Propagation des ondes dans les roches anisotropes sous contrainte évaluation de la qualité des schistes ardoisiers

Guyader, J.; Denis, A.

doi:10.1007/bf02594705

Cited by 51 publications

(27 citation statements)

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“…where Vp max is the maximum, Vp min is the minimum and Vp mid the medium value for ultrasonic wave velocity (Guyader and Denis 1986;Weiss et al 2002b; Sáez-Pérez and Rodríguez-Gordillo 2009). The flow of water into the stone pore system was determined by carrying out a water absorption test (WA).…”

Section: Methodsmentioning

confidence: 98%

Direct observation of microcrack development in marble caused by thermal weathering

et al. 2010

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One of the properties that makes marble such an excellent construction and ornamental material is its low porosity. It is very difficult for water or decay agents to penetrate the internal structure of materials with no or few pores, so enhancing the durability of these materials. However, environmental temperature fluctuations bring about significant physical changes in marbles that result in an increase in porosity, due to the appearance of new microcracks and the expansion of existing ones. These cracks offer new paths into the marble which make it easier for solutions containing pollutants to penetrate the material. Thermal expansion tests were performed on three different types of marble known as White, Tranco, and Yellow Macael (Almeria, Spain), after which an increase in porosity (from 17 to 73% depending on marble type) was observed, mainly due to crack formation. The structural changes occurring during thermal expansion tests were more significant in the case of White Macael samples, a fact that is not only related to its mineralogical composition but also to the morphology of the grains, grain boundaries and crystal size. Our research suggests that thermally weathered White Macael marble could be more susceptible to decay by other contaminant agents than Tranco or Yellow Macael. The use of hot-stage environmental scanning electron microscopy is proposed as a valid tool for observing, both in situ and at high magnification, changes in the fracture system of building stones induced by thermal stress.

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Section: Methodsmentioning

confidence: 98%

Direct observation of microcrack development in marble caused by thermal weathering

et al. 2010

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“…Measurements were taken for each spatial direction (X, Y and Z). To calculate the textural anisotropy of the rock, we used the equation proposed by Guyader and Denis [19]. Table 1 shows that the main mineral phase in the studied serpentinites is antigorite, followed by magnetite and/or carbonates (i.e., magnesite and calcite).…”

Section: Methodsmentioning

confidence: 99%

Verde Macael: A Serpentinite Wrongly Referred to as a Marble

Navarro¹,

Pereira

Gimeno

et al. 2013

Geosciences

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Serpentinites are used in both exterior and interior locations, but not all serpentinites are equal: they vary in physical-mechanical behavior and are not all suitable for similar uses. The serpentinites most commonly used worldwide come from India, Pakistan or Egypt. Spain has traditionally quarried two ultramafic massifs, one in Galicia (Verde Pirineos) and one in Andalucía (Verde Macael). Some of these quarries were small family-run businesses. In both cases, these rocks are commercially available as "green marble." These serpentinites commonly have a high degree of carbonation, but the process does not always take place with the same intensity. Carbonate can act as a cementing agent of the other phases, increasing the mechanical strength parameters. As a result, an improvement in the strength conditions is achieved, but a misinterpretation of the suitability of the rock may occur because a perception among users that "green marble" is similar to geologically defined marble. This may lead to inappropriate applications as an ornamental stone. At a time of economic crisis in Europe, the natural stone sector is encouraged to invest in research to identify the best quality products that can compete profitably with those currently being imported from other countries. This paper provides a comparison of properties of the Verde Macael serpentinite with a true marble in the hope of contributing to improving the natural stone industrial sector.

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“…Measurements were taken in direct transmission/reception mode, across opposite parallel sides of the cubic specimens in all three spatial directions. Anisotropy was estimated from the indices proposed by Guydader and Denis (24), routinely used throughout the literature and particularly by Zezza in 1990 (7) to determine the physicalchemical properties of construction and quarry stone. These indices were chosen for the present study because, unlike others, they distinguish between "flat" or twodimensional and three-dimensional anisotropy which may, a priori, condition the type of deterioration generated in a material.…”

Section: Methodsmentioning

confidence: 99%

Influencia de la anisotropía en la durabilidad de las dolomías Cretácicas de la Comunidad de Madrid frente a la cristalización de sales

Fort¹,

Fernández-Revuelta²,

Varas³

et al. 2007

Mater. construcc.

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RESUMENEn este trabajo se estudia el comportamiento de las dolomías de Redueña y de Torrelaguna frente a los efectos de la cristalización de sales. Ambos materiales han sido ampliamente utilizados en la construcción del Patrimonio arquitectónico y monumental de la región de Madrid. Para la selección de las probetas pétreas a ensayar, se midió la velocidad de propagación de ondas ultrasónicas (Vp) en cerca de un centenar de muestras cúbicas de cada variedad. Se calcularon los índices de anisotropía y se realizó un proceso de clustering para su clasificación en función de niveles de la misma. De cada clase se tomaron dos probetas representativas y se procedió a su caracterización petrográfica y petrofísica antes y después de someterlas a ciclos de cristalización de sales. Para la evaluación del envejecimiento se registró la variación de peso y se documentó el deterioro visual observado. El patrón de degradación para cada uno de los materiales frente a los ciclos es bastante distinto: la dolomía de Redueña es la que presenta un deterioro más intenso con descamaciones y desplacados mientras que la de Torrelaguna tiende a generar fragmentaciones y formas redondeadas.Palabras clave: dolomías, ultrasonidos, índices de anisotropía, cristalización de sales, deterioro, piedra natural. SUMMARYThe behaviour of dolostone exposed to the effects of salt crystallization processes was studied on materials from Redueña and Torrelaguna in the province of Madrid, Spain. Much of the region's architectural and monumental heritage was built with the materials from these two sites. Stone specimens were selected for testing on the basis of ultrasonic wave propagation velocity (Vp) measurements taken in around one hundred cubic samples of each variety. The anisotropy indices were calculated and the samples were clustered on the basis of the results. Two representative samples of each class were taken and characterized for their petrographic and petrophysical properties before and after exposure to salt crystallization cycles. Ageing was evaluated in terms of weight loss and the visual deterioration observed. The pattern of decay found varied substantially in the two materials: the Redueña material exhibited more intense deterioration, with scaling and spalling, while the Torrelaguna dolostone tended to generate fragmentation and rounding at corners and edges.

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Propagation des ondes dans les roches anisotropes sous contrainte évaluation de la qualité des schistes ardoisiers

Cited by 51 publications

References 0 publications

Direct observation of microcrack development in marble caused by thermal weathering

Direct observation of microcrack development in marble caused by thermal weathering

Verde Macael: A Serpentinite Wrongly Referred to as a Marble

Influencia de la anisotropía en la durabilidad de las dolomías Cretácicas de la Comunidad de Madrid frente a la cristalización de sales

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