Superplasticizer rau High Strength Concrete: Txhob Xav, Pib Crushing PSI

93% ntawm Engineers Dose Superplasticizers yuam kev. Ntawm no yog Pov Thawj.

A 2023 kawm los ntawm University of Texas taug qab 120 npaj-mix nroj tsuag. Tsuas yog 7% ntawm siab zog pob zeb mixes tiav lub hom phiaj lub zog nyob rau hauv thawj batch. Tus neeg txhaum? Kev siv tsis raug superplasticizers rau kev sib xyaw ua kom muaj zog. Cov neeg ua haujlwm feem ntau kho lawv zoo li kua zaub ntsev. Qhov ntawd yog qhov yuam kev ntau lab daus las. Tej zaum koj yuav nchuav nyiaj rau hauv av. Lub sij hawm kho nws.

Dab tsi tiag yog Superplasticizer rau High Strength Concrete Mixes?

Nws yog ib tug high-range dej reducer. Lub sijhawm. Koj lub hom phiaj yog dej-cement piv rau hauv qab no 0.35. Yog tsis muaj, koj mix yog qhuav, cib tsis ua haujlwm. Lub superplasticizer coats cement hais. Nws tawg cov clumps. Nws cia koj ncuav ib 60+ MPa sib tov uas ntws zoo li tus kheej-leveling av nkos. Tsis muaj superplasticizer, tsis muaj zog pob zeb. Tag nrho nres.

Polycarboxylate Ethers (PCE) vs. Naphthalene sulfonate (NSF): Lub Brawl

PCE yog huab tais. Nws chains molecules zoo li ib tug kab laug sab polymer. Nws muab rau koj 40% txo dej. Nws tuav slump rau 90 feeb. NSF yog lub tsev kawm ntawv qub brawler. Nws ua haujlwm. Nws yog pheej yig dua. Tab sis nws poob slump ceev. Rau siab zog sib tov (dhau 60 MPa), siv PCE. Rau qis zog los yog loj heev pours qhov twg cov nqi cai, NSF ua haujlwm. Tab sis tsis txhob cia siab tias muaj txuj ci tseem ceeb los ntawm NSF saum toj no 80 MPa. Cov neeg siv Reddit ntawm r /Pob zeb qhia PCE tshwj xeeb rau cov choj decks. Lawv hais yog lawm.

Ntau npaum li cas superplasticizer Koj puas xav tau tiag tiag?

Classic ntau yam yog 0.5% rau 2% los ntawm qhov hnyav ntawm cement. Pib ntawm 0.8% rau PCE. Thawb rau 1.5% rau qhov siab tshaj plaws dej txo. Overdosing yog ib qho cuab yeej. Mus dhau los 2%, thiab koj tau:

• Kev cais. Aggregates dab dej. Paste ntab. Lub zog poob.
• Ntau dhau retardation. Koj cov pob zeb nyob twj ywm mos rau 24 teev. Poob sijhawm.
• Cua cov ntsiab lus poob. Koj tua freeze-thaw tiv thaiv.

Ib tus neeg siv Reddit ntawm r/AskEngineers tau piav qhia txog txoj haujlwm uas lawv tau muab ob npaug rau koob tshuaj los kho qhov poob qis. Cov tub ntxhais kawm ntawm 45 MPa xwb ntawm 70 MPa. Kev poob tag nrho. Tsis txhob ua tus engineer ntawd. Siv lub rooj khiav, tsis yog koj ob lub qhov muag.

Vim li cas koj lub Superplasticizer tsis ua rau huab cua kub

Kub yog tus tua neeg uas ntsiag to. Ntawm 35 ° C, PCE poob lub neej poob rau 30 feeb. NSF tseem phem dua. Cov tshuaj tiv thaiv ua kom nrawm. Koj ntxiv dej ntau rau remix. Koj poob zog. Qhov kho: koob tshuaj plasticizer ntawm qhov chaw ua haujlwm, tsis yog tsob ntoo. Los yog siv cov tshuaj tiv thaiv superplasticizer. Ntau tus neeg siv ntawm Reddit hais kom ntxiv dej khov rau cov dej sib tov. Qhov ntawd ua haujlwm. Nws raug nqi nyiaj. Tab sis nws yeej ib tug load rejection.

Compatibility Npau suav phem: Cement thiab Admixtures

Tsis yog tag nrho cov cement ua si zoo. C3A cov ntsiab lus yog dab ntxwg nyoog. Siab C3A (dhau 8%) reacts hnyav nrog NSF. Koj tau txais flash teeb, los yog tsis muaj slump tuav txhua. PCE ua haujlwm zoo dua, tab sis tsis zoo tag nrho. Koj yuav tsum xeem. Use the Marsh cone or mini-slump test. If you use air-entraining agents with PCE, you risk high air content. The plasticizer traps air. You must use a defoamer. Many contractors skip this. Then they wonder why strength is low. Do not skip it.

Does Superplasticizer Reduce Shrinkage and Creep?

Kev tsis ncaj, yog. Lower water means less capillary pores. Less pores means less shrinkage. A superplasticized mix with w/c 0.30 has about half the drying shrinkage of a w/c 0.50 mix. But do not expect the plasticizer itself to shrink-proof the concrete. The reduction comes from the lower water content. That is the whole point: use the plasticizer to lower water, not just to make it flow. If you are adding plasticizer just to pour easily, you are wasting it.

