Cellulose ether yog ib hom organic polymer compound siv dav hauv cov khoom siv hauv tsev, tshwj xeeb tshaj yog cov khoom siv cement. Cellulose ether tuaj yeem ncua cov txheej txheem dej ntawm cov cement, yog li kho cov haujlwm ua haujlwm, teeb tsa lub sijhawm thiab kev txhim kho thaum ntxov ntawm cov cement paste.
(1). Kev ncua sij hawm hydration
Cellulose ether tuaj yeem ncua cov tshuaj tiv thaiv dej ntawm cov cement, uas yog ua tiav los ntawm cov txheej txheem hauv qab no:
1.1 Adsorption thiab shielding teebmeem
Cov tshuaj viscosity siab tsim los ntawm kev ua kom cov cellulose ether nyob rau hauv cov kua dej muaj peev xwm tsim tau ib zaj duab xis adsorption rau saum npoo ntawm cov cement hais. Qhov tsim ntawm zaj duab xis no yog vim lub cev adsorption ntawm hydroxyl pawg nyob rau hauv cellulose ether molecules thiab ions nyob rau saum npoo ntawm cov cement hais, uas ua rau lub nto ntawm cov cement hais yog shielded, txo kev sib cuag ntawm cov cement hais thiab dej molecules, yog li ntawd. ncua cov tshuaj tiv thaiv hydration.
1.2 Zaj duab xis tsim
Nyob rau theem pib ntawm cov cement hydration, cellulose ether tuaj yeem tsim ib zaj duab xis ntom ntom ntawm cov cement hais. Lub hav zoov ntawm cov yeeb yaj kiab no zoo cuam tshuam qhov kev sib txawv ntawm cov dej molecules mus rau sab hauv ntawm cov cement hais, yog li ncua cov dej ntawm cov cement. Tsis tas li ntawd, kev tsim cov yeeb yaj kiab no kuj tseem tuaj yeem txo qhov kev sib cais thiab kev nthuav tawm ntawm calcium ions, ntxiv ncua kev tsim cov khoom hydration.
1.3 Dissolution thiab tso dej tawm
Cellulose ether muaj zog nqus dej, tuaj yeem nqus dej noo thiab tso tawm maj mam. Cov txheej txheem tso dej no tuaj yeem kho cov dej ntws thiab ua haujlwm ntawm cov cement slurry rau qee qhov, thiab txo qis tus nqi ntawm cov tshuaj tiv thaiv dej los ntawm kev txo cov dej zoo thaum lub sij hawm hydration txheej txheem.
(2). Kev cuam tshuam ntawm cement theem muaj pes tsawg leeg
Cellulose ethers muaj qhov sib txawv ntawm cov dej ntawm cov cement sib txawv. Feem ntau, cellulose ether muaj qhov pom tseeb dua ntawm cov dej ntawm tricalcium silicate (C₃S). Lub xub ntiag ntawm cellulose ether yuav ncua lub hydration ntawm C₃S thiab txo qhov tso tawm ntawm cov dej thaum ntxov ntawm C₃S, yog li ncua kev loj hlob ntawm lub zog thaum ntxov. Tsis tas li ntawd, cellulose ethers kuj tuaj yeem cuam tshuam cov dej ntawm lwm cov khoom ntxhia xws li dicalcium silicate (C₂S) thiab tricalcium aluminate (C₃A), tab sis cov teebmeem no kuj me me.
(3). Rheology thiab structural teebmeem
Cellulose ether tuaj yeem ua kom cov viscosity ntawm cov cement slurry thiab cuam tshuam rau nws cov rheology. High viscosity slurry pab txo qhov kev daws teeb meem thiab stratification ntawm cov cement hais, cia cov cement slurry tswj kom zoo sib xws ua ntej teeb tsa. Cov yam ntxwv siab viscosity no tsis tsuas yog ncua cov txheej txheem dej ntawm cov cement, tab sis kuj txhim kho cov dej ntws thiab kev tsim kho ntawm cov cement slurry.
(4). Kev siv cov teebmeem thiab kev ceev faj
Cellulose ethers muaj cov txiaj ntsig tseem ceeb hauv kev tiv thaiv cov cement hydration thiab yog li ntawd feem ntau siv los kho lub sijhawm teem thiab fluidity ntawm cov ntaub ntawv cement. Txawm li cas los xij, qhov ntau npaum li cas thiab hom cellulose ether yuav tsum tau tswj xyuas kom meej, vim tias cov cellulose ether ntau dhau yuav ua rau muaj teeb meem xws li tsis muaj zog thaum ntxov thiab nce shrinkage ntawm cov khoom siv cement. Tsis tas li ntawd, ntau hom cellulose ethers (xws li methylcellulose, hydroxypropylmethylcellulose, thiab lwm yam) muaj cov txheej txheem sib txawv thiab cov teebmeem hauv cov cement slurries, thiab yuav tsum tau xaiv raws li kev thov tshwj xeeb.
Daim ntawv thov ntawm cellulose ether nyob rau hauv cov ntaub ntawv cement-based tuaj yeem tsis tsuas yog ncua cov tshuaj tiv thaiv hydration ntawm cov cement, tab sis kuj txhim kho kev tsim kho thiab ua haujlwm ntev ntawm cov khoom. Los ntawm kev xaiv tsim nyog thiab siv cov cellulose ethers, qhov zoo thiab kev tsim kho ntawm cov khoom siv cement tuaj yeem txhim kho tau zoo.
Post lub sij hawm: Aug-03-2024