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Deterioration of Brickwork Retaining Walls as a Result of Thaumasite Formation
Published in Christer Sjöström, Durability of Building Materials and Components 7, 2018
Salts were collected from either on or below the surface of the garage retaining walls and three different compounds were detected using XRD analysis. These were (i) sodium sulphate (thenardite), (ii) a double salt containing potassium and sodium sulphate (aphthitalite) and (iii) a double salt containing potassium and calcium sulphate (syngenite). Whereas the precipitation of sodium or calcium salts as crypto-efflorescence is relatively harmless, the occurrence of crypto-efflorescent salts containing potassium can seriously damage the front face of brickwork [1] [2].
Physical and Chemical Characterization of the Ash of Fallen Chinese Willow Leaves: Effects of Calcination Temperature and Aqueous Solution
Published in Combustion Science and Technology, 2020
Guorui Feng, Tingye Qi, Yuxia Guo, Jinwen Bai, Jun Guo
Water is the primary raw component of the cement-based materials; hence, water solubility and reactivity of willow leaf ash should be investigated. Some studies demonstrated that the water soluble components in the biomass ash (BA) predominantly include the alkaline minerals and mineral containing alkaline earth elements, such as (1) highly soluble chlorides (sylvite and halite), sulfates (arcanite, syngenite, ettringite, and gypsum), oxides (lime), hydroxides (portlandite), nitrates, carbonates, and bicarbonates; (2) certain less soluble carbonates (calcite), phosphates (phosphorites), and oxides (periclase); and (3) some slightly soluble phosphates (apatite) and silicates (Ca silicates and feldspars) (Vassilev et al., 2014).
Composition of renders and plasters of award-winning buildings in Lisbon (Portugal): A contribution to the knowledge of binders used in the 20th Century
Published in International Journal of Architectural Heritage, 2023
Luís Almeida, A. Santos Silva, Rosário Veiga, José Mirão
Finally, the presence of salt efflorescences (halite: NaCl; syngenite: K2Ca(SO4)2•H2O; eugsterite: Na4Ca(SO4)3•2(H2O) detected by XRD in the samples AR49-2A and AR49-11A (Figure 18) should be addressed, indicating contamination, which is consistent to what was reported relating to decay evidence in walls of AR49 (1923) case study by a previous study (Almeida et al. 2021).