文档介绍：预应力混凝土轨枕的裂缝及结构耐久性(Cracksandstructuraldurabilityofprestressedconcretesleepers)CrackanddurabilityofprestressedconcretesleeperIntroductionChinaprestressedconcretesleepersfromresearch,productionandapplication,whichlastedfortyyears,theyieldofmorethanbillion,paredwithothercountriesintheworldadoptconcretesleepers,,therehavebeenalotofdamagetotheconcretesleeper,relatestothetrafficsafety,,inadditiontotheremanufacturing,butalsoforhandling,transportandpillowwork,ontheline?Notonlyneedtospendalotofmanpowerandmaterialresources,sometimesaffecttraffic,,andthedamageforthesleeper,inadditiontoasmallamountisduetomechanicalloadingandunloading,identsandotherdamage,mostofitisduetothecracksofvariouskinds,,crackisdifficulttoavoid,soresearchcausescracksinprestressedconcretesleeperanditsharm,howtopreventandcontrolcracks,toimprovethedurabilityofconcretesleepers,prolongtheservicelifeofthesleeper,(crackunderrailpositivemoment)Thecracksinthesleeperonbothsidesofthelowerpart,undernormalcircumstances,thecrackwidthissmall,,,69barchordsleepersurveyresultsshowthatthesleeperattherailjoint,theproportionoftheverticalfracturesundertherailis60%;andthelargewaistrailrailverticalcrackreinforcementratio,69chord69respectively37%and20%.(horizontal)cracks(positivemomentandnegativebendingcracksinapillow)Thetype69sleeperon1981(1971-1976),thepositivemomentreinforcement69sleepercrackwere34%and11%(differentsections),69stringpillowcrackswere36%and13%(sections).Thewidthandlengthofcracksthantherailpillowinsomeseriou