Focus on Cellulose ethers

I-Hydroxypropyl methylcellulose ether ezindaweni zodaka lomlotha wempukane

I-Hydroxypropyl methylcellulose ether ezindaweni zodaka lomlotha wempukane

Umthelela we-hydroxypropyl methylcellulose ether ezimpahleni zodaka lomlotha wezimpukane wacwaningwa, kwahlaziywa ubudlelwano phakathi kokuminyana okumanzi namandla acindezelayo. Imiphumela yokuhlola ibonisa ukuthi ukwengeza i-hydroxypropyl methylcellulose ether ukuze indize udaka lomlotha kungathuthukisa kakhulu ukusebenza kokugcinwa kwamanzi odaka, kunwebe isikhathi sokubopha udaka, futhi kunciphise ukuminyana okumanzi namandla okucindezela odaka. Kukhona ukuhlobana okuhle phakathi kokuminyana okumanzi namandla okucindezela angama-28d. Ngaphansi kwesimo sokuminyana okumanzi okwaziwayo, amandla okucindezela angu-28d angabalwa ngokusebenzisa ifomula efanelekile.

Amagama angukhiye:fly umlotha; i-cellulose ether; ukugcinwa kwamanzi; amandla okucindezela; ukuhlobana

 

Njengamanje, i-fly ash isetshenziswe kakhulu kwezobunjiniyela bokwakha. Ukwengeza inani elithile le-fly ash odakeni ngeke nje kuthuthukise izakhiwo zemishini nokuqina kodaka, kodwa futhi kunciphise izindleko zodaka. Kodwa-ke, i-fly ash mortar ibonisa ukugcinwa kwamanzi okwanele, ngakho-ke indlela yokuthuthukisa ukugcinwa kwamanzi odaka sekuyinkinga ephuthumayo okufanele ixazululwe. I-Cellulose ether iyinhlanganisela esebenza kahle kakhulu evame ukusetshenziswa ekhaya naphesheya. Idinga kuphela ukwengezwa ngenani elincane ukuze ibe nomthelela omkhulu ezinkomba zokusebenza ezifana nokugcinwa kwamanzi namandla okucindezela odaka.

 

1. Izinto ezisetshenziswayo kanye nezindlela zokuhlola

1.1 Izinto ezisetshenziswayo

Usimende nguP·O 42.5 grade ojwayelekile usimende Portland okhiqizwa Hangzhou Meiya Cement Factory; umlotha wempukane usezingeniumlotha; isihlabathi siyisihlabathi esivamile esimaphakathi esine-fineness modulus engu-2.3, ukuminyana ngobuningi be-1499kg·m-3, kanye nomswakama ongu-0.14 %, udaka u-0.72%; i-hydroxypropyl methyl cellulose ether (HPMC) ikhiqizwa yi-Shandong Heda Co., Ltd., uhlobo luyi-75HD100000; amanzi okuxuba amanzi ampompi.

1.2 Ukulungiswa kodaka

Uma uhlanganisa udaka oluguquliwe lwe-cellulose ether, qala uhlanganise i-HPMC nosimende bese undiza umlotha kahle, bese uxuba nesihlabathi imizuzwana engu-30, bese ufaka amanzi futhi uhlanganise imizuzwana engekho ngaphansi kwe-180.

1.3 Indlela yokuhlola

Ukungaguquguquki, ukuminyana okumanzi, ukuchithwa kanye nesikhathi sokumiswa kukadaka olusanda kuxutshwa kuzolinganiswa ngokwemithethonqubo efanele ku-JGJ70-90 “Izindlela Zokuhlola Ukusebenza Okuyisisekelo Kodaka Lokwakha”. Ukugcinwa kwamanzi kodaka kunqunywa ngokwendlela yokuhlola yokugcina amanzi odaka kuSithasiselo A se-JG/T 230-2007 “I-Ready Mixed Mortar”. Ukuhlolwa kwamandla acindezelayo kusebenzisa isikhunta sokuhlola esingu-70.7mm x 70.7mm x 70.7mm cube bottomed. Ibhulokhi yokuhlola eyakhiwe yelashwa ekushiseni okungama-20±2)°C amahora angama-24, futhi ngemuva kokudilizwa, iyaqhubeka nokwelashwa endaweni enezinga lokushisa elingu-20.±2)°C kanye nomswakama ohlobene ongaphezu kuka-90% ukuya eminyakeni enqunywe kusengaphambili, ngokuya nge-JGJ70-90 “Indlela yokuhlola yokusebenza kwe-Building Mortar Basic “ukunqunywa kwamandla ayo okucindezela.

