混凝土砼外觀質量處理方法
發布時間:2014-07-12
0 前 言
bulunxianchangguanlishuipingruhe,tongdeshigongdoubukenengzaifeichanglixiangdetiaojianxiajinxingwangwanghuiyouyuzhongzhongyuanyin,huozheshijiegouxingshideteshu,huozheshiqihoutiaojiandeelie,huozheshishigongfangfa、
施工工藝的不規範等等,一般情況下,很容易在砼的澆築過程中或剛剛施工完不久產生表麵缺陷。砼的表麵缺陷大致可以歸納為如下四個方麵:
1、表麵裂縫;
2、表麵破損;
3、表麵顏色不均勻;
4、表麵漏筋;
不bu管guan是shi哪na一yi種zhong表biao麵mian缺que陷xian,都dou會hui對dui砼tong的de外wai觀guan質zhi量liang帶dai來lai不bu利li的de影ying響xiang。所suo以yi,找zhao到dao砼tong產chan生sheng表biao麵mian缺que陷xian的de內nei因yin,在zai施shi工gong中zhong有you針zhen對dui性xing的de采cai取qu預yu防fang措cuo施shi,對dui既ji有you的de缺que陷xian加jia以yi必bi要yao的de修xiu複fu處chu理li,以yi提ti高gao砼tong的de外wai觀guan質zhi量liang。
1 砼土表麵裂縫
砼tong表biao麵mian的de裂lie縫feng大da都dou是shi因yin為wei收shou縮suo而er產chan生sheng的de,主zhu要yao有you兩liang大da類lei,一yi類lei是shi剛gang剛gang澆jiao築zhu完wan成cheng的de砼tong表biao麵mian水shui分fen蒸zheng發fa變bian幹gan而er引yin起qi,另ling一yi類lei是shi因yin為wei砼tong硬ying化hua時shi水shui化hua熱re使shi砼tong產chan生sheng內nei外wai溫wen差cha而er引yin起qi。
剛gang剛gang澆jiao築zhu完wan成cheng的de砼tong,往wang往wang因yin為wei外wai界jie氣qi溫wen較jiao高gao,空kong氣qi中zhong相xiang對dui濕shi度du較jiao小xiao,表biao麵mian蒸zheng發fa變bian幹gan,而er其qi內nei部bu仍reng是shi塑su性xing體ti,因yin塑su性xing收shou縮suo產chan生sheng裂lie縫feng。這zhe類lei裂lie縫feng通tong常chang不bu連lian續xu,且qie很hen少shao發fa展zhan到dao邊bian緣yuan,一yi般ban呈cheng對dui角jiao斜xie線xian狀zhuang,長chang度du不bu超chao過guo30cm,但(dan)較(jiao)嚴(yan)重(zhong)時(shi),裂(lie)縫(feng)之(zhi)間(jian)也(ye)會(hui)相(xiang)互(hu)貫(guan)通(tong)。對(dui)這(zhe)類(lei)裂(lie)縫(feng)最(zui)有(you)效(xiao)的(de)預(yu)防(fang)措(cuo)施(shi)是(shi)在(zai)砼(tong)澆(jiao)築(zhu)時(shi)保(bao)護(hu)好(hao)砼(tong)澆(jiao)築(zhu)麵(mian),避(bi)免(mian)風(feng)吹(chui)日(ri)曬(shai),砼(tong)澆(jiao)築(zhu)完(wan)畢(bi)後(hou)要(yao)立(li)即(ji)將(jiang)表(biao)麵(mian)加(jia)以(yi)覆(fu)蓋(gai),並(bing)及(ji)時(shi)灑(sa)水(shui)養(yang)生(sheng)。另(ling)外(wai),在(zai)砼(tong)中(zhong)摻(chan)加(jia)適(shi)量(liang)的(de)引(yin)氣(qi)劑(ji)也(ye)有(you)助(zhu)於(yu)減(jian)少(shao)收(shou)縮(suo)裂(lie)縫(feng)。
