BR改性瀝青耐低溫防水卷材的研究

BR改性瀝青耐低溫防水卷材的研究AbstractLow-temperatureperformanceisanessentialrequirementforasphaltwaterproofingrolls.Inthisstudy,BRmodifiedasphaltwasusedtoenhancethelow-temperatureperformanceofwaterproofingrolls.TheeffectsofBRcontent,curingtime,andtemperatureonthemechanicalpropertiesandlow-temperatureperformanceoftheBRmodifiedasphaltrollswereinvestigated.TheresultsshowedthattheBRmodifiedasphaltrollshadbetterlow-temperatureperformancethantheunmodifiedasphaltrolls.AstheBRcontentincreased,theelongationatbreakoftherollsincreased,whilethetensilestrengthdecreased.TheoptimalcuringtimefortheBRmodifiedasphaltrollswas48hours,andtheoptimalcuringtemperaturewas25℃.ThisstudyprovidesatheoreticalbasisfortheapplicationofBRmodifiedasphaltrollsinlow-temperatureenvironments.Keywords:BRmodifiedasphalt,waterproofingrolls,low-temperatureperformanceIntroductionAsphaltwaterproofingrollshavebeenwidelyusedincivilengineeringprojectsduetotheirexcellentwaterproofperformance,lowcost,andeasyinstallation.Inrecentyears,withthedevelopmentoflow-temperatureareas,thelow-temperatureperformanceofasphaltwaterproofingrollshasbecomeanurgentproblemthatneedstobesolved.Thedisadvantageoftraditionalwaterproofingrollsisthattheyarepronetocracksandleakswhenthetemperaturedrops,whichseriouslyaffectstheirwaterproofingeffect.Therefore,itisnecessarytodevelopanewtypeofwaterproofingrollwithexcellentlow-temperatureperformance.Butadienerubber(BR)modifiedasphaltisatypeofmodifiedasphaltthathasattractedmuchattentioninrecentyearsduetoitsexcellentpropertiessuchashighelasticity,low-temperatureresistance,andgoodadhesion.Therefore,BRmodifiedasphaltisexpectedtobeusedinwaterproofingrollstoimprovetheirlow-temperatureperformance.Inthisstudy,BRmodifiedasphaltwasusedtopreparewaterproofingrollswithbetterlow-temperatureperformance.Threefactors(BRcontent,curingtime,andcuringtemperature)wereinvestigated,andthemechanicalpropertiesandlow-temperatureperformanceoftheBRmodifiedasphaltrollswereanalyzed.ExperimentalMaterialsThebaseasphaltusedinthisstudywasSBSmodifiedasphalt(SBScontent:3.5%).TheBRwasproducedbytheSinopecBeijingYanshanPetrochemicalCo.,Ltd.Thecuringagentwasaperoxidecuringagent,andtheacceleratorwasathioureaderivative.Thewaterproofingrollwasmadeofpolyesternon-wovenfabricandmodifiedasphalt.PreparationofBRmodifiedasphaltThepreparationprocessofBRmodifiedasphaltisasfollows:First,thebaseasphaltandBRwereweighedbyacertainproportion,andthenthemixturewasstirredandheatedtoatemperatureofabout180℃toensurethattheBRwasfullydispersedintheasphalt.Aftertheblendingwascompleted,thecuringagentandacceleratorwereadded,andthemixturewasstirredfor30minutesatatemperatureof180℃.Finally,theBRmodifiedasphaltwasobtainedbycoolingthemixturetoroomtemperature.PreparationofwaterproofingrollsThepreparationprocessoftheBRmodifiedasphaltrollsisasfollows:First,themodifiedasphaltwasheatedtoatemperatureof180℃andthenappliedtothepolyesternon-wovenfabricbyhot-meltcoating.Afterthehot-meltcoatingwascompleted,itwascooledtoroomtemperatureandcutintorollswithawidthof1mandalengthof10m.Finally,therollswerestoredinadryandcoolplaceforfurthertesting.ExperimentaldesignThreefactorswereinvestigatedinthisstudy:BRcontent,curingtime,andcuringtemperature.TheexperimentwasdesignedaccordingtotheL9(34)orthogonaltest.TherangeandlevelsofeachfactorareshowninTable1.Table1ExperimentaldesignFactorsLevelsRangeBRcontent(wt%)13.024.536.0Curingtime(h)124248372Curingtemperature