ブックタイトル「煉瓦造建造物の保存と修復」英語版

概要

「煉瓦造建造物の保存と修復」英語版

2-3. An overview of each type of damage? Salt damagewater infiltrationphoto 2-1 Brick surface with salt damageProgressing spalling due to salt crystalizationphoto 2-2 Salt damge of jointsBrick joints suffered from heavy salt damage, causingpowdering and loss.crystalizationof saltdryingphoto 2-3 Brick damaged by saltSome bricks show powdering due to salt damage.photo 2-4 Wall surface damaged by saltOn the plaster-finished interior walls, salts of a cotton-liketexture have formed mainly on the plaster surface. The redsquares show the areas of salt crystalization.figure 2-1Flow chart of salt damage・Appearance of salt damageSalt damage occurs when water that had entered into thebrick and joint evaporates and leaves salts dissolved in thewater to crystallize, involving volume expansion in brick’spores or on the surface, damaging the brick material (figure2-1) fn 1。In brick masonry structures, salt damage occurs dueto water entering from the roof or walls as well as waterabsorption from underground, resulting in spalling andpowdering on the brick surface.・About saltsSalts form as water entering into the brick material bondswith negative ions (anion) derived from acids and positiveions (cation) from alkalines in brick components dissolved inthis water fn 2。・Representative saltsSodium sulfate, sodium chloride, sodium nitrate, calciumsulfate, calcium carbonate, and magnesium sulfate, etc.・Negative ions (anion) derived from acidsChloride ion, sulfate ion, nitrate ion, carbonate ion, etc.・Positive ions (cation) derived from alkalinesSodium ion, potassium ion, calcium ion, magnesium ion,etc.・Cases of salt damage fn 3It has been said that areas where salt damage occurstrongly reflects the water permeability of the buildingmaterial.Photo 2-1 shows salt deposit concentrated in one area,causing damage on the brick surface. In photos 2-2 and 2-3,it can be seen that water accumulating in limited bricks orjoints due to higher water permeability, has induced saltdamage. In photo 2-4, what is supposedly salt of a cottonliketexture has appeared on the brick surface. On theplaster-finished interior walls, salts have formed on theplaster surface.83