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天然石材以其天然稳重.颜色壮丽及较好的抗风化稳采取于建造物的室内.外墙面装璜极大地凸起了建造的艺术后果.天然石材的装配施工有干挂法和湿贴法个中湿贴法具有施工轻便造你较底的长处,但也比较轻易产生一些质量通病凸起的二点等于石材概况泛碱现象,产生泛碱后的墙面“水印”斑斑,去之无效,拆之亦难,极大地损坏了建造装璜后果.广州近年建成的一些标记性公共建造.广场建造湿贴花岗岩有泛碱和析白流挂白胡子现象,有些甚至十分轻微,给这一建造造成无可挽回的损掉和圆满.为此剖析泛碱成因和作响应的预防措施具有重要意义.
一、泛碱现象AlkalizationEfflorescence湿贴天然石墙面在装配时代,石材板块会消失似“水印”一样的斑块,跟着镶贴砂浆的硬化和湿润,“水印”会稍微缩小,甚至有些消掉其孤立.疏散地出如今板块中,室内程度不轻微影响外不雅不大.但是跟着时光推移,特殊是外墙重复遭受雨水或者潮湿气象,水从板缝.墙根等部位侵入天然石的水斑逐渐变大并在板缝连成片,板块局部加深.光泽阴暗.板缝并发析出白色的结晶体长年不褪轻微影响外不雅此种现象称为泛碱现象.二原因剖析Analysis.天然石材结晶相对较粗,消失不少肉眼看不到的毛细管,花岗岩细孔率为
0.5~
1.5队大理石细孔率为
0.5~
2.0%其抗渗机能不如通俗水泥砂浆,花岗岩的吸水率
0.2〜
1.7%是较低的,水仍可由经由过程石材中的毛细管浸入面传到别的一面.天然石材的这种特征及毛细孔的消失,为粘接资估中的水.碱.盐等物资的渗入和析出并形成泛碱供给了通道.NaturalStonecrystalisrelativelythicktherearemanynakedeyecannotseethecapillarygraniteporerateof
0.
51.5%marbleporerateof
0.5〜
2.0%itsimpermeabilityislowerthanordinarycementmortarfgranitewaterabsorptionisaslowas
0.
21.7%watercanstillbethroughthestonefromthesurfaceofthecapillaryimmersion工㊀ach㊀dtheotherside.Thisnaturalstonefeaturesandthepresenceoftheporesforthebondingmateria1inthewateralkalisaltandtheinfiltrationofsubstancessuchasprecipitationprovidesthechannelforth㊀formingoftheAlkalization.
2.粘结材料产生含碱.盐等成份物资.重要为镶贴砂浆析出CaOH2氢氧化钙并追随过剩的拌合水,沿石材的毛细孔游离入侵板块,拌合水越多,挪移到砂浆概况的Ca0H2就越多,水分蒸发后Ca0H2就存积在板块里.其他,如在水泥中添加了含有钠Na+的外加剂黏土砖泥土含有的Na+.Mg2+.K+.Ca2+.Cl-So42-.C032-等遇水消融,会渗入渗出到石材毛细孔里,形成“白华”等现象.粘结材料产生的含碱.盐等成份物资是渗入石材毛细孔产生泛碱的直接物资起源.Bondedmaterialsproducedalkalisaltandotheringreclientsmaterial.PrecipitationismainlyXiangtiemortarCaOH2calciumhydroxideandfollowtheexcessmixingwaterintrusionalongthestone1sporesfreeplateAmixingmorewaterAmovetothemortarsurfaceofCaOH2moreandmoremoistureevaporatedCaOH2onthedepositaccumulatedontheplateinside.OthersrsuchasaddingcementadmixturescontainingsodiumNa+claysoilcontainsNa+Mg2+K+Ca2+C1-So42-,C032-,etc.dissolvedwithwaterAwillpenetrateintothestoneinsidetheporestoformawhitishsurfaceandsoonBondingmaterialsarethesourcematerialforalkalisaltandotheringredientstoformalkalization.
3.水的渗入.因为外墙接缝用水泥细砂砂浆勾缝,令防水后果差;地面水或者潮湿沿墙体或者砂浆层侵入石材板;装配时对石材洒水过多等原因,使水入侵石材板,并溶入Ca0H2和其他盐类物资进入石材毛细管形成泛碱.可见,水是泛碱物资的溶剂和载体.
