1反射裂縫分析 近10年來,各國對“白加黑”路麵反射裂縫產生氣理進行了大量的研究,並得到了基本一致的共識:反射裂縫的形成和發展是一個連續的過程,麵板接縫或裂縫可以看成原始的缺陷;在車輛通過接縫或裂縫時,加鋪層受到2次剪切1次ci彎wan曲qu,過guo程cheng是shi連lian續xu的de,由you於yu原yuan路lu麵mian的de裂lie縫feng和he接jie縫feng處chu無wu抗kang剪jian能neng力li,本ben來lai應ying由you原yuan裂lie縫feng或huo接jie縫feng承cheng擔dan的de應ying力li轉zhuan移yi到dao加jia鋪pu層ceng當dang中zhong,從cong而er在zai裂lie縫feng上shang方fang的de加jia鋪pu層ceng中zhong產chan生sheng應ying力li集ji中zhong,導dao致zhi加jia鋪pu層ceng在zai此ci處chu沿yan原yuan裂lie縫feng開kai裂lie反fan射she。國guo內nei外wai針zhen對dui反fan射she裂lie縫feng問wen題ti提ti出chu了le許xu多duo處chu理li措cuo施shi,各ge種zhong措cuo施shi具ju有you不bu同tong的de優you缺que點dian,其qi主zhu要yao特te性xing對dui比bi如ru表biao1。 tongshidaliangdeyanjiudouzhichu,fansheliefengbukenengxiaochu,zhishichuxiandechizaoeryi。zaishuinihunningtulumianshangchenggongpuzhuliqinghunningtumianceng,jiangfansheliefengdechuxianshijian、pinlvjiangzhizuidizhi,yanchanglumianshiyongshouming,shibengongchengdeyigeyanjiuzhongdian。genjuyanjiu,jieheguoneiwaichenggongdejingyan,nicaiyongzaijiushuinihunningtulumianyuliqinghunningtujiapucengzhijianshezhigaoqiangduhegaomoliangdeboxiangezhadefangan,duiliqinghunningtumiancengjinxingjiaqiangchuli。2材料性能試驗 2.1土工格柵材料性能試驗 試驗段擬采用玻璃纖維格柵來防治反射裂縫。與聚酯和聚丙烯纖維格柵、土工布相比,玻纖格柵具有以下優點:抗拉強度大,在20℃時的彈性模量是瀝青混凝土彈性模量的20bei,nengjiangfansheliefengyingliyouchuizhifangxiangzhuanweishuipingfangxiang,congerzengqiangliqinghunheliaodezhengtikanglaqiangdu。youyanjiuhaibiaomingmoliangyueda,yueyouliyujiangdijiapucengdewenduyingli;延伸性低,具有很高的抗變形能力,斷裂時的延伸率小於4%;高溫穩定性良好,物理化學性能穩定,玻璃熔點在1000℃左右,保證了其在高溫攤鋪時的穩定性;與瀝青混合料相容性好,保證其與瀝青混合料之間不產生滑動;qiansuohexianzhizuoyonghao,liqinghunheliaozhongdejiliaonengchuanguoboxiangezhajiegou,xingchengyigefuhedelixueqiansuotixi,bingnengtigaochuanhenengli,jianshaobianxing。jingshiyanjiance,dongnanboxiangezhawulilixuexingnengrubiao2所示。 2.2防水卷材材料性能 防(fang)水(shui)卷(juan)材(cai)既(ji)能(neng)阻(zu)止(zhi)地(di)下(xia)水(shui)及(ji)水(shui)泥(ni)混(hun)凝(ning)土(tu)路(lu)麵(mian)板(ban)縫(feng)的(de)水(shui)進(jin)入(ru)新(xin)加(jia)鋪(pu)瀝(li)青(qing)混(hun)凝(ning)土(tu)層(ceng),又(you)能(neng)防(fang)止(zhi)反(fan)射(she)裂(lie)縫(feng)的(de)產(chan)生(sheng)。通(tong)過(guo)比(bi)選(xuan),擬(ni)采(cai)用(yong)的(de)防(fang)水(shui)卷(juan)材(cai)為(wei)YN一自粘型彈性體瀝青路橋用防水卷材。材料具有的特征有:kanglaohuaxingnenghao,juyoulianghaodediwenrourenxing,juyoujihaodebutoushuixing,kangfushixinghao,kangchuankongxinghao,zhanjiexinghao,shigongfangbian,qingyixiubu。tongguozhijianshiyan,keyiquedingbutongwenduxiabutongcengjianjiechutiaojianshidezhanjiexingneng。shiyanjieguoru 表3。 