1. Thaum tshav kub kub hydration
Raws li kev tso tawm nkhaus ntawm cov dej kub ntawm lub sijhawm, cov txheej txheem hydration ntawm cov cement feem ntau muab faib ua tsib theem, uas yog, lub sijhawm pib dej (0 ~ 15min), lub sijhawm induction (15min ~ 4h), acceleration thiab teem sij hawm (4h ~ 8h), deceleration thiab hardening lub sij hawm (8h ~ 24h), thiab kho lub sij hawm (1d ~ 28h).
Cov txiaj ntsig kev ntsuam xyuas pom tau tias nyob rau theem pib ntawm induction (piv txwv li, thawj lub sij hawm hydration), thaum tus nqi ntawm HEMC yog 0.1% piv nrog cov cement slurry, ib qho exothermic ncov ntawm slurry yog siab heev thiab lub ncov yog ho nce. Thaum tus nqi ntawmHEMCnce mus rau Thaum nws yog siab dua 0.3%, thawj exothermic ncov ntawm slurry yog ncua, thiab lub ncov tus nqi maj mam txo nrog qhov nce ntawm HEMC cov ntsiab lus; HEMC yuav pom tseeb ncua lub sij hawm induction thiab lub sij hawm acceleration ntawm cov cement slurry, thiab cov ntsiab lus ntau dua, lub sij hawm induction ntev dua, lub sij hawm rov qab ntau dua, thiab qhov me me ntawm exothermic ncov; Kev hloov pauv ntawm cellulose ether cov ntsiab lus tsis muaj qhov cuam tshuam rau qhov ntev ntawm lub sijhawm deceleration thiab lub sijhawm ruaj khov ntawm cov cement slurry, raws li qhia hauv daim duab 3(a) Nws tau pom tias cellulose ether tuaj yeem txo qhov kub ntawm cov dej ntawm cov cement paste hauv 72 teev, tab sis thaum tshav kub ntawm hydration ntev dua 36 teev, qhov kev hloov ntawm cov ntsiab lus ntawm cellulose ether tuaj yeem txo qhov kub ntawm hydration ntawm cement paste hauv 72 teev, tab sis thaum tshav kub ntawm hydration ntev dua 36 teev, qhov kev hloov ntawm cov ntsiab lus ntawm cellulose ether tuaj yeem txo cov cua sov ntawm cov cement paste hauv 72 teev. raws li daim duab 3(b).
Fig.3 Variation trend of hydration heat release rate of cement paste with different content of cellulose ether (HEMC)
2. Mechanical zog:
Los ntawm kev kawm ob hom cellulose ethers nrog viscosities ntawm 60000Pa·s thiab 100000Pa·s, nws tau pom tias lub zog compressive ntawm cov hloov mortar tov nrog methyl cellulose ether txo qis nrog qhov nce ntawm nws cov ntsiab lus. Lub zog compressive ntawm cov mortar hloov kho nrog 100000Pa·s viscosity hydroxypropyl methyl cellulose ether nce ua ntej thiab tom qab ntawd txo qis nrog qhov nce ntawm nws cov ntsiab lus (raws li qhia hauv daim duab 4). Nws qhia tau hais tias kev koom ua ke ntawm methyl cellulose ether yuav txo tau lub zog compressive ntawm cement mortar. Qhov ntau npaum li cas, lub zog me me yuav yog; qhov me dua qhov viscosity, qhov ntau dua qhov cuam tshuam ntawm qhov poob ntawm mortar compressive zog; hydroxypropyl methyl cellulose ether Thaum qhov ntau npaum li cas tsawg dua 0.1%, lub zog compressive ntawm cov mortar tuaj yeem tsim nyog ntxiv. Thaum qhov ntau npaum li cas ntau dua 0.1%, lub zog compressive ntawm cov tshuaj khib yuav txo qis nrog qhov nce ntawm cov tshuaj, yog li cov tshuaj yuav tsum tau tswj ntawm 0.1%.
