Dab tsi ntawm cov dej-txo cov neeg ua haujlwm feem ntau siv hauv engineering?

Tam sim no, cov dej txo qis feem ntau suav nrog lignosulfonate, naphthalene, resin, molasses, thiab polycarboxylate hom. Txhua hom kuj muaj cua-entraining thiab tsis-air-entraining versions. Raws li lawv cov kev cuam tshuam ntawm kev teeb tsa thiab hardening ceev ntawm cov pob zeb, lawv tuaj yeem muab faib ua hom zoo tib yam, thaum ntxov-lub zog, thiab hom retarding.

Lignosulphonate Dej Reducer:

Lub ntsiab ntau yam yog calcium lignosulphonate, uas yog xim av-daj hmoov tau los ntawm cov kua khib nyiab ntawm cov ntaub ntoo tom qab dej cawv extraction los ntawm evaporation, sulfonation, concentration, thiab tshuaj tsuag kom qhuav. Kuj tseem muaj sodium lignosulphonate thiab magnesium lignosulphonate dej reducers. Nws cov koob tshuaj tsim nyog yog 0.2%-0.3%, nrog rau cov dej txo qis li ntawm 10%. Yog tias dej tsis txo qis, qhov kev poob qis tuaj yeem nce li 10 cm, thiab lub zog ntawm 28-hnub tuaj yeem nce 10% -20%. Yog tias lub zog khaws cia, 10% ntawm cov cement tuaj yeem txuag tau. Txawm li cas los xij, calcium lignosulphonate muaj qhov cuam tshuam tsis zoo ntawm cov pob zeb, feem ntau ncua sij hawm los ntawm 1-3 teev, thiab ntau dua li ntawm qhov kub thiab txias. Kev noj ntau dhau tuaj yeem ua rau mob hnyav. Tsis tas li ntawd, calcium lignosulphonate yog ib qho cua-entraining dej reducer, nce cua cov ntsiab lus ntawm pob zeb los ntawm 2% (tsis muaj tus reducer) mus rau 3.6%. Qhov no cuam tshuam cov pob zeb ua kom muaj zog tab sis muaj txiaj ntsig zoo rau nws cov Frost tsis kam.

Naphthalene Formaldehyde Dej Reducer:

Naphthalene-raws li dej reducers yog tsim los ntawm naphthalene thiab nws homologues, fractionated los ntawm thee tar, thiab ua tiav los ntawm sulfonation thiab condensation. Lawv muaj cov nyhuv dispersing zoo ntawm cov cement, ua rau cov dej txo qis, txhim kho lub zog, thiab kev txhim kho durability piv rau lignosulfonate, ua rau lawv cov dej txo qis. Tus nqi txo cov dej dav dav yog ntau dua 15%, nrog rau qhov tseem ceeb ntawm lub zog thaum ntxov, nce 28- hnub ua vaj tse zog ntau dua 20%. Qhov kev noj kom haum yog li ntawm 0.5% -1.5%, nrog rau tus nqi pH ntawm 7-9, ua rau nws tsim nyog rau txhua txoj haujlwm ua vaj tse, tshwj xeeb tshaj yog rau kev npaj cov pob zeb ua kom muaj zog thiab cov kua dej.

Molasses Dej Reducer:

Molasses-based water reducers siv cov kua khib nyiab los ntawm cov txheej txheem qab zib refining raws li cov khoom siv raw, neutralized nrog txiv qaub los ua cov xim av hmoov av los yog kua pasty. Dhau li ntawm kev txo cov dej dav dav, lawv muaj qhov cuam tshuam tseem ceeb, ua rau lawv cov dej txo qis, feem ntau ncua sij hawm pib thiab zaum kawg ntawm ntau dua 3 teev. Qhov kev noj kom haum yog 0.2%-0.3%, nrog rau cov dej txo qis ntawm 6%-10%. Lub sijhawm 28-hnub ua vaj tse lub zog nce los ntawm 15%-20%, thiab yog tias lub zog qub tau khaws cia, kwv yees li 10% ntawm cov cement tuaj yeem txuag tau.

Polycarboxylate Dej Reducer:

Polycarboxylate high-efficiency dej reducers muaj qhov sib txawv zoo li cov qauv. Los ntawm electrostatic repulsion thiab steric hindrance cuam tshuam, lawv txhawb cov dispersion ntawm cov cement hais, txhim kho kev ua haujlwm ntawm cov pob zeb sib tov. Lawv tuaj yeem txo qis kev siv dej thiab txhim kho ntau yam khoom ntawm lub cev ntawm pob zeb, suav nrog compressive, tensile, thiab flexural zog, nrog rau elastic modulus. Lawv kuj txhim kho cov pob zeb tiv thaiv Frost thiab impermeability, kho lub sijhawm teeb tsa, thiab txhim kho kev tsim kho. Tsis tas li ntawd, lawv txo cov ntshav thiab nce cov pob zeb ntom ntom, yog li txhim kho cov kav ntev. Cov koob tshuaj zoo yog 0.1%-0.2%. Polycarboxylate dej reducers muaj zog dispersing zog, tsawg npaum li cas, tsawg slump poob, zoo compatibility nrog sib txawv cements, tsis muaj teeb meem cuam tshuam, thiab yog me ntsis cua-entraining.