斜(xie)屋(wu)(wu)面(mian)作(zuo)为一种新型的建筑设(she)计形式,在(zai)施(shi)(shi)(shi)工(gong)(gong)(gong)技(ji)术上比(bi)平屋(wu)(wu)面(mian)有一定的技(ji)术难点,在(zai)施(shi)(shi)(shi)工(gong)(gong)(gong)过程(cheng)中,针对这(zhei)些(xie)技(ji)术难点,严格按施(shi)(shi)(shi)工(gong)(gong)(gong)规范的要(yao)求,做好施(shi)(shi)(shi)工(gong)(gong)(gong)技(ji)术方(fang)案,并在(zai)施(shi)(shi)(shi)工(gong)(gong)(gong)中认真加以实施(shi)(shi)(shi),就能高(gao)质量地完成(cheng)斜(xie)屋(wu)(wu)面(mian)工(gong)(gong)(gong)程(cheng)的施(shi)(shi)(shi)工(gong)(gong)(gong)。
①单(dan)面模(mo)板法
此(ci)法是坡屋面(mian)混凝(ning)土(tu)(tu)施(shi)(shi)工(gong)中较常用的(de)(de)(de)简易(yi)法,但影响(xiang)浇筑(zhu)质(zhi)量的(de)(de)(de)方(fang)面(mian)较多(duo),如(ru)屋面(mian)坡度(du)的(de)(de)(de)大小、模板的(de)(de)(de)光滑程度(du)和(he)(he)坍(tan)落度(du)的(de)(de)(de)影响(xiang)等。因混凝(ning)土(tu)(tu)无(wu)法按常规振(zhen)捣而导致不(bu)密实,须待(dai)混凝(ning)土(tu)(tu)处于(yu)初凝(ning)阶段再振(zhen)捣。此(ci)时混凝(ning)土(tu)(tu)的(de)(de)(de)可塑(su)性降低,再振(zhen)捣势必造成(cheng)混凝(ning)土(tu)(tu)的(de)(de)(de)内伤(shang)和(he)(he)裂纹。为(wei)此(ci),在施(shi)(shi)工(gong)中应采用一些(xie)措施(shi)(shi),如(ru)控制(zhi)混凝(ning)土(tu)(tu)坍(tan)落度(du)在30~50mm,利用焊接板筋做(zuo)抗滑移带和(he)(he)确定混凝(ning)土(tu)(tu)流(liu)向、分(fen)段施(shi)(shi)工(gong)等。为(wei)了保证板面(mian)的(de)(de)(de)平整(zheng)度(du),随(sui)捣随(sui)用1∶2.5水泥砂浆抹平。
②双面夹板法
屋面(mian)坡度要达到75°,必须采用双(shuang)面(mian)夹板(ban)法才能(neng)保证施工(gong)质量。施工(gong)需要用短钢筋作支架,并加设止(zhi)水(shui)片,以控制屋面(mian)厚(hou)度和(he)止(zhi)水(shui)、防渗。在两(liang)模板(ban)外侧面(mian)中(zhong)部设尺寸为400mm×400mm混凝(ning)土浇筑孔。
1、单(dan)面模板法
斜屋(wu)面(mian)(mian)(mian)混(hun)(hun)(hun)凝(ning)(ning)(ning)(ning)土在单面(mian)(mian)(mian)模板(ban)上施(shi)工(gong)(gong)主要靠(kao)混(hun)(hun)(hun)凝(ning)(ning)(ning)(ning)土自身的(de)(de)凝(ning)(ning)(ning)(ning)结力(li)、模板(ban)面(mian)(mian)(mian)的(de)(de)摩阻力(li)和钢筋网(wang)的(de)(de)张拉(la)阻力(li)的(de)(de)限制,至(zhi)混(hun)(hun)(hun)凝(ning)(ning)(ning)(ning)土硬化成型(xing)后不再沿(yan)斜面(mian)(mian)(mian)下滑。如(ru)果模板(ban)超过一定角度(du)后,在混(hun)(hun)(hun)凝(ning)(ning)(ning)(ning)土振捣时,模板(ban)对混(hun)(hun)(hun)凝(ning)(ning)(ning)(ning)土的(de)(de)摩阻力(li)不足以抵消混(hun)(hun)(hun)凝(ning)(ning)(ning)(ning)土顺模板(ban)面(mian)(mian)(mian)的(de)(de)下滑力(li)。混(hun)(hun)(hun)凝(ning)(ning)(ning)(ning)土初凝(ning)(ning)(ning)(ning)前,如(ru)缓慢位移持(chi)续发(fa)生,易导致混(hun)(hun)(hun)凝(ning)(ning)(ning)(ning)土不密实和内(nei)伤而渗漏。故建议当屋(wu)面(mian)(mian)(mian)的(de)(de)坡度(du)大于26°时,不宜采用单面(mian)(mian)(mian)模板(ban)法施(shi)工(gong)(gong)。
