Kev tsim kho tshiab hauv kev lees paub zoo ntawm cov pob zeb ua vaj tse tuaj yeem muab cov ntaub ntawv tseem ceeb txog kev ua tau zoo, kav ntev, thiab ua raws li cov qauv tsim hybrid.
Kev tsim kho ntawm kev ua vaj tse pob zeb tuaj yeem pom muaj xwm txheej ceev, thiab tus neeg cog lus yuav tsum tau xyuas qhov zoo thiab ua haujlwm ntev ntawm cov pob zeb cast-in-place. Cov xwm txheej no suav nrog kev cuam tshuam los nag thaum lub sij hawm nchuav, tom qab siv cov tshuaj tua kab mob, cov yas shrinkage thiab tawg cov sij hawm nyob rau hauv ob peb teev tom qab pouring, thiab pob zeb texturing thiab kho cov teeb meem. Txawm hais tias qhov kev xav tau ntawm lub zog thiab lwm yam kev ntsuas cov ntaub ntawv tau ua tiav, cov kws ua haujlwm yuav xav tau kev tshem tawm thiab hloov cov pavement qhov chaw vim lawv txhawj xeeb txog seb cov khoom siv hauv tsev puas ua tau raws li cov qauv sib xyaw.
Nyob rau hauv cov ntaub ntawv no, petrography thiab lwm yam complementary (tab sis kev) kev xeem txoj kev yuav muab cov ntaub ntawv tseem ceeb txog qhov zoo thiab durability ntawm qhob mixs thiab seb lawv ua tau raws li kev ua hauj lwm specifications.
Daim duab 1. Piv txwv ntawm fluorescence microscope micrographs ntawm qhob muab tshuaj txhuam ntawm 0.40 w/c (sab laug ces kaum) thiab 0.60 w/c (saum sab xis ces kaum). Daim duab sab laug qis qhia tau hais tias cov cuab yeej ntsuas qhov kev tiv thaiv ntawm lub tog raj kheej kheej kheej. Daim duab sab xis qhia txog kev sib raug zoo ntawm ntim resistivity thiab w / c. Chunyu Qiao thiab DRP, lub tuam txhab Twining
Abram Txoj Cai: "Lub zog compressive ntawm ib qho kev sib xyaw ua ke yog inversely proportional rau nws cov dej-cement piv."
Xib fwb Duff Abrams thawj zaug piav txog kev sib raug zoo ntawm dej-cement piv (w/c) thiab compressive zog nyob rau hauv 1918 [1], thiab tsim tam sim no hu ua Abram txoj cai: "Lub compressive zog ntawm pob zeb dej / cement ratio." Ntxiv nrog rau kev tswj lub zog compressive, cov dej cement piv (w / cm) yog tam sim no nyiam vim nws paub txog kev hloov ntawm Portland cement nrog cov ntaub ntawv cementing ntxiv xws li ya tshauv thiab slag. Nws kuj yog ib qho tseem ceeb parameter ntawm pob zeb durability. Ntau cov kev tshawb fawb tau pom tias cov pob zeb sib xyaw nrog w / cm qis dua ~ 0.45 yog qhov ruaj khov nyob rau hauv ib puag ncig hnyav, xws li thaj chaw raug rau lub voj voog khov-thaw nrog deicing ntsev los yog thaj chaw uas muaj cov sulfate siab hauv cov av.
Capillary pores yog ib feem ntawm cov cement slurry. Lawv muaj qhov chaw nruab nrab ntawm cov khoom siv cement hydration thiab unhydrated cement particles uas tau ntim dej ib zaug. [2] Capillary pores yog ntau finer tshaj entrained los yog trapped pores thiab yuav tsum tsis txhob totaub nrog lawv. Thaum cov capillary pores txuas nrog, cov kua dej los ntawm ib puag ncig sab nraud tuaj yeem txav mus los ntawm kev muab tshuaj txhuam. Qhov tshwm sim no hu ua kev nkag mus thiab yuav tsum tau txo qis kom ntseeg tau tias muaj zog. Lub microstructure ntawm qhov sib xyaw ua ke ruaj khov yog tias cov pores yog segmented es tsis txuas nrog. Qhov no tshwm sim thaum w / cm tsawg dua ~ 0.45.
