Kev cuam tshuam ntawm cellulose ethers ntawm evolution ntawm dej Cheebtsam thiab hydration khoom ntawm sulphoaluminate cement paste

Cov dej Cheebtsam thiab microstructure evolution nyob rau hauv cellulose ether hloov sulphoaluminate cement (CSA) slurry tau kawm los ntawm low-field nuclear magnetic resonance thiab thermal analyzer.Cov txiaj ntsig tau pom tias tom qab qhov sib ntxiv ntawm cellulose ether, nws adsorbed dej ntawm cov qauv flocculation, uas yog tus yam ntxwv ntawm qhov thib peb so ncov nyob rau hauv lub transverse so lub sij hawm (T2) spectrum, thiab tus nqi ntawm cov dej adsorbed tau zoo correlated nrog cov tshuaj.Tsis tas li ntawd, cellulose ether ua rau muaj txiaj ntsig zoo rau kev sib pauv dej ntawm sab hauv thiab inter-floc cov qauv ntawm CSA flocs.Txawm hais tias qhov sib ntxiv ntawm cellulose ether tsis muaj kev cuam tshuam rau hom hydration khoom ntawm sulphoaluminate cement, nws yuav cuam tshuam rau cov khoom hydration ntawm ib lub hnub nyoog tshwj xeeb.

Lo lus tseem ceeb:cellulose ether;sulfoaluminate cement;dej;hydration khoom

0,Ua ntej

Cellulose ether, uas yog ua los ntawm ntuj cellulose los ntawm ib tug series ntawm cov txheej txheem, yog ib tug tauj dua tshiab thiab ntsuab tshuaj admixture.Feem ntau cov cellulose ethers xws li methylcellulose (MC), ethylcellulose (HEC), thiab hydroxyethylmethylcellulose (HEMC) yog siv dav hauv tshuaj, kev tsim kho thiab lwm yam lag luam.Siv HEMC ua piv txwv, nws tuaj yeem txhim kho cov dej tuav thiab sib xws ntawm Portland cement, tab sis ncua kev teeb tsa ntawm cov cement.Nyob rau theem microscopic, HEMC kuj tseem muaj txiaj ntsig zoo rau lub microstructure thiab pore qauv ntawm cement paste.Piv txwv li, cov khoom hydration ettringite (AFt) feem ntau yuav yog luv luv-shaped, thiab nws nam piv yog qis dua;Nyob rau tib lub sijhawm, ntau qhov kaw qhov pores tau nkag mus rau hauv cov cement paste, txo cov xov tooj ntawm cov pores sib txuas.

Feem ntau ntawm cov kev tshawb fawb uas twb muaj lawm txog kev cuam tshuam ntawm cellulose ethers ntawm cement-based cov ntaub ntawv tsom rau Portland cement.Sulphoaluminate cement (CSA) yog cov pa roj carbon tsawg ntawm nws tus kheej tsim nyob rau hauv kuv lub teb chaws nyob rau hauv lub xyoo pua 20th, nrog anhydrous calcium sulphoaluminate ua cov ntxhia tseem ceeb.Vim tias muaj ntau ntawm AFt tuaj yeem tsim tau tom qab hydration, CSA muaj qhov zoo ntawm lub zog thaum ntxov, siab impermeability, thiab corrosion kuj, thiab yog dav siv nyob rau hauv lub teb ntawm pob zeb 3D luam ntawv, marine engineering tsim, thiab kho sai nyob rau hauv tsis tshua muaj kub ib puag ncig. .Nyob rau hauv xyoo tas los no, Li Jian et al.txheeb xyuas qhov cuam tshuam ntawm HEMC ntawm CSA mortar los ntawm qhov kev xav ntawm compressive zog thiab ntub ntom ntom;Wu Kai et al.kawm txog cov nyhuv ntawm HEMC ntawm cov txheej txheem hydration thaum ntxov ntawm CSA cement, tab sis cov dej hauv kev hloov kho CSA cement Txoj cai ntawm evolution ntawm cov khoom thiab slurry muaj pes tsawg leeg yog tsis paub.Raws li qhov no, txoj haujlwm no tsom mus rau kev faib tawm ntawm lub sijhawm hloov pauv hloov pauv (T2) hauv CSA cement slurry ua ntej thiab tom qab ntxiv HEMC los ntawm kev siv lub ntsuas hluav taws xob qis qis, thiab tshawb xyuas ntxiv txog kev tsiv teb tsaws thiab hloov txoj cai ntawm cov dej hauv cov dej. slurry.Kev hloov pauv ntawm cov cement paste tau kawm.

