Qhov cuam tshuam dab tsi ntxiv rau cov neeg ua dej txo qis muaj qhov cuam tshuam rau kev ua tau zoo thiab kev ua haujlwm zoo?

Nrog rau kev tsim kho tas mus li thiab kev txhim kho ntawm cov phiaj xwm hauv tsev, pob zeb, ua ib qho ntawm cov khoom siv tseem ceeb tshaj plaws, muaj kev cuam tshuam loj rau tag nrho cov kev tsim kho kom zoo. Los ntawm kev ntxiv cov dej-txo cov neeg ua haujlwm rau pob zeb, nws qhov kev ua tau zoo tuaj yeem txhim kho tau zoo. Txawm li cas los xij, tus yuam sij rau qhov no yog kev tswj kom zoo ntawm kev noj cov tshuaj txo cov dej. Tus nqi ntawm cov dej-txo tus neeg sawv cev ntxiv muaj qhov cuam tshuam loj heev rau qhov zoo thiab kev ua tau zoo ntawm cov pob zeb. Yog li ntawd, nws yog ib qho tseem ceeb kom tswj tau qhov ntau npaum li cas ntawm cov dej-txo tus neeg saib xyuas los ntawm kev tsom mus rau microscopic txhawm rau txhim kho qhov zoo thiab kev ua haujlwm ntawm pob zeb.

1. Kev soj ntsuam ntawm kev ua tau zoo thiab kev ua haujlwm ntawm cov neeg ua dej txo qis

Cov dej txo qis, tseem hu ua dispersants, yog cov khoom siv sab nraud siv hauv kev tsim cov pob zeb. Thaum siv hauv cov pob zeb sib tov, lawv pab tswj kev ua haujlwm zoo thiab tswj cov dej ntsiab lus zoo. Raws li ib tug surfactant, tus neeg saib xyuas dej-txo tuaj yeem txhim kho cov dej num ntawm cov pob zeb. Cov dej-txo cov neeg ua haujlwm zoo tswj cov dej hauv cov pob zeb sib xyaw, yog li txhim kho lub zog, ruaj khov, thiab impermeability ntawm cov pob zeb, optimizing nws cov kev ua tau zoo, thiab muab cov ntaub ntawv zoo rau kev tsim kho. Qhov no pab ua kom tau raws li cov qauv kev tsim kho tshuab, tswj kev tsim kho suab nrov, thiab txo qis kev siv cov cement.

Cement, ua cov khoom siv granular, feem ntau muaj qhov kab nruab nrab ntawm 7-80 microns. Nws yog zoo nyob rau hauv kev ntxhib los mos thiab ib tug powdery khoom. Cement hais feem ntau muaj qhov polar nto, nthuav tawm muaj zog hydrophilicity. Cov khoom zoo ntawm cov cement muaj qhov tshwj xeeb loj tshwj xeeb ntawm thaj chaw. Cov dej-txo cov neeg ua haujlwm kom ntseeg tau tias, thaum tswj kev ua haujlwm ntawm cov pob zeb ua haujlwm, cov ntsiab lus ntawm cov dej tau raug tswj xyuas, uas ua rau kev ua haujlwm ntawm cov pob zeb ua haujlwm. Muaj ntau ntau hom dej-txo cov neeg ua hauj lwm, nrog rau cov dej-txo cov neeg ua hauj lwm zoo tib yam thiab cov dej-txo cov neeg ua haujlwm siab. Cov dej-txo cov neeg ua haujlwm feem ntau txo cov ntsiab lus dej ntau dua 5%, thiab tom qab ib lub lim tiam, lub zog compressive ntawm cov pob zeb tuaj yeem nce 10%. Tom qab ib hlis, lub zog compressive nce 5%. Cov dej-txo cov neeg ua haujlwm siab tuaj yeem txo cov ntsiab lus ntawm cov dej, kom ntseeg tau tias cov pob zeb tseem nyob hauv lub xeev muaj kua, nrog rau cov dej txo qis dua 10%. Tom qab peb hnub, lub zog compressive ntawm cov pob zeb tuaj yeem nce 25%. Qhov tseem ceeb tshaj plaws ntawm kev ua vaj tse ultra-high-strength yog nws cov fluidity siab thiab qis dej-cement piv. Yog li ntawd, yuav tsum tau ua kom cov dej-txo cov neeg ua haujlwm siab lossis ultra-dosing txoj kev. Txawm li cas los xij, nws yog ib qho tseem ceeb rau kev tswj cov tshuaj kom zoo txhawm rau txhim kho cov pob zeb ua haujlwm thiab zoo.