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砼(tong)在(zai)硬(ying)化(hua)過(guo)程(cheng)中(zhong),會(hui)釋(shi)放(fang)大(da)量(liang)的(de)水(shui)化(hua)熱(re),使(shi)砼(tong)內(nei)部(bu)溫(wen)度(du)不(bu)斷(duan)上(shang)升(sheng),在(zai)大(da)體(ti)積(ji)砼(tong)中(zhong),水(shui)化(hua)熱(re)使(shi)溫(wen)度(du)上(shang)升(sheng)更(geng)加(jia)明(ming)顯(xian),在(zai)砼(tong)表(biao)麵(mian)與(yu)內(nei)部(bu)之(zhi)間(jian)形(xing)成(cheng)很(hen)高(gao)的(de)溫(wen)度(du)差(cha),特(te)別(bie)是(shi)在(zai)特(te)大(da)橋(qiao)大(da)體(ti)積(ji)承(cheng)台(tai)施(shi)工(gong)中(zhong),現(xian)場(chang)實(shi)測(ce)砼(tong)內(nei)外(wai)溫(wen)差(cha)有(you)時(shi)會(hui)達(da)到(dao)50℃yishang。biaocengtongshousuoshishoudaozuai,tongjiangshoula,yidanchaoguotongdeyingbiannengli,jiangchanshengliefeng。weilejinkenengjianshaoshousuoyueshuyishitongnengyouzugouqiangdudikangsuoyinqideyingli,jiubixuyouxiaokongzhitongneibushengwensulv。zaitongzhongchanjiashiliangdekuangfenmeihui,nengshishuihuareshifangsudujianhuan;控製原材料的溫度,在砼結構內部采用冷卻管通以循環水也能及時釋放水化熱能。
值得特別一提的是不同品牌水泥的混用也會使砼產生裂縫。不同品牌的水泥,其細度、強度、初終凝時間、安定性、化學成分等不盡相同,且還存在相容性問題。在砼施工時,應該嚴禁不同品牌、不同標號的水泥混在一起使用。
堿骨料反應也會使砼產生開裂。由於矽酸鹽水泥中含有堿性金屬成份(鈉和鉀),因yin此ci,砼tong內nei孔kong隙xi的de液ye體ti中zhong氫qing氧yang根gen離li子zi的de含han量liang較jiao高gao,這zhe種zhong高gao堿jian溶rong液ye能neng和he某mou些xie骨gu料liao中zhong的de活huo性xing二er氧yang化hua矽gui發fa生sheng反fan應ying,生sheng成cheng堿jian矽gui膠jiao,堿jian矽gui膠jiao吸xi水shui水shui分fen膨peng脹zhang後hou產chan生sheng的de膨peng脹zhang力li使shi砼tong開kai裂lie。
對於淺層裂縫的修補,通常是塗刷水泥漿或低粘度聚合物封堵,以防止水份侵入;對於較深或較寬的裂縫,就必須采用壓力灌漿技術進行修補。
2 砼表麵破損
砼表麵破損包括:表麵峰窩、表麵麻麵、表麵氣孔、表麵衝蝕等,至於表麵蜂窩,純粹是因為振搗不到位所至,在施工中隻要增強責任心就能避免,在這裏我主要就表麵麻麵、氣孔、衝蝕談幾點看法。
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砼表麵的氣孔主要是模板表麵攜帶的水、氣泡引起的。如果模板表麵有一定吸附性或透氣性的話(如采用木製模板),氣孔可以減少;ruocaiyongkangshentouxingqiangdegangmoban,zeqikongyibandoushiyinweizhendaobuchongfensuozhi。jishizhendaochongfen,yehaihuiyouqikong,tebieshizaitongdeshangcengbiaomianhuomobanxiangneiqingxiedeqingkuangxia,qikonghennanbimian。lingwai,suoshiyongdetuomojihetongpeihebiduichanshengqikongyeyouhendadeyingxiang,yibanqingkuangxia,zhanxingdadetongbizhanxingxiaodegengrongyichanshengqikong。
