Publication detail

Experimental Pilot Thermomechanical Study of Lower Carboniferous Greywacke: Temperature Effect on the Rock Mass Properties Investigated up to 1,200°C

BRABEC, M. KRMÍČEK, L. SOKOLÁŘ, R. ŠTETIAR, J. ŠIMÁČEK, R.

Original Title

Experimental Pilot Thermomechanical Study of Lower Carboniferous Greywacke: Temperature Effect on the Rock Mass Properties Investigated up to 1,200°C

Type

journal article in Web of Science

Language

English

Original Abstract

Greywacke, i.e., a non- to anchi-metamorphosed immature sandstone that contains more than 15 % clay minerals, occurs in most orogenic belts, with depositional ages ranging from Precambrian to recent. Our study focuses on thermomechanical rock properties of greywacke sampled in Koberice rice quarry (Lower Carboniferous Culm Basin, Drahany Upland, Bohemian Massif). Both relatively fine-grained and coarse-grained (with higher abundance of lithic fragments and small pebbles) intact rock core samples were tested. The experiment was divided into two sets. The first set made of the coarse-grained greywacke gave insight into the changes of properties across the whole temperature range, up to 1,200 degrees C. The second set of samples was used to study the behavior of the fine-grained greywacke in the lower temperature range, up to 400 degrees C. The lower temperature analysis showed an unexpected phenomenon at 200 degrees C to 300 degrees C, manifested by decrease in the strength coupled with higher values of deformation characteristics. These trends reverted at 400 degrees C. The described phenomenon may have been caused by changes in water content combined with clay minerals composition alternation. Alternatively, it could be also related to the rock "paleotemperature memory." " On the wider temperature range, the greywacke holds relatively well to the lower temperatures, with the strengths decreasing slowly after 400 degrees C and more rapidly after 800 degrees C. At 1,200 degrees C, partial melting at grain boundaries accompanied by formation of larger pores in the sample center was observed. Results of thermomechanical studies can be crucial during the design of underground constructions or for assessment of the fire damage on a rock-based constructions.

Keywords

rock mechanics; rock thermomechanics; greywacke; high-temperature influence; Bohemian Massif

Authors

BRABEC, M.; KRMÍČEK, L.; SOKOLÁŘ, R.; ŠTETIAR, J.; ŠIMÁČEK, R.

Released

1. 8. 2024

Publisher

AMER SOC TESTING MATERIALS

Location

W CONSHOHOCKEN

ISBN

1945-7553

Periodical

JOURNAL OF TESTING AND EVALUATION

Year of study

52

Number

5

State

United States of America

Pages count

15

URL

https://doi.org/10.1520/JTE20240003

BibTex

@article{BUT189483,
  author="Marek {Brabec} and Lukáš {Krmíček} and Radomír {Sokolář} and Juraj {Štetiar} and Roman {Šimáček}",
  title="Experimental Pilot Thermomechanical Study of Lower Carboniferous Greywacke: Temperature Effect on the Rock Mass Properties Investigated up to 1,200°C",
  journal="JOURNAL OF TESTING AND EVALUATION",
  year="2024",
  volume="52",
  number="5",
  pages="15",
  doi="10.1520/JTE20240003",
  issn="1945-7553",
  url="https://doi.org/10.1520/JTE20240003"
}