Fig.4 3d, 7d thiab 28d compressive zog ntawm MC1, MC2 thiab MC3 hloov cement mortar
(Methyl cellulose ether, viscosity 60000Pa·S, tom qab ntawd hu ua MC1; methyl cellulose ether, viscosity 100000Pa·S, hu ua MC2; hydroxypropyl methylcellulose ether, viscosity ·S300red pa).
3. Csijhawm ntau:
Los ntawm kev ntsuas lub sij hawm teem caij ntawm hydroxypropyl methylcellulose ether nrog viscosity ntawm 100000Pa·s nyob rau hauv ntau npaum li cas ntawm cov cement paste, nws tau pom tias nrog kev nce ntawm HPMC ntau npaum li cas, lub sij hawm pib pib thiab lub sij hawm zaum kawg ntawm cov cement mortar tau ntev. Thaum lub concentration yog 1%, lub sij hawm pib pib mus txog 510 feeb, thiab lub sij hawm teem zaum kawg mus txog 850 feeb. Piv nrog rau cov qauv dawb paug, lub sij hawm pib lub sij hawm yog ncua los ntawm 210 feeb, thiab lub sij hawm teem zaum kawg yog ncua los ntawm 470 feeb (raws li qhia hauv daim duab 5). Txawm hais tias nws yog HPMC nrog viscosity ntawm 50000Pa s, 100000Pa s lossis 200000Pa s, nws tuaj yeem ncua kev teeb tsa ntawm cov cement, tab sis piv nrog peb lub cellulose ethers, thawj zaug teeb tsa thiab lub sij hawm zaum kawg yog ntev nrog qhov nce ntawm viscosity, raws li qhia hauv daim duab 6. Qhov no yog vim hais tias cellulose ether yog adsorbed rau saum npoo ntawm cov cement hais, uas tiv thaiv dej los ntawm kev sib cuag nrog cov cement hais, yog li ncua lub hydration ntawm cement. Qhov ntau dua qhov viscosity ntawm cellulose ether, lub thicker lub adsorption txheej nyob rau saum npoo ntawm cov cement hais, thiab qhov tseem ceeb ntawm cov nyhuv retarding.
Fig.5 Cov nyhuv ntawm cellulose ether cov ntsiab lus ntawm kev teeb tsa lub sijhawm ntawm mortar
Fig.6 Cov txiaj ntsig ntawm cov viscosities sib txawv ntawm HPMC ntawm lub sijhawm teeb tsa ntawm cement paste
(MC-5(50000Pa·s), MC-10(100000Pa·s) thiab MC-20(200000Pa·s))
Methyl cellulose ether thiab hydroxypropyl methyl cellulose ether yuav ua rau lub sijhawm teem sijhawm ntawm cov cement slurry, uas tuaj yeem xyuas kom meej tias cov cement slurry muaj sijhawm txaus thiab dej rau cov tshuaj tiv thaiv hydration, thiab daws qhov teeb meem ntawm lub zog qis thiab theem kawg ntawm cov cement slurry tom qab hardening. tawg teeb meem.
4. Kev tuav dej:
Cov txiaj ntsig ntawm cellulose ether cov ntsiab lus ntawm kev tuav dej tau kawm. Nws tau pom tias nrog kev nce ntawm cov ntsiab lus ntawm cellulose ether, cov dej tuav tus nqi ntawm mortar nce, thiab thaum cov ntsiab lus ntawm cellulose ether ntau dua 0.6%, cov dej tuav tus nqi yuav ruaj khov. Txawm li cas los xij, thaum muab peb hom cellulose ethers (HPMC nrog viscosity ntawm 50000Pa s (MC-5), 100000Pa s (MC-10) thiab 200000Pa s (MC-20)), qhov cuam tshuam ntawm viscosity ntawm dej tuav yog txawv. Kev sib raug zoo ntawm tus nqi tuav dej yog: MC-5.
Lub sij hawm xa tuaj: Plaub Hlis-28-2024