Hnub Kawg:5,Tsib,2022

Thaum cov cement sib tov nrog dej, vim kev sib nrig sib attraction ntawm cov cement molecules, kev sib tsoo ntawm thermal motion ntawm cement hais nyob rau hauv cov kev daws, qhov opposite nqi ntawm cov cement minerals thaum lub sij hawm hydration txheej txheem, thiab tej yam kev koom tes ntawm cov solvated dej. zaj duab xis tom qab cov cement minerals yog hydrated. ua ke, kom cov cement slurry tsim cov qauv flocculation. Ib tug loj npaum li cas ntawm stirring dej yog qhwv nyob rau hauv lub flocculation qauv, thiaj li hais tias qhov saum npoo ntawm cov cement hais tsis tuaj yeem tiv tauj nrog dej, ua rau muaj kev nce hauv cov dej haus thiab tsis ua tiav qhov kev tsim kho yuav tsum tau ua.

Tom qab ntxiv cov superplasticizer, pawg hydrophobic ntawm lub charged superplasticizer molecule yog directionally adsorbed rau ntawm qhov chaw ntawm cov cement particle, thiab pawg hydrophilic taw qhia rau cov kua dej aqueous, tsim ib zaj duab xis adsorption ntawm cov cement particle, kom cov nto. ntawm cov cement particle muaj tib tus nqi. Nyob rau hauv qhov kev txiav txim ntawm hluav taws xob repulsion, cov cement hais yog sib cais los ntawm ib leeg, thiab cov qauv flocculation ntawm cov cement slurry yog disintegrated. Ntawm qhov tod tes, cov dej dawb hauv cov qauv flocculation ntawm cov cement slurry raug tso tawm, uas ua rau kom muaj kev sib cuag ntawm cov cement hais thiab dej, yog li ua kom lub fluidity ntawm qhov sib tov; Tsis tas li ntawd, qhov slippage ntawm cov cement hais kuj nce ntxiv vim cov thickening ntawm cov solvated dej zaj duab xis tsim nyob rau saum npoo ntawm cov cement hais. Qhov no yog lub hauv paus ntsiab lus uas cov dej txo cov neeg ua haujlwm txo cov dej siv vim yog adsorption, dispersion, ntub dej thiab lubrication.

Lub hauv paus ntsiab lus: Hauv luv luv, tus neeg saib xyuas dej txo qis feem ntau yog cov surfactant uas adsorbs ntawm cov cement hais, ua rau cov khoom pov thawj hluav taws xob. Cov khoom sib tsoo ib leeg vim yog tib lub zog hluav taws xob, kom cov cement particles dispersed, thiab cov dej ntau dhau ntawm cov khoom raug tso tawm kom txo cov dej. Ntawm qhov tod tes, tom qab ntxiv cov dej txo tus neeg sawv cev, ib zaj duab xis adsorption yog tsim nyob rau saum npoo ntawm cov cement hais, uas cuam tshuam rau hydration ceev ntawm cov cement, ua rau cov siv lead ua kev loj hlob ntawm cov cement slurry zoo dua, cov qauv network yog ntau dua. ntom, thiab txhim kho lub zog thiab cov qauv ntom ntom ntawm cov cement slurry.

Thaum cov slump ntawm pob zeb yog qhov zoo ib yam, cov admixture uas tuaj yeem txo cov dej haus yog hu ua pob zeb ua dej reducer. Tus neeg saib xyuas dej tau muab faib ua tus neeg saib xyuas dej zoo tib yam thiab cov dej ua kom muaj txiaj ntsig zoo. Cov uas muaj dej txo qis dua lossis sib npaug li 8% yog hu ua cov dej txo qis, thiab cov dej txo qis dua 8% yog hu ua cov dej txo qis. Raws li cov teebmeem sib txawv uas superplasticizers tuaj yeem ua rau pob zeb, lawv tau muab faib ua lub zog thaum ntxov superplasticizers thiab air-entraining superplasticizers.

Los ntawm kev qhia txog kev ua haujlwm ntawm kev ntxiv dej txo tus neeg sawv cev rau tus neeg saib xyuas kev sib khi, peb muaj kev nkag siab meej txog qhov teeb meem ntawm kev ntxiv cov dej txo tus neeg sawv cev hauv kev tsim kho tus neeg saib xyuas sealing. Hauv cov ntsiab lus yooj yim, lub luag haujlwm ntawm cov dej txo tus neeg sawv cev yog tus neeg sawv cev ua haujlwm saum npoo av, uas tuaj yeem ua rau cov khoom siv cement tam sim no tib lub electrode, thiab tso cov dej ntawm cov khoom los ntawm cov khoom ntawm lub cev ntawm tib lub zog repulsion, yog li txo cov dej.