Cellulose ethers yog ib hom organic polymer compounds uas tau hloov kho los ntawm cov cellulose ntuj. Lawv feem ntau siv rau hauv cov ntaub ntawv tsim kho, tshwj xeeb tshaj yog cov ntaub ntawv cement. Qhov cuam tshuam ntawm cellulose ether rau cov txheej txheem cement hydration feem ntau pom tseeb hauv cov hauv qab no: kev sib kis ntawm cov cement me me, kev khaws dej, cov nyhuv thickening, thiab qhov cuam tshuam rau morphology thiab kev txhim kho lub zog ntawm cov khoom cement hydration.
1. Kev Taw Qhia Txog Kev Ua Kom Huv Si Ntawm Cov Cement
Cov txheej txheem hydration ntawm cement yog ib qho kev sib xyaw ua ke ntawm cov tshuaj lom neeg thiab lub cev ntawm cement thiab dej. Cov kev sib xyaw no ua rau cov cement nplaum maj mam khov kho kom ua rau muaj cov qauv khov kho, thaum kawg tsim cov khoom hydration xws li calcium silicate hydrate (CSH) thiab calcium hydroxide (CH4). Thaum lub sijhawm no, qhov nrawm ntawm cov cement, qhov fluidity thiab dej khaws cia ntawm cov slurry, thiab kev tsim cov khoom hydration cuam tshuam ncaj qha rau lub zog thiab kev ruaj khov ntawm cov pob zeb kawg.
2. Lub tshuab ua haujlwm ntawm cellulose ethers
Cellulose ether ua lub luag haujlwm tseem ceeb hauv kev tswj hwm lub cev thiab tshuaj lom neeg hauv cov txheej txheem hydration cement. Cellulose ether feem ntau cuam tshuam rau cov txheej txheem hydration ntawm cement hauv ob txoj kev: ib qho yog los ntawm kev cuam tshuam rau kev faib tawm thiab evaporation ntawm cov dej hauv cov cement slurry; qhov tod tes yog los ntawm kev cuam tshuam rau kev sib cais thiab coagulation ntawm cov cement me me.
Kev tswj cov dej noo thiab kev khaws cia dej
Cov cellulose ethers tuaj yeem txhim kho qhov kev khaws cia dej ntawm cov khoom siv cement. Vim nws muaj zog hydrophilicity, cellulose ether tuaj yeem tsim cov tshuaj colloidal ruaj khov hauv dej, uas tuaj yeem nqus thiab khaws cov dej noo. Lub peev xwm tuav dej no yog qhov tseem ceeb hauv kev txo cov kab nrib pleb los ntawm kev poob dej sai hauv cov pob zeb thaum lub sijhawm ua kom dej noo. Tshwj xeeb tshaj yog nyob rau hauv qhov chaw qhuav lossis qhov kub siab, cellulose ether tuaj yeem tiv thaiv dej kom tsis txhob evaporate sai dhau thiab xyuas kom meej tias cov dej hauv cov cement slurry txaus los txhawb cov tshuaj tiv thaiv dej ib txwm muaj.
Rheology thiab Thickening
Cov cellulose ethers kuj tseem tuaj yeem txhim kho qhov rheology ntawm cov cement slurries. Tom qab ntxiv cellulose ether, qhov sib xws ntawm cov cement slurry yuav nce ntxiv ntau heev. Qhov xwm txheej no feem ntau yog vim cov qauv saw ntev tsim los ntawm cov cellulose ether molecules hauv dej. Cov molecule saw ntev no tuaj yeem txwv tsis pub txav mus los ntawm cov cement me me, yog li ua rau kom muaj viscosity thiab sib xws ntawm cov slurry. Cov khoom no tseem ceeb heev rau hauv cov ntawv thov xws li plastering thiab vuas nplaum, vim nws tiv thaiv cov cement mortar los ntawm kev ntws sai dhau thaum muab kev ua haujlwm zoo dua.
Ncua lub sijhawm ua kom dej noo thiab kho lub sijhawm teeb tsa
Cellulose ether tuaj yeem ncua qhov kev ua kom cov cement hydration thiab ua rau lub sijhawm teeb tsa thawj zaug thiab lub sijhawm teeb tsa zaum kawg ntawm cov cement slurry. Qhov teebmeem no tshwm sim vim tias cov molecules ntawm cellulose ether raug adsorbed rau ntawm qhov chaw ntawm cov cement me me, tsim ib qho thaiv uas tiv thaiv kev sib cuag ncaj qha ntawm dej thiab cov cement me me, yog li ua rau qeeb qhov kev ua kom cov dej tsis sib haum. Los ntawm kev ncua lub sijhawm teeb tsa, cellulose ethers tuaj yeem txhim kho kev ua haujlwm ntawm kev tsim kho, muab sijhawm ntau rau cov neeg ua haujlwm tsim kho los hloov kho thiab kho.
