Experimental Study on the Thermal Damage Characteristics of Limestone and Underlying Mechanism

Zhang, Weiqiang; Sun, Qiang; Hao, Shuqing; Wang, Bo

doi:10.1007/s00603-016-0983-3

Cited by 46 publications

(13 citation statements)

References 12 publications

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“…Experiments demonstrating thermal damage to unconfined limestones, dolomites, and marbles show decreases in V P of up to 75% (Sengun, ; Yavuz et al, ; W. Zhang et al, ). Limestone samples heated in an unconfined environment had an average 55% decrease in V P and 28% decrease in V S , due to pervasive thermal microfissuring (Martinho et al, ).…”

Section: Discussionmentioning

confidence: 99%

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Elastic Softening of Limestone Upon Decarbonation With Episodic CO₂ Release

2018

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Reactive transport under confining stress through porous media leads to complex, coupled feedback mechanisms between chemical and physical alteration. We exposed four intact limestone cores to hydrothermal conditions conducive to the wollastonite‐producing decarbonation reaction. We allowed for the episodic release of pore pressure to mimic pulsing flow in crustal systems and mitigate the accumulation of carbon dioxide (CO2). Energy‐dispersive X‐ray spectroscopy results show that all four reacted samples developed a new calc‐silicate phase during the reaction. Alteration from the fluid‐mediated reaction was pervasive but nonuniform, resulting in the development of a small volume of highly compliant pore space with grain contact softening. Lower initial velocity sensitivity to confining pressure and higher initial pore connectivity lead to more development of soft porosity. The relevance of the results lies in enhancing seismic monitoring capabilities of potentially seismogenic areas—large decreases in observed seismic velocity in limestone undergoing decarbonation can only be accounted for if the nonnegligible change in the elastic properties of the rock frame are understood. Since the potential for seismicity of a subsurface system depends both on the elastic stiffness and stress state of the rocks, rocks undergoing reactive transport cannot be modeled as though their elastic moduli are time independent. Accurate modeling of the subsurface behavior depends on understanding not just the particular rock reactions taking place but also the initial pore network and velocity sensitivity to confining pressure of those rocks, and how the elastic properties of that rock evolve.

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Section: Discussionmentioning

confidence: 99%

“…Experiments demonstrating thermal damage to unconfined limestones, dolomites, and marbles show decreases in V P of up to 75% (Sengun, 2014;Yavuz et al, 2010;W. Zhang et al, 2016).…”

Section: Development Of Soft Poresmentioning

confidence: 99%

Elastic Softening of Limestone Upon Decarbonation With Episodic CO₂ Release

2018

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“…As it can be seen, the general trend shows a gradual decrease of the properties in both types of rock. More specifically, the main changes in granites (Figure 2a) are observed from 500 • C due to the phase transition temperature from α-quartz to β-quartz at 573 • C. In contrast, in limestones, the changes are noticed from 300 • C due to dehydration, absorption, and the decomposition of some cement, and between 500 and 700 • C due to the decomposition of magnesium carbonate and dolomite, being mostly decomposed from 700 • C [62]. This variation of the strength of the rock matrix can exert an important impact on the degradation and detachment of rock blocks as well as the later fragmentation on rockfalls.…”

Section: Source Area: Effects Of Fires On the Rock Massmentioning

confidence: 96%

Effects of Wildfire on Rockfall Occurrence: A Review through Actual Cases in Spain

et al. 2021

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Understanding processes and conditions that lead to rockfalls during and after a wildfire in different geological contexts is crucial since this phenomenon is one of the major hazards in mountainous regions across Europe. Spain is one of the European countries with the highest rate of wildfires, and rockfalls cause high economic and social impact, with many fatalities every year. The increase of rockfalls during and after wildfires is connected with the merging of different factors, not only in the detached area but also in the propagation and potentially affected area. When wildfire occurred, many actions take place: changes in the mechanical conditions of the rocks, the loss of protective capacity from vegetation, the effect induced by firefighting activities and/or the impact by the high temperatures in the adopted protective measures. After the wildfire, there is an increase in frequency and intensity of rockfalls in the burned area, causing a major impact of rockfalls on not only road networks and built-up areas but also people living. Additionally, the removal of vegetation by wildfires causes an increase in the risk perception, related not only to detached blocks but also to the general appearance of the rock mass. In this review, the main factors that influence the occurrence of rockfalls after a wildfire are analyzed, and three actual case studies in Spain are presented to support the variety of conclusions obtained.

