Analysis of the alterations in porosity features of some natural stones due to thermal effect

Ugur, I.; Sengün, N.; Demirdag, S.; Altındağ, R.

doi:10.1016/j.ultras.2014.01.013

Cited by 18 publications

(7 citation statements)

References 25 publications

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“…In addition, feldspar and quartz, the two most abundant minerals in granite rocks, begin to show obvious differences in thermal expansion, as shown in Figure 16, which presents the curves of the thermal expansion coefficient of quartz and calcium feldspar with heating temperature [85]. It can be seen that the difference in the expansion coefficient between the two minerals gets larger and larger, and their uncoordinated thermal expansion leads to the initiation and propagation of cracks [27], so the porosity increases slightly at this stage ( Figure 11), and the P-wave velocity, UCS, and elastic modulus all have a small decrease (Figures 12-14). (3) At 300-500 °C, the attached water and physically combined water in the rock are almost evaporated, and the chemically bound water, such as crystal water and mineral structure water, begin to separate out, resulting in the destruction of the mineral lattice [29,84].…”

Section: Discussionmentioning

confidence: 99%

“…Many researchers have studied the variation of macroscopic rock properties after high-temperature heat treatment and achieved some progress. Regarding the pore structure, various experimental techniques, including CT scanning electron microscope (CT-SEM) [15], mercury intrusion porosimetry (MIP) [16][17][18][19][20], micro-CT [21,22], field emission scanning electron microscopy (FE-SEM) [23,24], low-field nuclear magnetic resonance (NMR) [25], photoacoustic spectrometry (PAS) [26], ultrasonic velocity measurement (UVM) [27], etc., were used to study the high-temperature effects on the porosity, pore size, and pore morphology of various materials such as calcareous sediments [21], coal [15,25], concrete [16], shale [22][23][24], granite [28,29], sandstone [18,19,28], limestone [17,20], and carbonate [27]. Almost all of the above studies have shown that thermal damage and microcracks are induced by high temperature and the rock porosity and permeability gradually increase with temperature, while the pore fractal dimension decreases.…”

Section: Introductionmentioning

confidence: 99%

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Mineral Composition, Pore Structure, and Mechanical Characteristics of Pyroxene Granite Exposed to Heat Treatments

et al. 2019

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In deep geoengineering, including geothermal development, deep mining, and nuclear waste geological disposal, high temperature significantly affects the mineral properties of rocks, thereby changing their porous and mechanical characteristics. This paper experimentally studied the changes in mineral composition, pore structure, and mechanical characteristics of pyroxene granite heated to high temperature (from 25 °C to 1200 °C). The results concluded that (1) the high-temperature effect can be roughly identified as three stages: 25–500 °C, 500–800 °C, 800–1200 °C. (2) Below 500 °C, the maximum diffracted intensities of the essential minerals are comparatively stable and the porous and mechanical characteristics of granite samples change slightly, mainly due to mineral dehydration and uncoordinated thermal expansion; additionally, the failure mechanism of granite is brittle. (3) In 500–800 °C, the diffraction angles of the minerals become wider, pyroxene and quartz undergo phase transitions, and the difference in thermal expansion among minerals reaches a peak; the rock porosity increases rapidly by 1.95 times, and the newly created pores caused by high heat treatment are mainly medium ones with radii between 1 μm and 10 μm; the P-wave velocity and the elastic modulus decrease by 62.5% and 34.6%, respectively, and the peak strain increases greatly by 105.7%, indicating the failure mode changes from brittle to quasi-brittle. (4) In 800–1200 °C, illite and quartz react chemically to produce mullite and the crystal state of the minerals deteriorate dramatically; the porous and mechanical parameters of granite samples all change significantly and the P-wave, the uniaxial compressive strength (UCS), and the elastic modulus decrease by 81.30%, 81.20%, and 92.52%, while the rock porosity and the shear-slip strain increase by 4.10 times and 11.37 times, respectively; the failure mechanism of granite samples transforms from quasi-brittle to plastic, which also was confirmed with scanning electron microscopy (SEM).

