1. Mhedziso ye cellulose ether (HPMC)
Hydroxypropyl methylcellulose (HPMC) inowanzoshandiswa cellulose ether komboni, iyo inogadziriswa kemikari kubva kune yakasikwa cellulose. Iyo ine yakanakisa solubility yemvura, firimu-inogadzira, thickening uye adhesive zvivakwa, saka inoshandiswa zvakanyanya mukuvaka zvinhu. Iko kushandiswa kweHPMC mune simende-yakavakirwa zvinhu kunonyanya kuvandudza kuyerera kwayo, kuchengetwa kwemvura uye kugadzirisa nguva yekumisikidza.
2.Basic process yekuisa simenti
Maitiro ekuita semende nemvura kuita mahydrates anonzi hydration reaction. Iyi nzira yakakamurwa kuita matanho akati wandei:
Induction period: Cement particles inotanga kunyunguduka, ichiita calcium ions uye silicate ions, ichiratidza mamiriro ekuyerera kwenguva pfupi.
Nguva yekumhanyisa: Zvigadzirwa zveHydration zvinowedzera nekukurumidza uye maitiro ekuisa anotanga.
Deceleration nguva: The hydration rate inoderera, simende inotanga kuoma, uye dombo rakasimba resimende rinoumbwa.
Nguva yekudzikamisa: Zvigadzirwa zveHydration zvishoma nezvishoma zvinokura uye simba rinowedzera zvishoma nezvishoma.
Nguva yekuseta inowanzopatsanurwa kuva yekutanga yekuseta nguva uye yekupedzisira yekuseta nguva. Nguva yekutanga yekuisa inoreva nguva iyo simende paste inotanga kurasikirwa nepurasitiki, uye yekupedzisira nguva yekuisa inoreva nguva iyo simende paste inorasa zvachose plastiki uye inopinda mudanho rekuoma.
3. Mechanism of the influence of HPMC on simende setting time
3.1 Kukora mhedzisiro
HPMC ine yakakosha kukora mhedzisiro. Inogona kuwedzera viscosity yesamende paste uye kugadzira yakakwirira-viscosity system. Uku kukora mhedzisiro kuchakanganisa kupararira uye sedimentation yemasimende zvimedu, uye nekudaro kukanganisa kufambira mberi kwe hydration reaction. Iyo thickening mhedzisiro inoderedza deposition rate ye hydration zvigadzirwa pamusoro pemasimende masimende, nekudaro kunonotsa nguva yekumisikidza.
3.2 Kuchengeta mvura
HPMC ine simba rekuchengetedza mvura rakanaka. Kuwedzera HPMC kune simende paste kunogona kuvandudza zvakanyanya kuchengetwa kwemvura kwepaste. Kuchengetedzwa kwemvura kwakakwirira kunogona kudzivirira mvura iri pamusoro pesimende kuti isanyungudike nekukasira, kuitira kuchengetedza zviri mukati mesimende paste uye kurebesa nguva ye hydration reaction. Pamusoro pezvo, kuchengetedza mvura kunobatsira simende paste kuchengetedza humidity yakakodzera panguva yekurapa uye kuderedza njodzi yekutsemuka kunokonzerwa nekurasikirwa kwemvura kwekutanga.
3.3 Hydration retardation
HPMC inogona kuumba firimu rinodzivirira rinovhara pamusoro pemasimende zvimedu, izvo zvinotadzisa iyo hydration reaction. Iyi firimu inodzivirira inodzivirira kusangana kwakananga pakati pesimende particles nemvura, nokudaro kunonoka hydration process ye simenti uye kuwedzera nguva yekuisa. Uku kunonoka mhedzisiro kunonyanya kuoneka mune yakakwira molecular uremu HPMC.
3.4 mwaritropy yakasimbiswa
Kuwedzerwa kweHPMC kunogonawo kuwedzera thixotropy ye simenti slurry (kureva, iyo fluidity inowedzera pasi pekuita kwesimba rekunze uye inodzokera kumamiriro ekutanga mushure mokunge simba rekunze rabviswa). Iyi thixotropic pfuma inobatsira kuvandudza kushanda kwesimende slurry, asi maererano nekuisa nguva, iyi yakakwidziridzwa thixotropy inogona kuita kuti slurry igovere pasi pesimba rekugera, zvichiwedzera kurebesa nguva yekuseta.
4. Kushandiswa kweHPMC kunobata nguva yekuseta simende
4.1 Kuzvigadzika pasi zvinhu
Muzvigadziriso zvepasi, simende inoda nguva yakareba yekutanga yekumisikidza yekuyera uye screeding mashandiro. Kuwedzera HPMC kunogona kurebesa nguva yekutanga yekumisikidza simende, zvichibvumira zvinhu zvekuzvimisa kuti zvive nenguva yakareba yekushanda panguva yekuvaka, kudzivirira dambudziko rinokonzerwa nekukasira kuseta simende slurry panguva yekuvaka.
