Hnub Kawg3 ,:seb, 2024

7. Kev cuam tshuam ntawm lub sijhawm sib xyaw thiab kev sib xyaw ceev

Lub sij hawm sib xyaw muaj qhov cuam tshuam ncaj qha rau cov ntsiab lus ntawm cov pob zeb thiab cov nyhuv dispersion ntawm cov pob zeb sib xyaw ntawm cov pob zeb, thiab cuam tshuam ncaj qha rau kev ua haujlwm, cov khoom siv kho tshuab thiab ua haujlwm ntev ntawm cov pob zeb. Yog tias cov khoom sib xyaw ua haujlwm nrawm dhau, nws yooj yim rau kev puas tsuaj rau cov qauv colloidal hauv cov cement thiab ob chav hluav taws xob txheej membrane rau ntawm qhov chaw ntawm cov cement, uas nws thiaj li yuav cuam tshuam rau lub sijhawm teem thiab slump ntawm cov pob zeb kom zoo. Qhov sib tov ceev yuav tsum tau tswj tsis pub dhau 1.5-3 feeb. Yog tias siv txoj kev sib xyaw qhuav, cov pob zeb tuaj yeem sib tov sib npaug los ntawm kev siv cov dej txo kom tsim nyog. Yog tias qhov kev daws yuav tsum tau ntxiv, cov dej yuav tsum tau txiav tawm ntawm qhov sib tov thaum lub sij hawm teeb tsa ntawm cov dej reducer kom ntseeg tau tias qhov sib npaug ntawm cov dej-cement ratio tsim. Txhawm rau kom ntseeg tau qhov kev poob qis ntawm cov pob zeb thiab muab kev ua si tag nrho rau lub luag haujlwm ntawm cov dej reducer, txoj kev sib xyaw tom qab tuaj yeem siv ncaj qha. Sib txawv los ntawm kev ua haujlwm siab dej reducer ntxiv txoj kev, qhov yooj yim ntawm kev sib xyaw ntawm cov pob zeb tuaj yeem ua kom ntseeg tau los ntawm kev siv cov txheej txheem tom qab sib xyaw kom haum. Yog tias xav tau lub tsheb thauj khoom sib tov los thauj cov pob zeb, cov dej reducer tuaj yeem muab ntxiv rau hauv lub tsheb sib tov 2 feeb ua ntej tshem tawm kom tsim nyog ua kom sib xyaw ceev ntawm cov khoom sib tov thiab txhim kho cov nyhuv tawm.

8. Kev cuam tshuam ntawm ambient kub thiab av noo

Lub sijhawm teeb tsa, hardening ceev thiab lub zog ntxov ntawm cov pob zeb sib xyaw yog ncaj qha ntsig txog qhov kub thiab txias. Tom qab ntxiv cov dej txo qis, qhov tshwm sim no pom tseeb dua, thiab cov nyhuv yuav tseem ceeb dua thaum lub sijhawm teeb tsa qis dua 20 degrees Celsius. Feem ntau hais lus, qhov kub thiab txias, qhov ceev ntawm cov cement hydration npaum li cas, thiab qhov evaporation tus nqi ntawm cov pob zeb yuav nrawm dua. Cov dej dawb hauv cov pob zeb yuav txuas ntxiv mus rau qhov chaw ua vaj tse los ntawm capillary, ntxiv rau kev ua kom cov dej ntws tawm ntawm cov cement. Cov dej dawb hauv cov pob zeb yog evaporated thiab txo qis, uas ua rau cov pob zeb poob ntxiv. Tsis tas li ntawd, cov nyhuv retarding ntawm qee cov khoom sib xyaw ua ke yuav raug txo qis dua 30 degrees Celsius. Yog li ntawd, yog hais tias nws yog tsim nyog los ua hauj lwm nyob rau hauv ib tug high kub ib puag ncig, nws yog tsim nyog los nce tus nqi ntawm cov pob zeb sib tov kom zoo kom tsis txhob tshwm sim ntawm cov dej evaporation. Ntoo calcium muaj qee yam kev teeb tsa qeeb. Nws tsuas tuaj yeem muaj lub zog muaj zog tom qab nchuav rau lub sijhawm ntev. Thaum lub sijhawm ua haujlwm txij nkawm, nws yog ib qho tsim nyog los txuas ntxiv lub sijhawm nres zoo li qub kom txaus thiab tsim kev siv tshuaj. Txwv tsis pub, cov pob zeb ua rau muaj kab nrib pleb loj, nto looseness thiab bulging thaum siv. Nyob rau hauv tus txheej txheem ntawm kev siv high-efficiency dej reducer, vim cov huab cua tsis tshua muaj entrainment, qhov teeb tsa qeeb tsis tuaj yeem lav tau, thiab lub sij hawm nres zoo li qub tsis tas yuav tsum tau ua thaum lub sijhawm ua kom sov. Yog li ntawd, nyob rau hauv tus txheej txheem ntawm ntxiv admixtures, muaj feem xyuam rau txoj hauj lwm txij nkawm yuav tsum tau ua tib zoo kom tsis txhob muaj dej evaporation loj thaum lub sij hawm tu txheej txheem.