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砼tong表biao麵mian產chan生sheng魚yu鱗lin斑ban也ye可ke以yi歸gui結jie為wei表biao麵mian的de衝chong蝕shi破po壞huai,這zhe往wang往wang同tong模mo板ban的de剛gang度du有you關guan係xi。當dang模mo板ban的de剛gang度du不bu足zu,砼tong結jie構gou物wu的de澆jiao築zhu高gao度du又you較jiao大da,在zai澆jiao築zhu上shang層ceng砼tong時shi,模mo板ban受shou到dao極ji限xian側ce壓ya力li,整zheng體ti微wei量liang位wei移yi,在zai模mo板ban與yu砼tong的de接jie壤rang處chu產chan生sheng空kong隙xi,而er這zhe時shi下xia層ceng砼tong還hai處chu於yu流liu塑su狀zhuang態tai,水shui沿yan著zhe模mo板ban與yu砼tong間jian的de空kong隙xi滲shen流liu,導dao致zhi脫tuo模mo後hou出chu現xian魚yu鱗lin狀zhuang的de斑ban紋wen。
砼(tong)的(de)這(zhe)種(zhong)缺(que)陷(xian)修(xiu)補(bu)時(shi),為(wei)了(le)獲(huo)得(de)可(ke)以(yi)接(jie)受(shou)的(de)砼(tong)表(biao)麵(mian)顏(yan)色(se),可(ke)以(yi)通(tong)過(guo)試(shi)驗(yan)之(zhi)後(hou),把(ba)白(bai)水(shui)泥(ni)與(yu)灰(hui)色(se)普(pu)通(tong)水(shui)泥(ni)按(an)一(yi)定(ding)比(bi)例(li)混(hun)在(zai)一(yi)起(qi)使(shi)用(yong),砂(sha)子(zi)應(ying)使(shi)用(yong)篩(shai)除(chu)了(le)粗(cu)顆(ke)粒(li)的(de)細(xi)砂(sha),砂(sha)漿(jiang)中(zhong)要(yao)摻(chan)用(yong)聚(ju)合(he)物(wu)(比如環氧樹脂、白乳膠等),用砂漿塊或光滑的石板抹麵以獲得光滑的表麵。
3 砼表麵顏色不均勻
施工中想要砼表麵顏色完全一致幾乎是不可能的,許多因素都會引起砼表麵顏色發生變化,比如原材料的種類、施工配合比、砼的養護條件、砼的振搗情況、脫模劑的使用情況、模板的表麵結構、模板的吸附性能等,還有拆模時人為造成的顏色變化,都會給人的感官上帶來不悅。
決定砼顏色的原材料主要是水泥或摻加的礦粉、粉fen煤mei灰hui等deng粘zhan結jie料liao,一yi旦dan粘zhan結jie料liao的de品pin種zhong或huo粘zhan結jie料liao的de用yong量liang發fa生sheng變bian化hua,都dou會hui導dao致zhi砼tong顏yan色se發fa生sheng改gai變bian。當dang砼tong和he易yi性xing欠qian佳jia,或huo在zai下xia料liao過guo程cheng中zhong砼tong粗cu細xi骨gu料liao發fa生sheng離li析xi,或huo振zhen搗dao不bu均jun勻yun等deng,導dao致zhi某mou些xie部bu位wei粗cu骨gu料liao集ji中zhong,某mou些xie部bu位wei砂sha漿jiang過guo於yu豐feng富fu,待dai砼tong硬ying化hua後hou顏yan色se不bu一yi致zhi。
砼表麵的鏽跡也是常見影響砼顏色的一個因素,鏽跡的產生有四種可能:第一種可能是由於含有黃鐵礦(硫化鐵)的骨料引起的,骨料中的黃鐵礦與空氣接觸後會發生氧化發應生成鐵鏽;第二種可能是從砼結構中伸出鋼筋(比如模板拉杆鋼筋、砼表麵漏筋)以及紮鋼筋用的鐵絲,暴露在外麵一段時間後也會產生鏽跡;第三種可能是由於模板表麵本身產生了鏽跡;第四種可能是由於砼結構上表麵露出的鋼筋長時間暴露在空氣中產生的鐵鏽隨雨水或養護水順砼表麵流下時,汙染了砼麵而產生鏽跡。
