斜屋(wu)面(mian)作为一(yi)种新型的(de)建筑设计形式,在施工(gong)(gong)技(ji)术(shu)上比平屋(wu)面(mian)有一(yi)定的(de)技(ji)术(shu)难(nan)点,在施工(gong)(gong)过(guo)程(cheng)中(zhong),针对这些技(ji)术(shu)难(nan)点,严格按施工(gong)(gong)规(gui)范的(de)要求,做好(hao)施工(gong)(gong)技(ji)术(shu)方案,并在施工(gong)(gong)中(zhong)认(ren)真加以实施,就(jiu)能高质量(liang)地完成斜屋(wu)面(mian)工(gong)(gong)程(cheng)的(de)施工(gong)(gong)。
①单面模板(ban)法
此法(fa)(fa)是坡(po)屋面混(hun)(hun)(hun)凝(ning)(ning)土施(shi)工(gong)中较(jiao)常用(yong)的(de)(de)简易法(fa)(fa),但影响浇筑质量的(de)(de)方面较(jiao)多,如屋面坡(po)度(du)的(de)(de)大小、模板(ban)(ban)的(de)(de)光滑(hua)程度(du)和(he)(he)坍落度(du)的(de)(de)影响等。因混(hun)(hun)(hun)凝(ning)(ning)土无法(fa)(fa)按常规振(zhen)捣(dao)而导(dao)致不密实(shi),须待混(hun)(hun)(hun)凝(ning)(ning)土处于初凝(ning)(ning)阶(jie)段再振(zhen)捣(dao)。此时混(hun)(hun)(hun)凝(ning)(ning)土的(de)(de)可塑性降低(di),再振(zhen)捣(dao)势必造成混(hun)(hun)(hun)凝(ning)(ning)土的(de)(de)内(nei)伤和(he)(he)裂纹(wen)。为此,在施(shi)工(gong)中应采用(yong)一些(xie)措施(shi),如控制(zhi)混(hun)(hun)(hun)凝(ning)(ning)土坍落度(du)在30~50mm,利用(yong)焊接板(ban)(ban)筋做(zuo)抗滑(hua)移带和(he)(he)确定(ding)混(hun)(hun)(hun)凝(ning)(ning)土流向、分段施(shi)工(gong)等。为了保(bao)证板(ban)(ban)面的(de)(de)平(ping)整度(du),随捣(dao)随用(yong)1∶2.5水泥砂(sha)浆抹平(ping)。
②双面夹板法
屋面(mian)坡度(du)要达到(dao)75°,必须采用(yong)双面(mian)夹板(ban)法(fa)才能保证施工质量。施工需要用(yong)短钢筋(jin)作支(zhi)架(jia),并加设止(zhi)水片,以控制屋面(mian)厚度(du)和止(zhi)水、防(fang)渗。在两模板(ban)外侧面(mian)中部设尺寸为400mm×400mm混凝土浇筑(zhu)孔。
1、单面(mian)模板法
斜屋面(mian)(mian)(mian)混(hun)(hun)(hun)(hun)凝(ning)(ning)(ning)土(tu)(tu)在单面(mian)(mian)(mian)模(mo)板(ban)(ban)(ban)上施工主(zhu)要靠混(hun)(hun)(hun)(hun)凝(ning)(ning)(ning)土(tu)(tu)自身(shen)的(de)凝(ning)(ning)(ning)结(jie)力(li)(li)、模(mo)板(ban)(ban)(ban)面(mian)(mian)(mian)的(de)摩阻(zu)力(li)(li)和(he)钢筋网的(de)张拉阻(zu)力(li)(li)的(de)限(xian)制,至(zhi)混(hun)(hun)(hun)(hun)凝(ning)(ning)(ning)土(tu)(tu)硬化(hua)成型后不再沿斜面(mian)(mian)(mian)下(xia)(xia)滑。如果模(mo)板(ban)(ban)(ban)超(chao)过(guo)一定角(jiao)度后,在混(hun)(hun)(hun)(hun)凝(ning)(ning)(ning)土(tu)(tu)振捣(dao)时(shi),模(mo)板(ban)(ban)(ban)对混(hun)(hun)(hun)(hun)凝(ning)(ning)(ning)土(tu)(tu)的(de)摩阻(zu)力(li)(li)不足以抵消混(hun)(hun)(hun)(hun)凝(ning)(ning)(ning)土(tu)(tu)顺模(mo)板(ban)(ban)(ban)面(mian)(mian)(mian)的(de)下(xia)(xia)滑力(li)(li)。混(hun)(hun)(hun)(hun)凝(ning)(ning)(ning)土(tu)(tu)初(chu)凝(ning)(ning)(ning)前,如缓(huan)慢位(wei)移持续发生(sheng),易导致混(hun)(hun)(hun)(hun)凝(ning)(ning)(ning)土(tu)(tu)不密实和(he)内(nei)伤而渗漏。故建(jian)议当屋面(mian)(mian)(mian)的(de)坡度大于26°时(shi),不宜采用单面(mian)(mian)(mian)模(mo)板(ban)(ban)(ban)法(fa)施工。