1. Kev sim

1.1 Cov khoom siv raw

Ob lub lag luam muaj cov sulphoaluminate cements tau siv, qhia tias yog CSA1 thiab CSA2, nrog qhov poob ntawm qhov hluav taws kub (LOI) tsawg dua 0.5% (feem ntau).

Peb qhov sib txawv hydroxyethyl methylcelluloses yog siv, uas yog suav hais tias yog MC1, MC2 thiab MC3 feem.MC3 yog tau los ntawm kev sib xyaw 5% (ntau feem) polyacrylamide (PAM) hauv MC2.

1.2 Mixing ratio

Peb hom cellulose ethers tau muab sib xyaw rau hauv cov sulphoaluminate cement feem, qhov ntau npaum li cas yog 0.1%, 0.2% thiab 0.3% (feem ntau, tib yam hauv qab no).Qhov sib npaug ntawm cov dej-cement yog 0.6, thiab cov dej-cement piv ntawm cov dej-cement piv tau zoo ua haujlwm tau zoo thiab tsis muaj los ntshav los ntawm kev ntsuas dej ntawm cov qauv sib xws.

1.3 Txoj kev

Cov khoom siv NMR uas tsis tshua muaj siv hauv kev sim yog PQ⁃001 NMR analyzer los ntawm Shanghai Numei Analytical Instrument Co., Ltd. Qhov sib nqus lub zog ntawm cov hlau nplaum ruaj khov yog 0.49T, proton resonance zaus yog 21MHz, thiab qhov kub ntawm cov hlau nplaum yog khaws cia tas li ntawm 32.0°C. Thaum lub sij hawm xeem, lub raj mis me me uas muaj cov qauv cylindrical tau muab tso rau hauv qhov kev sojntsuam coil ntawm qhov ntsuas, thiab CPMG raws li tau siv los sau cov teeb liab so ntawm cov cement paste.Tom qab inversion los ntawm kev txheeb xyuas software, T2 inversion nkhaus tau txais los ntawm kev siv Sirt inversion algorithm.Dej nrog ntau qib ntawm kev ywj pheej nyob rau hauv slurry yuav yog tus cwj pwm los ntawm qhov sib txawv ntawm kev so ncov nyob rau hauv lub transverse so spectrum, thiab cheeb tsam ntawm lub ncov so yog zoo correlated nrog cov dej, raws li cov hom thiab cov ntsiab lus ntawm cov dej nyob rau hauv lub slurry. tuaj yeem txheeb xyuas.Txhawm rau tsim kom muaj cov hlau nplaum sib nqus resonance, nws yog ib qho tsim nyog los xyuas kom meej tias qhov chaw zaus O1 (unit: kHz) ntawm lub xov tooj cua zaus yog raws li qhov zaus ntawm cov hlau nplaum, thiab O1 yog calibrated txhua hnub thaum kuaj.

Cov qauv no tau soj ntsuam los ntawm TG?DSC nrog STA 449C ua ke thermal analyzer los ntawm NETZSCH, lub teb chaws Yelemees.N2 tau siv los ua qhov chaw tiv thaiv, qhov cua sov yog 10°C / min, thiab ntsuas qhov ntsuas kub yog 30-800°C.

