Pore characteristics (&gt;0.1 mm) of non-air entrained concrete destroyed by freeze-thaw cycles based on CT scanning and 3D printing

Tian, Wei; Han, Nv

doi:10.1016/j.coldregions.2018.03.027

Cited by 74 publications

(17 citation statements)

References 24 publications

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“…Gao et al [4] used the quantitative stereoscopic image analysis method to measure pore structure parameters such as pore spatial distribution, total porosity, pore size, and subporosity. Chao et al [53] and Wei et al [54] also tested the pore distribution inside the concrete. With the deepening of the research on the pore structure of concrete, scholars agree that the influence of pore gradation, pore size, and sub-porosity of different pore gradation segments on the mechanical behaviors of concrete should not be ignored [12,55].…”

Section: Pore Size Distributionmentioning

confidence: 99%

Influence of Meso-Scale Pore Structure on Mechanical Behavior of Concrete under Uniaxial Compression Based on Parametric Modeling

2022

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Existing concrete random aggregate modeling methods (CRAMMs) have deficiencies in in the parameterization of the mesoscale pore structure. A novel CRAMM is proposed, whose pore structure is determined by the pore gradation, total porosity, sub-porosity, and pore size of each pore gradation segment. To study the influence of pore structure on the mechanical properties of concrete, 25 mesoscopic concrete specimens with the same aggregate structure but different meso-scale pore structures are constructed and subjected to uniaxial compression tests. For the first time, the influence of sub-porosity of each pore gradation segment, average pore radius (APR), pore specific surface area (PSSA), and total porosity on concrete failure process, compressive strength, peak strain, and elastic modulus were quantitatively and qualitatively analyzed. Results indicate that the pore structure makes the germination and propagation of the damage in cement mortar show obvious locality and affects the formation and expansion of macroscopic cracks. However, it does not accelerate the propagation of the damage in cement mortar from the periphery to the center of the specimen, nor does it change the phenomenon that the ITZ is more damaged than other meso-components of concrete before peak stress. Macroscopic cracks occur in the descending section of the stress–strain curve, and the sudden drops in the descending section of the stress–strain curve are often accompanied by the generation and expansion of macroscopic cracks. The quadratic polynomial, exponential, and power functions can well fit the relationship between total porosity and compressive strength and the relationship between PSSA and compressive strength. The linear, exponential, and power functions can well reflect the relationship between total porosity and compressive modulus and the relationship between compressive modulus and PSSA. For concrete specimens with the same total porosity, the elastic modulus and strength show randomness with the increase in the sub-porosity of macropores and are basically not affected by the APR. Based on the grey relational analysis, the effects of pore structure parameters on the elastic modulus and compressive strength are in the same order: total porosity > T [k1,k2] > T [k2,k3] > T [k3,k4] > T [k4,k5] > AVR > PSSA. The order of influence of the pore structure parameters on the peak strain is: T [k2,k3] > T [k1,k2] > T [k3,k4] > T [k4,k5] > APR > PSSA > total porosity.

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Section: Pore Size Distributionmentioning

confidence: 99%

Influence of Meso-Scale Pore Structure on Mechanical Behavior of Concrete under Uniaxial Compression Based on Parametric Modeling

2022

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“…The usefulness of the tomographic image method in evaluating shear tests is pointed out in [ 30 ]. There are studies that show how to determine the change in pore size of a concrete sample undergoing freezing cycles by tomography using a medical device [ 31 ]. Basic tomographic studies of steel-fiber-reinforced concretes are presented in [ 32 ].…”

Section: Introductionmentioning

confidence: 99%

Application of X-ray Computed Tomography to Verify Bond Failures Mechanism of Fiber-Reinforced Fine-Grain Concrete

et al. 2022

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This paper proposes the use of X-ray computed tomography (µCT, xCT) measurements together with finite element method (FEM) numerical modelling to assess bond failures mechanism of fiber-reinforced fine-grain concrete. Fiber-reinforced concrete is becoming popular for application in civil engineering structures. A dynamically developing topic related to concretes is the determination of bond characteristics. Nowadays, modern technologies allow inspecting the inside of the element without the need to damage its structure. This paper discusses the application of computed tomography in order to identify damage occurring in the structure of fiber-reinforced fine-grain concrete during bond failure tests. The publication is part of a larger study to determine the bonding properties of Ukrainian steel fibers in fine-grain concrete. The authors focused on the visual evaluation of sections obtained from tomographic data. Separately, the results of volumetric analysis were presented to quantitatively assess the changes occurring in the matrix structure. Finite element analysis is an addition to the substantive part and allows us to compare real damage areas with theoretical stress concentration areas. The result of the work is the identification of a path that allows verification of the locations where matrix destruction occurs.

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“…e research on the microstructure of the digital core was mainly based on the study of the 3D digital core. Knackstedt et al [2] controlled the finite size effect, discretion error, and statistical fluctuations to obtain high-precision results by using X-micron CT scanners; Tian and Han [3] used X-ray CT to examine the evolution of concrete internal damage. Wang et al [4] combined CT and the pore network model to analyze the influence of particle size on permeability in hydrate-containing porous media.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Microstructure and Low Permeability with 3D Digital Rock Modeling

Min

Yin

et al. 2022

Geofluids

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The sandstone microstructure and permeability are important parameters for quantitative evaluation of groundwater/oil/gas resources and prediction of flow rates of water/oil/gas. In this study, we applied seven low-permeability sandstone samples obtained from North China to research the microstructure and permeability based on digital core technology. Rock images were collected by X-ray microcomputed tomography (μCT), and then software (Avizo) was applied to analyze the microstructure and calculate the parameters such as porosity, connected porosity, average equivalent diameter, tortuosity, and shape factor. By introducing the shape factor into the Kozeny–Carman equation, we modified the Kozeny–Carman equation and found that the modified equation is a function of porosity, diameter of particles, tortuosity, and particle shape factor.

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Pore characteristics (>0.1 mm) of non-air entrained concrete destroyed by freeze-thaw cycles based on CT scanning and 3D printing

Cited by 74 publications

References 24 publications

Influence of Meso-Scale Pore Structure on Mechanical Behavior of Concrete under Uniaxial Compression Based on Parametric Modeling

Influence of Meso-Scale Pore Structure on Mechanical Behavior of Concrete under Uniaxial Compression Based on Parametric Modeling

Application of X-ray Computed Tomography to Verify Bond Failures Mechanism of Fiber-Reinforced Fine-Grain Concrete

Analysis of Microstructure and Low Permeability with 3D Digital Rock Modeling

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Pore characteristics (>0.1 mm) of non-air entrained concrete destroyed by freeze-thaw cycles based on CT scanning and 3D printing

Cited by 74 publications

References 24 publications

Influence of Meso-Scale Pore Structure on Mechanical Behavior of Concrete under Uniaxial Compression Based on Parametric Modeling

Influence of Meso-Scale Pore Structure on Mechanical Behavior of Concrete under Uniaxial Compression Based on Parametric Modeling

Application of X-ray Computed Tomography to Verify Bond Failures Mechanism of Fiber-Reinforced Fine-Grain Concrete

Analysis of Microstructure and Low Permeability with 3D Digital Rock Modeling

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Pore characteristics (>0.1 mm) of non-air entrained concrete destroyed by freeze-thaw cycles based on CT scanning and 3D printing