2.3土工格柵加筋試驗評價 weileduitugonggezhajiajinshezailiqingdibujinxingshiyanyanjiu,xuanyongbuqiekoushijiancanzhaoyiyoushiyanfangfa,duitugonggezhajiajinliqinghunningtujinxingwanqushiyan。weikaolvwendudeyingxiang,xuanze0℃和-10℃兩種試驗溫度,進行試驗比較。未加土工格柵試件用1號表示,底麵鋪設土工格柵試件用2號表示。試驗結果繪於圖1中。 由彎曲試驗可知,在加載初期,2號試件的應變增長較快,消耗的能量較大,其相應的應力值小於1haoshijianxiangtongshikedeyinglizhi。suizhejiaheshijiandeyanchang,tugonggezhachengshoulayingbian,shihunningtudeyingbiansulvjianxiao,cishiyinglizengchangjiaokuai,qieyouyutugonggezhadecunzai,2號試件破壞應變較1號試件增大一倍多,說明加筋瀝青混合料所需的能量大。根據彎曲試驗的應力一應變曲線,破壞時應變能U由彈性應變能和塑性應變能兩部分組成,可通過積分求得。從表4中可以看出,在O℃時,2號破壞時應變能比1號大42.1%,-10℃效果更明顯,應變能大180.6%。因此土工格柵加筋瀝青混凝土的整體穩定性比原瀝青混凝土有較大提高,具有更好的防裂性能。 3防裂措施的施工工藝 試驗路原為一級公路,寬32m,四車道,擬改建為六車道。加鋪後的路麵結構如圖2所suo示shi。由you於yu道dao路lu拓tuo寬kuan,存cun在zai新xin老lao路lu基ji結jie合he問wen題ti,在zai製zhi定ding防fang治zhi反fan射she裂lie縫feng措cuo施shi時shi不bu僅jin要yao考kao慮lv舊jiu水shui泥ni混hun凝ning土tu板ban上shang瀝li青qing混hun凝ning土tu加jia鋪pu層ceng的de反fan射she裂lie縫feng問wen題ti,同tong時shi需xu考kao慮lv新xin老lao路lu基ji處chu由you於yu沉chen降jiang差cha異yi引yin起qi的de裂lie縫feng問wen題ti。 3.1加鋪層厚度確定 有限元分析表明:適當增加加鋪層厚度對防治反射裂縫是十分有效的,但當罩麵層厚度大於12cm時再增加厚度對防治反射裂縫效果並不顯著,也不經濟。根據有關研究和工程實例,10cm左右的加鋪層厚度能有效防治或延緩荷載型和溫度型反射裂縫,並且經濟合理。3.2試驗路施工工藝 施工前預備工作。 第一階段試驗路整個施工工序包括:板底注漿、填縫料換填、防水卷材鋪設、找平層鋪築、土工格柵貼鋪、SMA瀝青加鋪層鋪築。由於施工期間溫度較低,且陰雨天氣較多,在施工之前把握好未來天氣變化情況,製定相應的施工進度。注漿。 根據路況調查,在綜合考慮對漿液要求的基礎上,再加上經濟分析,本試驗段采用配比為:水泥:粉煤灰:水=1:O.7:O.8,添加0.5%的SN一Ⅱ早強減水劑。注漿前後都進行了彎沉測量,並通過鑽芯取樣,以保證舊水泥混凝土板的地基強度達到設計要求。清縫、更換填縫料。 genjulukuangtiaozha,jiefengchudesunhuaijiaoyanzhong,tianfengliaosunshijiaoduo。yincizaijinxingjiapuzhiqian,xuduitianfengliaojinxinghuantian。qingfenghou,xuzhongxinzaifengneiyarubeichendai。zuihoujinxingjuanzhitianfengliaodepeiliao、攪拌和灌縫。鋪設防水卷材。 pushefangshuijuancaishiyingfeifanzhuzhongqiyujiubandezhanjiechengdu,zhezhuyaoshoujiubanganjingchengdujichaoshichengduyingxiang。shouxianqingsaojiefengliangce,ranhoucaiyongzhuanyongdeqingjiejizaijiefengliangce50cm範fan圍wei內nei塗tu刷shua,以yi提ti高gao粘zhan結jie強qiang度du。清qing潔jie劑ji表biao麵mian幹gan燥zao後hou,即ji可ke鋪pu貼tie防fang水shui卷juan材cai。使shi卷juan材cai平ping坦tan地di鋪pu貼tie在zai舊jiu水shui泥ni混hun凝ning土tu板ban上shang,同tong時shi,用yong橡xiang皮pi壓ya碾nian按an卷juan材cai縱zong向xiang鋪pu貼tie方fang向xiang壓ya實shi。防fang水shui卷juan材cai鋪pu貼tie後hou,嚴yan禁jin車che輛liang在zai其qi上shang轉zhuan彎wan、掉頭。試驗段南側的縱向和橫向接縫全部鋪貼寬度為33cm的防水卷材,而北側除縱縫鋪貼防水卷材外,在主點彎沉大於0.2mm和差異彎沉大於O.06mm的接縫處鋪貼防水卷材。灑布粘層瀝青。 weibaozhengliqinghunningtujiapucengyujiushuinihunningtubandelianghaolianjie,zaizhaopingcengpuzhuzhiqian,yingsabuyidingdezhancengliqing。zhancengliqingcaiyongruhualiqing,yongliangkongzhizai0.3~O.5kg/m。之間。鋪築瀝青找平層。 