Humidity, environmental pollution, cleaning with aggressive products for the chemical composition of the rock, etc give rise to the appearance of salts which cause stone decomposition, paint coats detachment, dust accumulation, etc.
Salts in the mural paintings of the upper section of the Church of the Monastery of San Jerónimo (Granada).
Laboratory tests in calcarenite test-tubes simulating alteration processes due to salt crystallization in the bases of building walls.
The treatments used up to now to deal with the problem have been directed, almost exclusively, to preserve the beauty of the affected monument, assuming, with an almost fatalist attitude, that the damage will go on as an effect of passing of time.
European experts joint in the SALTCONTROL project have collaborated in a new work line to deal with the problem: Blocking inside the stone the mineral salt crystallization process that ends up destroying it.
One of the works carried out in the framework of SALTCONTROL is the doctoral thesis “Prevención del daño debido a cristalización de sales en el patrimonio histórico construido mediante el uso de inhibidores de cristalización” (Damage prevention due to salt crystallization in national heritage through the use of crystallization inhibitors), read by Encarnación María Ruiz Agudo, under the supervision of Prof Carlos Manuel Rodríguez Navarro; as well as several papers published by scientific journals such as Journal of Physical Chemistry, Environmental Geology, Scanning y Journal of the Japanese Association for Crystal Growth.
According to Ruiz Agudo (Centro Andaluz del Medio Ambiente – Department of Mineralogy and Petrology of the University of Granada) “ornamental porous materials’ damage due to salt attack is one of the most aggressive alteration mechanisms that affect constructed heritage. In the last decades, we have developed different methods to prevent or reduce the damage due to salt crystallization in ornamental rock pores, almost all with little success”.
The thesis’s research line and the above mentioned papers have followed the recent techniques that intend to use additives to modify the crystallization process and prevent or reduce the damage produced in the rock. Up to now, most of the works in this field have assessed the efficiency of these treatments in slightly soluble salts, such as calcium and barium sulphates. The thesis “has proved the effectiveness of this type of treatment in highly soluble salts, such as sodium and magnesium sulphates, as well as sodium nitrate, which can usually be found in historic buildings”.
The research work has been applied to the case of the effects of these treatments in the rock extracted in Santa Pudia’s quarries (Escúzar,-Granada), used in the construction of Renaissance buildings in Granada such as the Monastery of San Jerónimo, the Cathedral or the Royal Chapel. These buildings show strong alteration phenomenon due to crystallization in sodium sulphate, magnesium and sodium nitrate.
The work has conducted to the carrying out of salt crystallization tests in laboratory, which simulate alteration processes due to salt crystallization in the bases on historic buildings’ walls. “Later –says Ruiz Agudo-, we prepared a method for the implementation of the treatment developed in practical cases of ornamental stone materials conservation. Finally, in a last phase of development of the research project, we applied such treatment in pilot areas on the Monastery of San Jerónimo (Granada), where there had been important problems due to salt crystallization”.
The final result of the research work proposes the application of low-cost additives, which have proved to be very effective in the fight against the problems of ornamental porous materials. On the other hand, the research work “involves a methodology to deal with the study of damage caused by salts and the selection of the most adequate type of additive for a specific substrate and type of salt. The object of the methodology is the study of the problem in situ, in order to carry out laboratory tests that allow to select the concentration, pH and the most appropriate application method and finally to go back to the building to test the treatment in pilot areas, which permits to guarantee the success in the application of salt crystallization inhibitors inside stony materials, as we have proved in San Jerónimo”.SALTCONTROL
Reference: Encarnación Mª Ruiz Agudo. Dpt Mineralogy and Petrology. Phone numbers. 958248535 - 958 24 8535. E-mail. firstname.lastname@example.org. Prof Carlos Manuel Rodríguez Navarro. Phone number. 958246616. E-mail. email@example.com
Antonio Marín Ruiz | CEAMA-Universidad de Granada
Building-Integrated Photovoltaics Moves from the Niche to the Mass Market
13.03.2019 | Fraunhofer-Institut für Solare Energiesysteme ISE
Seeing Through the Stones of Cathedrals
07.03.2019 | Otto-Friedrich-Universität Bamberg
A stellar flare 10 times more powerful than anything seen on our sun has burst from an ultracool star almost the same size as Jupiter
A localization phenomenon boosts the accuracy of solving quantum many-body problems with quantum computers which are otherwise challenging for conventional computers. This brings such digital quantum simulation within reach on quantum devices available today.
Quantum computers promise to solve certain computational problems exponentially faster than any classical machine. “A particularly promising application is the...
The technology could revolutionize how information travels through data centers and artificial intelligence networks
Engineers at the University of California, Berkeley have built a new photonic switch that can control the direction of light passing through optical fibers...
Physicists observe how electron-hole pairs drift apart at ultrafast speed, but still remain strongly bound.
Modern electronics relies on ultrafast charge motion on ever shorter length scales. Physicists from Regensburg and Gothenburg have now succeeded in resolving a...
Engineers create novel optical devices, including a moth eye-inspired omnidirectional microwave antenna
A team of engineers at Tufts University has developed a series of 3D printed metamaterials with unique microwave or optical properties that go beyond what is...
17.04.2019 | Event News
15.04.2019 | Event News
09.04.2019 | Event News
18.04.2019 | Life Sciences
18.04.2019 | Physics and Astronomy
18.04.2019 | Life Sciences