Microstructural analysis of lime paste with the addition of linseed oil, stand oil, and rapeseed oil

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.