Hydroxypropyl methylcellulose (HPMC), ua ib qho ntawm cov khoom siv polymer organic feem ntau siv rau hauv cov ntaub ntawv cement, feem ntau ua haujlwm los txhim kho kev ua haujlwm, kev khaws dej, thiab kev nplaum ntawm mortar lossis concrete. Txawm li cas los xij, ua ib qho hydrophilic polymer, HPMC kuj cuam tshuam rau cov txheej txheem hydration thiab microstructure ntawm cement rau ntau qib, yog li cuam tshuam rau cov khoom ntawm cov khoom tawv. Kev tshawb fawb tob tob txog nws cov txheej txheem ntawm kev ua haujlwm pab tswj hwm nws cov koob tshuaj hauv kev siv engineering, txhim kho kev ruaj khov ntawm lub cev thiab lub zog kawg.
1.Qhov cuam tshuam ncaj qha tshaj plaws ntawm HPMC rau cov txheej txheem cement hydration yog los ntawm nws cov txiaj ntsig khaws dej. Cement hydration xav tau dej dawb txaus, tab sis thaum lub sijhawm npaj mortar, vim muaj cov yam xws li kev nqus dej thiab evaporation ntawm lub substrate, dej yuav ploj sai sai, ua rau hydration tsis tiav. HPMC, los ntawm kev tsim cov qauv network peb-seem, ua rau viscosity thiab dej-tuav peev xwm ntawm slurry, khaws dej hauv lub cev thiab ncua kev tsiv teb tsaws chaw ntawm cov dej dawb. Cov txheej txheem no yog sib npaug rau "kev muab dej qeeb." Yog li ntawd, HPMC tuaj yeem qeeb qeeb qhov nqi hydration hauv cov theem thaum ntxov, tab sis nws txuas ntxiv muab dej noo rau cov cement me me, ua rau muaj dej ntau dua hauv theem nruab nrab thiab tom qab, yog li txhim kho qhov ceev ntawm cov qauv.
2.HPMC qhov kev cuam tshuam rau tus cwj pwm ntawm cov cement me me kuj tswj cov txheej txheem hydration. Tom qab o, HPMC tsim ib zaj duab xis nyias, ib feem adsorbed rau ntawm qhov chaw ntawm cov cement me me, inhibit qhov hydration reaction interface. Qhov muaj cov zaj duab xis adsorbed qeeb qhov kev sib cuag thawj zaug ntawm cov zaub mov xws li C3S thiab C2S thiab dej, ua rau lub sijhawm induction ntev thiab lub sijhawm hydration qeeb. Qhov no piav qhia vim li cas cov mortars uas muaj HPMC feem ntau qhia lub sijhawm teeb tsa ntev. Ntxiv mus, HPMC nrog cov qib hloov pauv siab lossis viscosity siab muaj peev xwm adsorption muaj zog dua thiab muaj kev cuam tshuam ntau dua rau hydration.
3.HPMC ua rau lub cev viscosity nce ntxiv, txo qhov fluidity ntawm cov cement paste thiab cuam tshuam rau kev tsiv teb tsaws chaw thiab crystallization morphology ntawm cov khoom hydration. Viscosity siab dua txwv qhov chaw loj hlob ntawm crystal, ua rau CSH gel thiab Ca (OH) ₂ crystals zoo dua, txhawb kev sib xyaw ua ke. Txawm hais tias lub zog thaum ntxov yuav txo qis, lub zog tom qab tau zoo dua vim muaj hydration tiav thiab txo cov capillary porosity.
4.Hais txog qhov microstructure, qhov ntxiv ntawm HPMC ua rau muaj cov qauv network denser ntawm cov khoom hydration. Nws yuav tsim cov adsorption lub cev tsis muaj zog nrog CSH gel, txhim kho interfacial adhesion thiab txo porosity. Qee qhov kev tshawb fawb qhia tau hais tias, ntawm cov nqi tsim nyog, HPMC tuaj yeem txhim kho cov qauv tsis zoo hauv thaj chaw hloov pauv interfacial (ITZ), txhim kho qhov tawv thiab tawg tsis kam ntawm cov mortar.
5.Qhov cuam tshuam ntawm HPMC rau kev ua kom cov cement noo yog ob sab. Kev ntxiv ntau dhau tuaj yeem ncua kev ua kom noo, ua rau lub zog txo qis thaum ntxov; tib lub sijhawm, cov organic ntau ntxiv tuaj yeem txo qhov kub ntawm cov khoom siv cementitious. Yog li ntawd, cov koob tshuaj yuav tsum tau tswj hwm kom zoo raws li hom mortar, hom khoom siv cementitious, thiab cov xwm txheej kev tsim kho. Piv txwv li, hauv cov ntaub ntawv tsim kho nyias txheej xws li cov nplaum pobzeb thiab hmoov putty, HPMC qhov kev khaws dej thiab lub sijhawm ncua sijhawm zoo; txawm li cas los xij, hauv cov mortars kho uas xav tau lub zog thaum ntxov siab, qhov viscosity thiab qhov sib piv ntxiv yuav tsum tau xaiv kom zoo.
6. HPMCQhov cuam tshuam rau cov txheej txheem hydration cement feem ntau yog pom tseeb hauv peb yam: ncua kev hydration thiab txhawb nqa cov tshuaj tiv thaiv theem tom qab los ntawm kev khaws dej; txuas ntxiv lub sijhawm induction los ntawm kev nqus; thiab hloov pauv cov morphology thiab cov qauv ntawm cov khoom hydration los ntawm kev nce viscosity. Kev tswj hwm tsim nyog ntawm hom thiab koob tshuaj ntawm HPMC tuaj yeem txhim kho kev ua haujlwm ntawm mortar thaum zam kev cuam tshuam ntau dhau rau lub zog thaum ntxov, ua tiav qhov sib npaug zoo tshaj plaws ntawm kev ua haujlwm thiab cov khoom siv kho tshuab.
Lub sijhawm tshaj tawm: Kaum Ib Hlis-17-2025