2. Qhov cuam tshuam ntawm High-Efficiency Water-Reduction Agent Dosage on Concrete Quality and Performance

1. Kev cuam tshuam rau Compressive Strength ntawm pob zeb

Ib qho ntawm cov khoom tseem ceeb ntawm cov pob zeb yog nws lub zog compressive, uas cuam tshuam rau lwm yam khoom ntawm pob zeb. Feem ntau, lub zog compressive ntawm cement paste cuam tshuam rau lub zog ntawm pob zeb. Qhov porosity, ntom, thiab lub zog ntawm cov cement paste yog cuam tshuam raws li hauv qab no:
R=ARC(C/WB)
Qhov twg:
R - Qhob compressive zog
A, B - empirical constants
RC - Cement zog

Siv cov qauv saum toj no, nws tuaj yeem txiav txim siab tias qhov sib piv ntawm cov dej-cement thiab qib ntawm hydration ntawm cov cement paste ncaj qha cuam tshuam rau lub zog compressive ntawm cov pob zeb. Ntxiv cov dej-txo tus neeg sawv cev rau cov pob zeb ua kom txo tau cov dej-cement piv thiab txo cov porosity ntawm cov cement paste, ua rau nws denser thiab nruj dua. Qhov no ua rau muaj kev nce hauv compressive zog ntawm cov pob zeb.

2. Kev cuam tshuam rau Durability ntawm pob zeb

(1) Kev cuam tshuam rau Kev Tiv Thaiv Kev Tiv Thaiv-Thaw
Cov dej-cement piv thiab cov ntsiab lus huab cua zoo heev cuam tshuam rau khov-thaw tsis kam ntawm pob zeb. Cov kev tshawb fawb tau pom tias qhov khov-thaw tsis kam ntawm pob zeb yog ncaj qha proportional rau nws cov dej-cement piv. Los ntawm kev tshawb fawb ntxiv cov dej-txo cov neeg ua haujlwm, qhov khov-thaw tsis kam ntawm cov pob zeb tuaj yeem ua kom zoo dua thiab txhim kho. Pob zeb muaj voids ntawm ntau qhov sib txawv, thiab cov khoom ntawm cov dej hauv cov pores kuj hloov nyob ntawm qhov pore loj. Cov qauv npuas hauv cov pob zeb muaj feem cuam tshuam rau nws qhov kev tiv thaiv khov-thaw. Lub khov-thaw kuj tuaj yeem txhim kho thaum huab cua cov ntsiab lus nce los ntawm 2%, tab sis yog tias cov ntsiab lus huab cua ntau dua 6%, nws tuaj yeem txo lub zog ntawm cov pob zeb thiab tsis zoo rau nws cov kav ntev. Cov ntsiab lus huab cua zoo yog nyob nruab nrab ntawm 2%-5%.

(2) Kev cuam tshuam rau Steel Corrosion
Kev tsim kho niaj hnub no feem ntau siv cov pob zeb muaj zog ntxiv. Lub firmness, stability, thiab durability ntawm cov qauv no yog txuas nrog carbonation ntawm pob zeb. Lub xub ntiag ntawm carbon dioxide nyob rau hauv cov huab cua ua rau corrosion ntawm pob zeb, maj mam hloov calcium hydroxide rau hauv calcium carbonate, yog li poob alkalinity. Yog hais tias cov pa roj carbon dioxide nkag mus rau hauv cov hlau reinforcement, nws yuav corrode lub passivation txheej thaum lub sij hawm, ua rau cov tshuaj corrosion ntawm cov hlau. Txawm hais tias cov khoom siv ntxiv nrog qee cov tshuaj chloride (Cl-) tau siv, ntxiv cov dej txo cov neeg ua haujlwm pab tswj cov pa roj carbon monoxide, yog li txhim kho cov khoom tiv thaiv carbonation ntawm cov cement thiab txo cov corrosion ntawm cov hlau reinforcement. Qhov no txhim kho lub durability ntawm cov pob zeb thiab ua kom muaj kev siv lub sij hawm ntev ntawm cov qauv.

(3) cuam tshuam rau permeability
Qhov sib piv ntawm dej-cement yog cuam tshuam nrog permeability ntawm pob zeb. Yog tias qhov sib piv ntawm cov dej-cement ntau tshaj 0.55, cov dej sib tov yuav ntau dua cov dej uas xav tau rau cov cement hydration, tawm hauv cov dej ntau dhau ntawm qhov sib tov. Qhov no nce qhov porosity thiab permeability ntawm cov pob zeb. Txawm li cas los xij, yog tias qhov sib piv ntawm cov dej-cement tsawg dhau thiab tsis ua tiav qhov kev xav tau ua haujlwm, cov qauv ntawm cov pob zeb yuav raug puas tsuaj, uas yuav cuam tshuam tsis zoo rau nws cov impermeability.