2、双面夹板法
双面(mian)(mian)模板(ban)法(fa)可(ke)以保证混(hun)凝土板(ban)达到(dao)内实外光的(de)(de)要(yao)求。但由于(yu)板(ban)的(de)(de)厚(hou)度(du)(du)小(xiao)(一般(ban)仅为100mm),除去钢(gang)筋和(he)保护(hu)层,中间间隙小(xiao)于(yu)50mm,若钢(gang)筋绑扎(zha)存在(zai)误差(cha),则振捣(dao)棒更难插入。因(yin)(yin)(yin)此(ci)施工(gong)中必(bi)须注意防止(zhi)钢(gang)筋位(wei)移及因(yin)(yin)(yin)混(hun)凝土浇(jiao)筑不到(dao)位(wei)而(er)造(zao)成(cheng)的(de)(de)蜂窝。因(yin)(yin)(yin)无法(fa)观察到(dao)模板(ban)内混(hun)凝土的(de)(de)饱满度(du)(du),可(ke)敲击进行听(ting)音检(jian)查,并在(zai)板(ban)底采用(yong)(yong)附着(zhe)式振捣(dao)器,使混(hun)凝土下(xia)淌充(chong)实。振捣(dao)时,采用(yong)(yong)直径33mm的(de)(de)小(xiao)振动(dong)棒,按(an)序插振,防止(zhi)漏(lou)插。对(dui)于(yu)死角(jiao)部位(wei)可(ke)以采用(yong)(yong)板(ban)外振与(yu)人(ren)工(gong)插钎相(xiang)结(jie)合。对(dui)于(yu)此(ci)法(fa)施工(gong),应严格控制混(hun)凝土的(de)(de)坍(tan)落度(du)(du),具体根据施工(gong)时的(de)(de)温度(du)(du)确定,一般(ban)控制在(zai)50~70mm。为保证层面(mian)(mian)的(de)(de)结(jie)构安全和(he)防水效果,对(dui)坡度(du)(du)大的(de)(de)斜屋面(mian)(mian),应优(you)先选用(yong)(yong)双面(mian)(mian)夹板(ban)法(fa)。
根(gen)据(ju)现(xian)行的(de)设计规范,现(xian)浇屋面板面的(de)混(hun)凝(ning)土(tu)(tu)(tu)要具有(you)一定的(de)抗(kang)渗要求,一般选用抗(kang)渗混(hun)凝(ning)土(tu)(tu)(tu),为(wei)(wei)确保混(hun)凝(ning)土(tu)(tu)(tu)拌制(zhi)质(zhi)量,对骨料的(de)要求应更(geng)为(wei)(wei)严(yan)(yan)格,砂子应为(wei)(wei)中砂且含(han)泥量不得(de)超过5%,碎石粒径以5~30mm为(wei)(wei)宜且含(han)泥量不得(de)大(da)于2%,骨料级(ji)配(pei)要合理,以增加混(hun)凝(ning)土(tu)(tu)(tu)的(de)和易性(xing)。根(gen)据(ju)施(shi)工经验,要严(yan)(yan)格控制(zhi)混(hun)凝(ning)土(tu)(tu)(tu)的(de)水灰比,混(hun)凝(ning)土(tu)(tu)(tu)的(de)坍落(luo)度以10~15cm左右为(wei)(wei)宜。
斜屋面尤其(qi)是陡斜屋面的(de)(de)混(hun)(hun)凝(ning)(ning)土(tu)(tu)浇筑,大(da)(da)的(de)(de)问(wen)题是混(hun)(hun)凝(ning)(ning)土(tu)(tu)滑动流淌造(zao)成局部(bu)离析(xi)(xi)而发(fa)生混(hun)(hun)凝(ning)(ning)土(tu)(tu)的(de)(de)质量问(wen)题,浇筑时混(hun)(hun)凝(ning)(ning)土(tu)(tu)倾落高(gao)度不(bu)大(da)(da)于600mm,因此不(bu)能(neng)从跳板上直接从高(gao)处(chu)向下倾倒混(hun)(hun)凝(ning)(ning)土(tu)(tu),混(hun)(hun)凝(ning)(ning)土(tu)(tu)浇筑时增加板面作业工(gong)人,特别在屋面低处(chu)浇筑混(hun)(hun)凝(ning)(ning)土(tu)(tu)时,建(jian)议全部(bu)用小(xiao)桶(tong)水平(ping)运输(shu)混(hun)(hun)凝(ning)(ning)土(tu)(tu)(禁(jin)止用斗车(che)),一小(xiao)桶(tong)一小(xiao)桶(tong)平(ping)铺,这(zhei)样可避(bi)免作业工(gong)人施(shi)工(gong)中贪图(tu)容易,盲目(mu)倾倒混(hun)(hun)凝(ning)(ning)土(tu)(tu),造(zao)成混(hun)(hun)凝(ning)(ning)土(tu)(tu)离析(xi)(xi)。
