the specimens, such as a change in colour or gloss, volume and changes in mineral composition were studied as well. Total and open porosity and pore size distribution were determined using mercury intrusion porosimetry (MIP) before and after the heating. Laboratory testing showed that the resistance to temperature load of both sandstones was very similar: both indicated high resistance up to 600 °C. After being heated to higher temperatures, the rocks decreased in strength rapidly. The temperature of 600°C was the limit or the critical temperature for preservation of the sandstones quality parameters. By MIP and by detailed mineralogical analysis, it was documented that temperatures above 600°C start changes in the microstructure and porosity of sandstones, including the creation of micro-cracks.

Key words: sandstone, thermal load, mineralogy, colour, gloss, porosity, strength

Manuskript doručený: 2016-12-21

Manuskript revidovaný: 2017-06-13