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

? Freeze-thaw damage・Freeze-thaw damageFreeze-thaw damage occurs aswater enters the brick and freezes,expanding its volume causingcracks in the brick, when the watertemperature reaches below zerodegrees Celsius (photos 2-5, 2-6) fn 4 .water infiltrationphoto 2-5 Brick surface damaged by freeze-thaw damageCracks have formed in the brick due to freezing.photo 2-6 Brick floor with infiltration of undergroundwater Plant growth can be also observed due to the humidenvironment and lighting for visitors.・Environment prone to freezethawdamageBecause freeze-thaw damageoccurs when water temperaturein the brick reaches belowfreezing, this can be consideredto be a deterioration mechanismcharacteristic to colder climates.Through this survey, a case offreeze-thaw was confirmed inthe brick floor of the vehiclemaintenance pit at the engine shedof Former Temiya Railway Facilitiesin Hokkaido.Also on the exterior wall at FormerOfficial Residence for Foreigners inAni Mine in Akita Prefecture, brickswith delaminated surfaces possiblydue to cracks that formed throughfreeze-thaw were seen.cracksbelow freezingtemperaturefigure 2-2freezing ofmoistureFlow chart of freeze-thaw? Biological damageBiological damage is deterioration owing to the appearanceand growth of lichen, algae, moss, herbaceous plants, as wellas trees.This type of damage influenced by water supply andhabitat occurs when such vegetation appears and growson bricks and joint surfaces and their growing roots applyforce on the brick. The appearance of lichen and algae(photo 2-7) can lead to growth of herbaceous plants livingon such biological matter, which can then bring about evenmore harsh damage to bricks. This phenomenon is calledplant succession fn 5 , which can develop into salt damage orfreeze-thaw damage when water enters through the roots ofvegetation.The major damage lichen and algae can bring to brickwalls is soiling. Mosses do not only soil the walls, but alsomay damage the brick surface by the growth of rhizoids(roots) (photo 2-8). With herbaceous plants and ivies, theycan cause cracks in bricks and joints with growing roots(photo 2-9). Additionally, trees can cause large damage tonot only brick elements, but also the structural body.photo 2-7 Growth of lichen and algae in the brickjoints spoil the appearance aethetically.photo 2-8 Growth of moss in the brick joints. Theblack color on the wall is camouflage paint appliedduring the Second World War.photo 2-9 Flourishing of herbaceous plants from thebrick joints.84Chapter 6A Collection of Case Studies of Preservation and Restoration of Brick Masonry Structures