一種新的考慮界面特性的珊瑚骨料混凝土三維細(xì)觀建模方法（英文）

一種新的考慮界面特性的珊瑚骨料混凝土三維細(xì)觀

建模方法（英文）

Abstract:Coralaggregateconcrete(CAC)isapromisingmaterialwhichpossessesexcellentdurabilityandpotentialsustainableaspectsinconstruction.TheinterfacefeaturesinCACplayanimportantroleinitsbehavior.Inthispaper,athree-dimensionalmultiscalemodelingmethodisproposedtostudytheinterfacecharacteristicsinCAC,whichtakesintoaccounttheparticlesizedistribution,contactstiffness,androughnessoftheinterface.TheresultsshowthattheinterfacepropertieshavesignificantinfluenceonthemechanicalbehaviorofCAC.Furthermore,theproposedmethodprovidesareliableandefficientwaytodesignCACwithdesiredproperties.

Introduction

Coralaggregateconcrete(CAC)hasattractedmoreattentioninrecentyearsduetoitssuperiordurabilityandsustainabilitycomparedtotraditionalconcrete.CACiscomposedofnaturalcoralaggregate,whichisanabundantresourceinmanycoastalregions.Duetoitsuniquechemicalcompositionandporousstructure,coralaggregatehashighcompressivestrength,lowwaterabsorption,andexcellentresistancetochlorideionpenetration.Inaddition,theproductionprocessofCACconsumeslessenergyandproduceslessCO2emissionsthantraditionalconcrete.

However,theinterfacebetweencoralaggregateandcementpasteiscomplexandhasastrongimpactonthemechanicalbehaviorofCAC.Theinterfaceproperties,suchasroughnessandcontactstrength,alsoaffectthetransferofstressbetweentheaggregateandthecementpaste.Therefore,itiscrucialtounderstandtheinterfacecharacteristicsinCACtooptimizeitsmechanicalpropertiesandimprovethedurabilityofconcretestructures.

Inthispaper,athree-dimensionalmultiscalemodelingmethodisproposedtoinvestigatetheinterfacepropertiesinCAC.Theeffectsoftheparticlesizedistribution,contactstiffness,andinterfaceroughnessareconsidered.TheresultsdemonstratethattheinterfacepropertieshaveasignificantinfluenceonthemechanicalbehaviorofCAC.TheproposedmodelcanbeusedtodesignCACwithdesiredproperties.

Methodology

Intheproposedmethod,thecoralaggregateismodeledasaseriesofsphericalparticleswithdifferentsizes,asshowninFigure1.Theparticlesizedistributionisderivedfromthemeasureddata.ThecementpasteismodeledasacontinuummaterialwiththepropertiesgiveninTable1.

Thecontactsurfacebetweenthecoralparticlesandthecementpasteismodeledusingacontactalgorithmbasedonthepenaltymethod,asshowninFigure2.Thenormalcontactstiffnessandcoefficientoffrictionareconsideredinthemodel,whichcanbecalculatedusingcontactmechanicstheory.

Theinterfaceroughnessisalsotakenintoaccountbyintroducingaroughnessparameterinthemodel.Theroughnessparameterisdefinedastheamplitudeofthesurfaceheightvariation,asshowninFigure3.

Theroughnessparameterisassumedtobeanormaldistributionwithameanvalueofzeroandastandarddeviationof0.1timestheparticlediameter.

Themultiscalemodelingmethodcombinesthediscreteelementmethod(DEM)andfiniteelementmethod(FEM).TheDEMisusedtosimulatethebehaviorofindividualcoralparticles,whiletheFEMisusedtosimulatethebehaviorofthecementpaste.Theboundaryconditionsofthesimulationaresetaccordingtotheexperimentalsetup.

ResultsandDiscussion

TheproposedmethodisappliedtostudythemechanicalbehaviorofCACunderuniaxialcompression.Thediameterofthecoralparticlesrangesfrom5mmto10mm.Figure4showsthestress-straincurvesofCACwithdifferentinterfaceproperties.ItcanbeseenthattheinterfacepropertieshaveasignificantinfluenceonthemechanicalbehaviorofCAC.Whentheinterfaceroughnessorcontactstiffnessincreases,thestrengthandstiffnessofCACdecrease.

Figure5showsthedistributionofthevonMisesstressintheCACspecimenwithdifferentinterfacepropertiesatthemaximumload.Itcanbeseenthatthestressdistributionisnon-uniform,andthestressinthecoralparticlesishigherthanthatinthecementpaste.Theinterfaceroughnessalsoaffectsthestressdistributionandcausesstressconcentrationattheinterface.

Conclusion

Athree-dimensionalmultiscalemodelingmethodisproposedtostudytheinterfacepropertiesinCAC,whichtakesintoaccounttheparticlesizedistribution,contactstiffness,andinterfaceroughness.The

resultsdemonstratethattheinterfacepropertieshaveasignificantinfluenceonthemechanicalbehaviorofCAC.TheproposedmethodprovidesareliableandefficientwaytodesignCACwithdesiredpropertie