为研究低温(3℃)养护条件和水灰比对混凝土抗氯离子渗透性和细观孔结构的影响规律及程度,采用气孔分析法 和直流电量法对低温(3℃)养护条件下和标准养护条件下的不同水灰比混凝土 28d细观孔结构和电通量进行测试。试验 结果表明:低温(3℃)养护条件对不同水灰比混凝土孔径分布有显著影响,使其孔径粗化严重,大孔含量增多,小孔含量减 少;气孔间距系数和平均孔径都明显大于对应标准养护条件下的混凝土,且都随着水灰比增大而增大,低温(3℃)对低水 灰比混凝土平均孔径影响程度大,对高水灰比混凝土平均孔径影响程度小;不同水灰比混凝土 28d电通量值也明显大于其 标准养护条件下的混凝土,且随着水灰比增大,电通量值逐渐增大,抗氯离子渗透性逐渐减弱;低温对不同水灰比混凝土孔 结构和抗氯离子渗透性都产生不利影响,使混凝土细观孔结构劣化,抗氯离子渗透性降低,且对低水灰比混凝土的影响程 度大。 关键词:低温养护条件;水灰比;混凝土;孔结构;渗透性 中图分类号:TU528 文献标志码:A 文章编号:1672-7029(2016)04-0648-06 Researchontheeffectlowtemperature(3℃)curingconditionand variouswater-cementratiohaveontheresistancetochlorideions penetrationandmesoscopicstructureofconcrete DUANYun,WANGQicai,ZHANGRongling,ZHANGShaohua,XURuipeng (CollegeofCivilEngineering,LanzhouJiaotongUniversity,Lanzhou730070,China) Abstract:Inordertostudytheinfluenceruleanddegreeofthechloridepenetrationresistanceandmesoscopic structureofconcrete,stomatalanalysismethodandDCpowerlawareadoptedinthisresearch.Thesetwometh odsareusedtomeasurethemesostructureandDCvalueoftheconcretewithdifferentwater-cementratiocured 28daysunderlowtemperature(3℃)andstandardcuringcondition.Theresultshowsthat:theeffectoncon creteporesizedistributionisobviouswithlowtemperature(3℃)curingconditiononthedifferentwater-ce mentratioofconcrete.Whentheapertureisseriouslycoarsened,thecoarseporeincreasesapparently,andthe numberofmesoscopicporedecreased.Porespacingfactorandaverageporediameterweresignificantlygreater thanthecorrespondingconcretestandardcuringconditions,anditgoeslargerwithahigherwater-cementratio. Butundertheconditionoflowtemperature(3℃),itbehavesarelativelyhighereffectontheaverageporedi ameterofconcretewithalowerwater-cementratioandlowereffectonitwitharelativelyhigherwater-cement ratio.TheDCvalueishigheronconcretewithdifferentwater-cementratiocured28dthanitiscuredunder standardcuringconditions.Besides,theDCvaluegoeshigherastheincreaseofwater-cementratio,andthe chloridepenetrationresistancedecreasesatthesametime.Lowtemperaturehasnegativeeffectbothonconcret
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