The thesis investigates the effect of siloxane-based water repellents on the
durability of monumental stones. Laspra, a micritic limestone typical for the Spanish
region of Asturias, and Repedea, an oolitic limestone from Moldavia, Romania were
selected for the present study, due to their regional / national significance and level of
usage. As for the siloxane-based water repellents, three worldwide used products,
namely Lotexan-N, Silres® BS 290 and Tegosivin HL 100 and a newly synthesized
nanocomposite material, TMSPMA, obtained starting from the 3(trimethoxysilyl)propyl
methacrylate as a precursor were investigated.
The limestones and the water repellents were thoroughly characterized using
specific techniques. The coating of the two monumental stones with the mentioned
products and the investigation of coating efficiency yielded to the conclusion that all
treatments induce good water repellent properties.
The treated limestones were afterwards submitted to different artificially
accelerated ageing tests – resistance against UV irradiation, resistance to salt mist action
and resistance to SO2 action in the presence of humidity –, the results being analyzed
according to standardized evaluation methods.
The durability of the treated stones was proved to depend on both stone
characteristics and water repellent chemical structure. All four water repellents induced a
good protection against UV irradiation, no significant differences among them being
noticed. As far as the resistance to salt mist action is concerned, the product that afforded
the best results when applied on Laspra was TMSPMA, and on Repedea, Silres® BS 290
or / and TMSPMA showed the highest efficiency. The best resistance to SO2 action in the
presence of humidity was conferred by Tegosivin HL 100 and TMSPMA when applied
on Laspra, while Silres® BS 290 and TMSPMA afforded better results in the case of
Repedea.
| Identifer | oai:union.ndltd.org:unibo.it/oai:amsdottorato.cib.unibo.it:2268 |
| Date | 13 October 2009 |
| Creators | Simionescu, Ana Bogdana <1977> |
| Contributors | Montoto, Modesto |
| Publisher | Alma Mater Studiorum - Università di Bologna |
| Source Sets | Università di Bologna |
| Language | English |
| Detected Language | English |
| Type | Doctoral Thesis, PeerReviewed |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
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