Cov nyhuv ntawm Graphene Ntawm Hloov Kho Asphalt Microstructures Raws li Atomic Force Microscopy

Abstract:Atomic force microscopy (AFM) tau siv los tshawb txog cov teebmeem ntawm graphene modifiers ntawm microstructure ntawm asphalt. Lub asphalt morphologies ua ntej- thiab tom qab-hnub nyoog asphalt morphologies thiab hloov asphalt tau ua thiab muab piv nrog kev tshuaj xyuas. Cov txheej txheem tsim ntawm asphaltic "nplua nuj qauv" thiab kev cuam tshuam ntawm graphene ntawm asphalt tau tham los ntawm classical txoj kev xav ntawm cov khoom siv science (theem transformation theory thiab diffusion theory). Cov txiaj ntsig tau pom tias graphene txhawb nqa lub nucleation ntawm "cov qauv muv", uas ua rau muaj tus lej nce ntxiv thiab txo qhov ntim ntawm "nplua nuj qauv" hauv kev hloov kho asphalt. Tsis tas li ntawd, lubanti-aging kev ua tau zoontawm kev hloov kho asphalt tau txhim kho tseem ceeb vim yog kev koom ua ke ntawm graphene.

Ntsiab lus:AFM; graphene; muv qauv; theem transformation txoj kev xav;anti-aging kev ua tau zoo 

Suav tshuaj ntsuab rau kev tiv thaiv kev laus ntxiv

1. Taw qhia

Asphalt yog ib qho nyuaj sib xyaw ntawm ntau yam hydrocarbons thiab lawv cov nonmetallic (oxygen, sulfur, thiab nitrogen) derivatives. Cov khoom ntawm asphalt muaj xws li alkanes, cycloalkanes, arenes thiab sulfur-muaj derivatives, polycyclic aromatic hydrocarbons, fused polycyclic arenes, thiab nonmetallic derivatives. Tsis tas li ntawd, cov ntsiab lus hlau (vanadium, nickel, magnesium, hlau, thiab calcium) muaj nyob hauv asphalt [1,2]. Txawm hais tias cov khoom thiab microstructure ntawm asphalt yog qhov tseem ceeb thiab cuam tshuam rau nws txoj kev taug kev, kev tshawb fawb microscopic hais txog asphalt tsis tshua muaj vim nws cov tshuaj lom neeg muaj pes tsawg leeg thiab cov kev tshawb fawb tsis txaus. Nyob rau hauv xyoo tas los no, kev sib raug zoo ntawm cov khoom siv bitumen, microstructure, thiab pavement kev ua tau zoo tau nce siab. Tshwj xeeb, cov kws tshawb fawb tau tsom mus rau atomic force microscopy (AFM), uas yog siv los tshawb xyuas cov qauv microscopic thiab cov txheej txheem ntawm asphalt.

Xyoo 1996, Loeber et al. thawj zaug pom qhov microstructure ntawm asphalt ntawm AFM, thiab hu ua microscopic topography ntawm asphalt li "nplua nuj qauv." Los ntawm kev txheeb xyuas cov txheej txheem tsim, nws tau pom ua ntej tias "tus qauv muv" yog vim asphaltene [3]. Pauli et al. pom tau hais tias cov microstructures feem ntau yog vim muaj kev sib cuam tshuam ntawm crystallizing paraffin waxes thiab cov seem uas tsis yog-wax asphalt Cheebtsam [4]. Ib yam li ntawd, Jäger A. et al. qhia tias "nplua nuj qauv" yog vim asphaltene [5]. De Moraes et al. speculated tias cov cuab yeej ntawm "tus qauv muv" zoo ib yam li microcrystalline wax [6]. Masson et al. tshawb xyuas lub microscopic topography ntawm 13 hom asphalt thiab pom tias qhov tsim ntawm "nplua nuj qauv" raug ntaus nqi rau cov ntsiab lus ntawm vanadium thiab npib tsib xee hauv asphalt [7].

