Peb tau kawm dab tsi los ntawm Polycarboxylic Superplasticizer dhau 20 xyoo dhau los?

Txog 20 xyoo dhau los, ib hom tshiab ntawm superplasticizer raws li polycarboxylate polymers (PCE) tau qhia rau North American kev tsim kho kev lag luam. Ib yam li kev taw qhia ntawm naphthalene-raws li admixtures nyob rau hauv 1970s ho txhim kho ntau yam engineering zog ntawm ob qho tib si tshiab thiab hardened pob zeb, polycarboxylates tau ntxiv elevated kev ua tau zoo ntawm pob zeb sib tov.

Piv txwv li, PCEs tau ua kom muaj kev txhim kho ntawm kev sib koom ua ke ntawm tus kheej thiab tswj kev poob qis rau ntau tshaj li ob teev yam tsis tas ncua sijhawm teem sijhawm. Kuv muaj txoj cai los ua ib feem ntawm R&D thiab kev lag luam pab pawg rau lub tuam txhab tshuaj lom neeg tseem ceeb uas tau tsim thawj cov khoom lag luam polycarboxylate hauv xyoo 1990. Zoo li tag nrho cov thev naus laus zis tshiab tau qhia rau hauv kev tsim kho, tau muaj qhov kev kawm nruj, qhia txog ntau yam khoom siv thiab kev siv hauv kev tsim vaj tsev. Tsab ntawv xov xwm no qhia txog qee qhov tseem ceeb ntawm kev ua haujlwm tau los ntawm ob qho tib si kev lag luam thiab kev tshawb fawb hauv chav kuaj. Cov txiaj ntsig ntawm polycarboxylate superplasticizers yav dhau los tau sib tham thiab luam tawm hauv Cov Khoom Siv Khoom Siv.

Tsev neeg Polycarboxylate

Lub sij hawm "polycarboxylate" encompasses ib tsev neeg loj ntawm cov polymers uas chemists tuaj yeem tsim los qhia cov kev ua yeeb yam tshwj xeeb rau kev sib xyaw ua ke. Ua raws li kev taw qhia ntawm lub hom phiaj PCE superplasticizers, cov khoom siv tshiab tau tsim tshwj xeeb los muab lub zog thaum ntxov thiab ntau theem ntawm kev tuav pov hwm, nrog rau kev muaj peev xwm sib txawv rau kev tswj hwm huab cua hauv cov pob zeb. Ib chav kawm ntawm polycarboxylates tsawg heev cuam tshuam rau kev poob qis tab sis muaj lub sijhawm tso tawm ua haujlwm uas tso cai rau kev poob qis kom nce kev kwv yees raws sijhawm sib xyaw (saib daim duab 1). Yog li ntawd, hom khoom no tuaj yeem muab ntxiv ntawm ntau npaum li cas rau cov pob zeb sib xyaw ua ntej kom ua tiav qhov kev xav tau khaws cia raws li kev ua haujlwm (lub sijhawm thauj, kub, ncua ua ntej tso tawm, thiab lwm yam). Feem ntau, superplasticizer yog tsim los ntawm kev sib xyaw ntawm ob lossis ntau dua PCEs kom ua tiav kev sib xyaw ua ke ntawm lub zog thaum ntxov thiab lub neej poob ntev. Cov kws tshawb nrhiav yuav txuas ntxiv mus kho cov qauv PCE polymer kom hloov mus rau cov khoom siv thiab kev tsim kho.

• Huab cua nkag

Yuav luag tag nrho cov polycarboxylate-raws li admixtures yog tsim nrog lub defoamer los tswj cov huab cua tsis xav tau feem ntau cuam tshuam nrog PCE polymers. Rau ob qho tib si huab cua-entrained thiab non-air-entrained pob zeb siv, cov ntsiab lus ntawm huab cua feem ntau tuaj yeem tswj tau zoo los ntawm kev xaiv cov khoom PCE superplasticizer uas zoo tshaj plaws nrog cov ntaub ntawv siv. Kev hloov pauv hauv cov ntsiab lus ntawm cov pa roj carbon monoxide hauv cov tshauv ya tuaj yeem ua rau muaj kev cuam tshuam cov huab cua zoo ib yam, vim tias qhov dej ntawm cov defoamers tuaj yeem ua rau lawv cov adsorption los ntawm carbon hauv ya tshauv. Zuag qhia tag nrho, PCE-raws li cov khoom lag luam tuaj yeem txhim kho qhov ua tau zoo ntawm huab cua-entraining admixtures (AEA) piv rau polynaphthalene sulfonate (PNS) raws li superplasticizers, tso cai rau qis dua ntawm AEA kom ua tiav cov ntsiab lus huab cua sib npaug.

