Kev Npaj Khoom Ntawm Polycarboxylic Acid Superplasticizer

Polycarboxylate superplasticizers, raws li cov neeg sawv cev ntawm lub thib peb tiam ntawm cov dej-txo cov neeg ua hauj nyob rau hauv Tuam Tshoj, muaj qhov zoo tshaj cov thawj tiam neeg sawv cev los ntawm lignosulfonates thiab lub thib ob tiam neeg sawv cev los ntawm naphthalene sulfonates, nrog rau cov dej txo tus nqi, zoo heev slump tuav, thiab txhawb zog. Polycarboxylate superplasticizers tshwj xeeb tshaj yog tsim rau kev npaj ua haujlwm siab, ua haujlwm siab, ruaj khov siab, thiab muaj zog ua kom pom tseeb. Cov hauv paus ntsiab lus ntawm kev npaj, txoj hauv kev, thiab kev ceev faj rau kev siv polycarboxylate superplasticizers yog raws li hauv qab no, vam tias yuav muab kev tshoov siab rau txhua tus.

1. Cov khoom siv raw

Acrylic acid (AA), sodium methacrylate (MAS), ammonium persulfate (APS) yog cov khoom lag luam muaj tshuaj reagents; polyoxyethylene monomer yog tus kheej tsim, nrog qib ntawm polymerization kwv yees li 9, 23, thiab 35; cement siv yog P.O42.5R.

2. Txoj Kev Npaj

Dissolve acrylic acid, sodium methacrylate, ammonium persulfate, thiab polyoxyethylene monomer hauv dej deionized los npaj 20% kev daws teeb meem. Nyob rau hauv ib lub khob peb-caj dab nruab nrog ib tug stirrer, reflux condenser, thiab tus pas ntsuas kub, ntxiv cov monomers thiab pib dropwise hauv batch. Tom qab qhov sib ntxiv, tuav cov tshuaj tiv thaiv ntawm 75 degree rau ib lub sijhawm. Thaum cov tshuaj tiv thaiv tiav, kho cov pH mus rau 7-8 siv 20% NaOH tov kom tau cov xim daj lossis xim liab-xim av polycarboxylate superplasticizer nrog kwv yees li ntawm 20%.

3. Mechanism of Action

1. Thaum cov superplasticizer ntxiv rau hauv pob zeb, nws pawg hydrophobic adsorb directionally mus rau qhov chaw ntawm cov cement hais, thaum hydrophilic pawg taw tes rau cov kua dej aqueous, tsim ib txheej monomolecular lossis multimolecular adsorbed txheej. Vim yog cov kev taw qhia adsorption ntawm surfactant, cov cement paste nto yog zoo li cov nqi, uas ua rau kev sib nrig sib repulsion. Qhov no tsis tsuas yog ua kom cov cement-dej system nyob rau hauv ib qho kev ncua kev ruaj ntseg tab sis kuj pab kom tawg cov flocculent qauv tsim thaum lub sij hawm pib sib tov nrog dej, yog li tso cov dej nyob rau hauv lub flocculent qauv thiab ua kom tiav cov dej txo. Qhov sib ntxiv ntawm superplasticizer pab txhim kho kev ua haujlwm ntawm cov pob zeb tshiab thiab txo qhov pore ntim hauv cov pob zeb cement vim qhov txo qis hauv dej-cement piv, ua rau cov cement pob zeb denser thiab txhim kho lub zog ntawm cov pob zeb. Lub superplasticizer kuj tseem cuam tshuam rau hydration ceev thiab teem sij hawm ntawm cov cement.
2. Cov nyhuv txo cov dej yog lub luag haujlwm tseem ceeb ua los ntawm cov surfactant hauv cov txheej txheem cement hydration. Lub superplasticizer tuaj yeem txo cov dej haus hauv ib chav tsev yam tsis muaj kev cuam tshuam rau kev ua haujlwm ntawm cov pob zeb, lossis txhim kho kev ua haujlwm tsis tau hloov cov dej haus, lossis ua tiav ob qho kev cuam tshuam yam tsis muaj kev hloov pauv huab cua ntawm cov khoom sib xyaw. Tam sim no, cov dej-txo cov neeg siv hauv cov pob zeb yog tag nrho cov surfactants, tshwj xeeb tshaj yog anionic surfactants.
3. Tom qab sib xyaw cov cement thiab dej, cov qauv flocculent tsim uas muaj ntau cov dej sib tov, yog li txo qhov kev ua haujlwm ntawm cov pob zeb tshiab (tseem hu ua kev ua haujlwm, uas yog hais txog lub peev xwm ntawm cov pob zeb tshiab kom nyob twj ywm, compact, thiab tiv thaiv kev sib cais thaum lub sijhawm ua haujlwm. sib tov, thauj, thiab nchuav). Yuav kom tswj tau qhov kev xav tau ntawm kev ua haujlwm thaum lub sijhawm tsim kho, nws yog ib qho tsim nyog yuav tsum tau ua kom cov dej sib tov ntxiv. Txawm li cas los xij, kev nce cov dej yuav ua rau muaj qhov pore ntau dhau ntawm cov qauv pob zeb cement, ua rau muaj kev cuam tshuam loj rau lub cev thiab cov khoom siv ntawm cov pob zeb tawv tawv. Los ntawm kev ntxiv cov nyiaj tsim nyog ntawm superplasticizer thaum lub sij hawm npaj cov pob zeb, cov nyhuv no tuaj yeem txo tau zoo.