Lub caij no, nws tau tshaj tawm tias qhov sib ntxiv ntawm Trinidad Lake asphalt thiab SBS modifiers tseem ceeb cuam tshuam rau cov nplej loj thiab kev faib tawm ntawm "cov qauv muv" [8,9]. Qee cov kws tshawb fawb tau tshaj tawm tias "tus qauv muv" yog vim qhov wrinkling ntawm nyias zaj duab xis ntsuas kwv yees li 10 nm tuab [2,10]. Ji et al. siv AFM los ntsuas qhov microstructure ntawm asphalt ntawm roughness txoj kev xav [11]. Hung tau tshawb xyuas qhov kev hloov pauv ntawm microstructure ntawm asphalt tom qab dej raug [12]. Txawm hais tias kev ua tiav, raws li pov thawj los ntawm AFM, tau pom zoo nyob rau hauv daim ntawv thov microscopic asphalt, cov txheej txheem tsim, mechanism, evolution txoj cai, thiab muaj feem cuam tshuam ntawm asphaltic "bee structures" tseem tsis tiav. Yog li ntawd, peb sim tshawb nrhiav cov txiaj ntsig ntawm additives ntawm microstructure ntawm asphalt thiab cia siab tias yuav ua tiav qee yam tseem ceeb.

'Me me nyhuv" nanomaterials ib txwm muaj ib tug ciam teb cov nyhuv thiab siab tshwj xeeb deg cheeb tsam, uas yuav ncaj qha los yog tsis ncaj qha mus rau ib tug tshwj xeeb nto nyhuv. Qee cov khoom siv nano xws li titanium dioxide (TiO2) [13], zinc oxide (ZnO) [14], graphene oxide (GO) [15], silicon dioxide (SiO2) [16], thiab montmorillonite [17] tau raug xaiv. Raws li kev hloov kho los txhim kho txoj kev ua tau zoo thiab txuas ntxiv kev ua haujlwm ntawm asphalt, qee qhov txiaj ntsig tseem ceeb tau ua tiav.ultraviolet kev laustsis kam ntawm fumed silica nanoparticles hloov bitumen thiab cov qhabnias qhia tau hais tias covanti-ultraviolet aging khoomntawm kev hloov kho asphalt yog txhim kho nrog kev nce ntawm nano silica cov ntsiab lus [18]. Zhang et al. pom tias qhov txo qis ntawm ZnO particle loj tuaj yeem txhim kho kev ua haujlwm ntawm asphalt binder thiab asphalt sib tov los ntawm kev txheeb xyuas qhov cuam tshuam ntawm ZnO particle loj ntawm asphalt lub cev [19].

Hauv peb txoj kev tshawb fawb, graphene raug xaiv los ua kev hloov kho asphalt. Qhov no feem ntau yog vim graphene yog ib qho tshiab quasi-ob-dimensional (2D) carbon-based nanomaterial nrog carbon atoms teem nyob rau hauv ib tug honeycomb lattice, thiab tau raug soj ntsuam raws li ib tug asphalt modifier vim nws compatibility nrog asphalt. Piv txwv li, Wu et al. tshawb pom tias kev koom ua ke me me ntawm graphene oxide (GO) txhim kho qhovanti-aging khoomntawm asphalt [20–22]. Shi et al. tshawb xyuas cov khoom thiab hloov kho mechanism ntawm GO-hloov asphalt. Lawv tau tshawb pom tias ib qho kab ntawm GO txwv kev txav ntawm asphalt molecules thiab txhim kho lawv cov kev ua haujlwm kub kub [23–25]. Moreno- Navarro et al. pom tias muaj cov graphene ua rau muaj qhov tseem ceeb dua elastic teb thiab txo cov thermal rhiab heev ntawm asphalt binder [26].

Yog li ntawd, hauv txoj kev tshawb no, qhov chaw ntawm lub hauv paus A-70 asphalt thiab graphene-hloov asphalt tau tshawb xyuas los ntawm AFM. Kev tsom xam ntau dua thiab kev sib tham yuav qhia meej txog cov laj thawj tsim thiab qhov cuam tshuam ntawm graphene ntawm asphaltic "bee structures". Cov kev cai ntawm cov khoom siv yooj yim, theem kev hloov pauv txoj kev xav, thiab diffusion txoj kev xav tau qhia los txhais cov txheej txheem ntawm graphene ntawm asphalt's microscopic "bee structures."

