Dab tsi yog cov khoom ntawm polycarboxylate superplasticizer?

Dab tsi yog cov khoom ntawm polycarboxylate superplasticizer?

Polycarboxylic acid dej txo tus neeg saib xyuas kev tshawb fawb yuav tsum tau daws 6 teeb meem loj

Polycarboxylic acid dej txo tus neeg sawv cev (PCE) tau txais kev hwm los ntawm cov kws tshawb fawb thiab cov neeg thov kev tsim vaj tsev txij li thaum nws yug los nyob rau xyoo 1980s vim nws cov tshuaj tsawg, cov dej txo qis (tsis pub tsawg dua 25%), cov txiaj ntsig zoo, muaj zog molecular adjustability, thiab tsis siv cov formaldehyde hauv cov txheej txheem synthesis, thiab lwm yam tshwj xeeb, tom qab qhov nrov ntawm PCE nyob rau hauv Tuam Tshoj txoj kev kub ceev railway thiab dam tej yaam num thaum pib ntawm lub xyoo pua 21st, ib tug nthwv dej ntawm kev tshawb fawb ntawm PCE tau mus ntev heev. . Tshwj xeeb tshaj yog tom qab Tuam Tshoj txoj kev tsheb ciav hlau ceev thiab cov phiaj xwm loj tau pib nrov rau daim ntawv thov PCE thaum pib ntawm lub xyoo pua 21st, ib nthwv dej tau tsim nyob rau hauv PCE kev tshawb fawb uas tsis tau ploj mus ntev. Hais txog kev tshawb fawb ntawm PCE, feem ntau ntawm cov kws tshawb fawb tau tsom mus rau qhov kev piav qhia ntawm nws cov txheej txheem ntawm kev ua, kev txhim kho ntxiv ntawm nws cov kev ua tau zoo, kev txhim kho cov khoom lag luam thiab kev ua kom zoo ntawm nws cov cuab yeej siv technology, nrog rau lub hom phiaj ntawm kev daws teeb meem ntawm kev tsim kho technology. ntawm cov cement pob zeb, txhim kho kev ua tau zoo ntawm cov pob zeb ua haujlwm (siab ua haujlwm siab, siab zog, siab toughness thiab siab durability), thiab ua tiav cov hom phiaj ntawm kev txuag nyiaj, rov ua dua tshiab, txuag hluav taws xob thiab txo qis emission. Txog rau tam sim no, txawm hais tias qee qhov txiaj ntsig tau ua tiav hauv kev tshawb fawb ntawm PCE, tab sis vim qhov kev paub ntawm PCE tseem nyob qis, tseem muaj teeb meem ntxiv los daws! Ntawm no peb muab rau 6 qhov teeb meem loj ntsig txog kev tshawb fawb PCE, txais tos los thuam thiab kho.

Qhov nyuaj 1: PCE mechanism

Kev sib xyaw ntawm PCE cement paste fluidity kev ua tau zoo yuav ua kom zoo dua qub. Cov kws tshawb fawb feem ntau ntseeg tias PCE yog adsorbed rau ntawm qhov chaw ntawm cov cement, thiab cov carboxylic acid pawg ntawm cov saw tseem ceeb ntawm PCE molecules adsorbed rau ntawm qhov chaw ntawm cov cement uas nyob ib sab ua rau dispersion los ntawm lub hauv paus ntsiab lus ntawm repulsion ntawm homogeneous nqi, ntxiv rau, sab saw. ntawm PCE molecules tuaj yeem muab qhov chaw tiv thaiv, yog li PCE muaj kev ua haujlwm zoo heev. Txawm li cas los xij, PCE adsorbed nyob rau saum npoo ntawm cov cement hais li cas? Seb nws yog qhov tshwm sim ntawm electrostatic kev txiav txim los yog tsav los ntawm entropy nce yog tseem inconclusive. Tsis tas li ntawd, lub sij hawm ntawm hydration induction lub sij hawm ntawm cov cement paste nrog PCE yog txuas ntxiv piv nrog cov cement paste yam tsis muaj PCE, uas yog macroscopically tshwm sim nyob rau hauv lub sij hawm ncua sij hawm ntawm cov cement paste. Tom qab ntawd, PCE ua li cas thiaj li paub txog kev thim rov qab ntawm cov cement paste? Vim li cas qhov dej ntawm cov cement muab tshuaj txhuam nrog PCE nrawm dua tom qab?

