Self-Compacting Concrete (SCC) yog ib qho cuab yeej ua vaj tse niaj hnub uas ntws los ntawm nws tus kheej qhov hnyav los sau cov formwork yam tsis tas yuav muaj kev vibration. Nws cov txiaj ntsig suav nrog kev txhim kho kev ua haujlwm, txo nqi zog, thiab txhim kho kev ua haujlwm zoo. Ua tiav cov yam ntxwv no yuav tsum muaj kev tswj xyuas meej ntawm kev sib xyaw, feem ntau nrog kev pab ntawm cov khoom sib xyaw xws li Hydroxypropyl Methylcellulose (HPMC). Cov cellulose ether polymer no ua lub luag haujlwm tseem ceeb hauv kev hloov kho cov khoom rheological ntawm SCC, txhim kho nws cov kev ruaj ntseg thiab cov yam ntxwv ntws.
Khoom thiab Kev Ua Haujlwm ntawm HPMC
Hydroxypropyl Methylcellulose (HPMC) yog non-ionic, dej-soluble polymer muab tau los ntawm cellulose. Nws cov khoom tseem ceeb muaj xws li:
Viscosity Modification: HPMC ua kom cov viscosity ntawm aqueous kev daws teeb meem, txhim kho thixotropic xwm ntawm cov pob zeb sib tov.
Dej Retention: Nws muaj peev xwm tuav tau dej zoo heev, uas pab tswj kev ua haujlwm ntawm pob zeb los ntawm kev txo cov dej evaporation.
Adhesion thiab Cohesion: HPMC txhim kho kev sib txuas ntawm cov theem sib txawv hauv cov pob zeb, txhim kho nws cov khoom sib txuas.
Stability Enhancement: Nws stabilizes lub ncua kev kawm ntawv ntawm aggregates nyob rau hauv lub mix, txo segregation thiab los ntshav.
Cov khoom no ua rau HPMC muaj txiaj ntsig zoo ntxiv hauv SCC, raws li nws hais txog cov teeb meem xws li kev sib cais, los ntshav, thiab tswj xyuas qhov xav tau ntws yam tsis muaj kev cuam tshuam kev ruaj ntseg.
Lub luag hauj lwm ntawm HPMC nyob rau hauv Self-Compacting Concrete
1. Txhim kho kev ua haujlwm
Lub luag haujlwm tseem ceeb ntawm HPMC hauv SCC yog txhawm rau txhim kho nws txoj haujlwm ua haujlwm los ntawm kev ua kom cov viscosity sib xyaw. Qhov kev hloov kho no tso cai rau SCC ntws yooj yim hauv nws tus kheej qhov hnyav, sau cov formwork nyuaj thiab ua tiav qib siab ntawm compaction yam tsis tas yuav muaj kev co. HPMC xyuas kom meej tias cov pob zeb tseem ua haujlwm tau ntev dua, uas yog tshwj xeeb tshaj yog muaj txiaj ntsig zoo rau cov dej loj lossis cov dej sib txawv.
Flowability: HPMC pab txhawb rau cov khoom sib xyaw thixotropic, cia nws nyob twj ywm kua thaum sib tov tab sis thicken thaum sawv. Qhov kev coj cwj pwm no txhawb nqa SCC tus yam ntxwv ntawm tus kheej-leveling, kom ntseeg tau tias nws ntws zoo los sau cov pwm thiab encapsulate reinforcing tuav yam tsis muaj kev sib cais.
Kev sib xyaw ua ke: Los ntawm kev tswj cov viscosity, HPMC pab tswj kom muaj kev sib luag zoo ib yam thoob plaws hauv kev sib xyaw, kom ntseeg tau tias txhua pawg ntawm SCC nthuav tawm kev ua haujlwm zoo ib yam ntawm cov dej ntws thiab kev ruaj ntseg.
2. Kev tswj kev sib cais thiab los ntshav
Kev sib cais (kev sib cais ntawm cov khoom sib xyaw ntawm cov cement paste) thiab los ntshav (dej nce mus rau saum npoo) yog qhov kev txhawj xeeb tseem ceeb hauv SCC. Cov phenomena no tuaj yeem cuam tshuam cov qauv kev ncaj ncees thiab qhov chaw tiav ntawm cov pob zeb.
Homogeneous Mix: HPMC lub peev xwm los ua kom cov viscosity ntawm cov cement paste txo qis kev txav ntawm cov dej thiab sib sau ua ke, yog li txo qhov kev pheej hmoo ntawm kev sib cais.
Txo los ntshav: Los ntawm khaws cov dej hauv qhov sib tov, HPMC pab tiv thaiv los ntshav. Qhov kev tuav dej no tseem ua kom cov txheej txheem hydration txuas ntxiv kom zoo, txhim kho kev txhim kho lub zog thiab kav ntev ntawm cov pob zeb.
