1. Lub hom phiaj ntawm kev ywg dej thiab kev kho yog tsuas yog rau cov kev xav tau ntawm cov cement hydration
Tom qab cov pob zeb tau nchuav thiab tsim, nws yuav tsum tau npog thiab watered kom tau raws li qhov yuav tsum tau ua kom cov pob zeb ua kom ntub dej rau qee lub sijhawm. Nyob rau tib lub sijhawm, txhawm rau tiv thaiv cov evaporation sai ntawm cov dej tu, nws kuj tseem npog nrog cov ntaub ntawv xws li yas zaj duab xis, cov hnab los yog cov hnab straw. Txawm li cas los xij, kev saib xyuas ntawm cov pob zeb tsis yog tsuas yog dej xwb, tab sis kuj suav nrog cov ntsiab lus dav thiab muaj txiaj ntsig, uas tuaj yeem suav nrog hauv ob lub ntsiab lus hauv qab no: ib qho yog ua kom cov pob zeb ua kom muaj dej txaus rau qee lub sijhawm kom tau raws. Qhov kev xav tau ntawm cov cement hydration Qhov thib ob yog los xyuas kom meej tias cov pob zeb muaj peev xwm tswj tau qhov kub siab tshaj plaws, qhov sib txawv ntawm qhov sib txawv ntawm sab hauv thiab sab nraud, thiab qhov sib txawv ntawm qhov sib txawv ntawm qhov chaw thiab qhov chaw nyob rau hauv qhov sib txawv ambient kub, thiab. ib tug haum cua txias npaum li cas thiab cua sov tus nqi.
2. Lub sijhawm pib tshiab ntawm pob zeb ua dej thiab kho yog 12h tom qab nchuav thiab sib sau
Qhov Specification rau Kev Txais Zoo ntawm Cov Khoom Siv Hluav Taws Xob Hluav Taws Xob (tom qab no hu ua "Quality Specification") qhia tias cov pob zeb yuav tsum tau npog thiab khaws cia nrog cov dej noo tsis pub dhau 12 teev tom qab ua tiav ntawm kev nchuav. Txawm li cas los xij, ntau tus neeg ua haujlwm tsim kev nkag siab yuam kev tias lub sijhawm pib tshiab ntawm kev ywg dej thiab kho tom qab kev ua vaj tse yog 12 teev tom qab, uas yog hais tias, ntev npaum li cov dej thiab kho tau ua ntej 12 teev tom qab ua tiav cov pob zeb ua tiav, cov lus qhia tshwj xeeb. raws li qhov yuav tsum tau ua. . Yog li ntawd, cov kws tshaj lij feem ntau yaum kom kev saib xyuas thiab kev ywg dej ntawm qhov chaw tsim kho, tab sis qee tus neeg yuav hais tias cov pob zeb nchuav tsuas yog ob peb teev, thiab nws tseem nyob deb ntawm 12 teev! Tsis txhob maj.
Vim qhov kev vam meej tas mus li thiab kev loj hlob ntawm cov cement thiab pob zeb thev naus laus zis, tshwj xeeb tshaj yog nyob rau xyoo tas los no, cov pob zeb ua haujlwm siab, cov pob zeb thaum ntxov, cov pob zeb muaj zog thiab cov pob zeb sib xyaw ua ke tau dav siv. Qhov kub deformation, ziab shrinkage deformation thiab nws tus kheej-shrinkage deformation ntawm cov pob zeb yog tag nrho cov loj vim yog vim li cas ntawm lub zog siab, siab thaum ntxov zog thiab me me dej-cement piv, thiab pob zeb tawg tshwm sim ib ntus. Ib qho ntawm cov laj thawj tseem ceeb yuav tsum nyiam cov neeg ua haujlwm tsim kho.