2. Cov txiaj ntsig thiab kev sib tham

2.1 Evolution of dej Cheebtsam

2.1.1 Undoped cellulose ether

Ob lub ncov so (txhais tau tias yog thawj zaug thiab thib ob so ncov) tuaj yeem pom meej meej nyob rau hauv lub sijhawm so (T2) spectra ntawm ob lub sulphoaluminate cement slurries.Thawj qhov kev so ncov pib los ntawm sab hauv ntawm cov qauv flocculation, uas muaj kev ywj pheej tsawg thiab lub sijhawm luv luv transverse so;Qhov thib ob so ncov pib los ntawm nruab nrab ntawm cov qauv flocculation, uas muaj ntau yam kev ywj pheej thiab lub sij hawm ntev transverse so.Nyob rau hauv sib piv, lub T2 coj mus rau thawj so ncov ntawm ob cements yog piv, thaum lub thib ob so ncov ntawm CSA1 tshwm tom qab.Qhov sib txawv ntawm sulphoaluminate cement clinker thiab tus kheej tsim cov cement, ob qhov kev so siab ntawm CSA1 thiab CSA2 ib feem sib tshooj ntawm thawj lub xeev.Nrog rau kev nce qib ntawm hydration, thawj lub ncov ntawm kev so maj mam maj mam muaj kev ywj pheej, thaj chaw maj mam txo qis, thiab nws ploj mus tag li ntawm 90 feeb.Qhov no qhia tau hais tias muaj qee qhov kev sib pauv dej ntawm cov qauv flocculation thiab cov qauv flocculation ntawm ob lub cement pastes.

Kev hloov pauv ntawm thaj chaw ncov ntawm qhov thib ob so ncov thiab kev hloov pauv ntawm T2 tus nqi sib raug rau lub apex ntawm lub ncov raws li tus yam ntxwv ntawm kev hloov pauv ntawm cov dej dawb thiab cov ntsiab lus ntawm lub cev thiab kev hloov pauv ntawm cov degree ntawm kev ywj pheej ntawm cov dej hauv slurry. .Kev sib xyaw ua ke ntawm ob tuaj yeem ua kom pom tseeb dua qhov txheej txheem dej ntawm slurry.Nrog rau kev nce qib ntawm hydration, thaj chaw ncov maj mam txo qis, thiab qhov hloov ntawm T2 tus nqi mus rau sab laug maj mam nce, thiab muaj qee qhov kev sib raug zoo ntawm lawv.

2.1.2 Ntxiv cellulose ether

Noj CSA2 tov nrog 0.3% MC2 ua piv txwv, T2 so spectrum ntawm sulphoaluminate cement tom qab ntxiv cellulose ether tuaj yeem pom.Tom qab ntxiv cellulose ether, lub thib peb so ncov sawv cev rau cov adsorption ntawm dej los ntawm cellulose ether tshwm nyob rau ntawm txoj hauj lwm uas lub transverse so lub sij hawm yog ntau tshaj 100ms, thiab lub ncov cheeb tsam maj mam nce nrog nce cellulose ether cov ntsiab lus.

Tus nqi ntawm cov dej ntawm cov qauv flocculation cuam tshuam los ntawm kev tsiv teb tsaws ntawm cov dej hauv cov qauv flocculation thiab cov dej adsorption ntawm cellulose ether.Yog li, tus nqi ntawm cov dej ntawm cov qauv flocculation muaj feem xyuam nrog cov qauv pore ntawm cov slurry thiab cov dej adsorption peev ntawm cellulose ether.Qhov chaw ntawm qhov thib ob so ncov txawv nrog Cov ntsiab lus ntawm cellulose ether sib txawv nrog ntau hom cement.Qhov chaw ntawm qhov thib ob so ncov ntawm CSA1 slurry txo qis tsis tu ncua nrog kev nce ntawm cellulose ether cov ntsiab lus, thiab yog qhov tsawg tshaj plaws ntawm 0.3% cov ntsiab lus.Nyob rau hauv sib piv, qhov thib ob so ncov cheeb tsam ntawm CSA2 slurry nce tsis tu ncua nrog nce cellulose ether cov ntsiab lus.

Sau cov kev hloov pauv ntawm thaj tsam ntawm qhov thib peb so ncov nrog qhov nce ntawm cov ntsiab lus ntawm cellulose ether.Txij li thaum lub ncov cheeb tsam cuam tshuam los ntawm qhov zoo ntawm cov qauv, nws yog ib qho nyuaj los xyuas kom meej tias qhov zoo ntawm cov qauv ntxiv yog tib yam thaum thauj cov qauv.Yog li ntawd, qhov piv ntawm cheeb tsam yog siv los ua tus yam ntxwv ntawm lub teeb liab tus nqi ntawm lub thib peb so ncov nyob rau hauv cov qauv sib txawv.Los ntawm qhov kev hloov pauv ntawm thaj tsam ntawm qhov thib peb so ncov nrog qhov nce ntawm cov ntsiab lus ntawm cellulose ether, nws tuaj yeem pom tau tias nrog kev nce ntawm cov ntsiab lus ntawm cellulose ether, thaj tsam ntawm peb lub ncov so hauv qhov pib pom kev nce ntxiv (hauv CSA1, thaum cov ntsiab lus ntawm MC1 yog 0.3%, nws yog ntau Qhov chaw ntawm lub thib peb so ncov txo qis me ntsis ntawm 0.2%), qhia tau hais tias nrog nce ntawm cov ntsiab lus ntawm cellulose ether, cov dej adsorbed kuj maj mam nce.Ntawm CSA1 slurries, MC1 tau nqus dej zoo dua li MC2 thiab MC3;Thaum ntawm CSA2 slurries, MC2 muaj qhov nqus dej zoo tshaj plaws.

