Vim li cas accelerators siv nyob rau hauv kev tsim kho shotcrete? Me ntsis kev paub txog cov khoom xyaw

Vim li cas accelerators siv nyob rau hauv kev tsim kho shotcrete? Me ntsis kev paub txog cov khoom xyaw

Nrog rau txoj kev loj hlob sai ntawm underground engineering thiab tsheb thauj mus los infrastructure kev tsim kho, daim ntawv thov ntawm shotcrete thev naus laus zis rau kev kho txoj kab nqes, kev txhawb nqa pob zeb, thiab cov xau thaiv hauv qhov blasting kev tsim kho thiab kev saib xyuas sai yog nce zuj zus. Shotcrete yog ib hom pob zeb uas tsim los ntawm kev kub ceev txau ntawm kev sib xyaw ntawm cov ntaub ntawv cementitious thiab sib sau ua ke rau saum npoo uas siv cov cua compressed lossis lwm qhov chaw siv hluav taws xob.

Kev tsim kho Shotcrete tau muab faib ua ob hom tseem ceeb: kev sib xyaw qhuav thiab ntub dej sib xyaw. Txoj kev sib xyaw qhuav siv cov hmoov accelerators, thaum txoj kev sib xyaw ntub dej siv cov kua accelerators. Hauv Suav teb, feem ntau ntawm kev siv tshuaj tua kab mob tseem siv txoj kev sib xyaw qhuav, nrog kev sib xyaw ntub dej tsuas yog kwv yees li 10% ntawm daim ntawv thov txhaj tshuaj. Txawm li cas los xij, raws li qhov yuav tsum tau ua kom zoo rau kev tua hluav taws hauv av engineering nce thiab kev paub txog ib puag ncig loj hlob, txoj kev sib xyaw ntub dej tau pom tias yog qhov kev tsis pom zoo rau kev txhim kho yav tom ntej ntawm shotcrete technology.

Accelerators yog cov tseem ceeb additives nyob rau hauv shotcrete, ua si lub luag hauj lwm tseem ceeb nyob rau hauv qhov chaw ceev thiab lub zog ntawm pob zeb. Lawv qhov ntau npaum li cas tsuas yog 2% -3% ntawm cov cement kom muaj nuj nqis hauv cov pob zeb, tab sis lawv tuaj yeem ua tiav qhov kev teeb tsa thawj zaug hauv 5 feeb thiab qhov chaw zaum kawg hauv 10 feeb, ua kom tau raws li qhov yuav tsum tau ua kom ceev ceev hauv kev tsim kho tshwj xeeb thiab ua kom muaj kev sib koom ua ke sai hauv qhov av los yog shafts. Yog li ntawd, kev tshawb fawb thiab kev siv cov accelerators yog qhov tseem ceeb ntawm kev txiav txim siab qib ntawm kev siv tshuab txhaj tshuaj.

Accelerators tuaj nyob rau hauv ntau hom, cais los ntawm cov khoom tsim raws li cov hmoov (khoom) los yog kua accelerators. Raws li cov ntsiab lus alkali, lawv tuaj yeem ua alkaline lossis tsis yog alkaline accelerators, nrog cov accelerators muaj Na2O cov ntsiab lus<1% considered non-alkaline. The development of accelerators has gone through stages such as high-alkali powder, low-alkali powder, high-alkali liquid, and low (non)-alkali liquid since the Swiss company Sika first developed Sigunite powdered accelerator in the 1930s.

Non-alkaline accelerators hais txog qhov teeb meem ntawm cov ntsiab lus siab alkali hauv cov tsoos accelerators. Cov pob zeb uas tsis yog-alkaline accelerators tuaj yeem ua tiav ntau dua 90% ntawm nws lub zog 28-hnub piv rau cov tsoos accelerators. Tsis tas li ntawd, cov accelerators uas tsis yog-alkaline yog tsis corrosive, ib puag ncig tus phooj ywg, thiab ua rau muaj kev pheej hmoo tsawg rau cov neeg ua haujlwm tsim kho. Qhov sib txawv yog hloov mus rau kev siv cov kua accelerators uas tsis yog-alkaline es tsis txhob siv cov tshuaj alkaline thiab low-alkali accelerators.