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“…Yavuz et al [16,17] investigated physical and mechanical properties, such as P-wave velocity, peak compressive strength, peak strain, and elastic modulus of marbles and limestones heated to several specific temperature levels from 25.°C to 900.°C. Microscopic examinations from thin sections showed that the damage in rocks at elevated temperatures was induced with varying severity depending on grain size, porosity, and structural and textural characteristics.…”

Section: State Of the Artmentioning

confidence: 99%

Experimental investigation of mechanical properties and energy features of granite after heat treatment under different loading paths

Zhang

Kang

2017

Teh. vjesn.

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EXPERIMENTAL INVESTIGATION OF MECHANICAL PROPERTIES AND ENERGY FEATURES OF GRANITE AFTER HEAT TREATMENT UNDER DIFFERENT LOADING PATHSJunwen Zhang, Xu Chen, Hengyi KangOriginal scientific paper Temperature and loading history are the two main factors that influence rock microstructure and physical and mechanical properties. To explore the influence of heat treatment and loading path on mechanical properties and energy features of granite, granite samples were first heat-treated at 25 °C, 300 °C, 600 °C, and 900 °C. Then, 12 groups of triaxial compression experiments were placed under three loading paths, as follows: uniaxial compression, conventional triaxial compression, and confining pressure unloading. Mechanical properties and energy features in the deformation and failure process based on these experimental results were systematically compared and analyzed. Results demonstrate that Young's modulus, uniaxial compressive strength, and triaxial compressive strength increased in the temperature range of 25 °C to 300 °C, but decreased in the temperature range of 300 °C to 900 °C. Under the same loading path, the gaps among total absorbed energy, dissipated energy, and elastic strain energy widened with increasing temperature from 25 °C to 900 °C. At the same temperature, the energy features' gap under confining pressure unloading is between uniaxial and triaxial compression. The conclusions drawn in this study provide a significant reference for the design and construction of rock engineering exposed to high temperature. Keywords: energy features; heat treatment; loading paths; triaxial compression Eksperimentalno ispitivanje mehaničkih svojstava i energetskih svojstava granita nakon toplinske obrade pri različitom načinu opterećenjaIzvorni znanstveni članak Povijest temperature i opterećenja dva su glavna čimbenika koji utječu na mikrostrukturu stijene i fizikalna i mehanička svojstva. Da bi se istražio utjecaj toplinske obrade i opterećenja na mehanička svojstva i energetske značajke granita, uzorci granita najprije su toplinski obrađeni na 25 °C, 300 °C, 600 °C i 900° C. Zatim je 12 skupina eksperimenata troosnog sabijanja podvrgnuto opterećenju na tri načina, kako slijedi: jednoosno sabijanje, konvencionalno troosno sabijanje i ograničeno tlačno rasterećenje. Sustavno se uspoređuju i analiziraju mehanička svojstva i značajke energije u procesu deformacije i oštećenja na temelju tih eksperimentalnih rezultata. Rezultati pokazuju da su Youngov modul, jednoosna tlačna čvrstoća i troosna tlačna čvrstoća porasli u temperaturnom području od 25 °C do 300 °C, ali su se smanjili u temperaturnom području od 300 °C do 900 °C. Pod istim načinima opterećenja, razlike između ukupne apsorbirane energije, raspršene energije i elastične energije naprezanja povećale su se s porastom temperature od 25 °C do 900 °C. Pri istoj temperaturi, razlika između energetskih značajki pod rasterećenjem ograničenim tlakom je između jednoosnog i troosnog sabijanja. Zaključci izneseni u ovoj studiji pružaju značajnu referencu za projektiranje...

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Experimental Study on the Thermal Damage Characteristics of Limestone and Underlying Mechanism

Cited by 46 publications

References 12 publications

Elastic Softening of Limestone Upon Decarbonation With Episodic CO₂ Release

Elastic Softening of Limestone Upon Decarbonation With Episodic CO₂ Release

Effects of Wildfire on Rockfall Occurrence: A Review through Actual Cases in Spain

Experimental investigation of mechanical properties and energy features of granite after heat treatment under different loading paths

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Experimental Study on the Thermal Damage Characteristics of Limestone and Underlying Mechanism

Cited by 46 publications

References 12 publications

Elastic Softening of Limestone Upon Decarbonation With Episodic CO2 Release

Elastic Softening of Limestone Upon Decarbonation With Episodic CO2 Release

Effects of Wildfire on Rockfall Occurrence: A Review through Actual Cases in Spain

Experimental investigation of mechanical properties and energy features of granite after heat treatment under different loading paths

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Product

Resources

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Elastic Softening of Limestone Upon Decarbonation With Episodic CO₂ Release

Elastic Softening of Limestone Upon Decarbonation With Episodic CO₂ Release