1. Txheej txheem cej luam ntawm cellulose ether (HPMC)
Hydroxypropyl methylcellulose (HPMC) yog ib qho cellulose ether compound uas siv ntau, uas yog hloov kho los ntawm cov cellulose ntuj. Nws muaj cov khoom zoo heev rau kev yaj hauv dej, ua zaj duab xis, ua kom tuab thiab nplaum, yog li nws siv dav hauv cov ntaub ntawv tsim kho. Kev siv HPMC hauv cov ntaub ntawv cement feem ntau yog los txhim kho nws cov kua dej, khaws dej thiab kho lub sijhawm teeb tsa.
2. Cov txheej txheem yooj yim ntawm kev teeb tsa cement
Cov txheej txheem ntawm cov cement sib xyaw nrog dej los ua cov hydrates hu ua hydration reaction. Cov txheej txheem no muab faib ua ntau theem:
Lub sijhawm pib ua kom sov: Cov cement me me pib yaj, tsim cov calcium ions thiab silicate ions, qhia txog lub xeev ntws luv luv.
Lub sijhawm ua kom nrawm dua: Cov khoom siv dej nce ntxiv sai sai thiab cov txheej txheem teeb tsa pib.
Lub sijhawm qeeb: Tus nqi hydration txo qis, cement pib tawv, thiab pob zeb cement khov kho tau tsim.
Lub sijhawm ruaj khov: Cov khoom siv dej maj mam loj hlob thiab lub zog maj mam nce.
Lub sijhawm teeb tsa feem ntau muab faib ua lub sijhawm teeb tsa thawj zaug thiab lub sijhawm teeb tsa zaum kawg. Lub sijhawm teeb tsa thawj zaug yog lub sijhawm uas cov cement pib poob qhov plasticity, thiab lub sijhawm teeb tsa zaum kawg yog lub sijhawm uas cov cement poob qhov plasticity tag nrho thiab nkag mus rau theem hardening.
3. Txoj kev cuam tshuam ntawm HPMC rau lub sijhawm teeb tsa cement
3.1 Cov nyhuv tuab
HPMC muaj cov nyhuv ua kom tuab heev. Nws tuaj yeem ua rau cov nplaum cement viscosity nce ntxiv thiab tsim cov txheej txheem viscosity siab. Cov nyhuv ua kom tuab no yuav cuam tshuam rau kev sib kis thiab kev tso dej ntawm cov cement, thiab yog li cuam tshuam rau kev nce qib ntawm cov tshuaj tiv thaiv hydration. Cov nyhuv ua kom tuab txo qhov nrawm ntawm cov khoom hydration rau ntawm qhov chaw ntawm cov cement, yog li ncua lub sijhawm teeb tsa.
3.2 Kev khaws dej
HPMC muaj peev xwm khaws dej tau zoo. Ntxiv HPMC rau hauv cov cement paste tuaj yeem txhim kho qhov khaws dej ntawm cov nplaum. Kev khaws dej ntau tuaj yeem tiv thaiv cov dej ntawm qhov chaw ntawm cement kom tsis txhob evaporate sai dhau, yog li ntawd thiaj li tswj tau cov dej hauv cov cement paste thiab ua kom lub sijhawm ntawm cov tshuaj tiv thaiv hydration ntev dua. Tsis tas li ntawd, kev khaws dej pab cov cement paste tswj cov av noo kom zoo thaum lub sijhawm kho thiab txo qhov kev pheej hmoo ntawm kev tawg los ntawm kev poob dej thaum ntxov.
3.3 Kev qeeb ntawm kev nqus dej
HPMC tuaj yeem tsim ib daim zaj duab xis tiv thaiv uas npog qhov chaw ntawm cov cement, uas yuav cuam tshuam rau cov tshuaj tiv thaiv dej. Daim zaj duab xis tiv thaiv no tiv thaiv kev sib cuag ncaj qha ntawm cov cement thiab dej, yog li ncua cov txheej txheem dej ntawm cement thiab ua kom lub sijhawm teeb tsa ntev dua. Qhov cuam tshuam qeeb no yog qhov pom tseeb tshwj xeeb hauv HPMC hnyav molecular siab.
3.4 Kev txhim kho thixotropy
Qhov ntxiv ntawm HPMC kuj tseem tuaj yeem txhim kho thixotropy ntawm cov cement slurry (piv txwv li, qhov fluidity nce ntxiv nyob rau hauv qhov kev ua ntawm lub zog sab nraud thiab rov qab mus rau lub xeev qub tom qab lub zog sab nraud raug tshem tawm). Cov khoom thixotropic no pab txhim kho kev ua haujlwm ntawm cov cement slurry, tab sis hais txog lub sijhawm teeb tsa, qhov kev txhim kho thixotropy no yuav ua rau cov slurry rov faib tawm nyob rau hauv lub zog shear, ntxiv ntev lub sijhawm teeb tsa.
4. Kev siv HPMC uas cuam tshuam rau lub sijhawm teeb tsa cement
4.1 Cov ntaub ntawv hauv pem teb uas siv tau tus kheej
Hauv cov ntaub ntawv hauv pem teb uas nws tus kheej leveling, cement xav tau lub sijhawm teeb tsa thawj zaug ntev dua rau kev ua haujlwm leveling thiab screeding. Ntxiv HPMC tuaj yeem ua rau lub sijhawm teeb tsa thawj zaug ntawm cement ntev dua, ua rau cov ntaub ntawv nws tus kheej leveling muaj lub sijhawm ua haujlwm ntev dua thaum lub sijhawm tsim kho, zam qhov teeb meem tshwm sim los ntawm kev teeb tsa ua ntej ntawm cov cement slurry thaum lub sijhawm tsim kho.