在(zai)乳(ru)化(hua)瀝(li)青(qing)完(wan)全(quan)破(po)乳(ru)之(zhi)後(hou)施(shi)工(gong)瀝(li)青(qing)找(zhao)平(ping)層(ceng),可(ke)采(cai)用(yong)瀝(li)青(qing)砂(sha)或(huo)稀(xi)漿(jiang)封(feng)層(ceng)材(cai)料(liao)。在(zai)施(shi)工(gong)前(qian),對(dui)路(lu)麵(mian)標(biao)高(gao)重(zhong)新(xin)測(ce)量(liang)一(yi)次(ci)。攤(tan)鋪(pu)時(shi),控(kong)製(zhi)不(bu)同(tong)的(de)鬆(song)鋪(pu)厚(hou)度(du),對(dui)本(ben)層(ceng)頂(ding)麵(mian)高(gao)程(cheng)進(jin)行(xing)嚴(yan)格(ge)控(kong)製(zhi)。基(ji)質(zhi)瀝(li)青(qing)采(cai)用(yong)國(guo)產(chan)70號石油瀝青。養護成型後厚度為5~7mm,因此其最大公稱粒徑為4.75mm,集料石質為湖州輝綠岩,屬中封層。它的幹礦料攤鋪量為5~8kg/m2。乳化瀝青用量為幹礦料質量百分比的10%~12%。瀝青稀漿封層施工後應立即施工玻纖格柵和瀝青混凝土麵層,間隔時間過長會影響粘接質量。鋪設土工格柵。 鋪(pu)設(she)土(tu)工(gong)格(ge)柵(zha)關(guan)鍵(jian)在(zai)於(yu)與(yu)上(shang)下(xia)層(ceng)的(de)緊(jin)密(mi)粘(zhan)結(jie),不(bu)能(neng)滑(hua)動(dong)。試(shi)驗(yan)段(duan)采(cai)用(yong)的(de)土(tu)工(gong)格(ge)柵(zha)帶(dai)自(zi)粘(zhan)膠(jiao),可(ke)直(zhi)接(jie)在(zai)已(yi)平(ping)整(zheng)的(de)找(zhao)平(ping)層(ceng)上(shang)鋪(pu)設(she)。格(ge)柵(zha)鋪(pu)設(she)采(cai)用(yong)汽(qi)車(che)改(gai)裝(zhuang)的(de)專(zhuan)用(yong)設(she)備(bei)進(jin)行(xing)鋪(pu)設(she),壓(ya)路(lu)機(ji)碾(nian)壓(ya)一(yi)遍(bian)。格(ge)柵(zha)搭(da)接(jie)距(ju)離(li)為(wei)縱(zong)向(xiang)接(jie)頭(tou)時(shi)搭(da)接(jie)距(ju)離(li)不(bu)小(xiao)於(yu)20cm,橫向搭接距離不小於15cm。攤tan鋪pu瀝li青qing混hun凝ning土tu時shi,運yun料liao車che不bu能neng在zai格ge柵zha上shang調tiao頭tou或huo轉zhuan彎wan,以yi免mian損sun壞huai玻bo纖xian格ge柵zha或huo引yin起qi局ju部bu起qi拱gong現xian象xiang。鋪pu設she的de土tu工gong格ge柵zha為wei單dan層ceng,即ji鋪pu設she在zai舊jiu水shui泥ni混hun凝ning土tu板ban上shang瀝li青qing砂sha找zhao平ping層ceng與yuAC-20瀝li青qing混hun凝ning土tu加jia鋪pu層ceng之zhi間jian。最zui後hou分fen兩liang層ceng攤tan鋪pu瀝li青qing混hun凝ning土tu加jia鋪pu層ceng。應ying該gai注zhu重zhong的de是shi,上shang述shu各ge道dao工gong序xu應ying盡jin量liang選xuan擇ze在zai較jiao好hao的de天tian氣qi進jin行xing,否fou則ze輕qing易yi造zao成cheng防fang水shui卷juan材cai與yu舊jiu水shui泥ni混hun凝ning土tu板ban、tugonggezhayuzhengpingcenghejiapucengzhijiandebuwanquanlianjie,yingxiangcailiaodezhanjieqiangduhelumianjiegoudezhengtiqiangdu。fangshuijuancaihetugonggezhadepushedoujianyiyougaigongsideshuliangongrenlaijinxing,yibaozhengshigongzhiliang。erbaochishigongxianchangdeqingjieyeshiburonghushidewenti。
4小結 舊水泥混凝土板塊之間接縫或裂縫引起的加鋪層反射裂縫問題仍是目前路麵工程中的一個難題,本文重點從防裂材料的選擇、材料性能試驗、施工工藝的角度出發,對防治反射裂縫的技術進行研究。本文研究成果運用於上海A30東南郊高速公路中的水泥混凝土路麵加罩瀝青混凝土麵層工程。該路通車一年多後,2005年12yueyouguandanweicaiyongxianjindechezaiquanzidongjianceshebei,duishiyanduanyuxianglinluduanjinxingquanmianhexitongdicelianghejianyan。tiaozhajieguobiaoming,lumianzongtishiyongzhuangkuanglianghao,meiyouchuxianfansheliefeng,jinyibudejiancehaijiangjixujinxing。
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