Nws tuaj yeem pom los ntawm kev hloov pauv ntawm thaj chaw thib peb so ncov ib chav tsev loj ntawm CSA2 slurry nrog lub sijhawm ntawm cov ntsiab lus ntawm 0.3% cellulose ether tias thaj tsam ntawm qhov thib peb so ncov ib chav tsev loj zuj zus nrog cov dej, qhia. Txij li thaum lub hydration tus nqi ntawm CSA2 yog sai dua li ntawm clinker thiab nws tus kheej-ua cement, cellulose ether tsis muaj sij hawm rau ntxiv dej adsorption, thiab tso tawm cov dej adsorbed vim qhov ceev ceev ntawm cov kua theem concentration nyob rau hauv slurry.Tsis tas li ntawd, cov dej adsorption ntawm MC2 muaj zog dua li ntawm MC1 thiab MC3, uas yog raws li cov lus xaus dhau los.Nws tuaj yeem pom los ntawm kev hloov pauv ntawm thaj chaw ncov ib chav tsev loj ntawm qhov thib peb so ncov ntawm CSA1 nrog lub sijhawm sib txawv ntawm 0.3% ntau npaum li cas ntawm cellulose ethers uas txoj cai hloov pauv ntawm qhov thib peb so ncov ntawm CSA1 txawv ntawm CSA2, thiab thaj tsam ntawm CSA1 nce luv luv nyob rau theem pib ntawm hydration.Tom qab nce sai, nws poob qis, uas tej zaum yuav yog vim lub sij hawm ntev ntawm cov hlab ntsha ntawm CSA1.Tsis tas li ntawd, CSA2 muaj ntau gypsum, hydration yog ib qho yooj yim los tsim ntau AFt (3CaO Al2O3 3CaSO4 32H2O), siv dej dawb ntau, thiab tus nqi ntawm cov dej haus ntau tshaj tus nqi ntawm cov dej adsorption los ntawm cellulose ether, uas yuav ua rau lub thaj tsam ntawm qhov thib peb so ncov ntawm CSA2 slurry txuas ntxiv txo.

Tom qab kev koom ua ke ntawm cellulose ether, thawj thiab thib ob so ncov kuj hloov mus rau qee qhov.Nws tuaj yeem pom los ntawm lub ncov dav ntawm qhov thib ob so ncov ntawm ob hom cement slurry thiab cov slurry tshiab tom qab ntxiv cellulose ether tias lub ncov dav ntawm qhov thib ob so ncov ntawm cov slurry tshiab yog txawv tom qab ntxiv cellulose ether.nce, lub ncov zoo li yuav diffuse.Qhov no qhia tau hais tias kev koom ua ke ntawm cellulose ether tiv thaiv cov agglomeration ntawm cov cement hais txog qee yam, ua rau cov qauv flocculation kuj xoob, ua rau cov dej tsis muaj zog, thiab ua kom muaj kev ywj pheej ntawm cov dej ntawm cov qauv flocculation.Txawm li cas los xij, nrog qhov nce ntawm qhov ntau npaum li cas, qhov nce ntawm qhov siab tshaj qhov dav tsis pom tseeb, thiab qhov siab tshaj plaws ntawm qee cov qauv txawm txo qis.Tej zaum nws yuav yog tias qhov nce ntawm qhov ntau npaum li cas nce viscosity ntawm cov kua theem ntawm slurry, thiab tib lub sijhawm, cov adsorption ntawm cellulose ether rau cov cement hais yog txhim kho kom ua rau flocculation.Lub degree ntawm kev ywj pheej ntawm noo noo ntawm cov qauv yog txo.

