1. Kutentha kwa madzi
Malinga ndi kakulidwe ka kutentha kwa madzi pakapita nthawi, njira yothira madzi ya simenti nthawi zambiri imagawidwa m'magawo asanu, omwe ndi nthawi yoyamba ya madzi (0 ~ 15min), nthawi yoyambitsa (15min ~ 4h), nthawi yofulumizitsa ndi kukhazikitsa (4h ~ 8h), nthawi yochepetsa mphamvu ndi kuuma (8h ~ 24h), ndi nthawi yoziziritsa (1d ~ 28d).
Zotsatira za mayeso zikusonyeza kuti pachiyambi cha kuyambitsa (monga nthawi yoyamba ya hydration), pamene kuchuluka kwa HEMC kuli 0.1% poyerekeza ndi slurry yopanda kanthu ya simenti, peak ya exothermic ya slurry imapita patsogolo ndipo peak imawonjezeka kwambiri. Pamene kuchuluka kwaHEMCKuwonjezeka kufika pa 0.3%, nsonga yoyamba ya exothermic ya slurry imachedwa, ndipo mtengo wake umachepa pang'onopang'ono ndi kuwonjezeka kwa HEMC; HEMC idzachedwetsa nthawi yoyambitsa ndi nthawi yofulumira ya slurry ya simenti, ndipo kuchuluka kwake kukakhala kwakukulu, nthawi yoyambitsa imakhala yayitali, nthawi yofulumira imakhala yocheperako, ndipo nsonga ya exothermic imakhala yaying'ono; kusintha kwa kuchuluka kwa cellulose ether sikukhudza kutalika kwa nthawi yochepetsera ndi nthawi yokhazikika ya slurry ya simenti, monga momwe zasonyezedwera pa Chithunzi 3(a). Zawonetsedwa kuti cellulose ether ingachepetsenso kutentha kwa hydration ya simenti mkati mwa maola 72, koma kutentha kwa hydration kukakhala kwa nthawi yayitali kuposa maola 36, kusintha kwa kuchuluka kwa cellulose ether sikukhudza kutentha kwa hydration ya simenti, monga Chithunzi 3(b).
Chithunzi 3 Kusintha kwa kayendedwe ka kutentha kwa madzi kwa simenti yokhala ndi kuchuluka kosiyanasiyana kwa ether ya cellulose (HEMC)
2. Mmakhalidwe achilengedwe：
Pofufuza mitundu iwiri ya ma ether a cellulose okhala ndi kukhuthala kwa 60000Pa·s ndi 100000Pa·s, zidapezeka kuti mphamvu yokakamiza ya matope osinthidwa osakanikirana ndi methyl cellulose ether imachepa pang'onopang'ono ndi kuwonjezeka kwa kuchuluka kwake. Mphamvu yokakamiza ya matope osinthidwa osakanikirana ndi 100000Pa·s viscosity hydroxypropyl methyl cellulose ether imawonjezeka kaye kenako imachepa ndi kuwonjezeka kwa kuchuluka kwake (monga momwe zasonyezedwera pa Chithunzi 4). Zikuwonetsa kuti kuphatikiza kwa methyl cellulose ether kudzachepetsa kwambiri mphamvu yokakamiza ya matope a simenti. Kuchuluka kwake, mphamvu yake idzakhala yaying'ono; kukhuthala kwake kukakhala kochepa, mphamvu yake idzakhala yayikulu pakutayika kwa mphamvu yokakamiza ya matope; hydroxypropyl methyl cellulose ether Pamene mlingo uli wochepera 0.1%, mphamvu yokakamiza ya matope ikhoza kuwonjezeka moyenera. Pamene mlingo uli woposa 0.1%, mphamvu yokakamiza ya matope idzachepa ndi kuwonjezeka kwa mlingo, kotero mlingo uyenera kulamulidwa pa 0.1%.
