Academic thesis

Annika Bachem: Combinations of biocide treatments and surface coatings of limestone are examined concerning their suitability as a protection layer against microbiological growth and its harmful effects. Back
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The tomb of Berta Koenigswarter on the Jewish cemetery "Strangriede" in Hanover (photo: C Kappen).
Abstract: The effects of the different surface coatings (limewash, limewash modified with acrylic resin, silicic acid ester- bound wash, a siloxane emulsion paint and a water repellent treatment) on the hygric characteristics of limestone are examined by measuring the capillary water absorption, the rate of drying after water absorption from the back side and the water vapour transmission. The measurements are carried out with unweathered and artificially weathered samples. The algicide properties of the coatings in combination with a treatment of the stone surface with one of three different biocide products is examined by a colonisation test. Two of the three biocides turn out to be highly effective. By the examination of the coatings colonized by fungi under the microscope it is detected that the silicic acid ester- bound wash is the only coating that is attacked and penetrated by the growing fungi. The examination of samples colonized by algae under the scanning electron microscope shows differences in the adhesion of the biofilm on the different coatings.
The suitability of the coatings for preventing the biocides from being washed out by water is tested by rinsing biocide- treated, coated samples and measuring the biocide concentration in the rinsing water.
Considering the whole test results, the limewash in combination with one of the highly effective biocides turns out to be the most suitable treatment.


SEM micrograph of a sample with microbial mat and photo of colonisation test of silicic-acid-ester treated samples.
  • academic institution: HAWK Hochschule für angewandte Wissenschaft und Kunst Hildesheim/ Holzminden/Göttingen
  • kind of theses:  Diplomarbeit
  • main Tutor:  Prof. Jan Schubert
  • assistant Tutor:  Prof. Dr. Karin Petersen
  • date:  2001
  • Language:  German
  • pages:  104
  • pictures:  45
Annika Bachem
Rehbockstr. 16
30167  Hannover
piepo-partner@[Diesen Teil loeschen]

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Creative Commons Lizenzvertrag This work is licensed under a Creative Commons BY-NC-ND 3.0 Germany License.
DOI (Digital Object Identifier) 10.5165/hawk-hhg/90

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