Yuav Ua Li Cas Ntxiv Superplasticizer: Qhov Tseem Ceeb

Tsis yog: Muab pov tseg rau ntawm cov cement qhuav. Txoj cai: Ntxiv nws nrog cov dej sib tov, los yog tom qab cov cement yog ntub. Yog koj ntxiv nws lig dhau lawm, nws tsis tawg. Koj tau txais clumps. Koj poob 15% ntawm qhov ua tau zoo. Txoj kev zoo tshaj plaws: ntxiv 80% ntawm cov dej, ntxiv cov superplasticizer, tom qab ntawd ntxiv cov dej seem thiab sib sau ua ke. Qhov no muab ib tug dispersion. Ntau tus neeg ua haujlwm cog qoob loo tsuas yog muab pov tseg rau saum cov aggregates. Qhov ntawd yog sloppy. Kho koj batching ib ntus.

Reddit vs. Lub Lab: Cov neeg siv tiag tiag hais li cas

Ntawm Reddit's r/Concrete, ib tus neeg siv qhia: 'Siv PCE rau a 90 MPa kab. Ntaus poob. Lub zog ntaus 95 MPa thiab 28 hnub. Tab sis peb poob kev tswj hwm huab cua. Xaus ntawm 7% huab cua. Yuav tsum redesign lub mix.’ Zaj lus qhia: PCE muaj zog heev, tiam sis nws tsis zam txim. Saib xyuas huab cua nkag mus tas li. Lwm tus neeg siv ntawm r/StructuralEngineering tau hais: 'NSF ua haujlwm zoo rau 50 MPa slabs. Vim li cas thiaj them 3x rau PCE?’ Qhov ntawd siv tau rau qis zog. Tab sis rau siab zog, NSF muaj kev pheej hmoo. Ua raws li PCE.

Kev dag nyiaj txiag: Superplasticizers Txuag Cement? Tsis tas li.

Yog lawm, koj tuaj yeem txo cov cement los ntawm 10-15% thaum tuav lub zog. Qhov ntawd txo qis CO2. Tab sis tus superplasticizer nws tus kheej raug nqi 2-3x ntau dua ib lub cubic meter dua li cov cement koj txuag. Yog li yog tias koj obsessed nrog thawj tus nqi, tej zaum koj yuav tsis txuag nyiaj. Cov nyiaj tiag tiag los ntawm kev ruaj khov. A 60 MPa sib tov nrog tsawg permeability kav 100 xyoo. A 30 MPa mix ntev 40 xyoo. Qhov ntawd yog qhov kev txuag tiag. Forward-xav tswv tswv tau txais qhov no. Cov neeg xav luv luv tsis txaus siab txog tus nqi superplasticizer.

Pumpability: Yuav Koj Superplasticized Mix Pump?

Cov sib tov muaj zog yog nplaum. Lawv muaj cov ntsiab lus siab paste. Lawv nqus tau zoo yog tias lub plasticizer muab koj ntws yam tsis muaj kev sib cais. PCE ua haujlwm zoo dua rau kev tso dej. NSF tuaj yeem ua rau 'stickiness’ uas ntsaws kab. Yog koj nqus dej 60+ meters vertically, tsuas yog siv PCE raws li superplasticizers. Ntxiv cov viscosity hloov tus neeg sawv cev (VMA) yog tias qhov sib tov yog ciam teb. Ib tus neeg cog lus ntawm Reddit tau hais: 'Peb yuav tsum tau twj tso kua mis 80 dab neeg. Tsis muaj VMA, lub mix bleed. Ntxiv VMA. Teeb meem daws tau.’

Peb Qhov Kev Txiav Txim: Qhov twg Superplasticizer yeej?

Rau siab zog pob zeb sib tov tshaj 60 MPa: Siv Polycarboxylate Ether (PCE). Txais tus nqi siab dua. Nws yog tib txoj hauv kev los lav lub zog thiab kev ua haujlwm. Rau mixs hauv qab 50 MPa, NSF zoo. Txuag cov nyiaj.

Tsis txhob kwv yees. Yuav ib lub PCE superplasticizer tsim kom muaj zog. Kuaj nws ntawm ib pawg me me. Ntsuas qhov poob qis, huab cua, thiab lub zog. Yog nws ua haujlwm rau koj, kev txiav txim ntau.

Peb pom zoo UltraFlow PCE-8000. Nws muab 40% txo dej nrog 2-teev slump tuav. Nws yog tsim los rau kev sib xyaw ua haujlwm siab. Ntau txhiab tus neeg cog lus siv nws. Tsis txhob yog tus txiv neej uas poob dej vim Chevron-Philipped NSF. Hloov tam sim no.

Tus neeg muab khoom
ConcreteAndMore yog ib qho kev ntseeg siab thoob ntiaj teb cov khoom lag luam ntawm cov khoom siv ua haujlwm siab thiab cov tshuaj siv tsim kho.. Nrog xyoo ntawm kev lag luam kev txawj ntse, peb tshwj xeeb hauv kev muab cov kev daws teeb meem tshiab suav nrog polycarboxylate superplasticizers, pob zeb fibers, defoamers, foaming agents, thiab advanced airgel thermal rwb thaiv tsev cov khoom. Yog tias koj txaus siab rau kev sib xyaw ua ke, thov koj xav tiv tauj peb!