Projects / Programmes
Development of novel bioresistant and stainfree stone surfaces
| Code |
Science |
Field |
Subfield |
| 1.06.01 |
Natural sciences and mathematics |
Geology |
Mineralogy and petrology |
| Code |
Science |
Field |
| P420 |
Natural sciences and mathematics |
Petrology, mineralogy, geochemistry |
| Code |
Science |
Field |
| 1.05 |
Natural Sciences |
Earth and related Environmental sciences |
natural stone, bioreceptivity, biodeterioration, staining
Researchers (13)
Organisations (5)
Abstract
The main goal of this project is to evaluate the bioreceptivity of the studied stone substrates with different mineralogical, chemical and physical properties and their susceptibility to staining. Furthermore, appropriate procedures will be developed and optimized for the prevention of biodeterioration, which will lead to the development of high bioresistant and stainfree stone surfaces. Research results will be applied in the field of modern buildings, historical buildings and stone monumets and to a minor extent to the preservation of the natural heritage.
The research project is primarily aimed at estimating the direct impact of the intrinsic properties of rocks on the susceptibility of stone for the growth of organisms. Previous research has, for instance, shown that studied calcitic marble has higher bioreceptivity than dolomitic marble. In the project bioreceptivity will be determined for differetn commonly used commercial types of stone, which are found in Slovenia. The same applies to the development of stains. The term: "intrinsic staining susceptibility" is proposed for susceptibility of stain formation due to the weathering of minerals. In the case of external staining the intrinsic properties are less important for stain formation, but the removal of such stains depends on the surface condition and stone properties. The mechanisms of the adhesion of microorganisms onto stone surfaces will be studied in conjunction with surface roughness. This will result in the identification of the most efficient methods of mechanical surface treatment during stone production.
In order to determine bioreceptivity and the likelihood of stains formation there is an urgent need for a standardized, reliable, and rapid laboratory method, since the growth of microorganisms in nature, as well as stain formation, can be a relatively long-term process. DFor bioreceptivity such method will be based on measurements of the autofluorescence of pioneering authotrophic organisms. In the first part of the project the basic mechanisms of biological degradation of stone will be also defined, as well as the sequentional development of biocolonization. Less focus will be given to the actual identification of microorganisms, since this is a relatively complex and broad area, and would need the attention of a separate project, although the most common metabolits and groups of microorganism. The method of multivariate analysis will be set to correlate the intrinsic properties of stone with their resistance to biodeterioration and stain formation.
In the second part of the project a variety of commercially available cleaning techniques and protective coatings will be evaluated. In connection with the latter, we will focus on those coatings which have a reported anti-microbial and/or stain resistant effect. In previous projects and parallel European project HEROMAT different self-cleaning photocatalytic coatings are being developed for the protection of selected mineral surfaces from different organic aggressors. In this project we will tailor properties of such coatings to be applicable to carbonate and silicate stone substrates, with emphasized stain resistant and anti-microrbial effect. Beside their antimicrobial effects, we will also focus on increased durability and adhesion. Such coatings need to be durable, to preserve the original colour of the stone, and not be deleterious to the stone substrate. The added value of this project is the development of non-toxic and harmless cleaning agents for the removal of lampenflore (algae coatings on karstic cave walls) in sensitive cave systems.
The project results will be used directly by industrial partners, and will also be disseminated among stakeholders and other interested parties since there is great demand for scientifically based data concerning the selection of appropriate stain-free and bioresistant surfaces.