9. Lub sij hawm cia cement

Nyob rau hauv ib txwm muaj xwm txheej, lub sijhawm luv ntawm cov cement, qhov fresher nws yuav tshwm sim, thiab qhov phem dua cov nyhuv plasticization ntawm cement yuav yog. Qhov fresher cov cement, lub zog zoo dua, thiab ntau dua ionic surfactants nws adsorbs. Rau cov cement uas nyuam qhuav ua tiav, nws cov dej txo qis qis thiab qhov poob qis yog ceev. Rau cov cement nrog lub sijhawm cia ntev, cov teeb meem no tuaj yeem zam tau zoo.

10. Alkali cov ntsiab lus hauv cov cement

Cov ntsiab lus alkali kuj muaj qhov cuam tshuam ncaj qha rau kev hloov pauv ntawm cov cement thiab dej reducer. Raws li cov ntsiab lus alkali ntawm cov cement nce, cov nyhuv plasticizing ntawm cov cement yuav deteriorate. Thaum cov ntsiab lus alkali ntau tshaj ib qho, nws tseem yuav muaj kev cuam tshuam loj heev rau lub sijhawm teem thiab poob ntawm cov cement. Tsis tas li ntawd, daim ntawv ntawm alkali hauv cov cement kuj muaj kev cuam tshuam ncaj qha rau kev siv cov dej txo qis. Nyob rau hauv ib txwm muaj xwm txheej, yog tias alkali muaj nyob rau hauv daim ntawv ntawm sulfate, nws cov nyhuv ntawm cov dej reducer yog tsawg dua li hauv daim ntawv ntawm hydroxide.

11. Gypsum hauv cement

Los ntawm kev ntxiv cov cement gypsum rau cov cement, hydration ntawm cov cement tuaj yeem ncua ntev heev, thiab ncaj qha adsorption ntawm cov cement thiab dej reducer tuaj yeem zam tau, yog li txhim kho kev hloov pauv ntawm cov cement thiab dej reducer. Raws li kev tshawb fawb ntau, tom qab ntxiv qee qhov nyiaj ntawm gypsum rau cov cement, qhov adsorption ntawm dej reducer ntawm cov cement ntxhia C3A tuaj yeem txo tau zoo. Qhov no feem ntau yog vim gypsum thiab C3A tuaj yeem ua rau cov calcium sulfonate, uas yuav ncaj qha npog ntawm C3A, tsis txhob muaj dej ntxiv ntawm C3A, uas tuaj yeem ua rau tsis muaj zog ntawm C3A cov khoom ntawm cov dej reducer. Ntau hom gypsum muaj qhov sib txawv ntawm qhov sib txawv thiab solubilities. Hom thiab cov ntsiab lus ntawm cov cement gypsum muaj kev cuam tshuam ncaj qha rau kev hloov pauv ntawm cov cement thiab dej reducer. Lub pore kua sulfate hauv cov cement pob zeb feem ntau yog los ntawm cov sulfate tsim los ntawm silicate cement, uas yuav muaj kev cuam tshuam ncaj qha rau cov cement hydration cov tshuaj tiv thaiv thiab kev ua haujlwm ntawm silicate cement pob zeb. Cov sulfate ions hauv gypsum feem ntau raug hloov pauv thaum lub sijhawm sib tsoo. Yog tias qhov kub ntawm cov txheej txheem sib tsoo yog siab, lub dihydrate gypsum yuav yog ib feem ntawm lub cev qhuav dej thiab tsim hemihydrate gypsum. Yog hais tias qhov kub hauv lub zeb yog siab dhau lawm, ib tug loj npaum li cas ntawm hemihydrate gypsum yuav tsim nyob rau hauv cov txheej txheem no, uas nws thiaj li ua rau tshwm sim ntawm cement pseudo-setting. Rau cov cement nrog tsawg alkaline sulfate Cheebtsam, nyob rau hauv lub zog adsorption ntawm sulfonic acid-raws li dej reducers, nws yuav ncaj qha ua rau cov pob zeb slump poob sai heev. Thaum cov ntsiab lus ntawm cov sulfate soluble nce, cov adsorption ntawm cov dej ua kom muaj txiaj ntsig zoo yuav ua rau pom qhov sib txawv ntawm qhov qis qis.

