Isikhathi sokumisa ukhonkolo siyipharamitha ebalulekile ethinta izinga lokwakha kanye nenqubekelaphambili. Uma isikhathi sokumisa siside kakhulu, singase siholele ekuqhubekeni kancane kancane kokwakhiwa futhi kulimaze ikhwalithi yokuqina kakhonkolo; uma isikhathi sokumisa sisifushane kakhulu, kungase kuholele ebunzimeni ekwakhiweni kokhonkolo futhi kuthinte umphumela wokwakha wephrojekthi. Ukuze ulungise isikhathi sokumisa ukhonkolo, ukusetshenziswa kwezixube sekuyindlela evamile ekukhiqizeni ukhonkolo wanamuhla.I-Hydroxyethyl Methyl Cellulose (HEMC), njenge-derivative ye-cellulose eguquliwe evamile, isetshenziswa kabanzi ku-concrete admixtures futhi ingathinta i-rheology, ukugcinwa kwamanzi, isikhathi sokubeka kanye nezinye izakhiwo zekhonkrithi.1. Izakhiwo eziyisisekelo ze-HEMC
I-HEMC i-cellulose eguquliwe, ngokuvamile eyenziwa nge-cellulose yemvelo ngokusebenzisa i-ethylation kanye nokusabela kwe-methylation. Ine-solubility enhle yamanzi, ukuqina, ukugcinwa kwamanzi kanye nezakhiwo ze-gelling, ngakho-ke isetshenziswa kabanzi ekwakhiweni, ekugqokeni, kumakhemikhali ansuku zonke kanye neminye imikhakha. Ngokukhonkolo, i-HEMC ivame ukusetshenziswa njenge-thickener, i-ejenti yokugcina amanzi kanye ne-ejenti yokulawula i-rheology, engathuthukisa ukusebenza kokhonkolo, ukwandisa ukunamathela nokwandisa isikhathi sokusetha.
2. Umthelela we-HEMC ngesikhathi sokumisa ukhonkolo
Ibambezela isikhathi sokusetha
Njengokuphuma kwe-cellulose, i-HEMC iqukethe inani elikhulu lamaqembu e-hydrophilic esakhiweni sayo samangqamuzana, angaxhumana nama-molecule amanzi ukuze enze ama-hydrates azinzile, ngaleyo ndlela abambezele inqubo ye-samente ye-hydration ngezinga elithile. Ukusabela kwe-hydration kasimende kuyindlela eyinhloko yokuqinisa ukhonkolo, futhi ukungezwa kwe-HEMC kungathinta isikhathi sokusetha ngezindlela ezilandelayo:
Ukugcinwa kwamanzi okuthuthukisiwe: I-HEMC ingathuthukisa kakhulu ukugcinwa kwamanzi kakhonkolo, inciphise izinga lokuhwamuka kwamanzi, futhi yandise isikhathi sokusabela kwe-cement hydration. Ngokugcina amanzi, i-HEMC ingagwema ukulahlekelwa amanzi ngokweqile, ngaleyo ndlela ibambezeleke ukuvela kwesilungiselelo sokuqala nesokugcina.
Ukunciphisa ukushisa kwe-hydration: I-HEMC ingase ivimbele ukungqubuzana nokuphendula kwe-hydration yezinhlayiya ze-cement ngokwandisa i-viscosity kakhonkolo nokunciphisa isivinini sokunyakaza kwezinhlayiya ze-cement. Izinga le-hydration eliphansi lisiza ukubambezela isikhathi sokumisa ukhonkolo.
Ukulungiswa kwe-Rheological: I-HEMC ingakwazi ukulungisa izakhiwo ze-rheological zikakhonkolo, ikhulise i-viscosity yayo, futhi igcine ukunamathisela okukhonkolo ku-fluidity enhle ekuqaleni, ukugwema ubunzima bokwakha obubangelwa ukuhlangana ngokweqile.
Izici ezinomthelela
Umphumela weI-HEMCekusetheni isikhathi asihlobene nje kuphela nomthamo wayo, kodwa futhi ithintwa ezinye izici zangaphandle:
Isisindo se-molecular kanye ne-degree of substitution of HEMC: Isisindo se-molecular and degree of substitution (i-degree of substitution of ethyl ne-methyl) ye-HEMC inethonya elikhulu ekusebenzeni kwayo. I-HEMC enesisindo esiphezulu samangqamuzana kanye nezinga eliphakeme lokushintsha ngokuvamile lingakha isakhiwo senethiwekhi esinamandla, esibonisa ukugcinwa kwamanzi okungcono kanye nezakhiwo ezishubile, ngakho umphumela wokulibaziseka ekumiseni isikhathi ubaluleke kakhulu.
