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http://www.monografias.com/trabajos6/clame/clame.shtml#labra)
Protección de Piedras
Cuando la piedra ha de quedar a la vista, es necesario
protegerla de los agentes atmosféricos. Con este
fin se aplican procedimientos químicos como la
silicatización, fluosilicatización, y
la fluoatación.
La silicación consiste en aplicar una solución
de una parte en peso de silicato potasio en 5 o 6 partes
de agua.
La fluosilicatización consiste en la aplicación
de soluciones incoloras y transparentes de fluoruros
metálicos con ácido fluorhidrico. Con
este método las piedras calcáreas heledizas
dejan de serlo.
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Protective patinas applied on stony façades
of historical buildings in the past
M. Alvarez de BuergoCorresponding Author Contact Information,
E-mail The Corresponding Author and R. Fort González
Instituto de Geología Económica (Institute
of Economical Geology) (CSIC-UCM), School of Geology,
Universidad Complutense de Madrid, 28040, Madrid, Spain
The ochre patina that covers the limestone façades
of Palacio de Nuevo Baztán is composed of calcite,
clay minerals, gypsum, quartz, potassium feldspar, alongside
traces of calcium oxalates, calcium phosphates, iron
oxides and hydroxides. It is a polistratified film,
rich in Ca, Si, Al and P, as well as Mg, K, Fe and Cl.
Results obtained indicate that the origin of the patina
lies in a treatment applied on the stone in the past,
consisting of a mixture of lime, gypsum, milk-derived
compounds and inorganic earth pigments. This film has
protected the stone on which it was applied, and should
be preserved in any further stages of intervention on
the stone façades.
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V2G-47426B9-7&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=364068469fec310830af86437f62befe
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Building Stone Magazine
Building Stone Magazine Building Stone Magazine Building
Stone Magazine
Winter 2007
Cleaning and maintenance restored Trinity Church to
its former beauty.
Photos courtesy of Gary Henry, PROSOCO
When builders constructed Manhattan's beautiful Trinity
Church in 1846, they could not have envisioned that
this ornate Gothic Revival sandstone structure, which
then dominated the lower Manhattan skyline with its
soaring neo-gothic spire, would someday rest in the
shadows of some of the world's tallest buildings.
Nor could they have envisioned that the golden sandstone
would need protection from the air and the rain, which
would become increasingly polluted over time. Forty
years later, conservators added a wax coating to preserve
the beautiful sandstone (specifically a New Jersey brownstone),
but whatever protection it provided was nullified by
the tendency of the sticky surface to attract dust and
dirt.
The cleaning effort was minimal because of the earlier
treatment of the stone. Unlike the 19th century wax
coating that attracted grime and trapped water vapor,
today's treatments are nearly 100-percent breathable,
letting vapor out without letting liquid in, and without
changing the appearance of the stone. "Water is
the greatest enemy of stone," Henry emphasizes.
"If allowed to penetrate into the story, it carries
contaminants from air pollution into the stone. But
the greatest threat to the integrity of the stone is
caused by the freeze-thaw cycle — the expansion
and contraction can damage the stone's structure. That's
why using the proper protective treatment is so important."
http://www.buildingstonemagazine.com/winter-07/clean.html
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Ver Rocas ornamentales: deterioro
y restauro
Ver Piedra de Santanyí
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