Ntau xyoo dhau los, cov pob zeb yas uas muaj dej muaj kuab heev tau ntsib nyob rau ntawm qhov chaw tsim kho. Lub ntim ntim tsis loj, cov qib pob zeb muaj zog thiab qib cement lub zog qis, cov cement ntau npaum li cas, cov qib dej thaum ntxov tsis siab, thiab qhov ziab qhuav tau txo. Tsis muaj tus kheej shrinking. Nyob rau hauv cov ntaub ntawv no, nws yuav tsim nyog yuav tsum tau xws li yas pob zeb yuav tsum tau watered thiab kho tsis pub dhau 12 teev tom qab pouring, tab sis rau niaj hnub pob zeb, watering thiab curing lig dhau lawm yuav ua rau tawg thiab puas lub peev xwm ua rau muaj kev phiv.
3. Lub sijhawm ntev ntawm cov dej thiab kho cov pob zeb
Qhov "Quality Specification" qhia tias rau cov pob zeb sib xyaw nrog Portland cement, Portland cement zoo tib yam los yog slag Portland cement, lub sij hawm watering thiab curing yuav tsum tsis pub tsawg tshaj 7d. Lub pob zeb yuav tsum tsis pub tsawg tshaj 14d. Nws yuav tsum tau taw qhia ntawm no tias qhov kev qhia tshwj xeeb tsuas yog lub sijhawm tsawg kawg nkaus rau kev ywg dej thiab kho, thiab tsis muab lub sijhawm zoo thiab lub sijhawm siab tshaj plaws rau kev ywg dej thiab kho. Txawm li cas los xij, qhov ntev ntawm qhov dej thiab kho lub sij hawm yog, qhov siab dua ntawm cov cement hydration thiab ntau dua qhov irreversible shrinkage ntawm cov cement. Yog hais tias cov cement particles tag nrho hydrated, lub resulting cement gel yuav tsis tsuas yog txhim kho lub zog ntawm cov pob zeb, tab sis kuj tsim loj shrinkage yuav ua rau pob zeb tawg nyob rau hauv mob hnyav. Zoo li lub ntim stabilization nyhuv ntawm aggregate nyob rau hauv pob zeb, ib co ntawm unhydrated cement hais los yog lwm yam inert tshuaj yuav tsum tau nyob rau hauv lub cement pob zeb kom stabilize lub ntim. Yog li ntawd, lub sij hawm ntev watering thiab curing, qhov zoo dua. Nws yog obviously tsis ncaj ncees lawm rau blindly ncua lub watering thiab txij nkawm lub sij hawm raws li "kev kho kom zoo". Kev nce qib thiab kev loj hlob ntawm cov cement niaj hnub thiab cov cuab yeej ua vaj tse yuav tsum tau "tsuas yog nyob rau hauv-lub sij hawm" watering thiab txij nkawm.
4. Thaum kawg cov pob zeb tau teeb tsa, thiab qhov chaw tseem ntub, yog li tsis txhob maj mus rau dej rau kev tu
Raws li peb txhua tus paub, kev tawg thaum ntxov ntawm cov pob zeb yog ib qho teeb meem tshiab uas tshwm sim los ntawm kev nce qib thiab kev loj hlob ntawm cov cement thiab pob zeb technology, thiab nws tus kheej shrinkage thiab kub shrinkage yog lub hauv paus tseem ceeb rau kev tawg thaum ntxov ntawm cov pob zeb ua haujlwm siab, lub zog siab. pob zeb thiab high-early-strength pob zeb.