12. Cement sib tsoo pab

Kev sib tsoo cov cement tuaj yeem txhim kho tau zoo los ntawm kev siv cov cement sib tsoo cov cuab yeej tsim nyog. Nyob rau hauv cov txheej txheem ntawm cov cement ntau lawm hauv ntau lub tuam txhab txawv teb chaws, kev sib tsoo cov khoom siv feem ntau yog siv rau hauv ntau qhov ntau. Nyob rau hauv xyoo tas los no, tom qab kev siv cov qauv cement tshiab hauv kuv lub teb chaws, cov kev xav tau rau lub zog thiab kev ua kom zoo ntawm cov cement tau raug txhim kho, uas tau muab cov kev xav tau ntau dua rau kev siv cov khoom sib tsoo. Tam sim no, muaj ntau hom kev sib tsoo cov cement, thiab tus naj npawb ntawm kev sib tsoo cov tuam txhab lag luam hauv kuv lub teb chaws kuj tseem qhia txog kev nce ntxiv. Ntau yam kev sib tsoo sib tsoo cov tuam txhab tau nqis peev tsis tu ncua hauv kev tshawb fawb thiab kev txhim kho kev lag luam, siv tau zoo thiab siv tau yooj yim sib tsoo. Txawm li cas los xij, qee qhov kev sib tsoo cov tuam txhab lag luam them nyiaj ntau dhau rau cov nqi tsim khoom thiab nqis peev me me hauv kev tshawb fawb ntawm kev sib tsoo kev ua haujlwm, uas muaj kev cuam tshuam tsis zoo rau nws cov kev siv: ① Kev siv cov tshuaj uas muaj halogen ntsev yuav ua rau corrosion. ntawm steel tuav hauv pob zeb. ② Kev siv ntau dhau ntawm lignin sulfonate ua rau muaj teeb meem loj ntawm kev tsis sib haum xeeb ntawm cov cement thiab pob zeb sib xyaw. ③ Yuav kom txo tau cov nqi tsim khoom tau zoo, feem ntau siv cov khoom pov tseg ntau, uas muaj kev cuam tshuam loj heev rau kev ua haujlwm ntawm cov pob zeb. Nyob rau hauv cov txheej txheem ua vaj tse tam sim no, cov ntsiab lus alkali thiab chloride ion, gypsum hom, thiab clinker minerals muaj qhov cuam tshuam ncaj qha rau kev faib cov cement hais. Hauv kev siv cov cuab yeej sib tsoo, qhov ruaj khov ntawm cov cement tsis tuaj yeem txi. Qhov sib xyaw ntawm cov khoom sib tsoo yog qhov nyuaj. Tsuas yog los ntawm kev siv cov cuab yeej sib tsoo tsim nyog tuaj yeem lav qhov cuam tshuam ntawm pob zeb. Thaum lub sij hawm tsim cov txheej txheem, kev sib tsoo pab neeg tsim khoom yuav tsum muaj kev nkag siab zoo ntawm lub tuam txhab txoj kev sib tsoo, thiab paub cov hom kev sib tsoo thiab cov cement particle grading.

13. Kev tsim vaj tsev sib xyaw ua ke

Qhov sib xyaw ua ke ntawm kev tsim kho yog qhov teeb meem tsim qauv engineering, tab sis nws muaj kev cuam tshuam ncaj qha rau kev sib xyaw ua ke ntawm cov pob zeb sib xyaw thiab cov cement. Raws li cov ntaub ntawv cuam tshuam, yog tias cov xuab zeb sib piv siab dhau lawm, nws yog ib qho yooj yim los ua kom lub fluidity ntawm cov pob zeb sib xyaw kom txo qis, thiab qhov poob qis yog qhov loj heev. Tsis tas li ntawd, cov duab, kev nqus dej thiab kev muab qhab nia ntawm cov pob zeb hauv qhov sib xyaw ua ke yuav cuam tshuam rau kev tsim kho, dej tuav, cohesion, fluidity thiab formability ntawm cov pob zeb rau qee yam. Cov kev sim cuam tshuam qhia tau tias los ntawm kev txo cov dej-cement piv, lub zog ntawm cov pob zeb tuaj yeem txhim kho rau qee yam. Nyob rau hauv cov xwm txheej ntawm kev siv dej zoo, ntau yam khoom ntawm cov cement pob zeb tuaj yeem siv tag nrho, yog li nws cov yas tuaj yeem txhim kho tag nrho, cov concentration ntawm admixtures tuaj yeem lav tau, thiab kev sib raug zoo ntawm cov khoom siv thiab cov cement tuaj yeem txhim kho.