Qhov nyuaj 2: Interpolation ntawm PCE

Plank et al. xaus lus tias PCE tej zaum yuav intercalated nyob rau hauv ib co hydration khoom. Lub mechanism ntawm PCE intercalation yog dab tsi? Qee cov kws tshawb fawb ntseeg tias PCE cov molecules nyob rau hauv cov kua theem ntawm cov cement paste yuav muab qhov chaw rau nucleation ntawm hydrated calcium silicate (CSH), yog li qhov no yog ib qho laj thawj rau qhov tshwm sim ntawm intercalation? Tsis tas li ntawd, cov ntxhia theem montmorillonite, xws li bentonite thiab montmorillonite, kuj muaj cov qauv laminar, yog li tuaj yeem nkag siab cov laj thawj rau kev sib cuam tshuam ntawm PCE pab hauv kev txhim kho av nkos-resistant PCE?

Qhov nyuaj 3: Thaum ntxov-lub zog PCE

Tam sim no, muaj ntau qhov kev tshawb fawb ntawm PCE lub zog thaum ntxov, thiab qee qhov tsawg ntawm cov khoom siv PCE thaum ntxov tau pib tshwm sim hauv khw, tab sis tib neeg tseem muaj kev tsis ntseeg txog cov txheej txheem ntawm PCE thaum ntxov. Cov txiaj ntsig loj ntawm cov txiaj ntsig tau pom tias kev koom ua ke ntawm PCE yuav ncua cov dej ntawm cov cement mus rau qhov sib txawv, txo cov hydration thaum tshav kub kub tso tawm ntawm cement paste nyob rau theem pib, thiab tib lub sij hawm txo cov tiam ntawm CH thaum ntxov hardening. ntawm cement paste. Nws yog debatable txog lub mechanism ntawm kev txiav txim ntawm thaum ntxov-zog PCE thiab seb hom PCE no puas tau txhawb cov dej ntawm cov cement paste.

Qhov nyuaj 4: Kev teeb tsa-txhim kho PCE

Tam sim no, tus neeg sawv cev ceev ceev ntau yam nyob rau hauv kev ua lag luam feem ntau yog txhuas sulfate-hom kua alkali-dawb ceev-setting tus neeg saib xyuas, hom kev ceev ceev tus neeg saib xyuas no muaj tsawg dua rau lub zog ntawm pob zeb nyob rau hauv lub lig theem, tab sis lub adaptability nrog cov ntaub ntawv cementitious tsis zoo heev. Tom qab ntawd puas muaj kev cia siab los tsim kom muaj kev txhawb nqa PCE, uas tuaj yeem txhawb nqa lub nucleation ceev ntawm CSH hauv cov cement paste thaum ntxov, yam tsis muaj kev cuam tshuam rau kev txhim kho lub zog ntawm cov cement paste tom qab? Cov txheej txheem ntawm kev ua ntawm txhuas sulfate-raws li kua alkali-dawb ceev-teeb neeg ua hauj lwm tej zaum yuav muab ntau soluble SO{10}} rau hauv cov kua theem, yog li txhawb kev tsim ntawm calcite alumina (AFt) nyob rau hauv cov cement paste. Yog li, nws puas tuaj yeem npaj PCE procoagulant uas adsorbs tsawg heev ntawm cov cement hais thiab complexes calcium ions, yog li txhawb CSH nucleation, los ntawm copolymerization ntawm carboxylic acid monomers nrog ntev sab chains, nonionic monomers, thiab macromonomers?