3. Cov nyhuv rau daim ntawv ntawm cov khoom siv cement hydration
Qhov muaj cov cellulose ethers kuj cuam tshuam rau qhov microstructure ntawm cov khoom siv cement hydration. Cov kev tshawb fawb tau qhia tias cov morphology ntawm calcium silicate hydrate (CSH) gel yuav hloov pauv tom qab ntxiv cellulose ether. Cellulose ether molecules yuav cuam tshuam rau cov qauv siv lead ua ntawm CSH, ua rau nws xoob dua. Cov qauv xoob no yuav txo qhov muaj zog thaum ntxov mus rau qee qhov, tab sis nws kuj pab txhim kho qhov tawv ntawm cov khoom.
Cov cellulose ethers kuj tseem tuaj yeem txo qhov kev tsim ntawm ettringite thaum lub sijhawm ua kom dej noo. Vim tias cellulose ether qeeb qeeb qhov kev ua kom dej noo, qhov kev tsim ntawm ettringite hauv cov cement raug txo qis, yog li txo qhov kev ntxhov siab sab hauv uas tshwm sim los ntawm kev nthuav dav thaum lub sijhawm kho.
4. Cov nyhuv rau kev loj hlob ntawm lub zog
Cov cellulose ethers kuj muaj feem cuam tshuam loj heev rau kev txhim kho lub zog ntawm cov khoom siv cement. Vim tias cellulose ethers qeeb qeeb qhov nrawm ntawm cov cement, kev txhim kho lub zog thaum ntxov ntawm cov cement pastes feem ntau qeeb dua. Txawm li cas los xij, thaum cov tshuaj tiv thaiv hydration txuas ntxiv mus, qhov cuam tshuam ntawm cellulose ether dej khaws cia thiab cov khoom hydration morphology tuaj yeem maj mam tshwm sim, uas yuav pab txhim kho lub zog hauv theem tom qab.
Yuav tsum nco ntsoov tias qhov ntxiv thiab hom cellulose ether muaj ob qho kev cuam tshuam rau lub zog. Ib qho ntau ntawm cellulose ether tsim nyog tuaj yeem txhim kho kev ua haujlwm ntawm kev tsim kho thiab ua rau lub zog tom qab nce ntxiv, tab sis kev siv ntau dhau tuaj yeem ua rau lub zog thaum ntxov ntawm cov ntaub ntawv cement-based txo qis thiab cuam tshuam rau cov khoom siv kho tshuab kawg. Yog li ntawd, hauv kev siv ua haujlwm, hom thiab koob tshuaj ntawm cellulose ether yuav tsum tau ua kom zoo thiab tsim raws li cov kev xav tau tshwj xeeb ntawm engineering.
Cellulose ether cuam tshuam rau cov txheej txheem hydration thiab cov khoom siv ntawm cov cement los ntawm kev txhim kho cov dej khaws cia ntawm cov khoom siv cement, kho qhov nrawm ntawm hydration, thiab cuam tshuam rau cov qauv ntawm cov khoom hydration. Txawm hais tias cellulose ethers yuav ua rau poob lub zog thaum ntxov, lawv tuaj yeem txhim kho qhov ruaj khov thiab tawv ntawm cov pob zeb hauv lub sijhawm ntev. Kev ntxiv ntawm cellulose ether kuj tseem tuaj yeem txhim kho kev ua haujlwm tsim kho, tshwj xeeb tshaj yog nyob rau hauv cov xwm txheej thov uas xav tau lub sijhawm ua haujlwm ntev thiab cov kev xav tau khaws cia dej siab. Nws muaj cov txiaj ntsig tsis tuaj yeem hloov pauv. Hauv cov ntawv thov engineering tiag tiag, kev xaiv tsim nyog ntawm hom thiab koob tshuaj ntawm cellulose ether tuaj yeem sib npaug lub zog, kev ua haujlwm tsim kho thiab cov kev xav tau ruaj khov ntawm cov khoom siv.
Lub sijhawm tshaj tawm: Cuaj hlis-27-2024