Qhov luaj li cas ntawm tus kheej-shrinkage ntawm pob zeb nyob ntawm qhov degree ntawm nws tus kheej ziab ntawm cov cement pob zeb, elastic modulus ntawm cov cement pob zeb thiab creep coefficient. Nyob rau hauv thaum ntxov theem tom qab pouring, tshwj xeeb tshaj yog nyob rau hauv thawj 24 teev tom qab pib, lub elastic modulus yog tsawg thiab cov creep coefficient yog loj. Yog li ntawd, qhov degree ntawm kev ziab nws tus kheej dhau los ua qhov tseem ceeb ntawm kev txiav txim siab tus kheej shrinkage. Kev ntub dej ntawm qhov chaw ntawm pob zeb thaum lub sijhawm pib tuaj yeem ua rau cov dej kho txuas nrog cov dej hauv cov qhov capillary hauv cov pob zeb tag nrho, txhawm rau muab cov khoom cementing hauv cov pob zeb kom hydrate nws. Qhov ntxiv hydration ntawm cov khoom siv cementitious txhawb kev ua kom zoo ntawm capillary pores. Thaum qhov tsis kam ntawm cov phab ntsa capillary pore tshaj qhov nro ntawm cov dej thiab tsis tuaj yeem mus txuas ntxiv mus rau hauv cov pob zeb, cov dej tso tseg. Nws tuaj yeem pom tau tias cov dej ntxiv cov nyhuv ntawm kev ywg dej thaum ntxov thiab kho tuaj yeem cuam tshuam zoo thaum ntxov shrinkage ntawm pob zeb.
Tus kheej-shrinkage ntawm pob zeb pib los ntawm nws thawj qhov chaw. Nws loj hlob sai heev nyob rau theem pib. Feem ntau nws tuaj yeem ua tiav hauv 24 teev, thiab tom qab ntawd nws yuav lwj sai. Nws tus nqi tuaj yeem ncav cuag (0.025~0.050) × 10-3. Qhov piv txo qis thiab nce nrog qhov nce ntawm qhov kub thiab txias. Nyob rau tib lub sijhawm, nrog kev nce ntxiv ntawm cov pob zeb ua kom muaj zog, nws qhov kawg tensile strain kuj poob qis los ntawm 4.0 × 10-3 2h tom qab tsim, thiab poob mus rau 0.04 × 10-3 hauv 6 ~ 12h, mus txog qhov kev pheej hmoo. lub sij hawm ntawm pob zeb tawg. Raws li cov kev cai ntawm "Quality Specification", raws li cov kev cai ntawm cov tsoos yas pob zeb, qhov tseeb pib lub sij hawm nyob rau hauv 12 teev tom qab pouring yog yuam kev pib watering thiab curing, thiab lub sij hawm obviously lags tom qab lub sij hawm txaus ntshai ntawm pob zeb tawg. . Lub sijhawm kawg los pib watering thiab curing yog tsis haum rau curing yuav tsum tau ntawm niaj hnub pob zeb. Muaj ntau tus neeg uas tsis ntseeg tias kev ywg dej thiab kho cov pob zeb tuaj yeem pib txhua lub sijhawm hauv 12 teev tom qab ua tiav cov pob zeb ua tiav, uas yog hais tias, kev ywg dej thiab kho hauv 12h lub sijhawm no tuaj yeem ntxov lossis lig. Lub plasticity yog qhov loj heev, thiab qhov kev nkag siab thiab kev coj ua no yog qhov tsis ncaj ncees lawm.
Yog hais tias lub zog siab thaum ntxov ntawm pob zeb yog suav tias yog qhov ua rau sab hauv ntawm nws qhov tawg thaum ntxov, tom qab ntawd nws cov dej thiab kev kho mob rov qab rau sab nraud thiab cuam tshuam ntawm cov dej ntxiv tom qab lub evaporation sai ntawm cov dej saum npoo av, uas yog sab nraud ua rau tawg thaum ntxov. pob zeb. Yog li ntawd, nws yog ib qho tsim nyog yuav tsum tau ua ntej lub sij hawm ntawm watering thiab curing ntawm cov pob zeb, yog li ntawd cov evaporating dej ntawm cov pob zeb nto yuav tsum tau replenished nyob rau hauv lub sij hawm, thiaj li mus cuag "thaum ntxov thiab raws sij hawm" watering thiab kho. Tshwj xeeb, tom qab cov pob zeb tau nchuav thiab pib qhov chaw pib, nws tsuas yog txwv rau "thaum ntxov thiab raws sijhawm" watering thiab curing thiaj li tsis ua kom cov pob zeb ua kom puas tsuaj. Cov dej txaus txaus kom tsis txhob muaj kev sib xyaw ua ke ntawm cov pob zeb yas shrinkage, autogenous shrinkage thiab qhuav shrinkage.
