Color changes in architectural limestones from pollution and cleaning

Grossi, Carlota M.; Brimblecombe, Peter; Esbert, R. M.; Alonso, Francisco

doi:10.1002/col.20322

Cited by 124 publications

(87 citation statements)

References 24 publications

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“…Health effects derive primarily from particle size and concentration in the air, but for the blackening of buildings the effects derive mainly from color (i.e., EC content) and cumulative flux. In particular one should note that modern deposits have taken on a slightly different color and now appear more brownish (26). These changes may arise from oxidation processes in the organic rich materials.…”

Section: Resultsmentioning

confidence: 99%

Carbon in Black Crusts from the Tower of London

Bonazza

Brimblecombe

Grossi

et al. 2007

Environ. Sci. Technol.

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This paper investigates the origin, fluxes, and transformation of carbon compounds within black crusts on the stone walls of the Tower of London. The crusts were analyzed for elemental and organic carbon, including the water soluble fraction. Elemental carbon and low solubility compounds such as oxalates appeared to be conserved because of long residence times. Conversely, more soluble ions, like chloride and formate would be removed from the layers relatively quickly by rainfall. At higher organic carbon concentrations acetic acid may be produced within the crusts from biological transformations. Currently, traffic sources contribute to increasingly organic rich crusts. The deposition of elemental carbon to buildings darkens surfaces and has important aesthetic implications. The increased organic content may have further aesthetic consequence by changing the color of buildings to warmer tones, particularly browns and yellows. Management of historic buildings requires us to recognize the shift away from simple gypsum crusts to those richer in organic materials.

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Section: Resultsmentioning

confidence: 99%

Carbon in Black Crusts from the Tower of London

Bonazza

Brimblecombe

Grossi

et al. 2007

Environ. Sci. Technol.

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“…To quantify color change, ∆E [39,41] (12) was used taking into account different values are reported in the literature to indicate the threshold of perceivable differences [40,42,43]. Considering the largest threshold (∆E > 5), the measured ∆E appears as perceivable by human eye in almost all cases, ranging from 1.5 for SP (minimal color difference) to above 30.0 (perceived as two different colors).…”

Section: Energy and Architectural Implicationsmentioning

confidence: 99%

Cool Marble Building Envelopes: The Effect of Aging on Energy Performance and Aesthetics

et al. 2016

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Marble envelopes represent a relatively common architectural solution used in variety of historic, modern and contemporary building facades. White marble envelopes have been shown to reduce solar heat gains, while improving indoor thermal comfort and energy efficiency in summer time. While marble is useful in this context, the urban atmosphere accelerates the degradation of marble elements. This leads to changes in optical characteristics, hence the aesthetics, and affects the energy efficiency benefits offered by white marble facades. These issues are investigated in order to predict the impact of degradation on energy performance and to the aesthetic value, such as change of color and luminosity. In this study, surface degradation of white marble is analyzed by means of accelerated weathering in the laboratory while examining changes to the optical characteristics of the materials. A dynamic simulation is carried out to assess the energy performance of a building as a case study.

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“…Tanto la parte superior como la inferior muestran una diferencia de color (ΔE*) menor de 3, por lo que el producto consolidante no afecta significantemente a los parámetros colorimétricos de los materiales pétreos después del tratamiento. Esta diferencia es menor de 5 según Normal 20/85, 1996 [23], lo que implica que al tener una diferencia menor de 3 se encuentre por debajo del umbral de la percepción y no puede ser detectada visualmente [24], [25], [26].…”

Section: ±127unclassified

Evaluación del tratamiento de consolidación de dolomías mediante nanopartículas de hidróxido de calcio en condiciones de alta humedad relativa

Villalba¹,

López-Arce²,

Zornoza-Indart³

et al. 2011

Bol. Soc. Esp. Ceram. Vidr.

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En este artículo se presentan los resultados del tratamiento aplicado a muestras de piedra dolomía mediante una solución coloidal isopropílica basada en nanopartículas de hidróxido de calcio en una concentración de 2,0g/l. El proceso de consolidación de la piedra ha sido monitoreado antes y después de su aplicación a los 28 días de estar expuesta a una atmósfera del 75% de humedad relativa. Se ha realizado un estudio morfológico y estructural del consolidante confirmándose el proceso de carbonatación. Los resultados de difracción de rayos X, microscopía electrónica (TEM y ESEM) y difracción de electrones realizados al producto consolidante han confirmado la transformación de la fase portlandita a los polimorfos de carbonato de calcio de tipo calcita, aragonito y vaterita. Los ensayos petrofísicos realizados a la piedra antes y después de su aplicación, han demostrado que se produce una mejora de las propiedades físicas e hídricas indicado por el aumento tanto en la velocidad de propagación de ultrasonidos como en la densidad del material y una disminución de su coeficiente capilar, así como de la porosidad abierta sin producirse modificaciones significativas en el color y el brillo. La aplicación del tratamiento de consolidación propuesto, con este tipo de soluciones coloidales de nanopartículas, es un método natural y compatible con las características petrológicas del sustrato, sin generar daños secundarios sobre la piedra, resultando un método eficaz para la mejora de la durabilidad de rocas carbonáticas. Palabras clave: Consolidación, piedra, polimorfos de carbonato de calcio, nanopartículas de hidróxido cálcico, humedad relativa. Evaluation of a consolidation treatment in dolostones by mean of calcium hydroxide nanoparticles in high relative humidity conditionsIn this article, the results of a treatment applied to dolomitic stones using an isopropyl colloidal solution based on calcium hydroxide nanoparticles with a concentration of 2.0g/l are presented. The consolidation process in the stone has been checked before and after 28 days of exposure to 75% relative humidity. Morphologic and structural studies of the consolidating product confirmed the carbonation process. X ray diffraction, electron microscopy (TEM and ESEM), and electron diffraction carried out on the consolidating product have confirmed the transformation of portlandite phase to calcium carbonate polymorphs, calcite, aragonite and vaterite. Petrophysical tests performed on the stone before and after the application of the product have shown the improvement in the physical and hydrical properties due to the increase in the ultrasound velocity and density of the material, and a decrease in the capillarity coefficient and open porosity without significant changes in colour and brightness. The application of the consolidating product in the proposed experimental conditions is a natural method, compatible with the petrological characteristics of the substrate, without secondary damages on the stone, being an effective method to improve the durabili...

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Color changes in architectural limestones from pollution and cleaning

Cited by 124 publications

References 24 publications

Carbon in Black Crusts from the Tower of London

Carbon in Black Crusts from the Tower of London

Cool Marble Building Envelopes: The Effect of Aging on Energy Performance and Aesthetics

Evaluación del tratamiento de consolidación de dolomías mediante nanopartículas de hidróxido de calcio en condiciones de alta humedad relativa

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