Qhov sib xyaw ntawm cov dej txo tus neeg sawv cev tshaj li qhov sib xyaw ua ke los ntawm ob peb zaug, thiab nws cov kev cuam tshuam rau kev ua tau zoo ntawm cov pob zeb yuav tsum tau txiav txim siab raws li qhov xwm txheej tshwj xeeb.
Nyob rau hauv thawj rooj plaub, nyob rau hauv lub ultra-high-lub zog pob zeb, vim hais tias cov dej-binder ratio yog ≤0.3 los yog txawm tsawg li 0.2, nws feem ntau qhia tau hais tias lub xeev ntawm cov pob zeb tsis rhiab rau tus nqi ntawm cov khoom.dej txo tus neeg sawv cev. Txhawm rau kom ua tiav qhov zoo tshaj plaws fluidity lub xeev, cov dej raug txo. Cov koob tshuaj ntawm tus neeg sawv cev feem ntau yog 5-8 npaug ntawm cov koob tshuaj ib txwm muaj, uas yog, ntau npaum li caspolycarboxylic acidyuav tsum mus txog 5% -8%. Rau cov pob zeb hauv qab C50, xws li cov ntsiab lus siab yog qhov tsis txaus ntseeg. Txawm li cas los xij, cov txiaj ntsig kev sim qhia tau hais tias lub zog ntawm cov pob zeb ntawm txhua lub hnub nyoog txhim kho zoo nyob rau hauv qhov nyiaj no, thiab 28d lub zog ntawm pob zeb tau npaj nrog lub zog no ntau dua 100MPa.
Yog vim li cas yog hais tias: lub dispersion ntawmdej txo tus neeg sawv cevntawm cement tsuas yog lub cev adsorption.Dej txo tus neeg sawv cevmolecules yog adsorbed rau saum npoo ntawm cov cement hais. Los ntawm steric hindrance thiab electrostatic repulsion, cov qauv flocculation ntawm cov cement hais yog disintegrated thiab dej dawb tso tawm. , Li no nce lub fluidity ntawm pob zeb, thiab vim hais tias ntawm nws tshwj xeeb comb-puab qauv, lubpolycarboxylic acidrawsdej txo tus neeg sawv cevtuaj yeem tiv thaiv cov cement hais los ntawm kev sib sau ua ke hauv ib lub sijhawm, yog li nws muaj kev ua haujlwm zoo slump. Thaum ib lub sij hawm dhau los, cov khoom siv cement hydration yuav ua tiav tag nrhodej txo tus neeg sawv cevmolecules adsorbed rau saum npoo ntawm cov cement hais. Tom qab lubdej txo tus neeg sawv cevmolecules yog shielded, dispersion ploj tag, thiab ces tsis muaj kev cuam tshuam los yog cuam tshuam rau cov pob zeb. Cov cement feem ntau yog dej Lub zog ntawm pob zeb tsim ib txwm.
Ntawm chav kawm, vim cov ntsiab lus siab ntawmdej txo tus neeg sawv cev, qhov concentration ntawmdej txo tus neeg sawv cevmolecules nyob rau hauv pob zeb yog loj. Tom qab qee cov molecules raug them los ntawm cov khoom siv cement hydration, cov molecules tshiab yog adsorbed rau ntawm cov khoom siv cement hydration, tiv thaiv cov cement hais los ntawm kev sib tshooj sai sai. Lub network tau tsim, uas txuas ntxiv lub sijhawm teeb tsa rau qee qhov, tab sis qhov chaw cement dav dav yuav tsis pub dhau 24 teev.
Hauv qhov thib ob, lubdej txo tus neeg sawv cevnws tus kheej muaj qee yam huab cua-entraining thiab retarding zog, thiab ob peb zaug ntawm over-admixture yuav muaj kev cuam tshuam ntau dua rau kev ua tau zoo ntawm pob zeb. Feem ntau hais lus, tus nqi ntawm retarding tivthaiv yog txiav txim raws li qhov kub thiab txias ib puag ncig, engineering yuav tsum tau thiab cov npaum li cas ntawmdej txo tus neeg sawv cev. Adsorption cuam tshuam rau lub cev hydration ntawm cov khoom cementitious. Nyob rau hauv cov ntaub ntawv sib sib zog nqus, lub sij hawm teem tau ntev heev, thiab nyob rau hauv qhov phem tshaj, lub pob zeb yuav tsis teem rau ob peb hnub los yog mus tas li. Feem ntau, rau cov pob zeb uas tau teem caij rau 2 hnub lossis ntev dua, vim qhov kev ncua ntev ntawm cov txheej txheem hydration, hom thiab ntau npaum li cas ntawm cov khoom hydration yuav hloov, uas ua rau lub zog ntawm cov pob zeb ua kom poob mus tas li. Ntawm chav kawm, rau subway occluding pawg (feem ntau 72-90h pib qhov chaw) thiab loj pob zeb siv xws li pawg hauv paus, kaus mom, dams, thiab lwm yam., yuav tsum tau teem sij hawm ntev. Feem ntau, lub zog theem yuav tsum tau nce kom tsim nyog thaum lub sij hawm tsim ntawm qhov sib tov sib xyaw. Xyuas kom meej tias 28d lub zog ua tau raws li cov qauv tsim.
Huab cua-entrainingdej txo tus neeg sawv cevyog super tov ob peb zaug. Thaum cov ntsiab lus huab cua ntawm cov pob zeb tsim nyog ntawm qhov sib xyaw ua ke, cov ntsiab lus ntawm cov huab cua yuav zoo heev tom qab sib xyaw super ntau zaus. Lub pob zeb slurry yog txawv txawv, thiab cov pob zeb yog lub teeb thiab ntab thaum shoveled, uas yog loj heev Thaum lub pob zeb yog xoob thiab ntxeem tau zoo li lub khob cij, lub zog ntawm cov pob zeb yog hnyav heev.
Hauv qhov thib peb, txawm tias tusdej txo tus neeg sawv cevnws tus kheej tsis muaj huab cua-entraining thiab retarding hom, tom qab tau muab ob npaug rau, yog hais tias cov dej noj tsis hloov nyob rau hauv lub sij hawm, lub workability ntawm lub tshiab pob zeb yuav deteriorated loj, ua rau loj secretion. Dej, kev sib cais, hauv qab rub, tawv, thiab lwm yam, thiab tsis zoo ib yam thiab ruaj khov tom qab nchuav, thiab sab hauv delamination, uas ua rau muaj kev nce hauv dej-rau-binder piv ntawm cov pob zeb nyob ib ncig ntawm lub steel bar, thiab txo lub zog. , uas ua rau lub steel tuav lub zog poob siab. Qhov loj ntawm cov ntshav los ntawm qhov hnyav dhau-admixture tseem yuav tshwm sim rau ntawm qhov chaw ntawm cov pob zeb thiab cov khoom hauv kev sib cuag nrog cov formwork, uas ua rau txo qis ntawm lub zog ntawm cov khoom no, thiab ntau qhov tsis xws luag xws li tawg, honeycombs, thiab pockmarked nto yog nquag tshwm sim thaum cov pwm raug tshem tawm, uas ua rau cov pob zeb muaj peev xwm tiv thaiv sab nraud erosion zoo heev txo, cuam tshuam rau lub durability ntawm pob zeb.
Post lub sij hawm: Dec-02-2021