5. Kev ywg dej thiab kho cov pob zeb yog qhov zoo tshaj plaws rau cov dej hnyav, kom cov dej tuaj yeem ua kom tiav thiab ua kom huv si.
Lub npog tom qab cov pob zeb tau nchuav thiab tsim yog los tiv thaiv cov evaporation sai ntawm cov dej kho kom txuag dej; Qhov thib ob yog los tiv thaiv kom tsis txhob tawg sai ntawm cov dej kub ntawm cov cement thaum lub caij txias, thiaj li ua kom ntseeg tau tias cov qhob seem muaj qhov tsim nyog kub gradient. Txhawm rau kom txuag tau cov ntaub ntawv npog, qee cov neeg tsis npog cov pob zeb thiab nchuav nrog dej siab. Qhov no tsis yog tsuas yog nkim dej xwb, tab sis kuj yooj yim ntxuav tawm lub pob zeb nto. Qhov tseem ceeb tshaj, cov dej siab ntws los ntawm cov pob zeb ua kom zoo thiab sai sai tshem tawm cov cua sov. , ua rau muaj kev poob qis hauv qhov kub thiab txias ntawm cov pob zeb nto. Yog hais tias nws yog nyob rau hauv lub ncov lub sij hawm ntawm cov pob zeb hydration tshav kub, yog hais tias qhov kub qhov sib txawv ntawm cov dej curing thiab cov pob zeb nto yog loj, qhov kub ntawm qhov sib txawv ntawm sab hauv thiab sab nraud ntawm cov pob zeb thiab qhov kub ntawm qhov sib txawv ntawm cov pob zeb nto thiab ib puag ncig. yuav loj dhau vim qhov kub thiab txias ntawm cov pob zeb. "Thermal shock" tshwm sim, ua rau tawg ntawm pob zeb nto; Nyob rau tib lub sijhawm, nws yog ib qho tsim nyog yuav tsum nco ntsoov tias kev saib xyuas thiab kev ywg dej tsis tuaj yeem cuam tshuam, thiab rov ua dua "thermal shocks" tuaj yeem ua rau cov pob zeb tawg ntau dua. Txoj kev tsim nyog ntawm kev ywg dej thiab kev saib xyuas yuav tsum yog cov dej me me.
6. Txhawm rau txhawm rau txhawm rau ua kom cov pob zeb tawv tawv, cov txheej txheem kho tsuas yog khaws cia kom sov yam tsis muaj cua txias
Thawj qhov kub ntawm cov pob zeb yog qhov tseem ceeb ntawm qhov kub siab tshaj plaws ntawm cov pob zeb. Rau cov pob zeb hauv lub xeev yas, kev kho cua txias thiab cua txias yuav txo qhov kub siab tshaj plaws thiab sib raug zoo txo qhov kub ntawm cov pob zeb tawg. Yog li ntawd, qhov txias ntawm cov pob zeb hauv lub xeev yas yog ib txoj hauv kev zoo los tiv thaiv cov pob zeb ntawm kev tawg.
Lub pob zeb pib tawv thiab ua kom muaj zog tensile kom txog thaum nws ncav cuag qhov kub siab tshaj. Txawm hais tias cov pob zeb tseem ua kom txias nyob rau theem no, nws feem ntau tsis hloov lub xeev tensile ntawm tag nrho cov pob zeb. Cov dej txias yuav ua rau cov pob zeb kub poob qis, uas yuav ua rau kom qhov kub thiab txias ntawm cov pob zeb, uas yuav ua rau pob zeb "thermal shock". Txawm hais tias nyob rau theem no, kev kho cov pob zeb ua kom txias kuj tseem yuav txo qhov kub siab tshaj plaws thiab qhov kub ntawm qhov tawg, tab sis txhawm rau tiv thaiv cov pob zeb tawg ntawm qhov tawg yog tshwm sim los ntawm qhov kub ntawm qhov sib txawv ntawm sab hauv thiab sab nraud. Kev kho cua txias thiab kev tu dej nyob rau theem no yuav tsum tau ceev faj. Ua ntej lub tensile stress yog generated nyob rau hauv lub pob zeb, nws yuav tsum tau txias nyob rau hauv lub sij hawm.