4. Ceev faj rau kev siv

1. Polycarboxylate superplasticizers yuav tsum zam kev sib cuag nrog cov ntaub ntawv hlau mus ntev. Txij li cov khoom no feem ntau yog acidic, ntev kev sib cuag nrog hlau tuaj yeem ua rau muaj kev cuam tshuam qeeb, ua rau tsis muaj xim thiab kev ua haujlwm degradation.
2. Polycarboxylate superplasticizers yog rhiab heev rau kev hloov pauv hauv cov ntaub ntawv raw. Cov kev hloov pauv tseem ceeb ntawm cov xuab zeb, pob zeb, thiab cov khoom siv ntxiv xws li ya tshauv thiab slag tuaj yeem cuam tshuam qhov kev ua tau zoo ntawm pob zeb uas muaj polycarboxylate superplasticizers. Yog li ntawd, rov sim dua thiab kho qhov ntau npaum li cas raws li cov ntaub ntawv hloov pauv yog qhov tsim nyog kom ua tiav cov txiaj ntsig zoo.
3. Tseem muaj teeb meem kev sib raug zoo nrog qee hom cement, uas tuaj yeem ua rau cov dej txo qis thiab poob qis dua. Thaum ntsib kev sib raug zoo tsis zoo, kev hloov kho rau cov tshuaj sib xyaw ua ke hauv cov pob zeb sib xyaw yog xav tau rau kev ua haujlwm zoo.
4. Vim tias qhov txo qis ntawm cov dej siab ntawm polycarboxylate superplasticizers, qhov poob ntawm cov pob zeb tshwj xeeb yog qhov tshwj xeeb rau kev siv dej. Yog li ntawd, nws yog ib qho tseem ceeb uas yuav tsum nruj me ntsis tswj cov dej siv. Cov dej ntau dhau tuaj yeem ua rau muaj kev sib cais, los ntshav, tawv tawv, thiab muaj huab cua ntau dhau.
5. Thaum siv polycarboxylate superplasticizers, nws raug nquahu kom nce lub sijhawm sib xyaw kom tsim nyog (feem ntau yog kwv yees li ob npaug ntawm cov khoom siv ib txwm siv) kom zoo dua siv cov nyhuv hindrance ntawm cov superplasticizers.
6. Polycarboxylate superplasticizers yog tshwj xeeb tshaj yog rhiab heev rau cov av nkos cov ntsiab lus ntawm aggregates. Cov ntsiab lus av nkos siab tuaj yeem txo lawv cov txiaj ntsig, yog li qhov zoo ntawm cov khoom sib xyaw yuav tsum tau tswj nruj me ntsis. Yog tias cov ntsiab lus av nkos nce, qhov ntau npaum ntawm polycarboxylate superplasticizer yuav tsum tau nce ntxiv.
7. Thaum muaj qhov kub thiab txias hloov nruab nrab nruab hnub thiab hmo ntuj, nws yog ib qho tseem ceeb uas yuav tsum tau saib xyuas cov kev hloov pauv hauv cov pob zeb tawg thiab kho cov tshuaj sib xyaw kom haum raws sijhawm (raws li lub hauv paus ntsiab lus ntawm kev txo qis hauv qhov kub thiab txias ntau dua).
8. Polycarboxylate superplasticizers yuav tsum tsis txhob tov nrog naphthalene-based superplasticizers. Kev sib tov yuav tsum tau zam, thiab txhua yam khoom siv uas tau siv nrog naphthalene superplasticizers yuav tsum tau muab ntxuav kom huv si kom tsis txhob poob ntawm cov txiaj ntsig ntawm polycarboxylate superplasticizers.
9. Thaum lub sij hawm kev sim (tsim), thaum qhov kev siv ntau npaum li cas tsuas yog ua tiav thiab pib ua haujlwm ntawm cov pob zeb ua tau raws li, tseem yuav muaj qhov poob loj hauv lub sijhawm. Yog li ntawd, thaum lub sij hawm kuaj (tsim), nws yog advisable kom nce qhov ntau npaum li cas (mus txog ib tug saturated theem) los daws qhov teeb meem ntawm slump poob.
10. Raws li polycarboxylate superplasticizers muaj cov dej txo qis thiab dispersibility, kev ua haujlwm ntawm cov pob zeb yuav tsum tau soj ntsuam feem ntau los ntawm kev ntsuas flowability es tsis yog poob ib leeg.
11. Thaum txo tus nqi ntawm cov khoom siv cementitious, nws yog ib qho tseem ceeb los xyuas kom meej kev tswj xyuas nruj dua ntawm cov dej-cement piv thaum tsim khoom. Yog tias qhov poob qis tseem ceeb tshwm sim, nws yuav tsum tau kho los ntawm kev ua kom cov tshuaj ntxiv los yog ntxiv nws dua, tsis yog los ntawm kev ntxiv dej, uas tuaj yeem txo qis zog.
12. Lub zog ntawm pob zeb yog tsuas yog txiav txim siab los ntawm dej-cement piv. Polycarboxylate superplasticizers, vim lawv cov dej txo qis, tuaj yeem yooj yim txo cov dej siv hauv cov khoom sib xyaw, yog li txo cov dej-cement piv thiab tag nrho cov nqi ntawm cov pob zeb. Kev hloov kho rau cov tshuaj sib xyaw ua ke yuav tsum tau ua nyob rau hauv lub sijhawm tiag tiag raws li cov khoom siv raw thiab qhov kub thiab txias cuam tshuam rau kev ua haujlwm ntawm cov pob zeb.