在zai拆chai模mo時shi,由you於yu一yi些xie人ren為wei的de因yin素su也ye會hui導dao致zhi砼tong表biao麵mian顏yan色se發fa生sheng變bian化hua。特te別bie是shi氧yang焊han氣qi割ge用yong的de氧yang炔que焰yan,其qi溫wen度du很hen高gao,施shi工gong中zhong往wang往wang由you於yu操cao作zuo不bu當dang將jiang氧yang炔que焰yan對dui著zhe砼tong麵mian熏xun烤kao,破po壞huai了le砼tong表biao麵mian原yuan有you的de顏yan色se。
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4 砼表麵露筋
砼tong表biao麵mian露lu筋jin主zhu要yao是shi因yin為wei鋼gang筋jin綁bang紮zha不bu牢lao,或huo保bao護hu層ceng墊dian塊kuai安an置zhi不bu規gui範fan,在zai砼tong澆jiao築zhu過guo程cheng中zhong鋼gang筋jin移yi位wei,有you時shi候hou是shi在zai砼tong澆jiao築zhu完wan成cheng後hou才cai發fa現xian鋼gang筋jin位wei置zhi放fang得de不bu對dui,致zhi使shi砼tong表biao麵mian至zhi少shao一yi個ge麵mian的de鋼gang筋jin保bao護hu層ceng厚hou度du不bu夠gou,甚shen至zhi完wan全quan沒mei有you了le保bao護hu層ceng。
表麵露筋的另一個方麵是因為砼漏振導致嚴重蜂窩,鋼筋暴露在外。
避免表麵露筋的有效措施是使用具有高度責任感的操作工人,提高操作人員的質量意識,加強監控力度,保證鋼筋布位準確、綁紮牢靠,保護層墊塊安置穩固,在砼振搗中操作細致。
如果出現表麵露筋,首先應分析露筋的原因和嚴重程度,再考慮修補所需要達到的目的,修補後不得影響砼結構的強度和正常使用。
露筋的修補一般都是先用鋸切槽,劃定需要處
理(li)的(de)範(fan)圍(wei),形(xing)成(cheng)整(zheng)齊(qi)而(er)規(gui)則(ze)的(de)邊(bian)緣(yuan),再(zai)用(yong)衝(chong)擊(ji)工(gong)具(ju)對(dui)處(chu)理(li)範(fan)圍(wei)內(nei)的(de)疏(shu)鬆(song)砼(tong)進(jin)行(xing)清(qing)除(chu)。如(ru)果(guo)鋼(gang)筋(jin)保(bao)護(hu)層(ceng)厚(hou)度(du)不(bu)夠(gou),必(bi)須(xu)要(yao)將(jiang)鋼(gang)筋(jin)向(xiang)裏(li)移(yi)動(dong)。準(zhun)備(bei)工(gong)作(zuo)做(zuo)完(wan)後(hou),可(ke)以(yi)采(cai)用(yong)噴(pen)射(she)砼(tong)工(gong)藝(yi)或(huo)壓(ya)力(li)灌(guan)漿(jiang)技(ji)術(shu)進(jin)行(xing)修(xiu)補(bu)。
5 結 語
砼(tong)的(de)外(wai)觀(guan)質(zhi)量(liang)問(wen)題(ti)還(hai)有(you)很(hen)多(duo)方(fang)麵(mian),比(bi)如(ru)因(yin)模(mo)板(ban)剛(gang)度(du)不(bu)足(zu)引(yin)起(qi)砼(tong)表(biao)麵(mian)鼓(gu)脹(zhang),因(yin)模(mo)板(ban)精(jing)度(du)不(bu)夠(gou)引(yin)起(qi)砼(tong)接(jie)縫(feng)處(chu)錯(cuo)牙(ya)等(deng)等(deng)不(bu)一(yi)而(er)足(zu)。我(wo)相(xiang)信(xin),在(zai)全(quan)體(ti)工(gong)程(cheng)技(ji)術(shu)人(ren)員(yuan)與(yu)施(shi)工(gong)操(cao)作(zuo)者(zhe)共(gong)同(tong)努(nu)力(li)下(xia),砼(tong)的(de)外(wai)觀(guan)質(zhi)量(liang)會(hui)進(jin)一(yi)步(bu)得(de)到(dao)提(ti)高(gao)。