1. Isishwankathelo se-cellulose ether (HPMC)
I-Hydroxypropyl methylcellulose (HPMC) yikhompawundi ye-cellulose ether esetyenziswa ngokuqhelekileyo, eguqulwa ngokwekhemikhali ukusuka kwiselulosi yendalo. Inonyibiliko oluhle kakhulu lwamanzi, ukwenza ifilimu, ukutyeba kunye neempawu zokuncamathelisa, ngoko ke isetyenziswa kakhulu kwizinto zokwakha. Ukusetyenziswa kwe-HPMC kwizinto ezisekelwe kwisamente ikakhulu kukuphucula ubumanzi, ukugcinwa kwamanzi kunye nokulungelelanisa ixesha lokumisela.
2. Inkqubo esisiseko yokumisela isamente
Inkqubo yokusabela kwesamente ngamanzi ukwenza i-hydrates ibizwa ngokuba yi-hydration reaction. Le nkqubo yahlulwe ngokwezigaba ezininzi:
Ixesha le-Induction: Iinqununu ze-cement ziqala ukuchithwa, zenza i-calcium ions kunye ne-silicate ions, ebonisa ukuhamba kwexesha elifutshane.
Ixesha lokukhawuleza: Iimveliso ze-hydration zanda ngokukhawuleza kwaye inkqubo yokumisela iqala.
Ixesha lokunciphisa: Izinga le-hydration liyancipha, i-samente iqala ukuqina, kwaye ilitye eliqinileyo le-samente lenziwa.
Ixesha lokuzinzisa: Iimveliso ze-hydration zikhula ngokuthe ngcembe kwaye amandla ayanda ngokuthe ngcembe.
Ixesha lokumisela lidla ngokwahlulwa libe lixesha lokuqala lokumisela kunye nexesha lokumisela lokugqibela. Ixesha lokuqala lokumisela libhekisela kwixesha apho i-cement paste iqala ukulahlekelwa yiplastiki, kwaye ixesha lokugqibela lokumisela libhekisela kwixesha apho i-cement paste ilahlekelwa ngokupheleleyo iplastiki kwaye ingena kwinqanaba lokuqina.
3. Inkqubo yempembelelo ye-HPMC kwixesha lokubeka isamente
3.1 Ukuqina kwesiphumo
I-HPMC inesiphumo esibonakalayo sokujiya. Inokunyusa i-viscosity ye-cement paste kwaye yenza inkqubo ye-viscosity ephezulu. Esi siphumo sokuqina siya kuchaphazela ukusasazeka kunye ne-sedimentation ye-cement particles, kwaye ngoko kuchaphazela inkqubela phambili ye-hydration reaction. Umphumo wokuqina unciphisa izinga lokubekwa kweemveliso ze-hydration kumphezulu weengqungquthela zesamente, ngaloo ndlela ulibazisa ixesha lokumisela.
3.2 Ukugcinwa kwamanzi
I-HPMC inomthamo olungileyo wokugcina amanzi. Ukongeza i-HPMC kwintlama yesamente kunokuphucula kakhulu ukugcinwa kwamanzi kwintlama. Ukugcinwa kwamanzi aphezulu kunokuthintela amanzi kumphezulu wesamente ukuba angabi ngumphunga ngokukhawuleza, ukuze kugcinwe isiqulatho samanzi kwintlama yesamente kunye nokwandisa ixesha lokuphendula kwe-hydration. Ukongezelela, ukugcinwa kwamanzi kunceda intlama yesamente igcine ukufuma okufanelekileyo ngexesha lenkqubo yokunyanga kunye nokunciphisa umngcipheko wokuqhekeka okubangelwa ukulahleka kwamanzi kwangaphambili.
3.3 Ukuncipha kwamanzi
I-HPMC inokwenza ifilimu ekhuselayo egubungela umphezulu wamasuntswana e-samente, eya kuthintela ukusabela kwe-hydration. Le filimu yokukhusela ikhusela ukudibanisa ngokuthe ngqo phakathi kweengqungquthela zesamente kunye namanzi, ngaloo ndlela ilibazisa inkqubo ye-hydration ye-samente kunye nokwandisa ixesha lokumisela. Esi siphumo sokulibaziseka sibonakala ngokukodwa kwi-HPMC ephezulu ye-molecular weight.
3.4 Uphuculo lwethixotropy
Ukongezwa kwe-HPMC kunokuphucula i-thixotropy ye-sement slurry (oko kukuthi, ukunyuka kwamanzi kuyanda phantsi kwesenzo samandla angaphandle kwaye kubuyele kwimeko yokuqala emva kokuba amandla angaphandle asusiwe). Le propathi yethixotropic inceda ekuphuculeni ukusebenza kodaka lwesamente, kodwa ngokwexesha lokumisela, le thixotropy eyomeleziweyo inokubangela ukuba i-slurry isasazeke phantsi kwamandla okucheba, yolule ngakumbi ixesha lokumisela.
