早期混凝土的温度应力及裂缝控制..docx

分类号:TUUDG:624学号位代码:10004硕士研究生学位论文论文题目:早期混凝土的温度应力及裂缝控制研究生:张玉梅指导教师:刘保东弓俊青专业:结构工程论文提交日期:2007年4月1d日论文答辩日期:2006年12月20日学位授予单位:北京交通大学二00七年四月日摘要:关键词:早期混凝土;温度应力;徐变;钢筋;裂缝分类号:Tu;THE ABSTRACTABSTRACT:This/Paper/stduied/thermal/stress/of/concrete/and/control/of/concrete/crack/at/early/ages;Using/finite/element/Program,the/htemral/stress/of/an/externally/restrained/concrete/slba/and/the/concrete/cushioncaPa/teariyages/are/simulated/firstly.And/the/nthere/sults/are/analyzed.The/heat/Production/induced/by/the/cementhy/dration/and/the/evolving/environmental/variation/are/considered/in/the/thermal/model.The/heat/ProductionChanges/with/time/and/it/15/the/key/afctor/of/concrete/temperuatres;the/bounday/conditions,which/15/htekey/Parameter/whiche/effcts/temPerautre/gradient,15/exPressed/by/convection/radiation/coefficient/according/to/conditions/such/as/curing/and/weather.Finiteelementmodel15asimPlifiedmodelofconsturctionPhasebecuasehtesiutcase15veyrcomPlex.ThevaribaleYoung5moduluswhichchangeswithtimeandreProducedobjectivestressofconcreteareconsideredinthemechanicalmode.ThisPaPerconsideredinfluenceofconcreteearly一agecreePandreinofrcementtoconcretestress:GeneralcreePmodelswhichareofrlong一termconcretecreeP,arenotfitofrconcreteateariyages,Relaxationafctor15getfromlong一termconcretecreeP,which15notfitofrearlyconcretetoo,ThisPaPerusedthemostwidelyusedufnciton,theDoublePowerLwaD(PL),ofrdescribingtheearly一agecreeP,ProvidinggoodPredictions.Theresultindicatesthateariy一agecreePreducesstressofearly一ageconcreteveyrmuch.Accordingtestresultofsomedocumentation,theeeffctofreinofrcementonthethermalstressandtheriskofcrackingarecalculatedinthisPaPer.Afterconsideringtheactiveactionofreinofrcement,theultimatestrainofconcretecouldbeincreasedandthecrackofconcretecouldbePrevented.Inoneword,iftheeeffctofcreePandreinofrcementofeariyconcrete15consideredProPerly,thecrackofconcreteatearlyageswillbecontrolledeeffctively.KEYWORDS:concrete/ateariyages;htermal/stress;cree/P;reinofrcement;crackCLASSNO:TU;T目录中文摘