2、双面夹板法
双(shuang)面(mian)模(mo)板(ban)法(fa)可(ke)以保(bao)证混(hun)(hun)凝(ning)(ning)土板(ban)达到内(nei)实外光的(de)(de)要求。但由于(yu)(yu)板(ban)的(de)(de)厚(hou)度(du)(du)小(xiao)(一般仅为100mm),除去钢(gang)筋(jin)和保(bao)护层,中间(jian)间(jian)隙小(xiao)于(yu)(yu)50mm,若钢(gang)筋(jin)绑扎存在误差,则振(zhen)(zhen)捣(dao)棒更难插入(ru)。因此(ci)(ci)施(shi)(shi)工(gong)(gong)中必须注意防止(zhi)钢(gang)筋(jin)位移及(ji)因混(hun)(hun)凝(ning)(ning)土浇筑不(bu)到位而造成的(de)(de)蜂窝。因无法(fa)观察到模(mo)板(ban)内(nei)混(hun)(hun)凝(ning)(ning)土的(de)(de)饱满度(du)(du),可(ke)敲击进行(xing)听音检查,并(bing)在板(ban)底采用(yong)附着式振(zhen)(zhen)捣(dao)器,使混(hun)(hun)凝(ning)(ning)土下(xia)淌(tang)充实。振(zhen)(zhen)捣(dao)时,采用(yong)直径33mm的(de)(de)小(xiao)振(zhen)(zhen)动(dong)棒,按序(xu)插振(zhen)(zhen),防止(zhi)漏插。对(dui)于(yu)(yu)死角(jiao)部位可(ke)以采用(yong)板(ban)外振(zhen)(zhen)与人工(gong)(gong)插钎相结合。对(dui)于(yu)(yu)此(ci)(ci)法(fa)施(shi)(shi)工(gong)(gong),应严格控制混(hun)(hun)凝(ning)(ning)土的(de)(de)坍落度(du)(du),具体根据施(shi)(shi)工(gong)(gong)时的(de)(de)温(wen)度(du)(du)确定,一般控制在50~70mm。为保(bao)证层面(mian)的(de)(de)结构安全(quan)和防水效果(guo),对(dui)坡度(du)(du)大的(de)(de)斜屋面(mian),应优先选用(yong)双(shuang)面(mian)夹板(ban)法(fa)。
根(gen)据现行(xing)的(de)(de)设计规范,现浇屋(wu)面板(ban)面的(de)(de)混(hun)(hun)(hun)凝土(tu)(tu)要具有一(yi)(yi)定的(de)(de)抗渗要求(qiu),一(yi)(yi)般选用(yong)抗渗混(hun)(hun)(hun)凝土(tu)(tu),为确保混(hun)(hun)(hun)凝土(tu)(tu)拌(ban)制(zhi)质量,对骨(gu)料(liao)的(de)(de)要求(qiu)应(ying)更为严格,砂子应(ying)为中(zhong)砂且含(han)泥量不得超过5%,碎石粒径(jing)以(yi)5~30mm为宜且含(han)泥量不得大于2%,骨(gu)料(liao)级(ji)配要合理,以(yi)增加混(hun)(hun)(hun)凝土(tu)(tu)的(de)(de)和易性。根(gen)据施(shi)工经验,要严格控制(zhi)混(hun)(hun)(hun)凝土(tu)(tu)的(de)(de)水灰比,混(hun)(hun)(hun)凝土(tu)(tu)的(de)(de)坍落度以(yi)10~15cm左右为宜。
斜屋(wu)面尤其是陡(dou)斜屋(wu)面的(de)混(hun)(hun)凝(ning)(ning)(ning)(ning)土(tu)浇(jiao)筑(zhu)(zhu),大的(de)问(wen)题是混(hun)(hun)凝(ning)(ning)(ning)(ning)土(tu)滑动(dong)流(liu)淌造成局部离析(xi)而发生混(hun)(hun)凝(ning)(ning)(ning)(ning)土(tu)的(de)质量问(wen)题,浇(jiao)筑(zhu)(zhu)时混(hun)(hun)凝(ning)(ning)(ning)(ning)土(tu)倾(qing)落高(gao)度不(bu)大于600mm,因此不(bu)能从跳板上直(zhi)接从高(gao)处(chu)向下(xia)倾(qing)倒(dao)混(hun)(hun)凝(ning)(ning)(ning)(ning)土(tu),混(hun)(hun)凝(ning)(ning)(ning)(ning)土(tu)浇(jiao)筑(zhu)(zhu)时增(zeng)加板面作(zuo)业工(gong)(gong)人(ren),特别在屋(wu)面低处(chu)浇(jiao)筑(zhu)(zhu)混(hun)(hun)凝(ning)(ning)(ning)(ning)土(tu)时,建议全部用小桶水平运输混(hun)(hun)凝(ning)(ning)(ning)(ning)土(tu)(禁止用斗车),一小桶一小桶平铺,这样可避免作(zuo)业工(gong)(gong)人(ren)施(shi)工(gong)(gong)中(zhong)贪图容易,盲(mang)目倾(qing)倒(dao)混(hun)(hun)凝(ning)(ning)(ning)(ning)土(tu),造成混(hun)(hun)凝(ning)(ning)(ning)(ning)土(tu)离析(xi)。
