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Paint and Protective Coatings
Published in Ryan Cruzan, Manager’s Guide to Preventive Building Maintenance, 2020
Efflorescence: Efflorescence is a white salt-like deposit that forms on the surface of masonry. As water migrates through masonry, it carries with it soluble salts which are deposited on the surface when the water evaporates. Efflorescence must be removed before painting or poor adhesion will result. Wire brushing, pressure washing, sand blasting, or washing with a solution of 25% muriatic acid (hydrochloric acid) will remove efflorescence. Muriatic acid is extremely caustic and protective gear must be worn when using it.
Deterioration of materials
Published in A. M. Sowden, The Maintenance of Brick and Stone Masonry Structures, 2020
Iron staining can be suppressed by repointing with a waterproofed mortar but is best avoided by using clean sands. Lime staining can be reduced by using mortars which do not contain lime or mortars formulated to reduce percolation. Silica staining is difficult to anticipate and avoid, but details which discourage water percolation will make it less likely. Silica stains are difficult to remove except with the very dangerous hydrofluoric acid. Efflorescence is usually temporary and is best either brushed off or left to be removed by weathering. Most stains except silica can be removed or reduced by careful water or acid treatment, but acid will attack poor mortars and so great care is necessary.
Mechanisms of Concrete Deterioration
Published in Satish Chandra, Yoshihiko Ohama, in Concrete, 2020
Efflorescence is the crystallization of single salts or mixtures of them on the surface of building materials. Some salts present in building materials, during the process, dissolve and rise toward the surface. With the evaporation of water, salt-bearing solution starts crystallizing. Seen as white spots on the concrete and brick surfaces, this is referred to as efflorescence. The source of solution can be internal as well as external. The external source is generally groundwater. It is seen mostly in brick constructions and natural stones and observed less frequently in concrete.
Compressed unfired blocks made with iron ore tailings and slag
Published in Cogent Engineering, 2022
Efflorescence is attributed to the deposit of the soluble salts on the brick surface. It is very common when there is presence of water-soluble salt, water and porous medium in the brick. Figure 11 shows the efflorescence test results on the prepared blocks. Most of the blocks did not show any sign of efflorescence, except for 82I-7 G which showed mild efflorescence. This suggests that prepared blocks were compact with minimum pores, which avoid the movement of the soluble salt through such medium. It also assures the potential of such blocks in practical applications and further suggests the positive interaction between GGBS, lime and IOT in developing much stable and durable building blocks.
Effect of polymer latex on the efflorescence, drying shrinkage and microstructure of alkali-activated slag paste
Published in Journal of Sustainable Cement-Based Materials, 2023
Duy-Hai Vo, Chao-Lung Hwang, Khanh-Dung Tran Thi, Mitiku Damtie Yehualaw, Min-Chih Liao, Hser Te Yu
Efflorescence, appearing on the surface of construction materials as a layer of white powder or nodular protrusions [31, 32], is a frequent problem attributable to the migration of soluble Ca2+ salt to the surface through pores and cracks in the structure. This phenomenon negatively affects the aesthetic appearance of buildings, as the salt degrades decorative coatings and veneer adhesives [32, 33]. Efflorescence has been shown to decrease the strength of concrete samples because of cement hydrate leaching [34, 35]. Besides, efflorescence is also a problem in the AAS binder due to the high content of alkali ions [31, 36]. AAS is typically activated using a sodium solution with a high concentration of Na2O. After hydration, a large volume of un-hydrated Na2O remains in the binder, leading to the presence of free Na+ ions in the alumino-silicate structure of AAS binder, which move to the surface of the paste samples and react with carbon dioxide, resulting in efflorescence [33, 37]. The formation of efflorescence is significantly affected by permeability, micro-cracks, and interconnecting pores. Thus, AAS increases the likelihood of efflorescence development due to the high alkaline solution concentration and the presence of micro-cracks. Several studies have reported the effectiveness of using additives to reduce efflorescence in AAM materials. Minfang Han et al. [38] reported that adding 5 A zeolite powder refined the pore structure and improved the efflorescence resistance of alkali-activated fly ash material. J. Wang et al. [32] used nano-silica to improve compressive strength and reduce efflorescence in AAS. However, no study in the literature has investigated using polymer latex to mitigate the development of efflorescence in AAS samples.
Fired clay bricks incorporating palm oil fuel ash as a sustainable building material: an industrial-scale experiment
Published in International Journal of Sustainable Engineering, 2021
Abdul Rachman Djamaluddin, Muhammad Akbar Caronge, M. W. Tjaronge, Rita Irmawaty
Efflorescence is a grey or white deposit of salts that forms on the surface of bricks, which can cause aesthetic problems on masonry structures. Efflorescence is considered as ‘slight’ if the white deposits cover less than 10% of the surface, ‘moderate’ when covering approximately 50% of the surface, and ‘heavy’ when covering more than 50% of the surface (Leiva et al. 2016).