4.2 Cov tshuaj khib ua ntej
Hauv cov tshuaj mortar uas tau sib xyaw ua ntej, HPMC tsis yog tsuas yog txhim kho qhov khaws dej ntawm cov tshuaj mortar xwb, tab sis kuj ua rau lub sijhawm teeb tsa ntev dua. Qhov no tseem ceeb heev rau cov sijhawm uas muaj kev thauj mus los ntev thiab lub sijhawm tsim kho, kom ntseeg tau tias cov tshuaj mortar ua haujlwm tau zoo ua ntej siv thiab zam kev nyuaj siab hauv kev tsim kho uas tshwm sim los ntawm lub sijhawm teeb tsa luv dhau.
4.3 Cov av nplaum sib xyaw qhuav
HPMC feem ntau ntxiv rau hauv cov av nplaum qhuav kom txhim kho nws txoj kev ua haujlwm. Qhov cuam tshuam ntawm HPMC ua rau cov av nplaum tuab dua, ua rau nws yooj yim rau kev siv thiab sib npaug thaum lub sijhawm tsim kho, thiab tseem ua rau lub sijhawm teeb tsa ntev dua, muab sijhawm txaus rau cov neeg ua haujlwm tsim kho los hloov kho.
5. Tej yam uas cuam tshuam rau lub sijhawm teeb tsa ntawm cov cement los ntawm HPMC
5.1 Tus nqi ntxiv ntawm HPMC
Qhov ntau ntawm HPMC ntxiv yog qhov tseem ceeb uas cuam tshuam rau lub sijhawm teeb tsa ntawm cov cement. Feem ntau, qhov ntau ntawm HPMC ntxiv, qhov ntau dua qhov pom tseeb ntawm lub sijhawm teeb tsa ntawm cov cement. Qhov no yog vim tias ntau cov HPMC molecules tuaj yeem npog ntau cov cement particle nto thiab cuam tshuam cov tshuaj tiv thaiv hydration.
5.2 Qhov hnyav ntawm HPMC
HPMC ntawm cov qhov hnyav molecular sib txawv muaj cov teebmeem sib txawv rau lub sijhawm teeb tsa ntawm cov cement. HPMC nrog cov qhov hnyav molecular siab feem ntau muaj cov nyhuv tuab dua thiab muaj peev xwm khaws dej, yog li nws tuaj yeem ncua lub sijhawm teeb tsa ntau dua. Txawm hais tias HPMC nrog cov qhov hnyav molecular qis kuj tuaj yeem ncua lub sijhawm teeb tsa, cov nyhuv tsis muaj zog heev.
5.3 Tej yam ib puag ncig
Qhov kub thiab av noo ib puag ncig kuj tseem yuav cuam tshuam rau qhov cuam tshuam ntawm HPMC rau lub sijhawm teeb tsa cement. Hauv qhov chaw kub siab, cov tshuaj tiv thaiv cement hydration raug nrawm dua, tab sis cov khoom khaws dej ntawm HPMC ua rau qhov cuam tshuam no qeeb. Hauv qhov chaw kub qis, cov tshuaj tiv thaiv hydration nws tus kheej qeeb, thiab qhov tuab thiab cov nyhuv khaws dej ntawm HPMC yuav ua rau lub sijhawm teeb tsa cement ntev dua.
5.4 Qhov sib piv ntawm dej thiab cement
Kev hloov pauv ntawm qhov sib piv ntawm dej thiab cement kuj tseem yuav cuam tshuam rau qhov cuam tshuam ntawm HPMC rau lub sijhawm teeb tsa cement. Ntawm qhov sib piv ntawm dej thiab cement siab dua, muaj dej ntau dua hauv cov cement paste, thiab qhov cuam tshuam ntawm dej khaws cia ntawm HPMC yuav muaj qhov cuam tshuam tsawg dua rau lub sijhawm teeb tsa. Ntawm qhov sib piv ntawm dej thiab cement qis dua, qhov cuam tshuam ntawm HPMC yuav tuab dua, thiab qhov cuam tshuam ntawm kev ncua sijhawm teeb tsa yuav tseem ceeb dua.
Ua ib qho tshuaj ntxiv rau cement, HPMC cuam tshuam rau lub sijhawm teeb tsa ntawm cement los ntawm ntau yam txheej txheem xws li thickening, water retention, thiab retardation ntawm hydration reaction. Kev siv HPMC tuaj yeem ua rau lub sijhawm teeb tsa thawj zaug thiab zaum kawg ntawm cement ntev dua, muab lub sijhawm ua haujlwm tsim kho ntev dua, thiab txhim kho kev ua haujlwm ntawm cov ntaub ntawv cement. Hauv kev siv ua haujlwm, cov yam xws li qhov ntau ntawm HPMC ntxiv, qhov hnyav molecular, thiab cov xwm txheej ib puag ncig ua ke txiav txim siab nws cov nyhuv tshwj xeeb rau lub sijhawm teeb tsa cement. Los ntawm kev kho cov yam ntxwv no kom raug, kev tswj hwm lub sijhawm teeb tsa cement kom meej tuaj yeem ua tiav kom tau raws li qhov xav tau ntawm ntau yam haujlwm tsim kho.
Lub sijhawm tshaj tawm: Lub Rau Hli-21-2024