3. Kev cuam tshuam rau pob zeb ua haujlwm

Kev ua haujlwm ntawm pob zeb yog cuam tshuam los ntawm ntau yam, suav nrog hom cement, dej cov ntsiab lus, tus nqi ntawm cov khoom siv, qhov kub thiab lwm yam. Thaum lwm yam xwm txheej zoo ib yam, hom thiab ntau npaum li cas ntawm cov dej-txo tus neeg sawv cev ua lub luag haujlwm tseem ceeb hauv kev ua haujlwm ua vaj tse. Slump feem ntau yog siv los ntsuas kev ua haujlwm, thiab tus nqi poob qis yog proportional rau tus nqi ntawm cov dej txo tus neeg siv. Cov qauv hauv qab no feem ntau pom:
Dej-txo tus neeg saib xyuas ntau npaum li cas=0.5% ntawm cov cement hnyav, uas ua rau kom poob qis. Txawm li cas los xij, yog tias qhov ntau npaum li cas tshaj 0.5%, qhov poob qis yuav txo qis. Qhov ntau npaum li cas ntawm cov tshuaj txo cov dej yog nyob ib ncig ntawm 0.25%, thiab nws tsis pom zoo kom tshaj qhov nyiaj no vim nws tuaj yeem ua kom nrawm. Rau cov dej-txo cov neeg ua haujlwm siab, qhov ntau npaum li cas yog nyob nruab nrab ntawm 0.50%-0.75%.

4. Kev cuam tshuam rau lub sij hawm ua vaj tse

Hauv kev siv engineering, lub sijhawm teem sijhawm ntawm kev ua vaj tse yog qhov tseem ceeb rau kev tsim kho. Nruab nrab ntxiv cov retarders tuaj yeem tswj tau lub sijhawm teeb tsa ntawm pob zeb. Txawm li cas los xij, thaum tus nqi ntawm cov dej-txo tus neeg sawv cev tshaj li ib theem, nws tuaj yeem cuam tshuam rau lub sijhawm teem ntawm lub pob zeb thiab tej zaum yuav ua rau ncua sij hawm. Kub kuj tseem cuam tshuam cov pob zeb nrog cov dej-txo cov neeg ua haujlwm. Raws li qhov kub thiab txias, cov tshuaj tiv thaiv hydration ntawm cov cement nrawm, uas yuav cuam tshuam rau qhov chaw thiab hardening ceev ntawm cov pob zeb.

5. Kev cuam tshuam rau pob zeb Rheological Properties

Yuav kom tau txais cov pob zeb zoo, nws yog ib qho tseem ceeb uas yuav tsum tau ua kom cov viscosity tawg, kom ntseeg tau tias cov cement hais tau tawg tag nrho hauv cov dej nruab nrab. Cement gel tsim tuaj yeem cuam tshuam los ntawm ntau yam. Yog hais tias ib tug npaum li cas ntawm cov dej-txo tus neeg sawv cev yog ntxiv rau cov tshiab sib xyaw ua vaj tse, cov nqi hluav taws xob ntawm cov cement hais nce, ua rau muaj zog repulsive ntawm cov khoom, uas nyob rau hauv lem cuam tshuam viscosity. Qhov no txhim khu kev ruaj ntseg ntawm cov dispersion system thiab txhim kho cov flowability ntawm cov pob zeb. Cov cement slurry nthuav tawm ntau lub xeev: diluted, coagulated, thiab thixotropic xeev. Cov xeev no tshwm sim los ntawm kev sib cais tsis tu ncua thiab decomposition ntawm cov qauv coagulated hauv cov cement slurry, xav txog tus nqi shear thiab ua rau txo qis tsis kam thiab viscosity. Los ntawm kev ntxiv cov dej-txo tus neeg sawv cev hauv ib qho piv txwv, cov yam ntxwv thixotropic ntawm cov pob zeb muaj zog. Qhov no yog vim hais tias cov cement particles muaj cov khoom adsorptive, thiab cov khoom siv hluav taws xob muaj peev xwm nce ntxiv. Kev vibration nce ntxiv yuav txhim kho cov dej ntws ntawm cov pob zeb, thaum tsis muaj dej-txo tus neeg sawv cev yuav txo nws cov khoom thixotropic.