Effect of Elevated Temperature on Rhyolitic Rocks' Properties.

Area of Science:

• Geotechnical Engineering
• Materials Science
• Rock Mechanics

Background:

• Understanding thermophysical and mechanical properties of rocks at high temperatures is crucial for underground geotechnical applications.
• Rhyolitic turf rock's response to elevated temperatures requires detailed investigation for safe and efficient design.

Purpose of the Study:

• To investigate the impact of high temperatures on the physical and mechanical properties of rhyolitic turf rock.
• To analyze microstructural changes in rhyolite rock after thermal exposure.

Main Methods:

• Heating intact cylindrical rhyolite core samples to temperatures of 200, 400, 600, and 800 °C.
• Determining uniaxial compressive strength (UCS) and elastic modulus of heated and unheated samples.
• Analyzing physical properties (density, color, absorption) and microstructural characteristics using SEM.

Main Results:

• Rhyolitic rock exhibited hardening below 600 °C.
• Above 600 °C, UCS and elastic modulus decreased, reaching 78.0% and 75.9% of original values at 800 °C.
• Density and pore volume remained largely unaffected, while color changes occurred at ≥400 °C, with microcracking and surface cracks evident at 600 °C.

Conclusions:

• High temperatures significantly alter the mechanical properties of rhyolitic rock, with degradation occurring above 600 °C.
• Thermal exposure induces microstructural damage, including particle displacement and cracking, affecting rock integrity.
• While density is stable, observable color changes and microstructural alterations necessitate careful consideration in high-temperature geotechnical designs.