2. Kev sim

Hauv txoj kev tshawb no, A-70 asphalt muab los ntawm Shandong Hi-speed Siv Cov Khoom Siv, Jinan, Tuam Tshoj, tau siv los ua asphalt hauv paus. Graphene-hloov asphalt yog hauv tsev thiab qhov ntau npaum ntawm graphene yog 1 feem pua ​​​​hauv qhov hnyav, uas yav tas los tau raug pov thawj los ua cov ntsiab lus graphene zoo [27]. 2.1. Kev Npaj ntawm AFM Cov Qauv Qhov luv- thiabkev laus mus ntevntawm asphalt tau simulated siv lub tshuab ua kom sov qhov cub (James Cox & Sons CS325B, Colfax, CA, USA) thiabsiab aging apparatus(Prentex PR9300, Sunnyvale, TX, USA), feem. Tsis muaj hnub nyoog, hnub nyoog luv luv, thiab hnub nyoog ntev asphalt tau npaj nyias. AFM cov qauv tau npaj los ntawm cov txheej txheem cua sov molding raws li hauv qab no: Ua ntej, molten asphalt tau muab tso rau hauv iav swb (10 hli × 10 hli × 1 hli) siv lub iav pas nrig. Tom qab ntawd, qhov poob tau muab tso rau hauv qhov cub thiab tilted 30◦ saum kab rov tav. Nws tau rhaub ntawm 150 ◦C rau 15 feeb, thiab ib txheej nyias ntawm asphalt coated nto ntawm tus swb los ntawm lub ntiajteb txawj nqus. Thaum kawg, cov iav swb coated nrog asphalt tau txias rau chav sov hauv huab cua. Cov zaj duab xis asphalt npaj los ntawm txoj kev no ntsuas ntau microns hauv thickness, uas zoo ib yam li qhov tseeb thickness ntawm asphalt films ntawm txoj kev [28].

2.2. Atomic Force Microscope Test

AFM (Bruker Multimode 8, Santa Barbara, CA, USA) tau ua los ua tus yam ntxwv ntawm lub hauv paus thiab graphene-hloov asphalt ua ntej thiab tom qab kev laus. Daim duab schematic ntawm AFM ua tau yog pom nyob rau hauv daim duab 1. Cov plaub yam tseem ceeb siv hauv AFM yog ib qho kev sojntsuam, cantilever, laser, thiab position-sensitive photodiode (PSPD). Thaum lub sij hawm scanning, qhov siab variation ntawm lub micro nto ntawm tus qauv yuav tsim ib tug me ntsis quab yuam, piv txwv li, ib tug attraction los yog repulsive quab yuam ntawm lub sojntsuam taub hau thiab cov qauv nto. Nyob rau hauv cov ntaub ntawv no, lub cantilever deviates raws li "Hooke's Law," uas ua rau muaj kev hloov nyob rau hauv lub reflection teeb liab ntawm lub laser illuminated nyob rau sab nraum qab ntawm lub cantilever. Qhov kev hloov pauv ntawm cov teeb liab laser tuaj yeem hnov ​​​​los ntawm PSPD, thiab qhov saum npoo ntawm cov qauv tuaj yeem tau txais tom qab kev kho mob [29]. Cov duab topography thiab theem-zoo sib xws tau txais nyob rau hauv lub intermittent kev sib cuag hom, qhov twg elastic tas li ntawm qhov kev sojntsuam yog 0.4 N / m, tus scanning tus nqi yog 1.5 Hz, lub scanning cheeb tsam yog 10 µm × 10 µm , thiab qhov kev daws teeb meem yog 10 nm.

Daim duab 1. Schematic daim duab ntawm AFM.

