Chemical and microstructural characterisation of lime and lime-metakaolin pastes with linseed oil

Author(s): C. Nunes, P. Mácová, D. Frankeová, R. Ševčík and A. Viani
Paper category: Proceedings
Book title: Proceedings of the International Conference on Sustainable Materials, Systems and Structures (SMSS2019) New Generation of Construction Materials
Editor(s): Marijana Serdar, Nina Štirmer, John Provis
ISBN: 978-2-35158-217-6,
Vol 1. ISBN: 978-2-35158-223-7
e-ISBN: 978-2-35158-218-3
Publisher: RILEM Publications SARL
Publication year: 2019
Pages: 402-409
Total Pages: 8
Language : English

Abstract: Linseed oil has been used since the Classical times as a water-repellent additive in lime mortars and other types of lime-based coatings to protect building structures exposed to severe weathering conditions, e.g., direct exposure to wind-driven rain. Recent studies have confirmed the potential of this environmentally-friendly additive in improving the durability of lime-based mortars. This study aims to investigate the effect of linseed oil on the microstructure of lime and lime-metakaolin pastes. The specimens were analyzed after a long period of curing in laboratory conditions. The results of thermal analysis, Fourier transform infrared spectroscopy, and powder X-ray powder diffraction (XRPD) demonstrated that linseed oil significantly hindered the carbonation reaction in both lime and lime-metakaolin pastes. Scanning electron microscopy analysis showed the presence of large hexagonal crystals of portlandite in the lime paste with linseed oil. The lime-metakaolin pastes exhibited common calcium silicate hydrates morphologies (fibres, flakes) and the paste with linseed oil exhibited a denser structure than the reference. This observation was in line with the results of XRPD quantitative phase analysis which indicated the double content of amorphous phases in the specimen with linseed oil in comparison with the reference. The results confirm previous indication that linseed oil can have a beneficial effect on the hardening reaction of lime-metakaolin by favoring hydration reactions to the detriment of carbonation under the curing conditions tested and/or by contributing to its stabilization.

Online publication : 2019
Publication type : full_text
Public price (Euros) : 0.00