Cellulose ethers, tshwj xeeb tshaj yog hydroxypropylmethylcellulose (HPMC) thiab methylhydroxyethylcellulose (MHEC), tau dav siv los ua cementitious khoom additives hauv kev tsim kho. Paub txog lawv cov khoom tuav dej, cov ntaub ntawv no tuaj yeem txhim kho kev ua haujlwm, rheology thiab kev sib raug zoo ntawm cov ntaub ntawv cementitious. Txawm li cas los xij, lawv lub zog ntawm cov cement hydration tsis yog ib txwm meej.
Cement hydration yog hais txog cov tshuaj tiv thaiv ntawm cov dej thiab cov khoom siv cementitious los tsim cov khoom siv dej xws li calcium silicate hydrate (CSH) thiab calcium hydroxide (Ca(OH)2). Cov txheej txheem no tseem ceeb heev rau kev txhim kho cov pob zeb ua kom muaj zog thiab kav ntev.
Qhov sib ntxiv ntawm cellulose ethers rau cov ntaub ntawv cementitious tuaj yeem muaj qhov zoo thiab qhov tsis zoo ntawm cov txheej txheem hydration. Ntawm qhov tod tes, cov dej tuav kev ua tau zoo ntawm cellulose ether tuaj yeem txhawb cov cement kom tsis tu ncua tau dej rau cov tshuaj tiv thaiv, yog li ua kom ceev thiab qib ntawm hydration. Qhov no shortens teem sij hawm, accelerates lub zog txoj kev loj hlob thiab txhim kho tag nrho cov khoom ntawm cov pob zeb.
Cellulose ether tuaj yeem ua raws li kev tiv thaiv colloid tiv thaiv kev sib sau thiab kev sib haum xeeb ntawm cov cement hais. Qhov no ua rau muaj qhov sib xws thiab ruaj khov microstructure, uas ntxiv dag zog rau cov khoom siv kho tshuab thiab ruaj khov ntawm pob zeb.
Ntawm qhov tod tes, kev siv ntau dhau ntawm cellulose ethers tuaj yeem cuam tshuam tsis zoo rau cov cement hydration. Vim tias cellulose ether yog ib feem ntawm hydrophobic, nws thaiv cov dej nkag mus rau hauv cov khoom siv gelling, ua rau qeeb lossis tsis tiav hydration. Qhov no ua rau txo qis lub zog thiab durability ntawm cov pob zeb.
Yog tias qhov concentration ntawm cellulose ether siab dhau lawm, nws yuav nyob hauv qhov chaw hauv cov cement slurry uas yuav tsum tau ntim los ntawm cov cement hais. Yog li ntawd, tag nrho cov khib nyiab cov ntsiab lus ntawm slurry yuav txo qis, ua rau txo cov khoom siv kho tshuab. Tshaj cellulose ethers tuaj yeem ua tau raws li qhov thaiv, tiv thaiv kev sib cuam tshuam ntawm cov cement thiab dej, ntxiv rau cov txheej txheem hydration qeeb.
Nws yog ib qho tseem ceeb los txiav txim siab qhov zoo ntawm cellulose ether siv los txhim kho cov khoom ntawm cov khoom siv gelled thaum tsis txhob muaj kev cuam tshuam tsis zoo ntawm cov dej. Tus nqi yog nyob ntawm ntau yam, xws li hom cellulose ether, cement muaj pes tsawg leeg, dej-cement ratio thiab kho tej yam kev mob.
Cellulose ethers, tshwj xeeb tshaj yog HPMC thiab MHEC, tuaj yeem muaj txiaj ntsig zoo ntawm cov cement hydration, nyob ntawm lawv cov concentration thiab cov ntsiab lus tshwj xeeb ntawm cov khoom cementitious. Tus nqi ntawm cellulose ether siv yuav tsum tau ua tib zoo txiav txim siab kom ua tiav cov khoom xav tau yam tsis muaj kev cuam tshuam cov khoom ntawm cov pob zeb. Nrog rau kev siv thiab kev ua kom zoo, cellulose ethers tuaj yeem pab txhawb kev txhim kho cov khoom siv ruaj khov, siv tau ntev thiab ruaj khov.
Post lub sij hawm: Aug-23-2023