Chithunzi 4 Mphamvu yokakamiza ya 3d, 7d ndi 28d ya MC1, MC2 ndi MC3 modified simenti mortar
(Methyl cellulose ether, kukhuthala 60000Pa·S, pambuyo pake amatchedwa MC1; methyl cellulose ether, kukhuthala 100000Pa·S, wotchedwa MC2; hydroxypropyl methylcellulose ether, kukhuthala 100000Pa·S, wotchedwa MC3).
3. Cnthawi yogawa：
Poyesa nthawi yokhazikitsa ya hydroxypropyl methylcellulose ether yokhala ndi kukhuthala kwa 100000Pa·s mu miyeso yosiyanasiyana ya simenti, zidapezeka kuti pakuwonjezeka kwa mlingo wa HPMC, nthawi yokhazikitsa koyamba ndi nthawi yokhazikitsa komaliza ya simenti idakulitsidwa. Pamene kuchuluka kwake kuli 1%, nthawi yokhazikitsa koyamba imafika mphindi 510, ndipo nthawi yokhazikitsa komaliza imafika mphindi 850. Poyerekeza ndi chitsanzo chopanda kanthu, nthawi yokhazikitsa koyamba imakulitsidwa ndi mphindi 210, ndipo nthawi yokhazikitsa komaliza imakulitsidwa ndi mphindi 470 (monga momwe zasonyezedwera pa Chithunzi 5). Kaya ndi HPMC yokhala ndi kukhuthala kwa 50000Pa s, 100000Pa s kapena 200000Pa s, imatha kuchedwetsa kukhazikitsa simenti, koma poyerekeza ndi ma cellulose ether atatu, nthawi yokhazikitsa koyamba ndi nthawi yokhazikitsa komaliza imakulitsidwa ndi kukhuthala kwa kukhuthala, monga momwe zasonyezedwera pa Chithunzi 6. Izi zili choncho chifukwa cellulose ether imayamwa pamwamba pa tinthu ta simenti, zomwe zimaletsa madzi kukhudzana ndi tinthu ta simenti, motero zimachedwetsa madzi kulowa mu simenti. Kukhuthala kwa cellulose ether kukakhala kwakukulu, kumakhuthalanso kwa madzi pamwamba pa tinthu ta simenti, ndipo kuchedwetsa kwake kumakhala kwakukulu.
Chithunzi 5. Zotsatira za kuchuluka kwa ether ya cellulose pa nthawi yoyika matope
Chithunzi 6. Zotsatira za kukhuthala kosiyanasiyana kwa HPMC pa nthawi yoyika phala la simenti
(MC-5(50000Pa·s), MC-10(100000Pa·s) ndi MC-20(200000Pa·s))
Methyl cellulose ether ndi hydroxypropyl methyl cellulose ether zidzakulitsa kwambiri nthawi yokhazikika ya simenti, zomwe zingatsimikizire kuti simenti ili ndi nthawi yokwanira komanso madzi okwanira kuti igwire bwino ntchito, ndikuthetsa vuto la mphamvu yochepa komanso vuto la kuchepa kwa simenti pambuyo pouma.
4. Kusunga madzi:
Zotsatira za kuchuluka kwa ether ya cellulose pa kusunga madzi zidaphunziridwa. Zapezeka kuti pamene kuchuluka kwa ether ya cellulose kumawonjezeka, kuchuluka kwa madzi mu matope kumawonjezeka, ndipo pamene kuchuluka kwa ether ya cellulose kuli koposa 0.6%, kuchuluka kwa madzi kumakhala kokhazikika. Komabe, poyerekeza mitundu itatu ya ether ya cellulose (HPMC yokhala ndi kukhuthala kwa 50000Pa s (MC-5), 100000Pa s (MC-10) ndi 200000Pa s (MC-20)), mphamvu ya kukhuthala pa kusunga madzi ndi yosiyana. Ubale pakati pa kuchuluka kwa madzi ndi: MC-5.
Nthawi yotumizira: Epulo-28-2024