Cov ntsiab lus tseem ceeb ntawm kev tsim vaj tse rau pob zeb sib xyaw nrog ntau yam khoom sib xyaw

(1) Admixtures

Admixtures yog siv me me (0.005%–5% ntawm cov cement hnyav) tab sis xa cov teebmeem tseem ceeb. Lawv qhov ntau npaum li cas yuav tsum raug xam kom raug, nrog rau qhov hnyav tsis tshaj 2%. Hom thiab ntau npaum li cas ntawm admixtures yuav tsum tau txiav txim siab raws li qhov xav tau kev ua tau zoo, kev tsim kho thiab huab cua, cov khoom siv raw, thiab cov khoom sib xyaw ua ke, los ntawm kev sim validation. Thaum siv hauv daim ntawv tshuaj, cov ntsiab lus ntawm cov dej hauv cov tshuaj yuav tsum tau muab tso rau hauv tag nrho cov dej sib tov. Yog tias siv ntau cov khoom sib xyaw ua ke thiab ua rau flocculation lossis nag lossis daus, cov kev daws teeb meem yuav tsum tau npaj nyias thiab ntxiv rau lub tov khoom ib tus zuj zus.

(2) Cov dej txo qis

Txhawm rau kom muaj kev sib xyaw ua ke, cov neeg ua dej txo qis yuav tsum zoo dua ntxiv rau hauv daim ntawv daws teeb meem. Lawv qhov ntau npaum li cas yuav raug nce kom haum nrog qhov kub thiab txias. Cov dej-txo cov neeg ua hauj lwm yuav tsum tau ntxiv rau lub tov khoom ib txhij nrog cov dej sib tov. Thaum siv cov khoom siv thauj mus los rau kev thauj mus los ua vaj tse, tus neeg saib xyuas dej tuaj yeem ntxiv ua ntej tshem tawm, ua raws li 60-120 vib nas this ntawm kev sib xyaw ua ntej tso tawm. Cov dej tsis tu ncua yog qhov tsim nyog rau kev tsim vaj tsev thaum qhov tsawg kawg nkaus txhua hnub kub siab tshaj 5 degree. Yog tias qhov ntsuas kub qis dua 5 degree, lawv yuav tsum tau siv ua ke nrog cov neeg ua haujlwm muaj zog thaum ntxov, thiab kev vibration kom zoo yuav tsum tau ua kom tshem tawm cov cua nkag. Cov pob zeb sib xyaw nrog cov dej-txo cov neeg ua hauj lwm yuav tsum tau kho kom zoo thaum ntxov. Hauv chav ua kom sov, qhov kub yuav tsum tsuas yog nce tom qab cov pob zeb nce mus txog qhov muaj zog. Cov neeg ua haujlwm siab dej-txo cov neeg ua haujlwm feem ntau ua rau poob qis hauv cov pob zeb, nrog rau 30% -50% txo hauv 30 feeb, yog li yuav tsum tau ceev faj thaum siv.

(3) Air-Entraining Agents thiab Air-Entraining Water-Reduction Agents

Qhob nrog siab khov-thaw kuj yuav tsum muaj xws li cua-entraining agents los yog cua-entraining dej-txo cov neeg ua hauj. Txawm li cas los xij, cov neeg ua haujlwm huab cua nkag tsis haum rau cov pob zeb prestressed lossis cov pob zeb ua kom zoo. Air-entraining agents yuav tsum tau ntxiv rau hauv daim ntawv daws teeb meem, zoo dua sib xyaw rau hauv cov dej sib tov ua ntej. Lawv tuaj yeem siv ua ke nrog cov dej-txo cov neeg ua haujlwm, cov neeg ua haujlwm thaum ntxov, cov retarders, lossis cov tshuaj tiv thaiv kab mob, tab sis cov tshuaj yuav tsum tau yaj tag nrho. Yog tias flocculation lossis nag lossis daus tshwm sim, cov tshuaj yuav tsum tau rhaub kom yaj. Qhob nrog cov cua-entraining agents yuav tsum tau tov mechanically rau 3-5 feeb. Lub sij hawm los ntawm kev tso tawm mus rau pouring yuav tsum tau tsawg, thiab kev co yuav tsum tsis txhob ntau tshaj 20 vib nas this los tiv thaiv huab cua cov ntsiab lus.

(4) Retarders thiab Retarding Water-Reduction Agents

Retarders yuav tsum tau ntxiv rau hauv daim ntawv tshuaj. Yog hais tias cov tshuaj muaj insoluble los yog tsis zoo soluble hais, nws yuav tsum tau kom huv si stirred ua ntej siv. Lub sijhawm sib tov tuaj yeem txuas ntxiv los ntawm 1-2 feeb. Retarders tuaj yeem siv ua ke nrog lwm cov khoom sib xyaw, tab sis tsuas yog yuav tsum pib kho tom qab cov pob zeb mus txog qhov kawg. Retarders tsis haum rau kev tsim vaj tsev thaum qhov kub thiab txias txhua hnub yog qis dua 5 degree, thiab lawv yuav tsum tsis txhob siv ib leeg nyob rau hauv thaum ntxov-lub zog pob zeb los yog chav-kho pob zeb.