Txawm hais tias nws tsis yooj yim rau kev ntsuas qhov w / cm ntawm cov pob zeb tawv tawv, ib txoj kev txhim khu kev qha tuaj yeem muab cov cuab yeej pov thawj tseem ceeb rau kev tshawb xyuas cov pob zeb uas muaj zog hauv qhov chaw. Fluorescence microscopy muab kev daws teeb meem. Nov yog qhov nws ua haujlwm.
Fluorescence microscopy yog ib qho txheej txheem uas siv epoxy resin thiab fluorescent dyes kom pom cov ntsiab lus ntawm cov ntaub ntawv. Nws yog feem ntau siv hauv kev kho mob sciences, thiab nws kuj tseem muaj cov ntawv thov tseem ceeb hauv cov ntaub ntawv tshawb fawb. Kev siv cov txheej txheem no hauv pob zeb tau pib ze li 40 xyoo dhau los hauv Denmark [3]; nws tau tsim nyob rau hauv Nordic lub teb chaws nyob rau hauv 1991 rau kwv yees lub w / c ntawm hardened pob zeb, thiab tau hloov kho nyob rau hauv 1999 [4].
Txhawm rau ntsuas qhov w / cm ntawm cov khoom siv cement (xws li pob zeb, mortar, thiab grouting), fluorescent epoxy yog siv los ua ib ntus nyias los yog pob zeb thaiv nrog lub thickness ntawm kwv yees li 25 microns lossis 1/1000 nti (Daim duab 2). Cov txheej txheem muaj xws li cov pob zeb pob zeb lossis lub tog raj kheej txiav rau hauv cov pob zeb tiaj tus (hu ua blanks) nrog thaj tsam li ntawm 25 x 50 mm (1 x 2 ntiv). Cov khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob Raws li w / cm nce, kev sib txuas thiab cov pores yuav nce, yog li ntau epoxy yuav nkag mus rau hauv cov tshuaj. Peb tshuaj xyuas cov flakes nyob rau hauv lub tshuab tsom, siv ib txheej ntawm cov ntxaij lim dej tshwj xeeb kom zoo siab rau cov fluorescent dyes nyob rau hauv epoxy resin thiab lim tawm tshaj tawm. Hauv cov duab no, cov cheeb tsam dub sawv cev rau cov khoom sib xyaw thiab cov cement uas tsis muaj dej. Qhov porosity ntawm ob yog qhov yooj yim 0%. Lub voj voog ntsuab yog qhov porosity (tsis yog porosity), thiab qhov porosity yog qhov pib 100%. Ib qho ntawm cov yam ntxwv no Lub speckled ntsuab "khoom" yog muab tshuaj txhuam (Daim duab 2). Raws li w / cm thiab capillary porosity ntawm pob zeb nce, cov xim ntsuab tshwj xeeb ntawm cov muab tshuaj txhuam yuav ci dua thiab ci dua (saib daim duab 3).
Daim duab 2. Fluorescence micrograph ntawm flakes qhia cov khoom sib sau ua ke, voids (v) thiab muab tshuaj txhuam. Kab rov tav teb dav yog ~ 1.5 hli. Chunyu Qiao thiab DRP, lub tuam txhab Twining
Daim duab 3. Fluorescence micrographs ntawm cov flakes qhia tau hais tias thaum lub w/cm nce, cov tshuaj ntsuab ntsuab maj mam ua kom ci. Cov khoom sib tov no yog aerated thiab muaj cov hmoov tshauv ya. Chunyu Qiao thiab DRP, lub tuam txhab Twining
Kev txheeb xyuas duab suav nrog rho tawm cov ntaub ntawv ntau los ntawm cov duab. Nws yog siv nyob rau hauv ntau yam kev tshawb fawb teb, los ntawm tej thaj chaw deb sensing microscope. Txhua pixel hauv cov duab digital yeej tseem ceeb dhau los ua cov ntaub ntawv taw qhia. Txoj kev no tso cai rau peb txuas cov lej mus rau qhov sib txawv ntsuab brightness qib pom hauv cov duab no. Tshaj li 20 xyoo dhau los los yog li ntawd, nrog rau kev hloov pauv hauv lub tshuab xam zauv lub zog thiab kev nrhiav cov duab digital, cov duab tsom xam tam sim no tau dhau los ua cov cuab yeej siv tau uas ntau tus kws tshawb fawb (xws li cov kws kho tsiaj txhu) tuaj yeem siv tau. Peb feem ntau siv cov duab tsom xam los ntsuas qhov capillary porosity ntawm slurry. Nyob rau tib lub sijhawm, peb pom tias muaj kev sib raug zoo ntawm kev sib raug zoo ntawm w / cm thiab capillary porosity, raws li qhia hauv daim duab hauv qab no (Daim duab 4 thiab daim duab 5).
