I-Cellulose ether izobambezela ukugeleza kukasimende ngamazinga ahlukahlukene, okubonakala ngokubambezela ukwakheka kwe-ettringite, ijeli ye-CSH ne-calcium hydroxide. Njengamanje, indlela ye-cellulose ether ebambezela ukusikwa kukasimende ikakhulukazi ihlanganisa ukucatshangwa kokunyakaza kwe-ion okuvinjiwe, ukuwohloka kwe-alkali kanye nokukhanyiswa.
1. I-hypothesis yokunyakaza kwe-ion okuvinjiwe
Kucatshangwa ukuthi ama-cellulose ethers akhulisa i-viscosity yesisombululo se-pore, avimbele izinga lokunyakaza kwe-ion, ngaleyo ndlela abambezele ukugeleza kukasimende. Kodwa-ke, kulokhu kuhlolwa, i-cellulose ether ene-viscosity ephansi inamandla anamandla okubambezela ukugeleza kukasimende, ngakho-ke le mbono ayibambeli. Eqinisweni, isikhathi sokunyakaza kwe-ion noma ukufuduka sifushane kakhulu, okusobala ukuthi asinakuqhathaniswa nesikhathi sokulibaziseka kwe-cement hydration.
2. Ukuwohloka kwe-alkaline
Ama-Polysaccharides avame ukucekelwa phansi kalula ngaphansi kwezimo ze-alkaline ukuze akhe ama-hydroxycarboxylic acids abambezela ukugeleza kukasimende. Ngakho-ke, isizathu esenza ukuthi i-cellulose ether ibambezeleke ukugeleza kukasimende kungase kube ukuthi yehlisa isiteleka se-alkaline ukuze kwakhiwe ama-hydroxycarboxylic acid, kodwa ucwaningo lwathola ukuthi i-Cellulose ether izinzile kakhulu ngaphansi kwezimo ze-alkali, yonakaliswa kancane kuphela, futhi imikhiqizo eyonakalisiwe ayinawo umphumela. ekubambezelekeni kokufakwa kukasimende.
3. I-Adsorption
I-Adsorption ingaba yisizathu sangempela sokuthi kungani i-cellulose ether ibambezela ukugeleza kukasimende. Izithasiselo eziningi ze-organic zizokhanga ezinhlayiyeni zikasimende kanye nemikhiqizo ye-hydration, ukuvimbela ukuchithwa kwezinhlayiya zikasimende kanye ne-crystallization yemikhiqizo ye-hydration, ngaleyo ndlela ibambezele ukugeleza nokumiswa kukasimende. Kwatholakala ukuthi i-cellulose ether ifakwa kalula ku-calcium hydroxide, C. S. Ingaphezulu lemikhiqizo ye-hydration efana ne-H gel ne-calcium aluminate hydrate, kodwa akulula ukukhangiswa ngesigaba se-ettringite ne-unhydrated. Ngaphezu kwalokho, ngokuphathelene ne-cellulose ether, umthamo we-adsorption we-HEC unamandla kunawe-MC, futhi ukuncipha kokuqukethwe kwe-hydroxyethyl ku-HEC noma i-hydroxypropyl ku-HPMC, amandla e-adsorption anamandla: ngokwemikhiqizo ye-hydration, i-hydrogen. Umthamo we-adsorption we-calcium oxide C. S. Umthamo we-adsorption ka-H unamandla. Ukuhlaziywa okwengeziwe futhi kukhombisa ukuthi amandla e-adsorption emikhiqizo ye-hydration kanye ne-cellulose ether inobudlelwano obuhambelanayo nokubambezeleka kokufakwa kukasimende: lapho i-adsorption iqina, ukubambezeleka okusobala kakhulu, kepha ukufakwa kwe-ettringite ku-cellulose ether akunamandla, kepha ukwakheka kwayo. ibambezeleke kakhulu. Ucwaningo luye lwabonisa ukuthi i-cellulose ether ine-adsorption eqinile ku-tricalcium silicate kanye nemikhiqizo yayo ye-hydration, ngaleyo ndlela ibambezeleka kakhulu ukugeleza kwesigaba se-silicate, futhi ine-adsorption ephansi ku-ettringite, kodwa ukwakheka kwe-ettringite kuvinjelwe. Ngokusobala ibambezelekile, lokhu kungenxa yokuthi ukwakheka okubambezelekile kwe-ettringite kuthintwa ibhalansi ye-Ca2+ esixazululweni, okuwukuqhubeka kwe-silicate hydration ebambezelekile ye-cellulose ether.
Emiphumeleni yokuhlola, ikhono lokuhlehlisa le-HEC linamandla kunele-MC, futhi ikhono le-cellulose ether lokubambezela ukwakheka kwe-calcium hydroxide linamandla kunalelo le-C. S. Ikhono le-H gel ne-ettringite linamandla, elinobudlelwano obuhambisanayo namandla okukhangisa we-cellulose ether kanye nemikhiqizo ye-cement hydration. Kuphinde kuqinisekiswe ukuthi i-adsorption ingase ibe isizathu sangempela sokuthi kungani i-cellulose ether ibambezeleka ukusimende, futhi imikhiqizo ye-cellulose ether kanye ne-cement hydration inobudlelwane obuhambisanayo. Lapho amandla e-adsorption eqinile emikhiqizo ye-cement hydration, kuba sobala kakhulu ukwakheka kwemikhiqizo ebambezelekile ye-hydration. Imiphumela yokuhlola yangaphambilini ibonisa ukuthi ama-ether e-cellulose ahlukene anemiphumela ehlukene ekubambezelekeni kwe-Portland cement hydration, futhi i-cellulose ether efanayo inemiphumela yokulibaziseka ehlukene emikhiqizweni ehlukene ye-hydration, okubonisa ukuthi imikhiqizo ye-Portland simende ye-hydration inemiphumela ehlukene ku-fiber. I-adsorption ye-cellulose ether iyakhetha, futhi ukufakwa kwe-cellulose ether emikhiqizweni ye-cement hydration nakho kuyakhetha.
Isikhathi sokuthumela: Feb-27-2023