Cov xwm txheej tam sim no ntawm cov hmoov accelerators pib hauv 1930s nrog Sigunite, tsim los ntawm Swiss tuam txhab Sika. Thaum ntxov alkaline hmoov accelerators, ua los ntawm inorganic ntsev cov ntaub ntawv xws li txiv qaub, sodium aluminate, thiab silicate thiab carbonate ntsev, ua tau raws li qhov yuav tsum tau kom ceev hardening tab sis raug kev txom nyem loj zog poob tom qab, xws li ntawm 20% mus rau 50%.

Nyob rau hauv Suav teb, vim qhov kev taw qhia qeeb ntawm kev siv tshuab tua hluav taws xob, kev tshawb fawb ntawm cov accelerators pib tom qab. Alkaline hmoov accelerators muaj qhov zoo xws li kev hloov pauv tau zoo, kev ua tau zoo nrog ntau hom cement, qhov teeb meem zoo, tus nqi qis, thiab cov txheej txheem kev npaj ua tiav. Txawm li cas los xij, lawv muaj ntau yam tsis xws luag, suav nrog kev poob qis hauv cov theem tom qab, txo cov pob zeb ua haujlwm ntev vim yog kev qhia ntawm alkali, siab rov qab thaum lub pob zeb txau, thiab muaj zog corrosiveness thaum npaj, ua rau muaj kev pheej hmoo rau cov neeg ua haujlwm.

Raws li txoj kev sib xyaw ntub dej maj mam dhau los ua ntau dua, kev tshawb fawb ntawm cov hmoov accelerators tau txo qis, hloov kev tsom mus rau kev kawm ntawm cov kua qis-alkali thiab tsis-alkali accelerators. Txawm li cas los xij, vim qhov yooj yim, yoog raws, thiab tus nqi qis ntawm txoj kev sib xyaw qhuav, ib feem ntawm cov phiaj xwm phom sij hauv Suav teb tseem siv cov hmoov accelerators.

Cov keeb kwm ntawm cov kua accelerators hnub rov qab mus rau xyoo 1970 nrog kev txhim kho ntawm Sika alkaline kua accelerators hauv Switzerland. Txawm li cas los xij, cov kua accelerators thaum ntxov no muaj cov ntsiab lus alkali, ua rau tsis zoo tom qab-theem pob zeb muaj zog thiab ua haujlwm ntev. Hauv kev sim los txhim kho kev ua tau zoo tom qab thiab tshem tawm kev puas tsuaj rau tib neeg kev noj qab haus huv, cov kws tshawb fawb hauv cov teb chaws tsim tau pib tsim cov kua alkali qis qis hauv xyoo 1970s. Lawv siv cov ntsev txhuas ua lub ntsiab teeb tsa nrawm, txo cov ntsiab lus alkali rau 10-20%, ua rau txo qis tom qab lub zog poob mus rau 20% -30%.

Nyob rau hauv Suav teb, vim qhov kev taw qhia lig ntawm txoj kev ntub dej sib xyaw, kev tshawb fawb ntawm cov kua accelerators lagged qab lub teb chaws tsim. Cov kua accelerators thaum ntxov, thaum ua tau raws li tus qauv yuav tsum tau ua, nthuav tawm lub zog qis thaum ntxov ntawm cov pob zeb. Txhawm rau hais txog qhov no, cov kws tshawb fawb tau tsom mus rau txo cov ntsiab lus alkali kom txo qis tom qab-theem lub zog poob thiab txhim kho kev ua haujlwm ntev. Niaj hnub no, low-alkali kua accelerators yog dav siv nyob rau hauv kev ua lag luam, muab cov kev pab cuam xws li tsawg npaum li cas thiab lub sij hawm luv luv. Txawm li cas los xij, cov no tseem qhia txog qee cov ntsiab lus alkali thiab tuaj yeem ua rau alkali-tag nrho cov tshuaj tiv thaiv, cuam tshuam rau lub sijhawm ntev ntawm kev txhaj tshuaj. Raws li qhov tshwm sim, cov kws tshawb fawb tau tig lawv lub siab mus rau cov kua accelerators uas tsis yog-alkali.