Daim duab 4. Piv txwv ntawm cov ntaub ntawv tau los ntawm fluorescence micrographs ntawm cov ntu nyias. Daim duab no qhia txog cov pixels ntawm ib qib grey muab rau hauv ib qho photomicrograph. Peb lub ncov sib haum mus rau aggregates (txiv kab ntxwv nkhaus), muab tshuaj txhuam (grey cheeb tsam), thiab void (unfilled ncov ntawm sab xis). Qhov nkhaus ntawm paste tso cai rau ib tug los xam qhov nruab nrab pore loj thiab nws tus qauv sib txawv. Chunyu Qiao thiab DRP, Twining Company Daim duab 5. Daim duab no qhia txog cov kev ntsuas nruab nrab ntawm w / cm capillary thiab 95% kev ntseeg siab nyob rau hauv qhov sib xyaw ua ke ntawm cov cement ntshiab, ya tshauv cement, thiab ntuj pozzolan binder. Chunyu Qiao thiab DRP, lub tuam txhab Twining
Hauv kev ntsuam xyuas zaum kawg, peb qhov kev ntsuam xyuas ywj pheej yuav tsum tau ua pov thawj tias cov pob zeb ntawm qhov chaw ua tau raws li qhov sib xyaw tsim tshwj xeeb. Raws li qhov ua tau, tau txais cov qauv tseem ceeb los ntawm qhov chaw uas ua tau raws li tag nrho cov qauv kev lees paub, nrog rau cov qauv los ntawm cov chaw muaj feem cuam tshuam. Cov tub ntxhais los ntawm cov txheej txheem lees paub tuaj yeem siv los ua tus qauv tswj, thiab koj tuaj yeem siv nws los ua tus qauv ntsuas rau kev ua raws li cov qauv tsim.
Hauv peb qhov kev paub dhau los, thaum cov kws ua haujlwm nrog cov ntaub ntawv pom cov ntaub ntawv tau txais los ntawm cov kev xeem no, lawv feem ntau lees txais qhov kev tso kawm yog tias lwm yam tseem ceeb ntawm engineering (xws li compressive zog) tau ntsib. Los ntawm kev muab cov kev ntsuas ntau ntawm w / cm thiab qhov tsim, peb tuaj yeem mus dhau qhov kev ntsuam xyuas tau teev tseg rau ntau txoj haujlwm los ua pov thawj tias qhov sib xyaw hauv nqe lus nug muaj cov khoom uas yuav txhais tau tias ua haujlwm zoo.
David Rothstein, Ph.D., PG, FACI yog tus thawj coj lithographer ntawm DRP, A Twining Company. Nws muaj ntau tshaj 25 xyoo ntawm kev paub txog petrologist thiab tus kheej tau tshuaj xyuas ntau tshaj 10,000 tus qauv los ntawm ntau tshaj 2,000 qhov project thoob ntiaj teb. Dr. Chunyu Qiao, tus thawj kws tshawb fawb ntawm DRP, lub tuam txhab Twining, yog tus kws tshawb fawb txog geologist thiab cov ntaub ntawv uas muaj ntau tshaj kaum xyoo ntawm kev paub txog cov khoom siv cementing thiab cov khoom siv pob zeb ntuj thiab ua tiav. Nws cov kws tshaj lij suav nrog kev siv cov duab tsom xam thiab fluorescence microscopy los kawm txog qhov ua tau zoo ntawm cov pob zeb, nrog rau kev tshwj xeeb ntawm kev puas tsuaj los ntawm deicing ntsev, alkali-silicon cov tshuaj tiv thaiv, thiab tshuaj tua kab mob hauv cov chaw kho dej khib nyiab.
Post lub sij hawm: Sep-07-2021