Effectofalkali-activatedsolutionconcentrationontheperformanceofalkali-activatedslagtunnelfireproofcoatingsDeng-dengZheng1,TaoJi1*,Wen-chengWang2,Hwai-chungWu1,21. CollegeofCivilEngineeringatFuzhouUniversity,350116,China2. DepartmentofCivilandEnvironmentalEngineeringatWayneStateUniversity,408202,USAAbstractTheeffectofsodiumhydroxidesolutionconcentrationontheperformanceofalkali-activatedslagtunnelfireproofcoatings(AAS-TFC),suchasbondingstrength,fireresistance,drydensityanddryingtime,etc.wasstudied.Thetestresultsrevealthat,whenthebyweightconcentrationofsodiumhydroxidesolutionislessthan10%,thebondingstrengthbeforeandafterfreezing-thawingcyclesandthedryingtimeincreasewiththeincreaseofthesolutionconcentration,andthedryingtimedecreaseswiththeincreaseofsolutionconcentration.Whentheconcentrationofsodiumhydroxidesolutionismorethan10%,theinfluenceofthesolutionconcentrationonthebondingstrength,fireresistance,drydensityanddryingtimeofAAS-TFCisnotobvious.ThechangeoftheconcentrationofsodiumhydroxidesolutiononthefireresistanceofAAS-TFCisnotobvious.Whensodiumhydroxidesolutionconcentrationwas3%,thepeiformance-to-priceratioofAAS-TFCisthehighest.OriginalityAlkali-activatedslagtunnelfireproofcoatingsareseldomstudied,andtheeffectofalkali-activatedsolutionconcentrationontheperformanceofalkali-activatedslagtunnelfireproofcoatings,especiallyfarthebondingstrengthbeforeandafterfreezing-thawingcycles,isstillnotexploredbyanyauthorwold-wide.Thereforetheoriginalityofthispaperisobvious.Keywords:Tunnelfireproofcoating;Alkali-activatedslag;Alkali-activatedsolutionconcentration;Bondingstrength;FireresistanceCorrespondingauthor:jt72163.com,Te!+86-13609597752,Fax+0591-878932741.1 ntroductionWiththerapiddevelopmentoftunnelfireproofcoatings(TFC),thehighwaytunnelofChinahasbecomethelongestallovertheworld.Asofearly2011,thetotalnumberofthehighwaytunnelreached7384,andthecumulativelengthofthehighwaytunnelhadbecomemorethan5(X)0km.Asthetunnelisoftenusedastransportationchannelsofpowercables,fiberopticcables,aqueducts,pipelines,andsoon,whenatunnelfireaccidentshappens,theharmitcausesisveryserious,whichcanleadtothelongtimeoftrafficjam,extremelydifficultrescue,largeeconomiclossesandotherseriousconsequences,andevenmayleadtoaseriesofsocialproblems(Chinahighwaysociety.,2012;BerhahlP.,1995;WuY.,2008).Theapplicationofalkali-activatedslagcementinTFChasobviousadvantages:(1)Simplifyingformulaandreducingthecost.Becausethealkali-activatedcementhasgoodhightemperatureperformance,itsapplicationinTFCcanreduceorgetridofsomecomponentsoftraditionalTFCwithrelativelyhighprices.Forexample,duetoprotectthehealthofconstructionworkers,wegotridoftheammoniumpolyphosphateofTFCthatcanproduceodorgas.(2)Improvingthefreezing-thawingresistingcycleperformanceofTFC.Thefreezing-thawingresistingcyclicperformanceofTFChasgottenmoreandmoreattentionnowadays.ThestandardofttFireretardantcoatingofconcreteStrUCtUreS(GA28375-2012)(ThenationalstandardofthePeoplesRepublicofChina,2012),whichwaspublishedin2012,hasspeciallyjoinedthebondingstrengthindexafterfreezingandthawingcycle.(3)Greenenvironmentalprotection.ReplacingordinaryPortlandcementwithalkali-activatedslagcementinTFC,thecarbondioxide,sulphurdioxideanddust,whichisproducedintheproductionprocessofPortlandcement,canbereduced.Itisbeneficialforenvironmentalprotection.Studieshaveshownthatthechangingoftheactivatorsolutionconcentrationhasinfluenceonthestrengthandsettingtimeofthealkali-activatedslagcement(ZhangY.Q.,2009).However,theresearchabouttheeffectoftheactivatorsolutionconcentrationonalkali-activatedslagtunnelfireproofcoatings(AAS-TFC)performanceswasstillnotavailable.Inthispaper,theactivatorsolutionconcentrationofTFCwaschanged,andtheeffectoftheactivatorsolutionconcentrationonthebondingstrength,fireresistance,drydensityanddryingtimeetc.ofAAS-TFChasbeenstudied.2 .RawmaterialsandmixproportionTFCisusuallycomposedofbondingmaterials,refractoryandheatinsulationmaterials,foammaterialsandadditives(WangX.G.,2(X)6;WangG.J.,2006).Thefoammaterials(suchasammoniumpolyphosphate,melamineandpentaerythritol,etc)ofTFCisexcluded,andalkali-activatedslagcement,asthemainbondingmaterialofTFC,wasusedtoinsteadPortlandcement.2.1 BondingmaterialsBondingmaterialsisconstitutedbythealkali-activatedslagcement,redispersiblepowderandPVA.Thealkali-activatedslagcementisconstitutedbysodiumhydroxideandslag.SodiumhydroxideisproducedbyKangpu-huiweicompanyinBeijing.SlagisproducedbyTainingconcreteplantinFuzhou.Polyvinylalcohol(PVA)isproducedbySifang-huagongcompanyinFuzhou.PVAisthetypeof1788-125,whichiswhitepowder,odorless,tasteless,andsmallerthan160mesh.2.2 RefractoryExpandedperliteisproducedbyYouchencompanyinFuzhou.Itsparticlesizeisabout3mm,anditspackingdensityis83kgm3.Expandedperliteisqualitativelight,adiabatic,non-toxic,soundabsorption,tasteless,non-combustible,etc,anditcanresisttothehightemperatureof130()C.ExpandedvermiculiteisalsoproducedbyYouchencompanyinFuzhou.Itsparticlesizeislessthan2mm,anditismaroon,anditspackingdensityof530kgm3.Sepiolit