Umthelela we-Redispersible Emulsion Powder ku-Slurry Structure

I-redispersible latex powder iyisisetshenziswa esivame ukusetshenziswa se-organic gelling etholakala ngokufafaza-omisa i-polymer emulsion nge-polyvinyl alcohol njenge-colloid evikelayo. Ingaphinde ihlakazwe ngokulinganayo emanzini ukuze yenze i-emulsion lapho ihlangana namanzi. Ukwengeza impushana ye-latex ehlakazeka kabusha kungathuthukisa ukusebenza kodaka lukasimende olusanda kuxutshwa.

Ngokushesha nje lapho izinto ezisekelwe ku-cement zengezwe nge-latex powder zithintana namanzi, ukusabela kwe-hydration kuqala, futhi isisombululo se-calcium hydroxide ngokushesha sifinyelela ukugcwala futhi amakristalu ayancishiswa, futhi ngesikhathi esifanayo, amakristalu e-ettringite nama-gel e-calcium silicate hydrate akhiwa. Izinhlayiya eziqinile zifakwa kujeli kanye nezinhlayiya zikasimende ezingenamanzi. Njengoba ukusabela kwe-hydration kuqhubeka, imikhiqizo ye-hydration iyakhula, futhi izinhlayiya ze-polymer kancane kancane ziqoqana emigodini ye-capillary, zenze ungqimba oluminyene olugcwele ebusweni bejeli kanye nezinhlayiya zikasimende ezingenawo amanzi. Izinhlayiya ze-polymer ezihlanganisiwe kancane kancane zigcwalisa ama-pores, kodwa hhayi ngokuphelele endaweni engaphakathi ye-pores. Njengoba amanzi encishiswa ngokuqhubekayo nge-hydration noma ukomiswa, izinhlayiya ze-polymer ezipakishwe eduze eduze kwejeli nasezimbotsheni ze-pores ziyahlangana zibe ifilimu eqhubekayo, zenze ingxube ye-interpenetrating ne-hydrated simende unamathisele futhi ithuthukise i-hydration Bonding yemikhiqizo kanye nama-aggregates.

Ngenxa yokuthi imikhiqizo ye-hydration enama-polymers yakha isendlalelo sesembozo ku-interface, ingase ithinte ukukhula kwamakristalu e-ettringite nama-coarse calcium hydroxide; futhi ngenxa yokuthi ama-polymers ajiya abe amafilimu ezimbotsheni ze-interface transition zone, izinto ezisekelwe kusimende ze-polymer I-transition zone iminyene. Amaqembu asebenzayo kwamanye ama-molecule e-polymer azophinde akhiqize ukusabela okuxhumanisa okuphambene ne-Ca2+ ne-A13+ emikhiqizweni ye-hydration kasimende ukuze akhe amabhondi akhethekile ebhuloho, athuthukise ukwakheka komzimba kwezinto ezisekelwe kusimende eziqinile, akhulule ingcindezi yangaphakathi, futhi anciphise ukukhiqizwa kwama-microcracks.

Njengoba isakhiwo sejeli sikasimende sikhula, amanzi adliwe futhi izinhlayiya ze-polymer kancane kancane zivalelwe kuma-pores. Njengoba usimende uba namanzi ngokwengeziwe, umswakama osezimbotsheni ze-capillary uyancipha, futhi izinhlayiya ze-polymer zinqwabelana phezu komkhiqizo we-cement hydration product gel/unhydrated usimende ingxube yezinhlayiyana kanye ne-aggregate, ngaleyo ndlela yakhe ungqimba oluvaleleke oluqhubekayo olunezimbotshana ezinkulu ezigcwalisiwe. ngezinhlayiya ze-polymer ezinamathelayo noma ezizinamathelayo.

I-emulsion ehlakazekile ye-latex powder e-redispersible ingenza ifilimu eqhubekayo engenamanzi (umzimba wenethiwekhi ye-polymer) ngemva kokumisa, futhi lo mzimba wenethiwekhi we-modulus polymer ophansi ungathuthukisa ukusebenza kukasimende; ngesikhathi esifanayo, ku-molecule ye-polymer Amaqembu athile e-polar kusimende asabela ngamakhemikhali nemikhiqizo ye-hydration kasimende ukuze akhe amabhuloho akhethekile, athuthukise ukwakheka komzimba wemikhiqizo ye-samente ye-hydration, futhi anciphise futhi anciphise ukukhiqizwa kwemifantu. Ngemuva kokuthi i-latex powder ye-redispersible ingeziwe, izinga lokuqala le-hydration likasimende liyancipha, futhi ifilimu ye-polymer ingakwazi ukugoqa kancane noma ngokuphelele izinhlayiya ze-cement, ukuze usimende ungabi namanzi ngokugcwele futhi izakhiwo zayo ezihlukahlukene zingathuthukiswa.