An investigation of thermal effects on micro-properties of granite by X-ray CT technique
TL;DR: In this article, the thermal effects on micro-properties of granite were experimentally studied and two indexes (heterogeneity coefficient and anisotropy coefficient) were proposed to describe the micro properties of granite.
About: This article is published in Applied Thermal Engineering.The article was published on 2018-07-25. It has received 171 citations till now. The article focuses on the topics: Anisotropy.
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TL;DR: In this article, an optimal basalt fiber content was determined basing firstly on suitable printability and then on mechanical performance using a self-developed 3D printer for extrusion of the cementitious material and also for mechanical enhancement of fiber alignment along the print direction.
224 citations
TL;DR: In this article, the results from tests performed to investigate the tensile mechanical characteristics of granite after exposure to heating and cooling treatments were analyzed using the Brazilian disc method, and the results showed that the water-cooled samples exhibited the largest decrease in P-wave velocity and the largest numbers of newly generated cracks on the surface, which indicates that the samples heated and cooled at higher cooling rates were more susceptible to the heating/cooling treatments.
124 citations
TL;DR: In this paper, the spatial gradient distributions of thermal shock-induced damage to granite with respect to associated deterioration mechanisms were investigated by computed tomography (CT) and image analysis techniques, and the influence of the preheating temperature on the spatial gradients of the damage was discussed.
Abstract: In this study, we attempted to investigate the spatial gradient distributions of thermal shock-induced damage to granite with respect to associated deterioration mechanisms. First, thermal shock experiments were conducted on granite specimens by slowly preheating the specimens to high temperatures, followed by rapid cooling in tap water. Then, the spatial gradient distributions of thermal shock-induced damage were investigated by computed tomography (CT) and image analysis techniques. Finally, the influence of the preheating temperature on the spatial gradients of the damage was discussed. The results show that the thermal shock induced by rapid cooling can cause more damage to granite than that induced by slow cooling. The thermal shock induced by rapid cooling can cause spatial gradient distributions of the damage to granite. The damage near the specimen surface was at a maximum, while the damage inside the specimen was at a minimum. In addition, the preheating temperature can significantly influence the spatial gradient distributions of the thermal shock-induced damage. The spatial gradient distribution of damage increased as the preheating temperature increased and then decreased significantly over 600 °C. When the preheating temperature was sufficiently high (e.g. 800 °C), the gradient can be ignored.
92 citations
TL;DR: In this paper, the effect of high temperatures up to 800°C on the physical and mechanical characteristics and fracturing behaviour of Beishan granite is experimentally studied with a combination of acoustic emission (AE), digital image correlation (DIC) and optical microscope observations.
Abstract: The effect of high temperatures up to 800 °C on the physical and mechanical characteristics and fracturing behaviour of Beishan granite is experimentally studied with a combination of acoustic emission (AE), digital image correlation (DIC) and optical microscope observations. The experimental results show that the responses of the P-wave velocity, the effective porosity, Young’s modulus, and the uniaxial compressive strength (UCS) of the granite to temperature are different. The critical temperature for the brittle–ductile transition of Beishan granite is between 500 and 600 °C. The counts, cumulative energy, b value, and waveform from AE and the full-field deformation evolution from DIC are combined to investigate the damage evolution and fracture mechanism in heated granite. It is found that a rise in temperature increases the number of AE events but reduces the cumulative energy release. Tensile microcracking mainly occurs in granite exposed to low temperatures, while shear fracturing gradually dominates in granite exposed to higher temperatures. With increasing temperature from 25 to 800 °C, the failure mode of granite specimens changes from being controlled by longitudinal splitting cracks to a single shear fracture and finally to multiple conjugate shear fractures. Microscopic observation of granite thin sections is conducted to further reveal the essential mechanism driving the physical–mechanical response and fracturing behaviour of heated Beishan granite.
70 citations
TL;DR: In this paper, an innovative technique called digital image correlation (DIC) was used to trace the fracture process, and important fracture parameters, such as the FPZ size and critical opening displacement, were measured by full-field displacement and strain measurement.
67 citations
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TL;DR: In this paper, the authors present a model for the development of the MICROSTRUCTURE in CERAMICS based on phase transformation, glass formation and glass-Ceramics.
Abstract: INTRODUCTION. Ceramic Processes and Products. CHARACTERISTICS OF CERAMIC SOLIDS. Structure of Crystals. Structure of Glasses. Structural Imperfections. Surfaces, Interfaces, and Grain Boundaries. Atom Mobility. DEVELOPMENT OF MICROSTRUCTURE IN CERAMICS. Ceramic Phase Equilibrium Diagrams. Phase Transformation, Glass Formation and Glass--Ceramics. Reactions with and between Solids. Grain Growth. Sintering and Vitrification. Microstructure of Ceramics. PROPERTIES OF CERAMICS. Thermal Properties. Optical Properties. Plastic Deformation, Viscous Flow and Creep. Elasticity, Anelasticity and Strength. Thermal and Compositional Stresses. Electrical Conductivity. Dielectric Properties. Magnetic Properties.
6,650 citations
"An investigation of thermal effects..." refers background in this paper
...Besides the studies of the thermal effects on the macro-behavior of rock, more and more attentions have been paid to the micro-mechanism of thermal cracked rock with the development of micro observation techniques [19, 29, 30]....
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TL;DR: In this paper, the effect of high temperature treatments (200, 300, 400, 500, 600, 700 and 800) on the crack damage, strength and deformation failure behavior of a granite was investigated.
406 citations
TL;DR: An extensive literature review was performed to assemble data on the following properties: modulus, Poisson's ratio, tensile strength, compressive strength, viscosity, thermal expansion, density, permeability, melting temperature, heat of fusion, specific heat, thermal conductivity and thermal diffusivity.
367 citations
TL;DR: In this paper, a series of 20 chevron cracked notched Brazilian disc (CCNBD) samples of Westerly granite were failed in a standard Mode I tensile test at room temperature in order to evaluate the effect of thermal damage on fracture toughness.
267 citations
TL;DR: In this paper, the authors studied the thermal effect on physical and mechanical properties of rock, such as mass, density, porosity, P-wave velocity, compressive strength, peak strain, elastic modulus, and acoustic emission of rock.
247 citations