Kev Sib Tw 5: Shrinkage-txo PCE

Ib tug series ntawm shrinkage yuav tshwm sim tom qab pob zeb casting, xws li yas ziab shrinkage, tshuaj shrinkage, nws tus kheej-shrinkage thiab hardening drying shrinkage, ua rau nws shrinkage tawg, uas cuam tshuam rau cov khoom siv kho tshuab thiab durability ntawm cov qauv. Ntau qhov kev ntsuam xyuas tau ua pov thawj tias kev koom ua ke ntawm cov neeg ua haujlwm zoo shrinkage tuaj yeem txo cov yas ziab kom qhuav, nws tus kheej-shrinkage thiab hardening drying shrinkage ntawm pob zeb ntau dua 40%, txo qhov tshwm sim ntawm cov kab nrib pleb loj hauv cov pob zeb ua vaj tse. Hais txog cov txheej txheem ntawm kev ua haujlwm ntawm kev txo qis tus neeg sawv cev, nws feem ntau lees paub tias (1) cov khoom sib xyaw ntawm shrinkage txo tus neeg saib xyuas kom txo tau qhov nro ntawm cov kua theem hauv cov pob zeb; (2) lub admixture ntawm shrinkage txo tus neeg sawv cev pab kom qeeb tus nqi ntawm evaporation ntawm cov dej hauv cov pob zeb; thiab (3) lub admixture ntawm shrinkage txo tus neeg sawv cev hloov lub pore qauv ntawm muab tshuaj txhuam rau hauv lub pob zeb. Tsis hais txog ntawm cov txheej txheem ntawm kev ua ntawm shrinkage reducers, lawv cov khoom siv loj dua (1% mus rau 3%) cuam tshuam rau kev txhawb siab ntawm lub zej zog engineering siv lawv. Txij li thaum lub aqueous tov ntawm PCE kuj muaj ib tug tsawg nto nro, kev cia siab tau pinned rau txoj kev vam meej thiab zus tau tej cov shrinkage-txo PCE. Txawm li cas los xij, txog niaj hnub no, tsis tau muaj qhov loj me me-txo cov khoom PCE.

Qhov nyuaj 6: PCE adaptability

Txawm hais tias qhov kev lag luam sib koom ntawm PCE hauv Tuam Tshoj cov dej txo tus neeg sawv cev kev lag luam tau tshaj 80%, tseem muaj qee cov neeg tsim khoom lag luam uas tsis muaj kev xaiv tab sis hloov PCE nrog naphthalene-raws li dej txo tus neeg sawv cev lossis aliphatic dej txo tus neeg sawv cev. Yog vim li cas rau qhov no yog tias tam sim no PCE cov khoom lag luam nyob rau hauv lub ntsej muag ntawm thaj chaw sib txawv ntawm cov khoom siv raw, nws qhov kev hloov pauv yog qhov nyuaj kom ua tau raws li qhov yuav tsum tau ua. Tuam Tshoj yog lub teb chaws loj heev, PCE nce qib thiab kev siv cov khoom sib txawv thiab lwm yam khoom siv ntxiv rau lub ntsej muag ntawm lub teb chaws, txawm tias siv cov cuab yeej siv cuab yeej technology, qee zaum tseem poob. Cov teeb meem no feem ntau cuam tshuam nrog kev hloov pauv ntawm PCE. Kev ua qauv zoo ntawm ntau hom PCE ntawm ntau yam khoom siv raw thiab lwm yam khoom siv los ntawm cov tes hauj lwm neural tej zaum yuav muaj txiaj ntsig zoo rau cov lag luam hauv kev txhim kho thiab kev siv PCE.
 

Cov ntaub ntawv los ntawm domestic Zhihu. "Concrete thiab Cement Products" Magazine

Source: Sun Zhenping
★★★ Nqe Lus Qhia: Txhawm rau xa cov ntaub ntawv ntau ntxiv rau cov neeg nyeem, phau ntawv xov xwm no yuav luam tawm qee cov lus zoo. Qhov no tsis txhais hais tias peb pom zoo nrog lawv cov kev xav lossis lees paub qhov tseeb ntawm lawv cov ntsiab lus. Txoj cai ntawm tsab xov xwm reprinted belongs rau tus thawj sau thiab tus thawj qhov chaw. Yog tias tsab xov xwm luam tawm muaj feem cuam tshuam txog kev cai lij choj thiab lwm yam teeb meem, thov hu lossis sau rau tus sau hauv ib lub lis piam kom cov ntawv xov xwm tuaj yeem siv cov kev ntsuas tsim nyog los daws lossis tshem tawm cov haujlwm tam sim ntawd!