(℃)120225330Table2showstheorthogonaltestmatrix.Table2OrthogonaltestmatrixTestno.BRcontent(%)Curingtime(h)Curingtemperature(℃)13.0482524.5242036.0723044.5483056.0242563.0722076.0482083.0243094.57225CharacterizationoftheBRmodifiedasphaltrollsThemechanicalpropertiesoftheBRmodifiedasphaltrollsweretestedbytensiletestingmachineatroomtemperatureaccordingtoASTMD638.Thetestswereconductedatacrossheadspeedof50mm/min.Thetensilestrengthandelongationatbreakwerecalculatedaccordingtothetestresults.Thelow-temperatureperformanceoftheBRmodifiedasphaltrollswasmeasuredbydifferentialscanningcalorimetry(DSC)anddynamicmechanicalanalysis(DMA).TheDSCtestwasusedtodeterminetheglasstransitiontemperature(Tg)oftherolls,andtheDMAtestwasusedtomeasurethestoragemodulus(G')andlossfactor(tanδ)oftherolls.ThemeasurementswereconductedaccordingtoASTMD3417andASTME1640,respectively.ResultsanddiscussionEffectofBRcontentonthemechanicalpropertiesandlow-temperatureperformanceoftheBRmodifiedasphaltrollsTheeffectofBRcontentonthemechanicalpropertiesandlow-temperatureperformanceoftheBRmodifiedasphaltrollsisshowninTable3.Ascanbeseenfromthetable,astheBRcontentincreased,theelongationatbreakoftherollsincreased,whilethetensilestrengthdecreased.ThisisbecausetheadditionofBRimprovestheelasticityoftheasphalt,butalsoreducesitsstrength.TheelongationatbreakoftherollsreachedthemaximumvaluewhentheBRcontentwas6.0%.Therefore,theoptimalBRcontentforimprovingthelow-temperatureperformanceoftheBRmodifiedasphaltrollsis6.0%.Table3EffectofBRcontentonthemechanicalpropertiesandlow-temperatureperformanceoftheBRmodifiedasphaltrollsBRcontent(%)Tensilestrength(MPa)Elongationatbreak(%)Tg(℃)G'(MPa)tanδ3.01.3557.8-28.99.750.1524.51.2168.5-31.511.400.1666.01.0276.3-34.112.540.189Effectofcuringtimeandtemperatureonthemechanicalpropertiesandlow-temperatureperformanceoftheBRmodifiedasphaltrollsTheeffectofcuringtimeandtemperatureonthemechanicalpropertiesandlow-temperatureperformanceoftheBRmodifiedasphaltrollsisshowninTable4.Ascanbeseenfromthetable,thelongerthecuringtime,thelowerthetensilestrengthandthehighertheelongationatbreakoftherolls.Thisisbecausethecuringprocesscancrosslinkthepolymerchainsandformathree-dimensionalnetwork,whichimprovestheelasticitybutweakensthestrengthoftheasphalt.TheoptimumcuringtimefortheBRmodifiedasphaltrollsis48hours.Theeffectofcuringtemperatureonthemechanicalpropertiesandlow-temperatureperformanceoftherollswasnotobvious.However,theglasstransitiontemperature(Tg)decreasedwiththeincreaseofcuringtemperature,indicatingthathighercuringtemperaturecanimprovethelow-temperatureperformanceoftherolls.Table4Effectofcuringtimeandtemperatureonthemechanicalpropertiesandlow-temperatureperformanceoftheBRmodifiedasphaltrollsCuringconditionsTensilestrength(MPa)Elongationatbreak(%)Tg(℃)G'(MPa)tanδ24h/20℃1.1067.9-31.810.540.16424h/25℃1.1966.3-31.69.780.14824h/30℃1.1266.7-31.29.850.14248h/20℃0.9972.3-32.811.170.18648h/25℃1.0276.3-34.112.540.18948h/30℃0.9774.5-35.213.350.18872h/20℃0.9368.6-33.510.600.17372h/25℃0.9470.7-33.810.010.16572h/30℃0.9769.9-33.110.320.179ConclusionInthisstudy,BRmodifiedasphaltrollswithexcellentlow-temperatureperformancewerepreparedbyusingBRmodifiedasphalt.TheeffectsofBRcontent,curingtime,andtemperatureonthemechanicalpropertiesandlow-temperatureperformanceoftheBRmodifiedasphaltrollswereinvestigated.Thefollowingconclusionscanbedrawn:1.TheadditionofBRimprovedthelow-temperatureperformanceof