3. Cov txiaj ntsig thiab kev sib tham

3.1. Cov txiaj ntsig ntawm Graphene ntawm Cov Khoom Tseem Ceeb ntawm Asphalt

Daim duab 2a,b qhia txog cov yam ntxwv ntawm lub hauv paus thiab graphene-hloov (qhov ntau npaum ntawm graphene yog 1.0 feem pua ​​​​hauv qhov hnyav) asphalt ua ntej thiab tom qab kev laus, feem. Raws li pom nyob rau hauv daim duab 2, ob qho tib si lub hauv paus thiab hloov kho asphalt qhia ib tug qauv ntawm kev nkag mus rau softening point, nce viscosity, thiab txo ductility tom qab lub sij hawm luv luv dov nyias zaj duab xis cub kuaj (RTFOT) laus. Qhov nce softening point thiab viscosity qhia tias asphalt ua nyuaj thiab nkig tom qab kev laus. Meanwhile, lubanti-aging khoomntawm asphalt kuj tseem raug soj ntsuam los ntawm kev sib piv cov kev hloov pauv ntawm cov indexes ua ntej thiab tom qab kev laus. Nws tuaj yeem xaus lus tias qhov hloov pauv ntawm txhua qhov ntsuas ntawm graphene-hloov asphalt qis dua li ntawm lub hauv paus asphalt. Qhov no qhia tias covanti-aging kev ua tau zoontawm cov graphene-hloov asphalt yog superior rau ntawm lub hauv paus asphalt. Tsis tas li ntawd, qhov kub-kub kev ua tau zoo ntawm kev hloov kho asphalt tau txhim kho vim yog kev koom ua ke ntawm graphene.

3.2. Cov nyhuv ntawm Graphene ntawm "Bee Structure

Daim duab 3a, b qhia 2D topography ntawm lub hauv paus thiab graphene-hloov asphalt ntsuas ntawm AFM, feem. Peb theem (Catana, peri, thiab paraphase) tau pom los ntawm cov duab qhia hauv daim duab 3. Cov "ntub qauv" tau tsim los ntawm cov kab sib txuas ntawm lub teeb thiab tsaus nti, uas sawv cev rau cov qauv convex thiab concave, raws li (7 30] . Tsis tas li ntawd, daim duab 3ab qhia ntau "cov qauv muv nyob rau hauv graphene-hloov asphalt nyob rau hauv tib qhov chaw tshawb nrhiav. Qhov siab ntawm lub teeb, ci ncov nce ntau thiab qhov tob ntawm lub hav tsaus ntuj poob, qhia txog kev txo qhov loj ntawm " muv qauv nyob rau hauv lub graphene-hloov asphalt, nyob rau hauv lwm yam lus, nyob rau hauv lub hauv paus asphalt, lub "ntub qauv" yog loj tab sis tsawg nyob rau hauv kom muaj nuj nqis.

Daim duab 3. Topography ntawm asphalt soj ntsuam ntawm AFM. (a) 2D duab ntawm lub hauv paus asphalt; (b) 2D duab ntawm graphene-hloov asphalt; (c) topographic profiles ntawm "bee structures" sau rau hauv (a); (d) topographic profiles ntawm "bee structures" sau npe nyob rau hauv (b).

AFM muab cov ntaub ntawv topographic nyob rau hauv daim ntawv ntawm qhov siab kab (los yog profiles), piv txwv li, qhov kev ncua deb ntawm qhov siab dua thiab qis dua ntawm "tus qauv muv." Daim duab 3c,d qhia cov duab saum toj kawg nkaus ntawm cov neeg sawv cev xaiv "nplua nuj qauv" sau rau hauv daim duab 3a, b, raws li. Raws li pom, qhov nruab nrab ntev ntawm "nplua nuj qauv" nyob rau hauv lub hauv paus asphalt yog 3-4 µm, whereas nws raug txo mus rau 2-3 µm nyob rau hauv lub graphene-hloov asphalt. Tsis tas li ntawd, qhov nruab nrab qhov siab ntawm "nplua nuj qauv" hauv lub hauv paus asphalt yog kwv yees li 44.2 nm, thaum nws raug txo kom txog li 35.4 nm hauv graphene-hloov asphalt. Qhov kev txo qis no qhia tau hais tias qhov ntim ntawm "nplua nuj qauv" hauv asphalt txo qis tom qab hloov kho los ntawm graphene. Los ntawm kev txheeb xyuas daim duab 3, nws tuaj yeem kwv yees tias qhov poob ntawm "ntub qauv" ntim hauv cov graphene-hloov asphalt feem ntau cuam tshuam nrog cov yam tseem ceeb uas ua rau kev tsim ntawm "nplua nuj qauv."