3. Txhim khu kev ruaj ntseg
HPMC pab txhawb rau kev ruaj ntseg ntawm SCC los ntawm kev txhim kho kev sib koom ua ke ntawm cov khoom sib xyaw. Qhov kev txhim kho kev ruaj ntseg no yog qhov tseem ceeb hauv kev tswj cov kev faib tawm ntawm cov khoom sib xyaw thiab tiv thaiv kev tsim cov voids lossis qhov chaw tsis muaj zog.
Kev sib koom ua ke: Cov nplaum nplaum ntawm HPMC txhawb kev sib raug zoo ntawm cov cement particles thiab aggregates, ua rau muaj kev sib xyaw ua ke uas tiv thaiv kev sib cais.
Stabilization: HPMC stabilizes lub microstructure ntawm cov pob zeb, tso cai rau txawm faib cov aggregates thiab tiv thaiv kev tsim ntawm laitance (ib txheej tsis muaj zog ntawm cov cement thiab cov khoom zoo ntawm qhov chaw).
Qhov cuam tshuam rau Mechanical Properties
1. Compressive zog
Kev cuam tshuam ntawm HPMC ntawm lub zog compressive ntawm SCC feem ntau yog qhov zoo. Los ntawm kev tiv thaiv kev sib cais thiab ua kom muaj kev sib xyaw ua ke, HPMC pab tswj kev ncaj ncees ntawm cov pob zeb ntawm microstructure, ua rau muaj zog zoo dua qub.
Hydration: Txhim kho cov dej khaws cia kom ua tiav cov dej tiav ntawm cov cement hais, ua rau kev txhim kho ntawm cov matrix muaj zog.
Uniform Density: Kev tiv thaiv kev sib cais ua rau muaj kev sib faib ntawm cov sib xyaw ua ke, uas txhawb nqa lub zog siab dua thiab txo qhov kev pheej hmoo ntawm cov ntsiab lus tsis muaj zog.
2. Durability
Kev siv HPMC hauv SCC txhim kho nws cov kav ntev los ntawm kev ua kom lub denser thiab ntau homogenous microstructure.
Txo permeability: Txhim kho cohesion thiab txo los ntshav txo qhov permeability ntawm cov pob zeb, txhim kho nws cov kev tiv thaiv rau ib puag ncig yam xws li khov-thaw cycles, tshuaj tua kab mob, thiab carbonation.
Txhim kho Deg Finish: Kev tiv thaiv los ntshav thiab kev sib cais ua kom lub ntsej muag du thiab ruaj khov dua, uas tsis tshua muaj kev sib tsoo thiab scaling.
Daim ntawv thov thiab kev txiav txim siab npaum li cas
Qhov ua tau zoo ntawm HPMC hauv SCC nyob ntawm nws qhov ntau npaum thiab cov kev cai tshwj xeeb ntawm kev sib xyaw. Cov nqi ntau npaum li cas ntawm 0.1% mus rau 0.5% ntawm cov cement hnyav, nyob ntawm seb cov khoom xav tau thiab cov yam ntxwv ntawm lwm cov khoom sib xyaw.
Mix Design: Ua tib zoo tsim qauv yog qhov tseem ceeb los txhim kho cov txiaj ntsig ntawm HPMC. Cov yam ntxwv xws li hom sib sau ua ke, cov ntsiab lus cement, thiab lwm yam khoom siv yuav tsum raug txiav txim siab kom ua tiav qhov xav tau ntawm kev ua haujlwm, kev ruaj ntseg, thiab lub zog.
Kev sib xyaw ua ke: HPMC yuav tsum sib haum nrog lwm cov khoom siv hauv kev sib xyaw, xws li superplasticizers thiab dej reducers, kom tsis txhob muaj kev cuam tshuam tsis zoo uas tuaj yeem cuam tshuam kev ua haujlwm ntawm SCC.
Hydroxypropyl Methylcellulose (HPMC) plays lub luag haujlwm tseem ceeb hauv kev txhim kho kev ua haujlwm ntawm tus kheej-Compacting Concrete (SCC). Nws muaj peev xwm hloov kho viscosity, txhim kho cov dej tuav, thiab ruaj khov ntawm qhov sib xyaw daws teeb meem tseem ceeb hauv SCC ntau lawm, suav nrog kev sib cais, los ntshav, thiab tswj kev ntws. Kev koom ua ke ntawm HPMC hauv SCC ua rau muaj kev ua haujlwm ntau dua, ruaj khov, thiab ruaj khov sib xyaw ua ke, ua rau nws muaj txiaj ntsig zoo rau kev siv pob zeb niaj hnub. Kev tsim kom zoo thiab kev sib xyaw yog qhov tseem ceeb rau kev siv tag nrho cov txiaj ntsig ntawm HPMC, kom ntseeg tau tias SCC ua tau raws li cov qauv kev ua tau zoo uas yuav tsum tau ua rau ntau yam kev tsim kho.
Post lub sij hawm: Jun-18-2024