4. Ukusetyenziswa okusebenzayo kweHPMC kuchaphazela ixesha lokuseta isamente
4.1 Izixhobo zomgangatho ozimele
Kwizixhobo zomgangatho ozimeleyo, i-samente idinga ixesha elide lokumisela ukulinganisa kunye nokusebenza kwe-screeding. Ukongeza i-HPMC inokwandisa ixesha lokuqala lokumisela i-samente, ukuvumela izinto zokuzilinganisa ukuba zibe nexesha elide lokusebenza ngexesha lokwakha, ukuphepha ingxaki ebangelwa ukusetwa kwangaphambili kwe-samente slurry ngexesha lokwakha.
4.2 Udaka oluxutywe kwangaphambili
Kwi-premixed mortar, i-HPMC ayiphuculi kuphela ukugcinwa kwamanzi odaka, kodwa yandisa ixesha lokumisela. Oku kubaluleke ngakumbi kwizihlandlo zohambo olude kunye nexesha lokwakha, ukuqinisekisa ukuba udaka lugcina ukusebenza kakuhle phambi kokusetyenziswa kunye nokuthintela ubunzima bokwakha obubangelwa lixesha elifutshane kakhulu lokumisela.
4.3 Udaka oluxutyiweyo olomileyo
I-HPMC isoloko yongezwa kudaka oluxubeneyo owomileyo ukuphucula ukusebenza kwayo kolwakhiwo. Isiphumo sokutyeba se-HPMC sandisa i-viscosity yodaka, okwenza kube lula ukufaka isicelo kunye nenqanaba ngexesha lokwakha, kunye nokwandisa ixesha lokumisela, ukunika abasebenzi bokwakha ixesha elaneleyo lokwenza uhlengahlengiso.
5. Izinto ezichaphazela ixesha lokumiselwa kwesamente yi-HPMC
5.1 Imali eyongeziweyo yeHPMC
Isixa se-HPMC esongeziweyo yinto ephambili echaphazela ixesha lokumisela isamente. Ngokubanzi, ubukhulu bexabiso le-HPMC elongeziweyo, kokukhona kucaca ngakumbi ukwandiswa kwexesha lokumisela isamente. Oku kungenxa yokuba iimolekyuli ezininzi ze-HPMC zinokugquma imiphezulu yesamente engaphezulu kwaye ithintele ukusabela koxinzelelo.
5.2 Ubunzima bemolekyuli ye-HPMC
I-HPMC yobunzima beemolekyuli ezahlukeneyo ineempembelelo ezahlukeneyo kwixesha lokubeka isamente. I-HPMC enobunzima obuphezulu bemolekyuli idla ngokuba nefuthe eliqinileyo lokujiya kunye nomthamo wokugcina amanzi, ngoko inokwandisa ixesha lokuseta kakhulu. Nangona i-HPMC enobunzima obuphantsi bemolekyuli inokwandisa ixesha lokumisela, umphumo ubuthathaka.
5.3 Iimeko zokusingqongileyo
Ubushushu be-Ambient kunye nokufuma kuya kuchaphazela isiphumo se-HPMC kwixesha lokumisela isamente. Kwimeko yobushushu obuphezulu, i-samente hydration reaction iyakhawuleza, kodwa ipropathi yokugcina amanzi ye-HPMC iyacotha esi siphumo. Kwimekobume yobushushu obuphantsi, ukushukuma kwamanzi ngokwawo kuyacotha, kwaye ukutyeba kunye nokugcinwa kwamanzi isiphumo se-HPMC kunokubangela ukuba ixesha lokumisela isamente landiswe kakhulu.
5.4 Umlinganiselo wesamente yamanzi
Utshintsho kumlinganiselo wesamente yamanzi luya kuchaphazela nefuthe le-HPMC kwixesha lokumisela isamente. Kumlinganiselo ophezulu wesamente yamanzi, kukho amanzi amaninzi kwintlama yesamente, kwaye umphumo wokugcinwa kwamanzi we-HPMC unokuba nefuthe elincinci kwixesha lokumisela. Kwinqanaba elisezantsi le-samente yamanzi, umphumo wokuqina we-HPMC uya kubonakala ngakumbi, kwaye umphumo wokwandisa ixesha lokumisela kuya kuba lukhulu ngakumbi.
Njengesongezo sesamente esibalulekileyo, i-HPMC ichaphazela kakhulu ixesha lokumisela isamente ngeendlela ezahlukeneyo ezifana nokujiya, ukugcinwa kwamanzi, kunye nokubuyiswa kokuphendula kwe-hydration. Ukusetyenziswa kwe-HPMC kunokwandisa ixesha lokuqala nelokugqibela lokumisela isamente, ukunika ixesha elide lomsebenzi wokwakha, kunye nokuphucula ukusebenza kwemathiriyeli esekwe kwisamente. Kwizicelo ezisebenzayo, izinto ezinjengobungakanani be-HPMC eyongeziweyo, ubunzima bemolekyuli, kunye neemeko zokusingqongileyo ngokudibeneyo zimisela umphumo wayo othile kwixesha lokumisela isamente. Ngokulungelelanisa ngokufanelekileyo le miba, ulawulo oluchanekileyo lwexesha lokumisa isamente lunokuphunyezwa ukuhlangabezana neemfuno zeeprojekthi zokwakha ezahlukeneyo.
Ixesha lokuposa: Jun-21-2024