簡(jiǎn)介:12670單詞,16000英文字符,5000漢字出處TAKEWAKAK,YAMAGUCHIT,MAEDASSIMULATIONMODELFORDETERIORATIONOFCONCRETESTRUCTURESDUETOCHLORIDEATTACKJJOURNALOFADVANCEDCONCRETETECHNOLOGY,2003,12139146外文文獻(xiàn)SIMULATIONMODELFORDETERIORATIONOFCONCRETESTRUCTURESDUETOCHLORIDEATTACKKOJITAKEWAKA1,TOSHINOBUYAMAGUCHI2ANDSATOSHIMAEDA3RECEIVED13JANUARY2003,ACCEPTED23MAY2003ABSTRACTREINFORCEDCONCRETESTRUCTURESINAMARINEENVIRONMENTSUFFERDETERIORATIONCAUSEDBYTHECORROSIONOFREINFORCEMENTVARIOUSRESEARCHPROJECTSHAVEINVESTIGATEDTHISPROBLEM,YETFEWEVALUATIONTECHNIQUESHAVEBEENDEVELOPEDUNTILNOWINTHISSTUDY,ASIMULATIONMODELFORDETERIORATIONOFCONCRETESTRUCTURESDUETOCHLORIDEATTACKWASCONSTRUCTEDTHISMODELCOMBINESCHLORIDEANDOXYGENPENETRATIONMODELSANDAREINFORCEMENTCORROSIONMODEL,TAKINGINTOCONSIDERATIONVARIATIONSINCONCRETEQUALITYANDTHEEXISTENCEOFDEFECTSSUCHASCRACKSBYUSINGTHEPROPOSEDMODEL,ITWASPOSSIBLETOESTIMATETHEPROGRESSOFREINFORCEMENTCORROSIONANDTHECORROSIONCRACKGENERATIONTIMINGINCONCRETE1INTRODUCTIONRECENTLY,THEEARLYDETERIORATIONOFREINFORCEDCONCRETESTRUCTURESHASBECOMEAMAJORPROBLEMREINFORCEMENTCORROSIONDUETOCHLORIDEATTACKCANBECONSIDEREDASONEOFTHEMAINCAUSESVARIOUSRESEARCHPROJECTSHAVEINVESTIGATEDTHISPROBLEMHOWEVER,THEREHAVEBEENFEWEVALUATIONTECHNIQUESUNTILNOWBECAUSEOFTHEVARIATIONSINTHEQUALITYOFCONCRETE,WHICHISAPOROUSMATERIALTHEFACTTHATEXPERIMENTSONDETERIORATIONTAKEALONGTIMEHASALSOBEENACONTRIBUTINGFACTORFORTHELIMITEDAMOUNTOFDATAOBTAINEDTHUSFARINTHISSTUDY,CONSTRUCTIONOFASIMULATIONMODELFORTHEDETERIORATIONOFCONCRETESTRUCTURESDUETOCHLORIDEATTACKHASBEENATTEMPTEDTHISMODELCOMBINESCHLORIDEANDOXYGENPENETRATIONMODELSANDAREINFORCEMENTCORROSIONMODEL,TAKINGINTOCONSIDERATIONVARIATIONSINCONCRETE3WHEREVRDENSITYOFPOREVOLUMEOFCONCRETE,V∞TOTALPOREVOLUMEOFUNITCONCRETEM3/M3,RRADIUSOFPOREM,ANDBANDCPARAMETERSTHATDEPENDONW/CACCORDINGTOTHEIRORIGINANDCHARACTERISTICS,PORESCANBECLASSIFIEDASMACROPORES,CAPILLARYPORESANDGELPORESSINCECAPILLARYPORESANDMACROPORESAREPARTICULARLYRELEVANTTOTHEQUALITYOFCONCRETE,THEDISTRIBUTIONSOFTHESETWOTYPESOFPORESARECONSIDEREDDEPENDENTONW/CASSHOWNINFIG2HUCHIKAWAETAL1991THETWOPARAMETERVALUES,BANDC,USEDFOREACHW/CARESHOWNINTABLE1THESEVALUESHAVEBEENDETERMINEDTAKINGINTOCONSIDERATIONBOTHACTUALCONCRETEDATAANDTHEPARAMETRICEFFECTINTHEPENETRATIONMODELDESCRIBEDINSECTION3323AGGREGATEDISTRIBUTIONRECENTRESEARCHSHOWSATHINLAYERBETWEENTHECEMENTPASTEANDAGGREGATE,ESPECIALLYCOARSEAGGREGATE,INCONCRETECANMOREEFFECTIVELYEXPLAINTHEPHENOMENAOFCHLORIDEDIFFUSIONASWELLASCAPILLARYPORESTHISTHINLAYERISCALLEDTHEINTERFACETRANSITIONZONEITZINORDERTOCONSIDERTHEEFFECTSOFITZ,COARSEAGGREGATES5MMTO20MMINDIAMETERARESETRANDOMLYINTHEMODELCONCRETETHEVOLUMEINCONCRETEANDTHESIZEDISTRIBUTIONOFCOARSEAGGREGATEAREDETERMINEDBYTHEMIXPROPORTIONOFTHECONCRETEINTHISRESEARCH,JSCECODEVALUESAREUSEDASSTANDARDVALUESJSCE2002TOTALVOLUMEANDSIZEDISTRIBUTIONSARESHOWNINTABLE2ANDTABLE3,RESPECTIVELY24RELATIVEWATERCONTENTADDITIONALLY,CONSIDERINGTHEEFFECTOFTHERELATIVEWATERCONTENTOFTHECONCRETEONTHEDETERIORATIONPROCESS,SOMEOFTHEMACROANDCAPILLARYPORESAREDEFINEDASWATERFILLEDPORES,WHILETHEOTHERPORESAREDEFINEDASAIRFILLEDPORES,ASSHOWNINFIG1ANINCREASEINRELATIVEWATERCONTENTMEANSANINCREASEINTHENUMBEROFWATERFILLEDPORESTHERELATIVEWATER
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