Significance for science
Biodeterioration is relatively young scientific field which comprised the fields of material science and microbiology. The proposed research work added mainly to the understanding of material (geological) part of this field, with the focus on bioreceptivity in the sense of the correlation between the intrinsic properties of stone and its susceptibility to biocolonization. Further, with systematic scientifically-based approaches, based on knowledge of industry needs we added to development of new knowledge in the field of geology, chemistry (development and tailoring of functional coatings for protection of stone surfaces) and in the field of microbiology. The following achievements of the project represent contributions to the development of science: (1) Developed rapid laboratory protocol for the determination of stone bioreceptivity, going to be proposed to CEN Technical Committee for Natural stone (TC 246), responsible for development of technical specifications for natural stone. Development of method has already been communicated with some of the committee members. (2) Developed a 3D bioreceptivity evaluation protocol with use of merge of fluorescent optical images in different focal planes. The method was also applied to confocal microscopy but the former method has proved to be easier, cheaper and more applicable to industry and testing laboratories since not all laboratories have confocal microscopy. (3) Achieved 3D visualization of biodeterioration patterns by means of microtomography down to 1 µm resolution. (4) A contribution towards an understanding of the successive colonization of different stone surfaces. (5) A contribution to the understanding of photocatalytic activity on carbonate and silicate stone surfaces. The research work results in the systematic evaluation of bioreceptivity and stain susceptibility for a broad range of stones. We understand correlation between bioreceptivity / stain resitance and the intrinsic properties of stones (chemical-mineralogical composition, microstructure, surface properties). Cooperation with foreign research, project consortiums and standardization comittees as well through publishing original scientific papers and other scientific contributions dissemination of the research findings to a broader research area was enabled. In this way the project research group simultaneously optimized and developed new methodological approaches in the field, which contributed to the development of international science and new knowledge.
Significance for the country
Two of the industrial partners involved in the project received knowledge and information for development of materials and coatings with a high resistance to biocolonization and staining, i.e. Marmor Hotavlje d.o.o. for protection of stone surfaces and JUB d.o.o. for development of hydrophobic coatings. Company Helios was also involved in the project in development of photocatalytic coatings. The results of the project can be directly linked to their businesses, and increasing their value in going beyond the stage of business as usual. The third cofinancer Postojnska jama d.d. received information which helped to increase the sustainable management of Postojna cave, one of the biggest world underground touristic attraction, which annually visit over 600.000 tourists. Through the project workshops a ripple effect was created, impacting other stakeholders such as stone producers, construction companies, protection and cleaning companies, coating producers as well as conservators and restaurateurs of cultural heritage. Importance of the project for development of Slovenian industry as well as society as a whole can be summarized as following: (a) Transfer of systematic and scientifically proven data about bioreceptivity, stain formation, and the prevention of biocolonization and staining and vice versa transfer of market experiences and the market situation from industry to the research group (e.g. experiences about durability of inbuilt stone, functionality of different stone protective coatings and cleaning methodologies). Appropriate cleaning and protective coatings for an individual type of stone among the flood of commercially available products can now be selected on scientifically and expertly evaluation. (b) Evaluation of industry own products and of products which they are using based on testing according to developed rapid and effective laboratory methods. This is also important for the evaluation of the real behaviour of each stone product, as well as for the efficiency of conservative procedures for historical sites. (c) A novel photocatalytic coating and information important for development of new hydrophobic coating, which will increase the competitiveness of the partners not only in Slovenia but also on foreign markets. (d) Positioning on new markets, which is very important for construction and its connected sectors slowly restoring after the recent global and national recession. The Marmor Hotavlje is already in more than 80% active on foreign markets. The company has recently for example signed business contract with Apple Company for production of high functional stone office tables. Such new value-added products will present additional push (offer) and pull (demand) opportunities. (e) New opportunities for lasting cross-sectorial collaboration between stone producers and coating producers. Such an exchange of experience and knowledge is essential for development of both sectors. Further, such cooperation is also impacting development of more sustainable, effective and cost efficient protection agents for natural and cultural heritage, which has large impact on tourism. (f) Development of new competences and skills in industry as well as capacity building among all the actors of new solutions for production and protection of natural stone. Graduate and master students were involved in the project research program (two thesis, one graduate and one master were produced) as well as two young researchers, including lead researcher. At the end, as one of the important long term impacts of the project is preservation of modern stone architecture, stone culture heritage as well as preservation of sensitive abiotic and biotic karstic cave systems which indirectly impact preservation of value, not only on national but also on global level. Through international cooperation the above described new discoveries in research field have directly promoted Slovenian research area and increase its recognition in Europe.
Most important scientific results
Annual report
2013,
2014,
2015,
final report
Most important socioeconomically and culturally relevant results
Annual report
2013,
2014,
2015,
final report