4.2 Premixed dhaka
Mune premixed dhaka, HPMC haingogadzirisi chete kuchengetwa kwemvura kwedhaka, asiwo inowedzera nguva yekuisa. Izvi zvinonyanya kukosha kuzviitiko zvine chekufambisa chakareba uye nguva yekuvaka, kuve nechokwadi chekuti dhaka rinochengetedza kushanda kwakanaka risati rashandiswa uye kudzivirira matambudziko ekuvaka anokonzerwa nenguva pfupi yekumisa.
4.3 Dry-yakasanganiswa dhaka
HPMC inowanzowedzerwa kune yakaoma-yakasanganiswa dhaka kuti ivandudze kuita kwayo kuvaka. Iko kukora mhedzisiro yeHPMC inowedzera viscosity yedhaka, zvichiita kuti zvive nyore kuisa uye chiyero panguva yekuvaka, uye zvakare inorebesa nguva yekumisikidza, ichipa vashandi vekuvaka nguva yakakwana yekugadzirisa.
5. Zvinhu zvinokanganisa nguva yekuseta simende neHPMC
5.1 HPMC yekuwedzera huwandu
Huwandu hweHPMC hwakawedzerwa chinhu chakakosha chinokanganisa nguva yekumisikidza simende. Kazhinji, iyo yakakura huwandu hweHPMC hwakawedzerwa, zvakanyanya kujeka kuwedzera kwekugadzika nguva yesimende. Izvi zvinodaro nekuti akawanda HPMC mamorekuru anogona kuvhara mamwe simende particle nzvimbo uye kutadzisa hydration maitiro.
5.2 Molecular huremu hweHPMC
HPMC yehuremu hwakasiyana hwemamorekuru ine mhedzisiro dzakasiyana pakugadzika nguva yesimende. HPMC ine huremu hwemamorekuru hwepamusoro kazhinji ine simba rekukora uye simba rekuchengetedza mvura, saka inogona kurebesa nguva yekumisikidza zvakanyanya. Kunyangwe HPMC ine yakaderera molecular uremu inogona zvakare kurebesa nguva yekumisikidza, mhedzisiro yacho haina kusimba.
5.3 Mamiriro ezvakatipoteredza
Ambient tembiricha uye humidity zvinokanganisawo maitiro eHPMC pane simende yekuseta nguva. Munzvimbo yekupisa yakanyanya, simende hydration reaction inokwidziridzwa, asi nzvimbo yekuchengetedza mvura yeHPMC inononoka kuita izvi. Munzvimbo yakadzika tembiricha, hydration reaction pachayo inononoka, uye iko kukora uye kuchengetedza mvura mhedzisiro yeHPMC inogona kukonzera simende yekuisa nguva kuti irebeswe zvakanyanya.
5.4 Mvura-simende ratio
Shanduko muyero yemvura-simende ichakanganisawo maitiro eHPMC pane simende yekuisa nguva. Pamwero wepamusoro wemvura-simende, kune mvura yakawanda mune simende paste, uye mvura yekuchengetedza mhedzisiro yeHPMC inogona kuita shoma pane yekumisikidza nguva. Payero yakaderera yemvura-simende, iko kukora kweHPMC kuchave kuri pachena, uye mhedzisiro yekuwedzera nguva yekumisikidza ichave yakakosha.
Sechinhu chakakosha semendi yekuwedzera, HPMC inokanganisa zvakanyanya nguva yekumisikidza simende kuburikidza nenzira dzakasiyana-siyana dzakadai sekukora, kuchengetedza mvura, uye kunonoka kwe hydration reaction. Kushandiswa kweHPMC kunogona kurebesa nguva yekutanga uye yekupedzisira yekugadzika simende, kupa nguva yakareba yekushanda yekuvaka, uye kugadzirisa mashandiro esimende-yakavakirwa zvinhu. Mumashandisirwo anoshanda, zvinhu zvakaita senge huwandu hweHPMC hwakawedzerwa, huremu hwemamorekuru, uye mamiriro ezvemamiriro ekunze akabatana anoona maitiro ayo chaiwo pane simende yekumisikidza nguva. Nokugadzirisa zvinhu izvi zvine musoro, kunyatsodzora nguva yekumisa simende kunogona kuwanikwa kuzadzisa zvinodiwa zvezvirongwa zvekuvaka zvakasiyana.
Nguva yekutumira: Jun-21-2024