Hnub Kawg Ua Ntawv Thov: Kaum Ib Hlis 7, 2022
Lub luag haujlwm ntawm cov khoom sib xyaw ua ke yog txhawm rau txhim kho cov khoom ntws ntawm cov pob zeb thiab txo cov khoom siv cementitious hauv pob zeb. Yog li ntawd, pob zeb admixtures yog siv dav hauv ntau yam kev tsim kho.
Lub mechanism ntawm kev txiav txim ntawm qhob admixtures:
Feem ntau siv naphthalene-raws li admixtures thiab polycarboxylate-raws li admixtures yog cov organic tebchaw nrog hnyav molecular hnyav (feem ntau 1500-10000) thiab nyob rau hauv qeb ntawm surfactants.
Lub molecule ntawm surfactant muaj ib tug bipolar qauv, ib kawg yog ib tug uas tsis yog-polar lipophilic pawg (los yog ib tug tsis-polar hydrophobic pab pawg neeg), thiab lwm yam kawg yog ib tug polar hydrophilic pawg. Tom qab cov surfactant yaj hauv dej, nws tuaj yeem ua si ntau yam haujlwm xws li dispersing, wetting, emulsifying, foaming thiab ntxuav thaum txo qhov nro.
A. Adsorption-dispersion
Lub fluidity ntawm ib qho kev sib tov yog nyob ntawm tus nqi ntawm cov dej dawb hauv cov pob zeb. Tom qab cov khoom sib xyaw ntxiv rau hauv cov pob zeb, cov cement particles disperse ib leeg vim yog cov kev taw qhia adsorption ntawm cov admixture molecules rau saum npoo ntawm cov cement hais, uas ua rau electrostatic repulsion ntawm lawv. Raws li qhov tshwm sim, cov qauv flocculation ntawm cov cement raug rhuav tshem, thiab ntau cov dej dawb raug tso tawm, uas ua rau kom muaj dej ntau ntawm cov pob zeb sib xyaw.
B. Wetting
Vim yog qhov kev taw qhia ntawm cov khoom sib xyaw ua ke ntawm cov khoom cement, ib qho monomolecular solvated dej zaj duab xis yog tsim. Cov yeeb yaj kiab dej no ua rau thaj chaw sib cuag ntawm cov cement thiab dej ntawm ib sab, thiab muaj qee qhov ntub dej ntawm qhov tod tes. Yog li ntawd, cov cement yog tag nrho hydrated thiab lub zog ntawm cov cement nce sai heev.
Lub luag haujlwm tseem ceeb ntawm kev sib xyaw ua ke:
1. Yog tias tsis txo cov dej hauv chav tsev, qhov sib piv ntawm cov dej-binder tseem tsis hloov, uas txhim kho kev ua haujlwm ntawm cov pob zeb tshiab thiab txhim kho cov dej ntws; Vim tias qhov chaw sib txuas tau zoo heev ntawm cov cement thiab dej, cov cement yog hydrated, txawm tias cov dej-binder ratio Invariant, lub zog ntawm cov pob zeb feem ntau muaj kev txhim kho.
2. Nyob rau hauv cov xwm txheej ntawm kev tuav ib qho kev ua haujlwm, txo cov dej siv, txo cov dej-binder piv, thiab txhim kho lub zog ntawm cov pob zeb.
3. Raws li kev tswj hwm lub zog, txo cov khoom siv cementitious, txo cov dej siv, khaws cov dej-binder piv tsis hloov, thiab txuag cov cement thiab lwm cov ntaub ntawv cementitious.
Yuav ua li cas kom zoo thiab siv cov khoom sib xyaw ua ke:
Kev yuav khoom kom raug thiab siv cov khoom siv sib xyaw tuaj yeem tsim muaj txiaj ntsig kev lag luam thiab kev lag luam. Nws tuaj yeem tsis tsuas yog txhim kho lub zog ntawm pob zeb, tab sis kuj txo tus nqi ntawm cov pob zeb sib xyaw ua ke.
Txoj kev tshwj xeeb yog raws li nram no:
ib. Test link
Kev ntsuam xyuas thiab kev ntsuam xyuas ntawm ntau yam kev ntsuas ntawm cov khoom sib txuas yog qhov txuas tseem ceeb ua ntej kev yuav khoom sib tham. Los ntawm kev xeem, cov qauv tsim nyog ntawm ntau yam kev ntsuas ntawm cov khoom sib xyaw yuav tsum raug txiav txim siab. Xws li cov ntsiab lus ntawm admixtures, dej txo tus nqi, ceev, slurry fluidity, pob zeb txo tus nqi thiab lwm yam kev qhia. Nws tau pom zoo tias qhov kev txo qis ntawm cov dej pob zeb yog siv los ua qhov taw qhia tseem ceeb los ntsuas qhov zoo ntawm cov khoom sib xyaw.
b. Kev yuav khoom
Tom qab cov txheej txheem tsim nyog rau cov khoom sib xyaw tau qhia meej, kev sib tham txog kev yuav khoom tuaj yeem pib. Nws tau pom zoo tias cov neeg tsim khoom sib xyaw yuav tsum tau caw cov ntawv sib tw raws li cov qauv tsim nyog tau txiav txim los ntawm qhov kev xeem. Nyob rau hauv qhov tseeb hais tias cov khoom zoo ntawm cov khoom sib xyaw tsis yog qis dua qhov kev xav tau ntawm kev sib tw, tus neeg muag khoom yuav tsum txiav txim siab raws li lub hauv paus ntsiab lus ntawm kev sib tw ntawm tus nqi qis.
Nyob rau tib lub sijhawm, kev xaiv cov khoom siv sib xyaw ua ke yuav tsum ua tib zoo xav txog cov chaw tsim khoom lag luam, kev thauj mus los, kev thauj mus los, peev txheej, kev tsim khoom thiab muab cov qib zoo ntawm cov nroj tsuag loj sib xyaw lossis cov phiaj xwm loj hauv engineering, thiab kev pab cuam tom qab muag. thiab qib. Raws li ib qho taw qhia rau cov chaw tsim khoom tshuaj ntsuam.
c. Txais link
Qhov chaw sib tov yuav tsum kuaj cov khoom sib xyaw ua ntej cov khoom sib xyaw yuav tsum tau muab tso rau hauv qhov chaw cia, thiab cov txiaj ntsig kev xeem tuaj yeem muab tso rau hauv qhov chaw cia tsuas yog tom qab qhov kev ntsuam xyuas tau tsim nyog raws li cov qauv kos npe hauv daim ntawv cog lus. Nws raug nquahu kom paub qhov txawv ntawm cov cim tseem ceeb thiab cov cim qhia siv. Los ntawm kev xyaum mus sij hawm ntev, tus kws sau ntawv ntseeg tias qhov ntsuas tseem ceeb ntawm cov khoom sib xyaw yog cov dej-txo tus nqi (mortar) thiab pob zeb ua kom txo qis tus nqi; Cov cim qhia yog qhov ntom ntom (qhov tshwj xeeb lub ntiajteb txawj nqus), cov ntsiab lus ntawm cov khoom thiab cov kua dej ntawm cov cement paste. Vim lub sij hawm sim, cov kev ntsuas uas feem ntau raug kuaj hauv qhov kev lees paub txuas yog qhov ntom ntom, qhov dej ntawm cov cement paste thiab cov dej txo tus nqi (mortar).
Post lub sij hawm: Nov-07-2022
