Gypsum accumulation on carbonate stone

McGee, Elaine S.; Mossotti, Victor G.

doi:10.1016/0957-1272(92)90028-q

Cited by 18 publications

(12 citation statements)

References 5 publications

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“…), weathering patterns may vary based on the microfacies of the stone (Nicholson, 2001). Mcgee and Mossotti (1992) made already a comparison between gypsum crust formation and the underlying stone structure. Limestone and marble briquette samples were both identically exposed at the same site conditions and an appreciable difference was observed in the development of the weathering crusts.…”

Section: Discussionmentioning

confidence: 99%

Holistic approach of pre-existing flaws on the decay of two limestones

Dewanckele

Boone²,

Kock³

et al. 2013

Science of The Total Environment

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This study aims to understand the influence of the microfacies and the determination of pre-existing flaws on the weathering behavior of two types of limestones. Therefore, both Lede and Noyant limestones were independently weathered by strong acid tests and freeze-thaw cycles. In order to characterize the weathering patterns inside the stones, a combination of high resolution X-ray CT, SEM-EDS and thin section microscopy was used. The advantage of high resolution X-ray CT is its non-destructive character and the obtained 3D structural information. By using this technique, a time-lapse sequence of the weathering patterns was obtained for both gypsum crust formation as well as crack formation due to freezing and thawing. This way, a clear link could be made with the initial non-weathered state. Thin section microscopy and SEM-EDS provided additional chemical information. The focus of this study lies in the processes that occur in the bioclast fragments in the stone and the influence of the surrounding cement or matrix. The results show that weathering patterns vary for both limestones although the causes of weathering were similar. In case of the Noyant stone, the weathering by crystallizing gypsum was mainly restricted to the microporous matrix of the stone, while in case of the Lede stone, several foraminifera and shell fragments were preferentially recrystallized. In general, the underlying microstructure determines the weathering pattern of the stone.

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Section: Discussionmentioning

confidence: 99%

Holistic approach of pre-existing flaws on the decay of two limestones

Dewanckele

Boone²,

Kock³

et al. 2013

Science of The Total Environment

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“…It is possible that the intergranular crystals are an artifact, because accumulation of gypsum crystals is predominantly a surficial phenomenon. Analysis and examination of limestone from an older building has shown that although elevated levels of sulfate are detected for some distance into the stone, gypsum in crystal form is restricted to the near surface area (McGee and Mossotti, 1992).…”

Section: Comparison Of the Weathering Of The Marblesmentioning

confidence: 99%

Philadelphia Merchants' Exchange conservation strategy; marble characteristics and deterioration

McGee¹

1996

Open-File Report

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In the sample column: E = east facade, W = west facade, Ic = light crust, dc = dark crust, w = wall, c = column, p = pilaster, # = number of column (or column closest to the wall area sampled). Abbreviations: grd = ground, abv = above, accuml = accumulation, sm = small, col = column, ab = about, plstr = pilaster. Phases column shows estimate from X-ray difl&action analyses of relative abundances of the phases in each sample.

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“…Such sulfate-induced limestone decay is widely believed to proceed via formation of sparingly soluble Ca 2+ salts from the reaction of limestone with SO 2 or acid rain, of which the hemi-hydrate (CaSO 4 .0.5H 2 O) and gypsum (CaSO 4 .2H 2 O) are most commonly formed dependent on relative humidity3. Dry deposition occurs when sulfation proceeds in sheltered areas, resulting in salt crystallisation and the genesis of ‘gypsum crusts' (notably over porous and sculpted surfaces), which can in turn fracture the underlying stone45. Wet deposition likewise involves initial surface sulfation, but subsequent dissolution of weathered stonework under rainwater, causing more gradual weathering of external limestone facia6.…”

mentioning

confidence: 99%

Preservation of York Minster historic limestone by hydrophobic surface coatings

Walker

Wilson

Lee

et al. 2012

Sci Rep

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Magnesian limestone is a key construction component of many historic buildings that is under constant attack from environmental pollutants notably by oxides of sulfur via acid rain, particulate matter sulfate and gaseous SO2 emissions. Hydrophobic surface coatings offer a potential route to protect existing stonework in cultural heritage sites, however, many available coatings act by blocking the stone microstructure, preventing it from ‘breathing' and promoting mould growth and salt efflorescence. Here we report on a conformal surface modification method using self-assembled monolayers of naturally sourced free fatty acids combined with sub-monolayer fluorinated alkyl silanes to generate hydrophobic (HP) and super hydrophobic (SHP) coatings on calcite. We demonstrate the efficacy of these HP and SHP surface coatings for increasing limestone resistance to sulfation, and thus retarding gypsum formation under SO2/H2O and model acid rain environments. SHP treatment of 19th century stone from York Minster suppresses sulfuric acid permeation.

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Gypsum accumulation on carbonate stone

Cited by 18 publications

References 5 publications

Holistic approach of pre-existing flaws on the decay of two limestones

Holistic approach of pre-existing flaws on the decay of two limestones

Philadelphia Merchants' Exchange conservation strategy; marble characteristics and deterioration

Preservation of York Minster historic limestone by hydrophobic surface coatings

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