Microstructure and fracture in three dimensions

Landis, Eric N.; Nagy, Edwin; Keane, Denis T.

doi:10.1016/s0013-7944(02)00157-1

Cited by 123 publications

(46 citation statements)

References 7 publications

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“…Accordingly, structural changes due to thermal, mechanical or hydrochemical processes can be investigated by alternating experimental episodes and imaging stages. A few experiments using CµT have recently been published, for example, in relation with the sintering or compaction of glass beads (Bernard et al, 2002;Bernard et al, 2004;Richard et al, 2003), the crack growth in mortar under compressive loading (Landis et al, 2003), or the dissolution of fractures in carbonated rocks (Gouze et al, 2003). Presently, most of the technological and data processing problems have been resolved and complex media can be investigated.…”

Section: Introductionmentioning

confidence: 99%

Hydraulic Properties and Microgeometry Evolution Accompanying Limestone Dissolution by Acidic Water

Noiriel

Bernard

Gouze

et al. 2005

Oil & Gas Science and Technology - Rev. IFP

100

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Résumé -Évolution des paramètres hydrauliques et de la microgéométrie d'un calcaire pendant sa dissolution par une eau acide -Nous reportons dans cet article les résultats d'une expérience de percolation réactive menée, à température ambiante, dans un calcaire poreux par une eau saturée en CO 2 à la pression partielle de 0,1 MPa, afin d'évaluer les relations entre la chimie de l'eau et les modifications hydrodynamiques et structurales de l'échantillon. Une méthode d'analyse, basée sur l'utilisation répétée de l'imagerie microtomographique à rayons X, a été développée pour suivre en détail l'évolution de la structure et de l'interface fluide-solide de l'échantillon, tandis que sa porosité et sa perméabilité augmentaient au cours de sa dissolution. Plusieurs mécanismes à l'origine de l'augmentation rapide de la perméa-bilité ont été identifiés. Au début de l'expérience, cette augmentation a été reliée à la dissolution et à la migration concomitantes de particules carbonatées. Ensuite, la perméabilité a continué d'augmenter par suite de la dissolution des aspérités à l'interface fluide-solide, et de l'accroissement de la connectivité du réseau poral. Abstract -Hydraulic Properties and Microgeometry Evolution Accompanying Limestone Dissolution By Acidic Water -A reactive flow-through experiment by carbon dioxide-saturated water at the partial pressure of 0.1 MPa and room temperature was conducted on a porous limestone in order to identify the relationships between fluid chemistry, hydrodynamics and structural properties. Periodic imaging by nondestructive X-ray microtomography allowed following the evolution of the core micro-geometry and fluid-rock interface in detail while its porosity and permeability increased due to dissolution. Several mechanisms were successively involved in the rapid permeability increase. Early in the experiment, the permeability increase was related to concomitant particle dissolution and displacement. Later on, permeability continued to rise due to solid-fluid interface smoothing and to pore connectivity increase.

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Section: Introductionmentioning

confidence: 99%

Hydraulic Properties and Microgeometry Evolution Accompanying Limestone Dissolution by Acidic Water

Noiriel

Bernard

Gouze

et al. 2005

Oil & Gas Science and Technology - Rev. IFP

100

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“…Por esse motivo explica-se a ruptura em forma de cone e com planos cisalhantes a 45º em corpos de prova de concreto de formato cilíndricos. A Figura 5 apresenta exemplos dessa forma de ruptura (MAZARS; BAZANT, 1989;LANDIS;NAGY;KEANE, 2003;NEVILLE, 1997).…”

Section: Situaçãounclassified

Avaliação da resistência à compressão, resistência à tração e formação de microfissuras em concretos produzidos com diferentes tipos de cimentos, quando aplicado um pré-carregamento de compressão

Vieira

Molin

2011

Ambient. constr.

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Muitas empresas construtoras que querem competitividade no mercado buscam soluções para aumentar a velocidade de seus empreendimentos, tal como a redução do tempo de execução da estrutura, redução do tempo de escoramento e execução antecipada das alvenarias, sem respeitar o prazo mínimo de cura do concreto. A retirada precoce do escoramento submete a estrutura a uma carga prematura. Os danos causados pela incompleta reação de hidratação e cura do concreto podem desencadear um processo generalizado de formação de microfissuras. O presente estudo avaliou o comportamento de diferentes tipos de concretos produzidos com quatro diferentes tipos de cimentos, quando submetidos a uma carga precoce de compressão, analisando-se suas propriedades mecânicas. A análise incluiu a avaliação da resistência à compressão, resistência à tração e microestrutura interna do concreto, através de microscopia eletrônica de varredura. Os resultados indicaram que há possibilidade de um processo de formação de microfissuras causadas pelo carregamento precoce no concreto e que há tendência de diminuição dos valores de resistência à tração. Entretanto, verificou-se, mediante análise de microscopia, que as microfissuras formadas pelo carregamento precoce tendem a se recuperar se o processo de cura for retomado ou se cessar o pré-carregamento.

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“…Especially for mortar and concrete, Landis et al (2000) applied X-ray CT to mortal, then discussed relation between fracture energy and induced crack area in com-1 pression test. Landis et al (2003) also applied to concrete, then the fracture within a specimen was visualized and fracture energy was analyzed under cyclic uniaxial compression test. Wang et al (2003) visualized voids or cracked surfaces using X-ray CT, and suggested a damage tensor for representing damage.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Micro-damage of Concrete Specimens under Cyclic Uniaxial Loading by X-ray CT Method

Tanikura

Jung

Shintani

et al. 2016

ACT

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The X-ray CT method was applied to evaluate micro-damage -namely, deterioration of concrete specimens under cyclic uniaxial loading tests. The μ-focus X-ray CT scanner was used. Concrete cylinders with a diameter of 50 mm and a length of 100 mm were prepared as specimens. Cyclic uniaxial loading tests were conducted on the specimens. The X-ray CT images of the specimens were taken at the loading level 0, 60, 70, 80 and 90 percent of their uniaxial compressive strength. For three dimensional CT images of the specimen, the Three Dimensional Medial Axis Analysis (3DMA) method was applied to evaluate porosity and width, length, persistence of cracks which represent deterioration of the specimen. As the results, slight micro-fracturing occurs until a loading level R = 60%, and starts to increase at R of 60% to 70%. The cracking occurs in a part of the mortar near boundary between aggregate and mortar, and the crack links to another crack with increasing loading level. The degree of cracking varies according to the position dependent on the final apparent fracture surface of the specimen. It is concluded that the X-ray CT method with 3DMA is effective for not only evaluating the state of micro-cracking within the specimen, but also estimating the process of deterioration of the specimen with an increasing loading level.

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Microstructure and fracture in three dimensions

Cited by 123 publications

References 7 publications

Hydraulic Properties and Microgeometry Evolution Accompanying Limestone Dissolution by Acidic Water

Hydraulic Properties and Microgeometry Evolution Accompanying Limestone Dissolution by Acidic Water

Avaliação da resistência à compressão, resistência à tração e formação de microfissuras em concretos produzidos com diferentes tipos de cimentos, quando aplicado um pré-carregamento de compressão

Evaluation of Micro-damage of Concrete Specimens under Cyclic Uniaxial Loading by X-ray CT Method

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