Microstructural analysis of lime paste with the addition of linseed oil, stand oil, and rapeseed oil. (30th March 2020)

• Record Type: Journal Article
• Authors: Nunes, Cristiana; Viani, Alberto; Ševčík, Radek
• Is Part Of: Construction & building materials. Volume 238(2020)
• Publication Date: 2020-03-30
• Subjects: Vegetable oils -- Lime -- Fatty acids -- Water-repellency -- Microstructure; Building materials -- Periodicals; 624.18
• DOI: 10.1016/j.conbuildmat.2019.117780
• Languages: English
• ISSNs: 0950-0618

Abstract

Highlights: We studied the microstructure of lime paste with the vegetable oils up to 1 year. Pastes with oil showed large rounded voids assigned to air-entrapment. Pastes with 1.5 wt% of linseed and rapeseed oils were hydrophobic. Carbonation was delayed in the presence of oil after 28 days of curing. Oils promoted the development of CaCO3 polymorphs and amorphous phases. Abstract: This work aims to study the microstructural evolution of lime paste with the addition of linseed, stand, and rapeseed oils to explore their potential as protective coatings for porous building materials. Paste samples with two dosages of each oil were studied in terms of wettability, porous structure, and composition up to 360 days of curing. The results showed that in the early stage of curing, the carbonation reaction was accelerated with oil addition, but after 28 days, the carbonation was significantly delayed. A striking difference between the porous structure of the pure lime paste and the pastes with oil was observed. Linseed and rapeseed oil were more reactive with lime than stand oil, thus, affecting the microstructure of the paste more significantly. They also altered the carbonation reaction pathways by favouring the formation of amorphous products. The lower reactivity of stand oil is attributed to the considerably lower amount of unsaturated fatty acids as compared with the other oils. Rapeseed oil promoted higher water-repellence and a more homogeneous distribution of bubble-like pores than the other oils.