混(hun)凝土浇(jiao)(jiao)筑时(shi)应从屋(wu)面两头(tou)低(di)处同(tong)时(shi)开始(shi),两面坡面同(tong)时(shi)浇(jiao)(jiao)注(zhu)为佳,混(hun)凝土的浇(jiao)(jiao)筑应连续施(shi)(shi)工不留(liu)置(zhi)施(shi)(shi)工缝。如(ru)特(te)殊情况必(bi)须留(liu)置(zhi)施(shi)(shi)工缝时(shi),施(shi)(shi)工缝的位置(zhi)应在(zai)结(jie)构受力(li)较小处,一(yi)般距(ju)现(xian)(xian)浇(jiao)(jiao)板支座1m,不可(ke)在(zai)现(xian)(xian)浇(jiao)(jiao)板中心部(bu)位置(zhi)留(liu)置(zhi)施(shi)(shi)工缝。
斜屋面(mian)(mian)(mian)的(de)(de)混(hun)(hun)凝(ning)(ning)(ning)(ning)土(tu)(tu)(tu)(tu)振(zhen)(zhen)捣(dao)密实一直是一个施工(gong)(gong)难题,为控(kong)制板(ban)的(de)(de)浇筑厚度(du)(du),应(ying)(ying)在(zai)板(ban)面(mian)(mian)(mian)按(an)1000mm×1000mm均匀布置(zhi)厚度(du)(du)控(kong)制点。根据(ju)经(jing)验(yan)认为,对于(yu)梁的(de)(de)振(zhen)(zhen)捣(dao)要特别注意插式振(zhen)(zhen)动(dong)器振(zhen)(zhen)捣(dao)在(zai)各区段均匀,振(zhen)(zhen)捣(dao)时间过长易造成局部粗骨料(liao)集中,砂浆(jiang)与粗骨料(liao)分离。对于(yu)板(ban)面(mian)(mian)(mian)混(hun)(hun)凝(ning)(ning)(ning)(ning)土(tu)(tu)(tu)(tu),振(zhen)(zhen)捣(dao)过多混(hun)(hun)凝(ning)(ning)(ning)(ning)土(tu)(tu)(tu)(tu)易流动(dong),造成板(ban)面(mian)(mian)(mian)平(ping)整(zheng)度(du)(du)难以控(kong)制,一般做(zuo)法是在(zai)施工(gong)(gong)中先(xian)用(yong)(yong)(yong)人工(gong)(gong)均匀摊铺(pu)混(hun)(hun)凝(ning)(ning)(ning)(ning)土(tu)(tu)(tu)(tu),注意混(hun)(hun)凝(ning)(ning)(ning)(ning)土(tu)(tu)(tu)(tu)厚度(du)(du)应(ying)(ying)足(zu)够,用(yong)(yong)(yong)抹子拍实,待混(hun)(hun)凝(ning)(ning)(ning)(ning)土(tu)(tu)(tu)(tu)接(jie)近初(chu)凝(ning)(ning)(ning)(ning)时用(yong)(yong)(yong)平(ping)板(ban)振(zhen)(zhen)动(dong)器按(an)板(ban)块的(de)(de)浇筑顺(shun)序均匀走二(er)遍,接(jie)槎(cha)处(chu)则应(ying)(ying)多走一遍即可,板(ban)面(mian)(mian)(mian)振(zhen)(zhen)捣(dao)后再用(yong)(yong)(yong)人工(gong)(gong)对局部不(bu)平(ping)整(zheng)及板(ban)厚度(du)(du)不(bu)足(zu)的(de)(de)板(ban)面(mian)(mian)(mian)进行修整(zheng),然后用(yong)(yong)(yong)水泥砂浆(jiang)对板(ban)面(mian)(mian)(mian)混(hun)(hun)凝(ning)(ning)(ning)(ning)土(tu)(tu)(tu)(tu)表面(mian)(mian)(mian)修整(zheng),以取得良好的(de)(de)表面(mian)(mian)(mian)观感(gan)。
混凝土浇筑(zhu)完成后要(yao)做好浇水(shui)养(yang)护(hu),由(you)于(yu)夏季气(qi)温(wen)高,水(shui)份蒸发量大,斜屋面浇水(shui)养(yang)护(hu)效果差,因(yin)此夏季施工后应强调使用(yong)草袋覆(fu)盖养(yang)护(hu)为(wei)佳,以防止混凝土因(yin)暴晒而碳化(hua)和缩水(shui)龟(gui)裂,浇水(shui)湿润(run)养(yang)护(hu)不得少于(yu)14d。
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