Limewashes with linseed oil: effect on the moisture transport of natural stone

0532347 - ÚTAM 2021 RIV DE eng C - Konferenční příspěvek (zahraniční konf.)
Nunes, Cristiana Lara - Mlsnová, Kateřina - Válek, Jan
Limewashes with linseed oil: effect on the moisture transport of natural stone.
Monument future. Decay and conservation of stone. Proceedings of the 14th International congress on the deterioration and conservation of stone. Halle: Mitteldeutscher Verlag, 2020 - (Siegesmund, S.; Middendorf, B.), s. 591-596. ISBN 978-3-96311-172-3.
[International congress on the deterioration and conservation of stone /14./. Göttingen (DE), 07.09.2020-12.09.2020]
Grant CEP: GA ČR(CZ) GA18-28142S
Klíčová slova: limewash * linseed oil * water-repellency * moisture transport * protective coating
Obor OECD: Materials engineering

Limewashes have been used worldwide as surface finishing coats on a large variety of porous materials since time immemorial. Linseed oil was traditionally used in many parts of Europe as an additive to both fresh mortar and to limewash paints to impart water-repellency to the coatings. The amount of oil is a crucial aspect because it influences the degree of water repellency. In this work, limewashes with increasing dosage of linseed oil (0.5%, 1%, 1.5%, 3%, and 5% with respect to the weight of lime) have been prepared and applied on two types of stone (Opuka and Mšeno) with different porous structure to study the effect of the coatings on the moisture transport. The contact angle with water drops, the water absorption by capillarity, and the drying rate were measured. The results showed that only oil dosages equal to or above 1.5% create hydrophobic surfaces. In one type of stone (Opuka), the effect of the limewashes on the moisture transport was shallow, both regarding the water absorption by capillarity and the drying rate, which is probably related to the low amount of limewash uptaken by the stone. The limewash with 1.5% of oil showed the best results in terms of water-repellency without affecting the drying rate with respect to the reference (uncoated) stone.
Trvalý link: http://hdl.handle.net/11104/0310875