 

2. Imiphumela yokuhlolwa nokuhlaziya

2.1 Ukuminyana okumanzi

Kungabonakala ebudlelwaneni obuphakathi kokuminyana kanye nenani le-HPMC ukuthi ukuminyana okumanzi kuyehla kancane kancane ngokunyuka kwenani le-HPMC. Uma inani le-HPMC lingu-0.05%, ukuminyana okumanzi kodaka kungu-96.8% we-benchmark mortar. Lapho inani le-HPMC liqhubeka nokukhuphuka, Ijubane lokuncipha lokuminyana okumanzi liyashesha. Uma okuqukethwe kwe-HPMC kungu-0.20%, ukuminyana okumanzi kodaka kungamaphesenti angama-81.5 kuphela odaka lwebhentshimakhi. Lokhu kungenxa yomphumela wokungenisa umoya we-HPMC. Amabhamuza omoya angenisiwe andisa i-porosity yodaka futhi anciphise ukubumbana, okuholela ekwehleni kokuminyana kwevolumu yodaka.

2.2 Ukusetha isikhathi

Kungabonakala ebuhlotsheni phakathi kwesikhathi sokuhlangana kanye nenani le-HPMC ukuthi isikhathi sokuhlangana sikhula kancane kancane. Uma umthamo ungu-0.20%, isikhathi sokusetha sikhuphuka ngo-29.8% uma siqhathaniswa nodaka lwereferensi, sifinyelela cishe ku-300min. Kungabonakala ukuthi lapho umthamo ungu-0.20%, isikhathi sokusetha sinokushintsha okukhulu. Isizathu ukuthi uL Schmitz et al. bakholelwa ukuthi amangqamuzana e-cellulose ether akhangwa kakhulu emikhiqizweni yokukhipha amanzi njenge-cSH ne-calcium hydroxide, futhi awavamile ukukhangisa esigabeni sokuqala samaminerali se-clinker. Ngaphezu kwalokho, ngenxa yokwanda kwe-viscosity yesisombululo se-pore, i-cellulose ether iyancipha. Ukuhamba kwama-ion (Ca2+, so42-…) kusixazululo se-pore kubambezela inqubo yokufakwa kwamanzi.

2.3 Ukwendlaleka kanye nokugcinwa kwamanzi

Kokubili izinga le-delamination nokugcinwa kwamanzi kungabonakalisa umphumela wokugcina amanzi wodaka. Kusuka kubudlelwano obuphakathi kwezinga le-delamination kanye nenani le-HPMC, kungabonwa ukuthi izinga le-delamination libonisa inkambiso enciphayo njengoba inani le-HPMC linyuka. Uma okuqukethwe kwe-HPMC kungu-0.05%, izinga le-delamination liyancipha kakhulu, okubonisa ukuthi lapho okuqukethwe kwe-fiber ether kukuncane, izinga le-delamination lingancishiswa kakhulu, umphumela wokugcinwa kwamanzi ungathuthukiswa, nokusebenza nokusebenza ukusebenza kodaka kungathuthukiswa. Uma sibheka ubudlelwano phakathi kwendawo yamanzi kanye nenani le-HPMC, njengoba inani le-HPMC likhula, ukugcinwa kwamanzi nakho kuba ngcono kancane kancane. Uma umthamo ungaphansi kuka-0.15%, umphumela wokugcina amanzi ukhuphuka kancane kakhulu, kodwa lapho umthamo ufinyelela ku-0.20%, umphumela wokugcina amanzi uthuthuke kakhulu, usuka ku-90.1% lapho umthamo ungu-0.15%, kuya ku-95%. Inani le-HPMC liyaqhubeka nokukhula, futhi ukusebenza kokwakhiwa kodaka kuqala ukuwohloka. Ngakho-ke, uma kucatshangelwa ukusebenza kokugcinwa kwamanzi nokusebenza kokwakha, inani elifanele le-HPMC lingu-0.10%~0.20%. Ukuhlaziywa kwendlela yokugcina amanzi: I-Cellulose ether iyi-polymer encibilikayo emanzini, ehlukaniswe i-ionic ne-non-ionic. I-HPMC i-non-ionic cellulose ether eneqembu le-hydrophilic, iqembu le-hydroxyl (-OH) kanye nebhondi ye-ether (-0-1) kufomula yayo yesakhiwo. Lapho encibilika emanzini, ama-athomu omoya-mpilo eqenjini le-hydroxyl kanye nesibopho se-ether namanzi Amamolekyuli ahlotshaniswa nokwenza izibopho ze-hydrogen, okwenza amanzi alahlekelwe yi-fluidity, futhi amanzi amahhala awasekho mahhala, ngaleyo ndlela afinyelele umphumela wokugcinwa kwamanzi nokuqina.