• Kev cuam tshuam ntawm Clays

Nyob rau hauv sib piv rau PNS superplasticizers, PCE polymer yog nkag thiab irreversibly adsorbed los ntawm tej av nplaum nplua uas tej zaum yuav muaj nyob rau hauv ntau yam aggregate qhov chaw. Daim duab 2 qhia txog yuav ua li cas cov av nplaum uas muaj cov xuab zeb nrog methylene xiav tus nqi ntawm 1.30 tuaj yeem cuam tshuam rau qhov yuav tsum tau noj ntau npaum li cas ntawm PNS piv rau PCE-based superplasticizers kom ua tiav kev poob qis. Feem ntau, nrog cov av nplaum tsis muaj av lossis cov av nplaum qis, PCEs tau txhaj tshuaj ntawm ib feem peb ntawm PNS-raws li superplasticizers rau qhov zoo sib xws. Txawm li cas los xij, thaum cov av nplaum muaj nyob hauv qee cov xuab zeb, qhov ntau npaum ntawm PCE txog li 50% siab dua PNS yuav xav tau. Yog li, yog tias qhov kev npaj txhij txog nce ntawm PCE superplasticizer ntau npaum li cas tshwm sim, kev tshuaj xyuas cov av nplaum nplua hauv cov khoom sib sau yuav tsum tau ua ntej.

• Flexible Dosage

Tsis zoo li PNS-raws li superplasticizers, uas yuav tsum tau ntxiv nyob rau hauv ncua sij hawm (piv txwv li, tom qab cov cement thiab dej tau pib sib tov), ​​PCEs kuj tsis hnov ​​​​tsw rau lub sijhawm ntxiv, tso cai rau kev hloov pauv ntau dua thaum lub sijhawm ua vaj tse pob zeb.

• Incompatibility nrog PNS Superplasticizers

Kev siv PCEs thiab PNS-raws li cov khoom hauv tib qho kev sib xyaw ua ke tuaj yeem ua rau poob haujlwm sai. Yog li, ob lub thev naus laus zis no, PNS thiab PCE, yuav tsum tsis txhob muab tso rau hauv tib qho kev sib xyaw ua ke.

• Strength Synergy nrog Calcium-based Set Accelerators

Thaum PCE superplasticizers siv nrog rau cov txheej txheem accelerators thiab corrosion inhibitors uas muaj calcium ntsev, qhov kev npaj txhij txog lub zog tau pom zoo piv rau cov khoom sib xyaw zoo sib xws uas siv cov khoom siv PNS. Qhov kev sib koom ua ke hauv kev txhim kho lub zog yog thawj zaug hauv kev sib xyaw uas muaj calcium nitrite-based corrosion inhibitor. Cov ntaub ntawv sau tseg hauv Table 1 tau tshaj tawm los ntawm cov neeg tsim khoom ua vaj tse uas yav dhau los tau siv ua ke ntawm lignosulfonate-based ASTM C494 Hom A dej reducer thiab hom G PNS / lignin-based superplasticizer los tsim cov pawg prestressed.

Qhov sib txawv ntawm lub zog zoo kawg nkaus tau ua tiav los ntawm kev hloov cov superplasticizer los ntawm PNS rau polycarboxylate tau raug lees paub los ntawm kev tshawb fawb thiab tuaj yeem pab txo qis cov ntsiab lus cement thaum tseem ua tau raws li qhov yuav tsum tau muaj zog. Qhov zoo siab, qhov sib txawv ntawm lub zog tsis zoo li cuam tshuam rau qhov kub ntawm cov dej ntau ntxiv, tab sis yog qhov sib txawv ntawm microstructure uas ua los ntawm kev sib xyaw ntawm calcium-based accelerating lossis corrosion-inhibiting admixtures thiab polycarboxylate-based admixtures.

Lub PCE superplasticizer hloov ob qho tib si PNS / lignin thiab Hom A cov khoom txo cov dej ntawm li ib feem peb ntawm qhov ntau npaum li cas. Tsis tas li ntawd, nws yog ib qho tseem ceeb uas qhov ntau npaum li cas ntawm AEA yuav tsum ua kom tau raws li cov ntsiab lus ntawm huab cua raug txo los ntawm 50% hauv PCE-admixed pob zeb.

Hauv cov ntsiab lus, thaum lub tuam txhab kev lag luam tau txais kev nkag siab tseem ceeb rau kev siv ntau yam thiab nkag siab txog cov kev txwv ntawm PCE superplasticizers, chemists, koom tes nrog cov kws tshaj lij thev naus laus zis, yuav txuas ntxiv hloov cov qauv polymer los tsim cov peev txheej tshiab los tsim, tso, thiab txuas ntxiv cov kev pabcuam. lub neej ntawm pob zeb sib tov.