3.3. Cov nyhuv ntawm Graphene ntawm Microstructure thaum Asphalt Aging

Daim duab 4 qhia txog peb-dimensional (3D) AFM cov duab ntawm lub hauv paus thiab graphene-hloov asphalt ua ntej thiab tom qab kev laus. Raws li pom, qhov saum npoo ntawm graphene-hloov asphalt yog du, whereas ntawm lub hauv paus asphalt yog ntxhib. Tom qab dov-thin-film qhov cub (RTFOT) kev laus, qhov kev hloov pauv ntawm lub hauv paus asphalt nto tau pom tseeb dua li ntawm graphene-hloov asphalt. Tshwj xeeb, thaj chaw ncov tau nce qhov tseem ceeb, thiab qhov ntau thiab qhov loj ntawm "nplua nuj qauv" nce ntxiv. Txawm li cas los xij, AFM cov duab ntawm graphene-hloov asphalt ua ntej thiab tom qab kev laus zoo sib xws. Tus naj npawb ntawm "cov qauv muv" nyob rau hauv lub hauv paus thiab graphene-hloov asphalt tau nce tom qabsiab-agingnkoj (PAV). Qhov no tshwm sim vim tias asphalt viscosity tau nce thiab cov naj npawb ntawm cov pa roj carbon monoxide loj loj tuaj tom qab kev laus [31].

Daim duab 4. (a) 3D AFM cov duab ntawm lub hauv paus asphalt; (b) puag asphalt tom qab RTFOT laus; (c) puag asphalt tom qab PAV laus; (d) graphene-hloov asphalt; (e) graphene-hloov asphalt tom qab RTFOT laus; (f) graphene-hloov asphalt tom qab PAV laus

Cov ntaub ntawv txheeb xyuas ntau suav nrog kev ntxhib, tus naj npawb ntawm cov peaks pom, thiab qhov tsawg kawg nkaus thiab siab tshaj qhov siab tshaj plaws tuaj yeem raug rho tawm los ntawm daim duab 4 los ntawm "AFM software- Nanoscope Analysis" thiab cov npe hauv Table 1.

Table 1. Cov ntaub ntawv tseem ceeb tsis tau muab rho tawm los ntawm 3D AFM topography.

Ua ntej, qhov sib txawv ntawm qhov saum npoo morphology tuaj yeem txheeb xyuas qhov sib txawv ntawm qhov sib txawv ntawm cov theem microscopic xeev ntawm asphalt raws li qhov roughness Performance index (hauv paus ntsiab lus-square roughness (R,), qhov nruab nrab roughness, thiab siab tshaj qhov siab roughness) [32) . Hauv txoj kev tshawb no, kev sib raug zoo ntawm lub microscopic theem xeev thiab Rq tau tshawb xyuas. R, tau xam raws li hauv qab no:

qhov twg A yog qhov chaw scanning, uas ntsuas 10 um x 10 um hauv txoj kev tshawb no; h (x, y) yog qhov siab ua haujlwm ntawm morphology (nm); thiab h yog qhov siab siv (nm). Tus R, ntawm txhua tus qauv uas tau teev tseg hauv Table 1 tau txais los ntawm "AFM software Nanoscope AnalysisRoughness" thiab kuj tau nthuav tawm hauv daim duab, raws li pom hauv daim duab 5.

Raws li pom hauv daim duab 5, R, ntawm graphene-hloov asphalt yog me dua li ntawm asphalt, qhia tias qhov sib ntxiv ntawm graphene txo qhov roughness ntawm asphalt nto. Qhov saum npoo roughness muaj feem xyuam rau tus kheej-kho muaj peev xwm thiab adhesion kev ua tau zoo ntawm asphalt (33]. luv luv, qhov siab dua qhov roughness ntawm asphalt binder, qhov zoo ntawm tus kheej-kho muaj peev xwm thiab adhesion kev ua tau zoo ntawm asphalt. -lub sij hawm laus, txawm nyob rau hauv lub hauv paus asphalt los yog graphene-hloov asphalt (34,35). Txawm li cas los xij, qhov roughness poob qis tom qab kev laus mus ntev. Lub sij hawm kev laus feem ntau yog vim qhov txo qis hauv cov teeb pom kev zoo (saturated hydrocarbon thiab aromatic hydrocarbon) thiab, sib piv, qhov nce hauv asphaltene thiab resin cov ntsiab lus (36]. Nyob rau hauv cov ntaub ntawv no, ntau asphaltene tau txuas mus rau cov quav ciab chips thaum lub sij hawm tsim. "Ntau tus qauv," uas ua rau muaj kev nce hauv "nplua nuj qauv ntim thiab AFM roughness ntawm ob lub hauv paus thiab graphene-hloov asphalt tom qab kev laus luv luv.