2.4 Amandla acindezelayo

Kusukela ebudlelwaneni phakathi kwamandla okucindezela kanye nenani le-HPMC, kungabonakala ukuthi ngokwanda kwenani le-HPMC, amandla okucindezela we-7d no-28d abonise ukwehla komkhuba, okwakubangelwa ikakhulukazi ukwethulwa kwenombolo enkulu. amabhamuza omoya yi-HPMC, okwandise kakhulu ukubola kodaka. ukwanda, okuholela ekwehleni kwamandla. Uma okuqukethwe kungu-0.05%, amandla okucindezela angu-7d ehla kakhulu, amandla ehla ngo-21.0%, futhi amandla okucindezela angu-28d ehla ngo-26.6%. Kungabonakala ejikeni ukuthi umthelela we-HPMC emandleni okucindezela usobala kakhulu. Lapho umthamo umncane kakhulu, uzoncishiswa kakhulu. Ngakho-ke, ekusetshenzisweni okungokoqobo, umthamo wayo kufanele ulawulwe futhi usetshenziswe ngokuhambisana ne-defoamer. Ephenya isizathu, uGuan Xuemao et al. kholelwa ukuthi okokuqala, lapho i-cellulose ether yengezwa odakeni, i-polymer eguquguqukayo ezimbotsheni zodaka iyakhula, futhi lezi polymers nezimbotshana eziguquguqukayo azikwazi ukuhlinzeka ngokusekela okuqinile lapho ibhulokhi yokuhlola icindezelwa. I-matrix eyinhlanganisela ibuthakathaka ngokuqhathaniswa, ngaleyo ndlela inciphisa amandla okucindezela odaka; okwesibili, ngenxa yomphumela wokugcinwa kwamanzi we-cellulose ether, ngemva kokwakhiwa kwebhulokhi yokuhlola udaka, amanzi amaningi ahlala odakeni, futhi isilinganiso sangempela samanzi-samende siphansi kunalokho ngaphandle Kwalezo zinkulu kakhulu, ngakho amandla okucindezela. lodaka luzoncishiswa kakhulu.

2.5 Ukuhlobana phakathi kwamandla acindezelayo kanye nokuminyana okumanzi

Kungabonakala ejikeni lobudlelwano phakathi kwamandla acindezelayo kanye nokuminyana okumanzi ukuthi ngemva kokufaka umugqa wawo wonke amaphuzu esithombeni, amaphuzu ahambisanayo asatshalaliswa kahle nhlangothi zombili zomugqa wokulinganisa, futhi kukhona ukuhlobana okuhle phakathi kokuminyana okumanzi nokucindezela. izakhiwo zamandla, futhi ukuminyana okumanzi kulula futhi kulula ukukukala, ngakho amandla okucindezela odaka 28d angabalwa ngesibalo esimisiwe somugqa wokulinganisa. Isibalo sokulinganisa somugqa siboniswa kufomula (1), R²=0.9704. Y=0.0195X-27.3 (1), lapho, y amandla okucindezela angu-28d odaka, i-MPa; X ukuminyana okumanzi, kg m-3.

 

3. Isiphetho

I-HPMC ingathuthukisa umphumela wokugcina amanzi wodaka lomlotha wempukane futhi yandise isikhathi sokusebenza sodaka. Ngesikhathi esifanayo, ngenxa yokwanda kwe-porosity yodaka, ukuminyana kwayo ngobuningi namandla okucindezela kuzokwehla kakhulu, ngakho-ke umthamo ofanele kufanele ukhethwe kuhlelo lokusebenza. Amandla okucindezela angu-28d odaka anokuxhumana okuhle nokuminyana okumanzi, futhi amandla okucindezela angu-28d angabalwa ngokulinganisa ukuminyana okumanzi, okunenani elibalulekile lereferensi yokulawulwa kwekhwalithi yodaka ngesikhathi sokwakha.


Isikhathi sokuthumela: Feb-08-2023
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