(5) Cov Neeg Ua Haujlwm Thaum Ntxov thiab Lub Zog Thaum Ntxov Dej-txo cov neeg sawv cev

Qee cov neeg ua haujlwm thaum ntxov tau ntxiv rau hauv cov hmoov qhuav qhuav, thaum lwm tus siv los ua kev daws teeb meem, ua raws li cov lus qhia rau kev thov kom raug. Cov hmoov qhuav qhuav yuav tsum tau qhuav-sib xyaw nrog cov cement thiab aggregates ua ntej ntxiv dej, nrog lub sijhawm sib tov tsis pub tsawg tshaj 3 feeb. Thaum siv hauv daim ntawv tshuaj, 40-70 degree dej sov tuaj yeem siv los ua kom nrawm nrawm. Tom qab pouring, lub pob zeb yuav tsum tau them nrog yas zaj duab xis rau kho. Nyob rau hauv ib puag ncig uas tsis muaj qhov kub thiab txias, cov ntaub ntawv rwb thaiv tsev yuav tsum tau ntxiv rau kev tiv thaiv thermal, thiab kev kho dej yuav tsum pib tam sim ntawd tom qab qhov kawg teeb tsa kom muaj dej noo. Rau chav kho kom sov, cov txheej txheem kho yuav tsum tau txiav txim siab sim.

(6) Antifreeze Agents

Antifreeze agents yog categorized los ntawm qhov kub thiab txias xws li -5 degree , -10 degree , thiab -15 degree . Hom tsim nyog yuav tsum raug xaiv raws li qhov ntsuas kub txhua hnub. Cov pob zeb sib xyaw nrog cov tshuaj tiv thaiv kab mob yuav tsum siv Portland MAAs lossis Portland cement zoo tib yam nrog qib zog tsis pub tsawg dua 42.5 MPa. High-alumina cement yog nruj me ntsis txwv tsis pub. Chloride ntsev, nitrite ntsev, thiab nitrate-based antifreeze agents kuj raug txwv nyob rau hauv cov pob zeb prestressed. Cov khoom siv raw rau pob zeb yuav tsum tau preheated, thiab qhov kub ntawm qhov sib tov tawm ntawm lub tov khoom yuav tsum tsis pub tsawg tshaj 10 degree. Qhov ntau npaum ntawm cov tshuaj tiv thaiv kab mob thiab cov dej-cement piv yuav tsum tau tswj nruj me ntsis. Lub sij hawm sib tov yuav tsum yog 50% ntev dua nyob rau hauv ib txwm muaj mob. Tom qab pouring, lub pob zeb yuav tsum tau them nrog yas zaj duab xis thiab rwb thaiv tsev ntaub ntawv, thiab dej curing yog txwv tsis pub nyob rau hauv sub-zero tej yam kev mob.

(7) Nthuav cov neeg sawv cev

Qhov ntau npaum li cas ntawm cov neeg sawv cev nthuav dav yuav tsum tau txiav txim siab los ntawm kev sim sib xyaw ua ntej kev tsim kho kom ntseeg tau tias qhov tseeb nthuav dav. Kev sib xyaw ua ke yuav tsum tau siv, nrog lub sijhawm sib xyaw yam tsawg kawg ntawm 3 feeb, thiab lub sijhawm sib xyaw yuav tsum txuas ntxiv 30 vib nas this piv rau cov pob zeb tsis muaj cov khoom sib xyaw. Shrinkage-compensating qhob yuav tsum tau vibrated mechanically los xyuas kom meej compaction. Txhawm rau sau cov pob zeb nrog qhov poob siab tshaj 150mm, tsis siv neeg kho tshuab kev co yuav tsum tsis txhob siv. Kev nthuav cov pob zeb yuav tsum tau kho nyob rau hauv qhov chaw ntub dej tsawg kawg yog 14 hnub lossis siv cov tshuaj tua kab mob rau kev kho kom ntev.

(8) Accelerators

Thaum siv cov accelerators, lawv cov kev sib raug zoo nrog cov cement yuav tsum tau ua tib zoo sim, thiab kev siv ntau npaum li cas thiab kev siv yuav tsum tau tswj nruj me ntsis. Yog tias cov cement muaj cov qib siab C3A thiab C3S, cov pob zeb sib tov yuav tsum tau nchuav los yog txau li ntawm 20 feeb. Tom qab tsim, cov pob zeb yuav tsum tau khaws cia kom noo thaum kho kom tsis txhob tawg.