Kev daws teeb meem tuaj yeem siv los piav qhia txog qib ntawm kev sib cais ntawm thawj thiab thib ob so ncov.Qib ntawm kev sib cais tuaj yeem suav tau raws li qib kev daws teeb meem = (Thawj tivthaiv-Asaddle) / Ua ntej tivthaiv, qhov twg Afirst tivthaiv thiab Asaddle sawv cev rau qhov siab tshaj plaws ntawm qhov siab tshaj plaws ntawm thawj qhov chaw so thiab qhov amplitude ntawm qhov qis tshaj ntawm ob lub ncov, raws.Cov degree ntawm kev sib cais tuaj yeem siv los ua tus yam ntxwv ntawm cov dej sib pauv ntawm cov qauv slurry flocculation thiab cov qauv flocculation, thiab tus nqi feem ntau yog 0-1.Tus nqi siab dua rau Kev Sib cais qhia tau hais tias ob feem ntawm cov dej yog qhov nyuaj dua los pauv, thiab tus nqi sib npaug li 1 qhia tias ob qhov dej tsis tuaj yeem pauv tau txhua.

Nws tuaj yeem pom los ntawm kev suav cov txiaj ntsig ntawm kev sib cais degree tias kev sib cais ntawm ob lub cements tsis ntxiv cellulose ether yog sib npaug, ob qho tib si yog li 0.64, thiab qhov sib cais degree yog txo qis tom qab ntxiv cellulose ether.Ntawm ib sab, qhov kev daws teeb meem txo qis ntxiv nrog qhov nce ntawm qhov ntau npaum li cas, thiab qhov kev daws teeb meem ntawm ob lub ncov txawm poob rau 0 hauv CSA2 tov nrog 0.3% MC3, qhia tias cellulose ether ho txhawb kev sib pauv dej hauv thiab nruab nrab ntawm cov flocculation qauv.Raws li qhov tseeb hais tias kev koom ua ke ntawm cellulose ether yeej tsis cuam tshuam rau txoj haujlwm thiab thaj chaw ntawm thawj lub ncov so, nws tuaj yeem xav tias qhov txo qis hauv kev daws teeb meem yog ib feem vim qhov nce ntawm qhov dav ntawm qhov thib ob so ncov, thiab cov qauv xoob flocculation ua rau cov dej pauv ntawm sab hauv thiab sab nraud yooj yim dua.Tsis tas li ntawd, qhov sib tshooj ntawm cellulose ether nyob rau hauv cov qauv slurry ntxiv txhim kho cov qib dej pauv ntawm sab hauv thiab sab nraud ntawm cov qauv flocculation.Ntawm qhov tod tes, kev daws teeb meem ntawm cellulose ether ntawm CSA2 muaj zog dua li ntawm CSA1, uas tej zaum yuav yog vim qhov chaw me me thiab qhov loj me me ntawm CSA2, uas yog rhiab heev rau cov nyhuv dispersion ntawm cellulose ether tom qab. kev koom ua ke.

2.2 Kev hloov pauv hauv slurry muaj pes tsawg leeg

Los ntawm TG-DTG spectra ntawm CSA1 thiab CSA2 slurries hydrated rau 90 min, 150 min thiab 1 hnub, nws tuaj yeem pom tias cov khoom hydration tsis hloov ua ntej thiab tom qab ntxiv cellulose ether, thiab AFt, AFm thiab AH3 yog tag nrho. tsim.Cov ntaub ntawv qhia tau hais tias qhov decomposition ntau ntawm AFt yog 50-120°C;Lub decomposition ntau ntawm AFm yog 160-220°C;Lub decomposition ntau ntawm AH3 yog 220-300°C. Nrog rau kev nce qib ntawm hydration, qhov poob ntawm cov qauv maj mam nce, thiab cov yam ntxwv DTG peaks ntawm AFt, AFm thiab AH3 maj mam ua kom pom tseeb, qhia tias qhov tsim ntawm peb cov khoom hydration maj mam nce.