混凝土(tu)浇筑(zhu)(zhu)时(shi)(shi)应(ying)从屋面两头低处同(tong)时(shi)(shi)开(kai)始(shi),两面坡面同(tong)时(shi)(shi)浇注为佳,混凝土(tu)的浇筑(zhu)(zhu)应(ying)连续施(shi)工(gong)(gong)不留(liu)置施(shi)工(gong)(gong)缝(feng)(feng)。如特(te)殊情况必须留(liu)置施(shi)工(gong)(gong)缝(feng)(feng)时(shi)(shi),施(shi)工(gong)(gong)缝(feng)(feng)的位置应(ying)在结构受力较(jiao)小处,一(yi)般距现浇板(ban)支座(zuo)1m,不可在现浇板(ban)中心部(bu)位置留(liu)置施(shi)工(gong)(gong)缝(feng)(feng)。
斜屋面(mian)(mian)的(de)混(hun)凝(ning)土振(zhen)(zhen)捣(dao)密实一直是(shi)一个施工(gong)难(nan)题,为控制(zhi)(zhi)板的(de)浇(jiao)筑厚(hou)(hou)度(du),应在板面(mian)(mian)按(an)1000mm×1000mm均(jun)(jun)匀(yun)布(bu)置厚(hou)(hou)度(du)控制(zhi)(zhi)点。根据经验(yan)认(ren)为,对于梁的(de)振(zhen)(zhen)捣(dao)要(yao)特别注意(yi)插式振(zhen)(zhen)动(dong)器振(zhen)(zhen)捣(dao)在各区段均(jun)(jun)匀(yun),振(zhen)(zhen)捣(dao)时间(jian)过(guo)(guo)长易造(zao)成(cheng)(cheng)局部粗(cu)骨料集(ji)中,砂(sha)浆(jiang)与粗(cu)骨料分离。对于板面(mian)(mian)混(hun)凝(ning)土,振(zhen)(zhen)捣(dao)过(guo)(guo)多(duo)混(hun)凝(ning)土易流(liu)动(dong),造(zao)成(cheng)(cheng)板面(mian)(mian)平(ping)整度(du)难(nan)以控制(zhi)(zhi),一般做法是(shi)在施工(gong)中先用(yong)人(ren)工(gong)均(jun)(jun)匀(yun)摊(tan)铺混(hun)凝(ning)土,注意(yi)混(hun)凝(ning)土厚(hou)(hou)度(du)应足(zu)够,用(yong)抹子拍实,待(dai)混(hun)凝(ning)土接近初凝(ning)时用(yong)平(ping)板振(zhen)(zhen)动(dong)器按(an)板块的(de)浇(jiao)筑顺序均(jun)(jun)匀(yun)走二遍(bian),接槎处则应多(duo)走一遍(bian)即可,板面(mian)(mian)振(zhen)(zhen)捣(dao)后(hou)再用(yong)人(ren)工(gong)对局部不(bu)平(ping)整及板厚(hou)(hou)度(du)不(bu)足(zu)的(de)板面(mian)(mian)进行修整,然后(hou)用(yong)水泥砂(sha)浆(jiang)对板面(mian)(mian)混(hun)凝(ning)土表面(mian)(mian)修整,以取得良好(hao)的(de)表面(mian)(mian)观感。
混凝土(tu)浇(jiao)筑完成(cheng)后要做(zuo)好(hao)浇(jiao)水(shui)养(yang)护(hu),由于夏季气(qi)温(wen)高,水(shui)份(fen)蒸发(fa)量(liang)大,斜屋(wu)面浇(jiao)水(shui)养(yang)护(hu)效果差,因此夏季施工后应强调使用草袋覆(fu)盖养(yang)护(hu)为佳,以防止混凝土(tu)因暴晒而碳化和缩水(shui)龟(gui)裂,浇(jiao)水(shui)湿润(run)养(yang)护(hu)不得(de)少于14d。
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