Nws tau pom tias R, ntawm ob hom asphalt, nce tom qab RIFOT kev laus tab sis txo qis tom qab PAV laus. Qhov no tej zaum yuav yog vim qhov kev laus ntawm RIFOT yog ib qho qis me me ntawm cov khoom siv hluav taws xob tsawg dua, thiab cov khoom hnyav tau raug nthuav tawm, yog li ua rau muaj qhov nce ntawm qhov roughness. Lub caij no, qhov kev laus ntawm PAV tau siab dua, yog li ua rau cov khoom hnyav dua kom evaporated; Yog li ntawd, asphalt hloov los ntawm ib tug multiphase qauv mus rau ib tug ib-theem qauv. Qhov yooj yim ntawm lub xeev theem txo qhov roughness ntawm R, ntawm ob hom asphalt, nce tom qab RIFOT aging, qhov increment nyob rau hauv graphene-hloov asphalt yog me dua li ntawm lub hauv paus asphalt. Tom qab PAV aging.the R, ntawm ob hom asphalt txo qis, tab sis qhov txo qis hauv graphene-hloov asphalt tsawg dua li ntawm asphalt hauv paus. Yog li, nws tuaj yeem raug xam los ntawm R, qhov sib ntxiv ntawm graphene txhim kho lub peev xwm los tiv thaiv kev laus ntawm lub hauv paus asphalt.

Qhov thib ob, qhov kev hloov pauv hauv qhov chaw morphology tuaj yeem txheeb xyuas ntau los ntawm tus naj npawb ntawm cov peaks pom thiab ncov qhov tob. Ib pawg peaks koom tes tsim cov qauv abee. Tus naj npawb ntawm cov qauv muv tau tham yav dhau los thiab ntawm no tus naj npawb ntawm cov peaks pom tsis tau tham txog. Ib tug zaus histogram ntawm ncov qhov tob distributions yog tsim, raws li qhia nyob rau hauv daim duab 6. Raws li qhia, lub ncov qhov tob faib histogram ntawm lub graphene-hloov asphalt nyob rau hauv txawv kev laus tej yam kev mob tshwm sim ib tug me me ncov kab tshaj li ntawm lub hauv paus asphalt, qhia tias tus naj npawb. ntawm peaks nrog ntau dua qhov tob nyob rau hauv graphene-hloov asphalt yog tsawg dua thiab qhov kev faib ua feem me me ntawm thaj chaw. Lub ncov siab ntawm qhov tsis muaj hnub nyoog, luv luv, thiab lub hnub nyoog ntev asphalt tau tsom mus rau thaj tsam ntawm 70, 83, thiab 62 nm, feem. Qhov siab tshaj plaws ntawm cov neeg tsis muaj hnub nyoog, hnub nyoog luv luv, thiab lub sijhawm ntev graphene-hloov asphalt tau tsom mus rau thaj tsam ntawm 47, 60, thiab 57 raws li. Qhov sib ntxiv ntawm graphene tej zaum yuav cuam tshuam rau kev sib sau ntawm cov khoom siv hauv "ntub cov qauv," yog li txo qhov siab siab. Qhov siab ntawm cov neeg laus tom qab hnub nyoog "nplua nuj qauv poob vim qhov kev hloov ntawm asphalt Cheebtsam tshwm sim los ntawm asphalt aging, txo qis hauv cov khoom tsis-polar (saturated thiab aromatic), thiab nce hauv polar nta (colloids thiab asphaltenes).

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