Los ntawm cov feem loj ntawm txhua cov khoom hydration hauv cov qauv ntawm cov hnub nyoog sib txawv, nws tuaj yeem pom tau tias AFt tiam ntawm cov qauv dawb paug thaum muaj hnub nyoog 1d tshaj li cov qauv sib xyaw nrog cellulose ether, qhia tias cellulose ether muaj kev cuam tshuam zoo rau. hydration ntawm slurry tom qab coagulation.Muaj ib qho kev ncua sij hawm.Thaum 90 feeb, AFm ntau lawm ntawm peb cov qauv tseem zoo li qub;ntawm 90-150 feeb, kev tsim cov AFm hauv cov qauv dawb paug tau qeeb qeeb dua li ntawm ob pawg ntawm cov qauv;tom qab 1 hnub, cov ntsiab lus ntawm AFm hauv cov qauv dawb paug yog tib yam li cov qauv sib xyaw nrog MC1, thiab AFm cov ntsiab lus ntawm MC2 qauv tau qis dua hauv lwm cov qauv.Raws li rau cov khoom hydration AH3, tiam tus nqi ntawm CSA1 dawb paug qauv tom qab hydration rau 90 feeb yog ho qeeb dua li ntawm cov cellulose ether, tab sis lub tiam tus nqi tau sai sai tom qab 90 feeb, thiab AH3 ntau lawm tus nqi ntawm peb cov qauv. yog sib npaug ntawm 1 hnub.

Tom qab CSA2 slurry tau hydrated rau 90min thiab 150min, tus nqi ntawm AFT ua nyob rau hauv cov qauv tov nrog cellulose ether yog ho tsawg dua li ntawm cov dawb paug qauv, qhia tias cellulose ether kuj muaj ib tug tej yam retarding nyhuv ntawm CSA2 slurry.Hauv cov qauv ntawm lub hnub nyoog 1d, nws tau pom tias AFt cov ntsiab lus ntawm cov qauv dawb paug tseem siab dua li cov qauv sib xyaw nrog cellulose ether, qhia tias cellulose ether tseem muaj qee yam cuam tshuam rau hydration ntawm CSA2 tom qab kev teeb tsa zaum kawg, thiab qhov degree ntawm retardation ntawm MC2 yog ntau dua li cov qauv ntxiv nrog cellulose ether.MC 1.Thaum 90 feeb, tus nqi ntawm AH3 ua los ntawm cov qauv dawb paug yog me ntsis tsawg dua li cov qauv sib xyaw nrog cellulose ether;ntawm 150 feeb, AH3 ua los ntawm cov qauv dawb paug tshaj li ntawm cov qauv sib xyaw nrog cellulose ether;ntawm 1 hnub, AH3 ua los ntawm peb cov qauv sib npaug.

3. Cov lus xaus

(1) Cellulose ether tuaj yeem txhawb kev sib pauv dej ntawm cov qauv flocculation thiab cov qauv flocculation.Tom qab kev koom ua ke ntawm cellulose ether, cellulose ether adsorbs dej hauv slurry, uas yog tus cwj pwm los ntawm qhov thib peb so ncov nyob rau hauv lub transverse so lub sij hawm (T2) spectrum.Nrog rau qhov nce ntawm cov ntsiab lus ntawm cellulose ether, cov dej nqus ntawm cellulose ether nce, thiab thaj tsam ntawm qhov thib peb so ncov nce.Cov dej absorbed los ntawm cellulose ether yog maj mam tso rau hauv lub flocculation qauv nrog lub hydration ntawm slurry.

(2) Kev koom ua ke ntawm cellulose ether tiv thaiv cov agglomeration ntawm cov cement hais rau qee yam, ua rau cov qauv flocculation kuj xoob;thiab nrog kev nce ntawm cov ntsiab lus, cov kua theem viscosity ntawm slurry nce, thiab cellulose ether muaj kev cuam tshuam ntau dua rau cov cement hais.Cov txiaj ntsig zoo adsorption txo qis qhov kev ywj pheej ntawm dej ntawm cov qauv flocculated.

(3) Ua ntej thiab tom qab sib ntxiv ntawm cellulose ether, hom hydration khoom nyob rau hauv sulphoaluminate cement slurry tsis hloov, thiab AFt, AFm thiab txhuas kua nplaum raug tsim;tab sis cellulose ether me ntsis ncua kev tsim cov hydration khoom nyhuv.