Txoj kev tshawb fawb ntawm cov tsis-alkali kua accelerators pib hauv 1990s hauv Tebchaws Europe thiab Tebchaws Meskas, me ntsis tom qab hauv Suav teb. Cov kev tshawb fawb tseem ceeb yog nrhiav cov khoom siv tshiab los hloov cov alkali hlau ntsev hauv cov kua accelerators. Ntawm lawv, aluminium sulfate, vim nws tsis muaj cov ntsiab lus ntawm alkali hlau, zoo txhawb cov cement hydration thiab txhim kho mortar lub zog thaum ntxov. Nws yog tam sim no suav hais tias yog cov khoom siv zoo tshaj plaws rau kev npaj cov kua accelerators uas tsis yog-alkali. Cov kws tshawb fawb thoob ntiaj teb tau ua cov kev tshawb fawb dav dav ntawm cov kua accelerators npaj nrog txhuas sulfate. Cov khoom ua tau zoo thiab ruaj khov, xws li MEYCOSA series los ntawm BASF thiab Sigunite®A series los ntawm Sika, sawv cev rau qib siab tam sim no ntawm cov kua accelerators uas tsis yog-alkali.

Tsis yog-alkali kua accelerators yog lub hom phiaj ntawm txoj kev loj hlob tam sim no thiab yav tom ntej, txo qhov kev pheej hmoo ntawm alkali-tag nrho cov tshuaj tiv thaiv thiab kev txhim kho tom qab-theem lub zog hauv pob zeb. Txawm li cas los xij, txoj kev loj hlob ntawm cov kua accelerators uas tsis yog-alkali yog nyob rau hauv nws cov theem pib, thiab cov kev cov nyom muaj xws li loj npaum li cas (6%-12%), tsis txaus cia stability, thiab cov nqi siab dua thiab cov nqi piv rau cov tsoos alkaline kua thiab hmoov accelerators. .

4.2 Kev sib xyaw ntawm Accelerators

Txhuas ntsev, silicate ntsev, carbonate ntsev, thiab hydroxides yog cov hom alkali tseem ceeb hauv accelerators. Aluminium ntsev thiab txhuas alkali yog cov khoom tseem ceeb tshaj plaws hauv cov kua accelerators uas tsis yog-alkali. Rau txhuas ntsev, aluminium sulfate yog cov khoom siv zoo tshaj plaws, thiab kev siv txhuas sulfate yog qhov chaw tseem ceeb hauv cov kua accelerators uas tsis yog-alkali tau txais kev saib xyuas thiab kev tshawb fawb.

4.4 Accelerator Production Process

4.4.1 Liquid Accelerators

Alkaline Accelerators: Sodium hydroxide thiab dej yog tov rau hauv cov tshuaj tiv thaiv kab mob, thiab tom qab nplawm, aluminium hydroxide ntxiv. Cov sib tov yog rhuab mus rau 110 degree, ces txias los tsim cov khoom kawg.

Non-alkaline Accelerators: Fluorosilicic acid yog ntxiv rau cov tshuaj tiv thaiv hlab ntsha thiab nplawm ntawm chav tsev kub thiab atmospheric siab. Aluminium sulfate yog ntxiv thiab nplawm kom txog thaum tag nrho yaj. Cov pH tom qab ntawd hloov mus rau 5, ua rau cov khoom kawg.

4.4.2 Powdered Accelerators

4.4.2.1 Qhov hnyav thiab sib xyaw

Cov ntaub ntawv nyoos xws li txhuas tshauv (qhov loj me {{0}}}cm), limestone (particle loj 0.5-1.2cm), thiab muaj alkali (sodium carbonate) yog thauj los ntawm lub kaw lus conveyor mus rau ib qho khoom hnyav. Aluminium sulfate