Admixtures effect on fresh state properties of aerial lime based mortars

Effect of water-repellent admixtures on the behaviour of aerial lime-based mortars

“…Nevertheless, in mixtures with a high dose of additive, a large amount of water was needed in order to achieve the set slump. These results are in agreement with those obtained in lime mortars by Seabra et al [1], who observed that the presence of an AEA led to a slight decrease in slump values. It was evident that in the aforementioned paper, the mixing water was set, so slump values changed.…”

“…Atzeni et al and Arandigoyen et al conducted research into fresh state properties and pore structure and capillary porosity, respectively, of lime pastes [8,9], while rheological behaviour of lime mortars was discussed by Seabra et al [1,10]. Other authors have carried out research on the carbonation, long-term mechanical behaviour and durability of aerial, dolomitic and hydraulic lime mortars [11,12].…”

“…Several drawbacks and incompatibilities related to the use of cement mortars for Cultural Heritage restoration work have been highlighted: high mechanical strength, efflorescence phenomena owing to formation of large amounts of soluble salts by migration of alkaline ions, low water vapour permeability and higher thermal expansion coefficient than most masonry [1][2][3][4]. In view of these shortcomings, lime-based mortars show greater compatibility with ancient building materials and fulfil the recommendations of ICCROM [5] about the use of materials similar to the original ones in repair works.…”

“…They also reported an increase in the number of macropores when an AEA -a fatty alcohol derived -was added, with a significant reduction of retraction fissures taking place. Seabra et al [1] gave details on fresh state behaviour of aerial lime-based mortars modified with a water-retaining agent, a plasticizer and an AEA. Fortes-Revilla et al studied the addition of a superplasticizer in slaked lime-metakaolin mortars, reporting increased strength and reduced porosity [18].…”

Ageing of lime mortars with admixtures: Durability and strength assessment

“…The extent to which a mortar is affected by these deterioration factors is a function of the mortar's properties, which depend, in turn, on several issues, such as the kind and characteristics of the binder and the aggregate, the binder/aggregate ratio, the amount of mixing water, the mortar's permeability [9][10][11][12], the water absorption capacity through capillarity [10,13], water intake [7,14,15], the presence of admixtures and the curing conditions [16][17][18]. SO 2 exposure is supposed to affect the mortars because gaseous SO 2 has been widely reported to react with calcium carbonate, giving rise to the formation of both calcium sulphite hemihydrate (CaSO 3 .1/2H 2 O) and calcium sulphate dihydrate (CaSO 4 ·2H 2 O) on the mortar's surfaces [6,8,[19][20][21].…”