1. Kutentha kwa hydration
Malingana ndi kumasulidwa kwa kutentha kwa hydration pakapita nthawi, ndondomeko ya hydration ya simenti nthawi zambiri imagawidwa m'magawo asanu, omwe ndi nthawi yoyamba ya hydration (0 ~ 15min), nthawi yophunzitsira (15min ~ 4h), mathamangitsidwe ndi nthawi (4h ~ 8h), deceleration ndi kuumitsa nthawi (8h ~ 24h), ndi curing periodd (1 ~ 8h).
Zotsatira zoyesa zikuwonetsa kuti kumayambiriro kwa induction (ie, nthawi yoyamba ya hydration), pamene kuchuluka kwa HEMC ndi 0.1% poyerekeza ndi slurry yopanda kanthu ya simenti, nsonga ya exothermic ya slurry imapita patsogolo ndipo nsonga yake ikuwonjezeka kwambiri. Pamene kuchuluka kwaMtengo HEMCKuwonjezeka kwa Pamene kuli pamwamba pa 0,3%, nsonga yoyamba ya exothermic ya slurry imachedwa, ndipo mtengo wamtengo wapatali umachepa pang'onopang'ono ndi kuwonjezeka kwa zinthu za HEMC; HEMC mwachiwonekere idzachedwetsa nthawi yopititsa patsogolo ndi nthawi yowonjezereka ya slurry ya simenti, ndipo zowonjezereka , kutalika kwa nthawi yopititsa patsogolo, kubwezera mmbuyo nthawi yothamanga, ndi kuchepetsa nsonga ya exothermic; kusintha kwa cellulose ether zilibe zotsatira zoonekeratu pa kutalika kwa nthawi deceleration ndi kukhazikika nthawi ya simenti slurry, monga momwe chithunzi 3 (a) Zikuoneka kuti mapadi ether akhoza kuchepetsa kutentha kwa hydration wa simenti phala mkati 72 hours, koma pamene kutentha kwa hydration ndi yaitali kuposa 36 hours hydration pa kutentha pang'ono okhutira ndi kusintha kwa cellulose kusintha kwa cellulose ether. phala, monga Chithunzi 3(b).
Chithunzi cha 3 Kusintha kwa kutentha kwa hydration kutentha kwa phala la simenti ndi zinthu zosiyanasiyana za cellulose ether (HEMC)
2. Mechanical katundu:
Pophunzira mitundu iwiri ya ma cellulose ethers okhala ndi viscosities ya 60000Pa · s ndi 100000Pa · s, zidapezeka kuti mphamvu yopondereza ya matope osinthidwa osakanikirana ndi methyl cellulose ether idachepa pang'onopang'ono ndi kuchuluka kwa zomwe zili. Mphamvu yopondereza ya matope osinthidwa osakanikirana ndi 100000Pa · s viscosity hydroxypropyl methyl cellulose ether imawonjezeka poyamba ndiyeno imachepa ndi kuwonjezeka kwa zomwe zili (monga momwe tawonetsera pa Chithunzi 4). Zimasonyeza kuti kuphatikizidwa kwa methyl cellulose ether kudzachepetsa kwambiri mphamvu yopondereza ya matope a simenti. Kuchuluka kwake kumakhala kocheperako, mphamvuyo idzakhala yochepa; ang'onoang'ono mamasukidwe akayendedwe, m'pamenenso amakhudza kwambiri kutaya matope compressive mphamvu; hydroxypropyl methyl cellulose ether Pamene mlingo uli wochepera 0.1%, mphamvu yopondereza ya matope ikhoza kuwonjezeka moyenerera. Pamene mlingo uli woposa 0.1%, mphamvu yopondereza ya matope idzachepa ndi kuwonjezeka kwa mlingo, choncho mlingo uyenera kuyendetsedwa pa 0.1%.
Fig.4 3d, 7d ndi 28d compressive mphamvu ya MC1, MC2 ndi MC3 yosinthidwa matope a simenti
(Methyl cellulose ether, viscosity 60000Pa·S, pambuyo pake amatchedwa MC1; methyl cellulose ether, viscosity 100000Pa·S, yotchedwa MC2; hydroxypropyl methylcellulose ether, viscosity 100000Pa·S, yotchedwa MC2).
3.Cnthawi yowerengera:
Poyesa nthawi yoyika hydroxypropyl methylcellulose ether ndi viscosity ya 100000Pa · s mu milingo yosiyanasiyana ya simenti ya simenti, zinapezeka kuti ndi kuwonjezeka kwa mlingo wa HPMC, nthawi yoyamba yoyika ndi nthawi yomaliza ya matope a simenti inatalikitsidwa. Pamene ndende ndi 1%, nthawi yoyamba yokhazikitsa imafika mphindi 510, ndipo nthawi yomaliza yomaliza imafika mphindi 850. Poyerekeza ndi chitsanzo chopanda kanthu, nthawi yokhazikika yoyambira ikuwonjezedwa ndi mphindi 210, ndipo nthawi yomaliza yomaliza imakulitsidwa ndi mphindi 470 (monga momwe tawonetsera pa Chithunzi 5). Kaya ndi HPMC yokhala ndi mamasukidwe a 50000Pa s, 100000Pa s kapena 200000Pa s, imatha kuchedwetsa kuyika kwa simenti, koma poyerekeza ndi ma ethers atatu a cellulose, nthawi yoyika koyamba ndi nthawi yomaliza yokhazikika imatalikitsidwa ndi kuwonjezereka kwa mamasukidwe akayendedwe, monga momwe tawonetsera pa Chithunzi 6. Izi ndichifukwa choti cellulose ether imadsorbed pamwamba pa tinthu tating'ono ta simenti, zomwe zimalepheretsa madzi kukhudzana ndi tinthu tating'ono ta simenti, motero amachedwetsa kuthira kwa simenti. Kuchuluka kwa mamasukidwe a cellulose ether, kumapangitsanso kukhuthala kwa ma adsorption pamwamba pa tinthu tating'ono ta simenti, ndipo kumachepetsanso kwambiri.
Mkuyu.5 Mphamvu za cellulose ether pokhazikitsa nthawi ya matope
Fig.6 Zotsatira za ma viscosity osiyanasiyana a HPMC pakuyika nthawi ya phala la simenti
(MC-5(50000Pa·s), MC-10(100000Pa·s) ndi MC-20(200000Pa·s))
Methyl cellulose ether ndi hydroxypropyl methyl cellulose ether kwambiri kutalikitsa nthawi yoika simenti slurry, amene angathe kuonetsetsa kuti simenti slurry ndi nthawi yokwanira ndi madzi hydration anachita, ndi kuthetsa vuto la mphamvu otsika ndi mochedwa siteji slurry simenti pambuyo kuumitsa. vuto losweka.
4. Kusunga madzi:
Zotsatira za ether za cellulose pakusunga madzi zidaphunziridwa. Zimapezeka kuti ndi kuchuluka kwa zomwe zili mu cellulose ether, kuchuluka kwa madzi osungiramo matope kumawonjezeka, ndipo pamene zomwe zili mu cellulose ether zimakhala zazikulu kuposa 0,6%, kusungirako madzi kumakhala kokhazikika. Komabe, poyerekezera mitundu itatu ya ma cellulose ethers (HPMC yokhala ndi mamasukidwe a 50000Pa s (MC-5), 100000Pa s (MC-10) ndi 200000Pa s (MC-20)), chikoka cha mamasukidwe akayendedwe pa kusunga madzi ndi chosiyana. Ubale pakati pa kuchuluka kwa kusunga madzi ndi: MC-5.
Nthawi yotumiza: Apr-28-2024