Uhlobo lukasimende: Izinhlobo ezahlukene zikasimende zinamazinga ahlukene e-hydration, ngakho-ke umphumela we-HEMC ezinhlelweni ezihlukene zikasimende nawo uhlukile. I-Ordinary Portland Cement inezinga elisheshayo le-hydration, kuyilapho isimende esishisayo esiphansi noma usimende okhethekile unezinga eliphansi le-hydration, futhi indima ye-HEMC kulezi zinhlelo ingase ibonakale kakhulu.
Izimo zemvelo: Izimo zemvelo ezifana nezinga lokushisa nomswakama zinethonya elibalulekile ngesikhathi sokubeka ukhonkolo. Amazinga okushisa aphezulu azosheshisa ukusabela kwe-hydration kasimende, okuholela ekunciphiseni isikhathi sokusetha, futhi umphumela we-HEMC ezindaweni zokushisa eziphezulu ungase ube buthakathaka. Ngokuphambene nalokho, ezindaweni zokushisa eziphansi, umphumela wokulibaziseka we-HEMC ungase ubonakale ngokucacile.
Ukugxila kwe-HEMC: Ukugxila kwe-HEMC kunquma ngokuqondile izinga lomthelela wayo kukhonkolo. Ukugxila okuphezulu kwe-HEMC kungakhuphula kakhulu ukugcinwa kwamanzi kanye ne-rheology yekhonkrithi, ngaleyo ndlela kubambezeleke ngokuphumelelayo isikhathi sokumisa, kodwa i-HEMC ngokweqile ingabangela uketshezi olubi lwekhonkrithi futhi kuthinte ukusebenza kokwakhiwa.
Umphumela we-Synergistic we-HEMC nezinye izixube
I-HEMC ivame ukusetshenziswa nezinye izixube (ezifana nezinciphisi zamanzi, ama-retarders, njll.) ukuze kulungiswe ngokugcwele ukusebenza kukakhonkolo. Ngokubambisana kwababuyisela emuva, umphumela wokulibaziseka wokusetha we-HEMC ungase uthuthukiswe nakakhulu. Isibonelo, umthelela we-synergistic we-retarder ethile efana nama-phosphates nezingxube zikashukela ne-HEMC unganweba ngokuphawulekayo isikhathi sokumisa sikakhonkolo, ofanele amaphrojekthi akhethekile ezindaweni ezishisayo noma ezidinga isikhathi eside sokwakha.
3. Eminye imiphumela ye-HEMC ezakhiweni ezikhonkolo
Ngaphezu kokulibazisa isikhathi sokusetha, i-HEMC nayo inomphumela obalulekile kwezinye izakhiwo zekhonkrithi. Isibonelo, i-HEMC ingathuthukisa i-fluidity, anti-segregation, ukusebenza kokupompa nokuqina kokhonkolo. Ngenkathi ulungisa isikhathi sokusetha, imiphumela yokuqina nokugcinwa kwamanzi ye-HEMC ingavimbela ngokuphumelelayo ukuhlukaniswa noma ukopha kokhonkolo, futhi ithuthukise ikhwalithi jikelele nokuzinza kokhonkolo.
I-Hydroxyethyl methylcellulose (HEMC) ingabambezela ngempumelelo isikhathi sokusetha sikakhonkolo ngokusebenzisa ukugcinwa kwayo kahle kwamanzi, ukuqina kanye nemiphumela yokulawula i-rheological. Izinga lethonya le-HEMC lithintwa yizici ezifana nesisindo sayo samangqamuzana, izinga lokushintshwa, uhlobo lukasimende, inhlanganisela ye-admixture kanye nezimo zemvelo. Ngokulawula ngokunengqondo umthamo kanye nengxenye ye-HEMC, isikhathi sokusetha singanwetshwa ngokuphumelelayo ngenkathi kuqinisekiswa ukusebenza kokwakhiwa kokhonkolo, futhi ukusebenza nokuqina kokhonkolo kungathuthukiswa. Kodwa-ke, ukusetshenziswa ngokweqile kwe-HEMC kungase futhi kulethe imiphumela engemihle, njengokungabi namanzi kahle noma ukugeleza kwamanzi okungaphelele, ngakho-ke idinga ukusetshenziswa ngokuqapha ngokuvumelana nezidingo zangempela zobunjiniyela.
Isikhathi sokuthumela: Nov-21-2024