Kev paub nrov nrov: plaub lub tswv yim tseem ceeb ntawm kev ua ntawm cov dej txo cov neeg ua haujlwm, thawj kev faib tawm ntawm cov dej txo cov neeg ua haujlwm yog cov no

Cov dej-txo tus neeg sawv cev muaj kev ua haujlwm ntawm adsorption dispersion, lubrication thiab ntub dej, thiab nws yog ib qho yooj yim los sib tov cov pob zeb sib npaug nrog cov dej me me, kom cov kev ua haujlwm ntawm cov pob zeb sib xyaw tshiab tshiab tau txhim kho, uas yog cov nyhuv plasticizing. ntawm admixture dej-txo tus neeg sawv cev rau ntawm cov pob zeb tshiab sib xyaw. Koj puas paub tias lub tshuab ua haujlwm ntawm cov dej reducer yog dab tsi? Dab tsi yog kev faib cov dej txo cov neeg ua haujlwm?

Dab tsi yog Mechanisms of Action of Water Reducers?

LubricationCov dej reducers muaj cov pab pawg hydrophilic nrog cov polarity muaj zog, yog li cov yeeb yaj kiab adsorption ntawm cov cement hais tuaj yeem tsim cov dej khov dej ruaj khov nrog cov dej molecules. Cov yeeb yaj kiab dej no muab cov lubrication zoo, txo cov zawv zawg tiv thaiv ntawm cov cement hais, yog li ntxiv dag zog rau cov kua dej ntawm cov pob zeb.

DispersionTom qab sib tov cov cement nrog dej, vim yog cov dej ntawm cov cement hais, ib txheej txheej ob txheej yog tsim, tsim ib zaj duab xis dej solvated. Cement particles nthuav tawm cov nqi anisotropic ntawm lawv qhov chaw, ua rau muaj kev sib koom ua ke ntawm lawv. Qhov no ua rau muaj cov qauv flocculated, nrog 10% mus rau 30% ntawm cov dej sib tov ntim los ntawm cov cement hais thiab tsis tuaj yeem koom nrog hauv kev khiav dawb thiab lubrication, yog li cuam tshuam rau lub fluidity ntawm cov pob zeb sib tov. Thaum ntxiv cov dej reducers, lawv cov molecules tuaj yeem taw qhia lawv tus kheej ntawm qhov chaw ntawm cov cement, imparting tib nqi (feem ntau tsis zoo) thiab tsim electrostatic repulsion, uas txhawb kev tawg ntawm cov cement hais thiab disintegration ntawm cov qauv flocculated. Qhov no tso tawm cov dej ntim rau hauv cov dej ntws, ua kom cov dej ntws zoo ntawm cov pob zeb sib tov.

Tswj Tso Tawm los ntawm Grafted Copolymer Sab ChainsHauv kev tsim cov dej tshiab xws li polycarboxylate dej reducers, qee cov hlua txuas txuas mus rau cov molecules ntawm cov dej reducers tsis tsuas yog muab kev cuam tshuam steric tab sis kuj koom nrog hauv cov cement hydration. Nyob rau hauv ib puag ncig alkalinity siab, cov hlua sab no tuaj yeem maj mam tawg, yog li tso cov polycarboxylic acids nrog cov teebmeem dispersive, uas tuaj yeem txhim kho qhov tawg ntawm cov cement hais thiab tswj kev poob qis.

Steric HindranceDej reducers muaj hydrophilic sab chains nyob rau hauv lawv cov qauv, uas txuas mus rau hauv aqueous daws, yog li tsim ib tug hydrophilic peb-dimensional adsorption txheej ntawm tej thickness nyob rau saum npoo ntawm adsorbed cement hais. Thaum cov cement hais los ze rau ib leeg, cov txheej txheem adsorption pib sib tshooj, tsim kom muaj kev cuam tshuam tsis zoo. Kev sib tshooj ntau dua ua rau muaj kev cuam tshuam ntau dua steric, uas ua rau muaj kev cuam tshuam loj heev ntawm cov coagulation ntawm cov cement hais, tswj kom zoo slump hauv pob zeb.

Dab tsi yog hom dej reducers?

Raws li Material CompositionXws li lignosulfonates, polycyclic aromatic ntsev, dej-soluble resin sulfonates, naphthalene-raws li dej reducers, aliphatic dej reducers, amino dej reducers, thiab polycarboxylate dej reducers.

Raws li qhov tshwm simMuab faib ua kua thiab hmoov. Cov khoom ua kua feem ntau muaj cov ntsiab lus ntawm 20%, 40% (tseem hu ua concentrate), thiab 60%; hmoov khoom feem ntau muaj cov ntsiab lus ntawm ib ncig ntawm 98%.

Raws li Chemical CompositionXws li lignosulfonate water reducers, naphthalene water reducers, melamine water reducers, amino sulfonate water reducers, fatty acid water reducers, thiab polycarboxylate high-efficiency water reducers.

Raws li kev txo qis dej thiab txhim kho kev muaj peev xwmMuab faib mus rau hauv cov pa dej reducers (tseem hu ua plasticizers, nrog cov dej txo qis qis dua 8%, siv lignosulfonates ua tus qauv), cov dej ua tau zoo (tseem hu ua superplasticizers, nrog cov dej txo qis tsawg dua 14%, suav nrog naphthalene, melamine, amino sulfonate, thiab aliphatic hom), thiab cov dej ua haujlwm siab (nrog rau cov dej txo qis qis dua 25%, siv cov polycarboxylate dej reducers raws li tus qauv), ntxiv muab faib ua lub zog thaum ntxov, tus qauv, thiab hom retarding. .