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Mineral Composition, Pore Structure, and Mechanical Characteristics of Pyroxene Granite Exposed to Heat Treatments

et al. 2019

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“…In general, the sensitivity in the case of little cracking damage remains poor, and then, the results cannot provide a quantitative measure of the damage [26,27]. Porosity of construction materials has been reported previously [28] and Hernández et al [7,8] utilized UPV test to determine the porosity of cement mortars. Lafhaj et al [4] found some correlations between permeability, porosity and UPV of cement mortars.…”

Section: Introductionmentioning

confidence: 99%

Ultrasonic Pulse Velocity—Compressive Strength Relationship for Portland Cement Mortars Cured at Different Conditions

et al. 2020

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The purpose of this paper is to establish some correlations between the main technical parameter with regard to the cement-based materials technology, the 28-day compressive strength, and ultrasonic pulse velocity of standard mortar samples cured at three different conditions—(i) under water at 22 °C; (ii) climatic chamber at 95% RH and 22 °C; (iii) lab ambient, 50% RH, and 22 °C—and after five curing periods of 1, 2, 7, 14, and 28 days. Good correlations for each curing conditions were obtained. All the positive linear relationships showed better R2 than exponential ones. These findings may promote the use of ultrasonic pulse velocity for the estimation of the 28-day compressive strength of standard Portland cement samples within the factory internal quality control.

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“…Brotóns et al [44] investigated the effect of thermal treatment on physical and mechanical properties of calcarenite. Ugur et al [45] studied the changes in porosity features of natural stones after thermal treatment. The effect of thermal treatment on petrographic and mineralogical composition of coal mining wastes was analyzed by Nowak [46].…”

Section: Introductionmentioning

confidence: 99%

Effects of Thermal Treatment on Mineral Composition and Pore Structure of Coal

et al. 2021

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With the increasing depth of coalbed methane (CBM) exploitation, temperature becomes the main factor affecting the efficiency of CBM exploitation. The change of temperature has significant influence on the mineral composition and pore structure of coal. To study the effects of thermal treatment on mineral composition and pore structure of coal, X-ray diffraction (XRD) test, scanning electron microscopy (SEM) test, and mercury intrusion test were carried out for three groups of coal. The mineral composition and pore structure of coal specimens after thermal treatment (25, 50, 75, and 100°C) were analyzed. The results show that the main mineral compositions of three groups of coal specimens after different temperatures are basically unchanged, and the maximum diffracted intensity after different temperature treatments decreases first and then increases with the increasing temperature. The count of fissures decreases first and then increases with temperature, and the count of pores increases first and then decreases with the increasing temperature. The velocity of mercury injection in high pressure (100~400 MPa) of coal specimens increases first and then decreases with temperature. The porosity, pore area, median pore diameter, and average pore diameter increase with the increasing temperatures. The volume of microfracture decreases, then increases, and finally decreases. The volume of macropore and mesopore increases slowly, and that of transition pore decreases slowly with the increasing temperature. Meanwhile, the volume of micropore increases first and then decreases during the process of thermal treatment. The fractal dimension of pore size ranges from 2.6 to 2.9 and increases linearly with the increasing temperature.

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Analysis of the alterations in porosity features of some natural stones due to thermal effect

Cited by 18 publications

References 25 publications

Mineral Composition, Pore Structure, and Mechanical Characteristics of Pyroxene Granite Exposed to Heat Treatments

Mineral Composition, Pore Structure, and Mechanical Characteristics of Pyroxene Granite Exposed to Heat Treatments

Ultrasonic Pulse Velocity—Compressive Strength Relationship for Portland Cement Mortars Cured at Different Conditions

Effects of Thermal Treatment on Mineral Composition and Pore Structure of Coal

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