3.Waterinfiltration.Astheouterwalljointismadewithcementsandmortarresultingpoorwaterproof;surfacewaterorwetlayerofmortaralongthewallorinvasivestoneplate;installingthestonewateringtoomuchandotherreasonssothatthewaterintrusionstonepanelsandintegrationintotheCaOH2andothersaltsintothestonebycapillaryformationofpan-alkali.Thisprovesthatwateristhealkalizationsolventandcarrier.泛碱产生道理.Theory
二、预防措施Precautionmeasures针对泛碱现象的成因,可以响应从割断泛碱的门路,削减CaOH
2.盐类等生成物及削减水的侵入三方面采用措施进行预防.一施工前豫备.设计上斟酌清除泛碱尽可能设计成干挂情势;斟酌好构造的防水处理;选择吸水率及其他物理机能相符请求的石材板等..施工前要充分斟酌可能产生泛碱的各施工工艺环节提前作好预防措施如无掌控应先做样板..有关材料应先磨练后应用,不单请求外不雅尺寸及格,并且其物理机能指标也要及格.Apre-constructionpr㊀paration
1.Usedesign“toeliminatethealkalizationasfaraspossibledesignedtodryhangingform;consideredgoodwaterproofingtreatmentchoosewaterabsorptionandotherstonepan㊀IswithphysicalpropertiesthatmeettherequirementsThematerialshouldbetestedbeforeusingandtheapp㊀arancesizequalifiedandtheirphysicalperformanceshouldalsobequalified.二应用防碱背涂剂.石板装配前在石材不和和正面背涂专用途理剂,该溶剂将渗入石材阻塞毛细管,使水.CaOH
2.盐等其他物资无法侵入,割断了泛碱现象的门路.无背涂处理,泛碱不成防止,经背涂处理的石材的粘接性不受影响..在石材板底涂刷树脂胶,再贴化纤丝网格布,形成抗拉防水层但切不成淡忘在正面作涂刷处理.Bth㊀useofanti-alkali-coatingPaint.SlatestonebeforeinstallationinthebackandsidebackTu-specifictreatmentagentthesolventwouldpenetratestoneplugthecapillarysothatthewaterCaOH2saltandothersubstancescannotbepenetratedcutoffthewaythephenomenonofalkalization.Ifthereisnobasecoatingprocessingalkalizationisinevitabletheadhesionisnotaffectedbyapplyingthebasecoating..Applyresinglueonthebaseofthestonepanelandpastewithfibermeshtoformwaterprooflayer.Donotforgettoapplythesidewiththesametreatment.三削减CaOH
2.盐等物资生成.镶贴用的水泥砂浆宜掺入削减剂,以削减Ca0H2析此粘贴法砂浆稠度宜为6~8cm灌浆法砂浆稠度宜为8〜12cm..室外镶贴可采取水泥基商品胶粘剂干混料,它具有优越的保水性,能大大减轻水泥凝结泌水.室内镶贴可采取石材化学胶粘剂点粘.CreductionofCaOH2saltandothersubstancesgenerated.XiangtieusedformixingcementmortarshouldreducethedosetoreducetheCaOH2precipitationandpasteFrancemortarconsistencymightbedesirablefor6〜8cmgroutingmortarconsistencymightbedesirablefor8〜12cm..Cement-basedproductscanbeusedoutdoorsXiangtieadhesivedrymixturewhichhasgoodwaterretentioncangreatlyr㊀due㊀concl㊀nsationBleedingofcement.StonecanbeusedindoorsXiangtiechemicaladhesivestickypoint.四防止水的侵入
1.功课前不成大量对石材和墙面淋水.2•地面墙根下应设置防潮层.洗手间.浴室等用水房间的外壁若有石材装璜,其内壁应需作防渗处理..外墙石材装璜面,为防止从板缝侵入,墙面板块必须离缝镶贴缝宽不该小于5nlm,应用石材专用硅碉耐候密封胶密封..室外施工搭设防雨蓬处理好门窗框周边与外墙的接缝,防止雨水渗漏入墙..镶贴完成后,室外石材周全积喷涂有机硅防水剂或者其他无色护面涂剂.DtopreventwaterintrusionDonotspraytoomuchwateronth㊀ston㊀andthewall.Dampproofmembraneshouldbeinstalledonthewallinthewashroom.Thewallshouldbetreatedwithwaterproofingmaterials.ForoutdoorstonewallsinordertopreventwaterintrusionfromthejointthewallplatetobeawayfromtheseamXiangti㊀,Jointshouldnotb㊀lessthan5mmtheuseofstonespecialsiliconesealant.Outdoorconstructionneedsatemporarycanopytopreventrainseffectduringconstruction.Awningwindowframesaroundthedoorhandleandtheexteriorjointstopreventrainwaterleakingintothewall.Spraythewholewallsurfacewithwaterrepellent.四.管理方法天然石材墙面一旦消失泛碱现象,因为可溶性碱(或者盐)物资已沿毛细孔渗入渗出到石材里面(渗出石板概况的可以清除),很难清除,故应侧重预防,泛碱产生后只可作以下拯救..尽快对墙体.板缝.板面等周全进行防水处理,防止水分持续入侵使泛碱再也不扩展..可应用市情上的石材泛碱清洗剂,该清洗剂是由非离子型的概况活性剂及溶剂等制成的无色半透明液体对于部份天然石材概况泛碱的清洗有必然的后果.但是在应用前,必然要先作小样试块,以磨练后果和决议是否采取.总之,清除湿贴天然石墙面泛碱重在预防,只要探明其产生的根起源基础因,而在设计.材料.施工各环节中严厉把关,科学防治,就完整可防止泛碱现象的产生,使天然石材这种古老的建造材料为现代建造再放光荣.。