7. Rwb thaiv tsev mulch pib thaum lub mulch yog watered
Ua ntej cov pob zeb ncav cuag qhov siab tshaj plaws ntawm cov cement hydration, nws yuav tsum nyob rau hauv lub tshav kub dissipation theem, thiaj li yuav tau txais ib tug qis tshaj plaws kub thiab cracking kub. Yog hais tias lub rwb thaiv tsev yog siab heev pib los ntawm watering thiab curing coverage, nws yuav counterproductive, tab sis yuav ua rau kom lub siab tshaj plaws kub ntawm cov pob zeb thiab ua rau tawg. Lub sijhawm txuag hluav taws xob kom raug yuav tsum pib los ntawm qhov txias ntawm cov pob zeb, tsis yog ua ntej.
Ib qho ntawm lub hom phiaj ntawm kev siv cov cua sov preservation nyob rau hauv lub pob zeb txias theem yog kom txo tau cov cua sov nyob rau hauv lub pob zeb, thiaj li yuav txo tau qhov kub ntawm gradient ntawm seem. Qhov thib ob lub hom phiaj yog ncua lub sij hawm kub dissipation ntawm cov pob zeb, kom nws muaj peev xwm ua tau zoo tag nrho nws lub zog loj hlob muaj peev xwm, thiab ua kom lub zog so thiab nkag ntawm cov pob zeb ua kom pom tseeb, thiab nws cov kev ntxhov siab sab hauv tuaj yeem txo tau raws li. Nyob rau tib lub sijhawm, vim qhov nce ntawm cov pob zeb muaj hnub nyoog, qhov tensile kev ua tau zoo ntawm cov pob zeb yog sai dua nws cov kev ua haujlwm compressive, uas tuaj yeem tiv thaiv thiab txo cov pob zeb tawg.
Qhov kub gradient ntawm cov pob zeb nto yog ib qho ntawm cov laj thawj tseem ceeb uas txwv cov kab nrib pleb ntawm cov pob zeb. Qhov nce thiab poob ntawm qhov kub ntawm atmospheric cuam tshuam rau qhov kub thiab txias gradient ntawm sab hauv ntawm cov pob zeb, thiab qhov ntxhab ntawm qhov hloov pauv kub yuav ua rau muaj kev cuam tshuam rau qhov siab ntawm qhov kub thiab txias hloov ntawm cov pob zeb saum npoo thiab cov cua sov. Kev tiv thaiv zoo ntawm cov ntaub ntawv thermal rwb thaiv tsev tuaj yeem txo qhov kub thiab txias. Kub gradient hla ib ntu.
Kev xyaum ua vaj tse tau ua pov thawj tias qhov kub thiab txias hloov yog qhov tseem ceeb thiab nyuaj heev ntawm cov qauv ua vaj tse, thiab qhov siab ntawm qhov kub thiab txias gradient tuaj yeem suav tias yog qhov ceev ntawm "loading" ntawm pob zeb, thiab muaj kev cuam tshuam tseem ceeb rau lub cev thiab cov khoom siv ntawm cov pob zeb. . Qhov ntsuas kub tam sim ntawd tuaj yeem suav tau tias yog kev thauj khoom ceev ceev ntawm cov pob zeb, uas tuaj yeem ua rau muaj qhov nce ntawm tensile kev nyuaj siab thiab elastic modulus ntawm cov pob zeb, thaum txo qhov kawg tensile lub zog ntawm cov pob zeb thiab tsis muaj zog ntawm kev tawg. Kev thauj khoom qeeb ntawm cov pob zeb tuaj yeem ua rau txo qis hauv tensile kev nyuaj siab thiab elastic modulus ntawm cov pob zeb piv nrog rau kev thauj khoom sai, thaum lub zog tensile kawg ntawm cov pob zeb nce. Nyob rau tib lub sijhawm, qhov kub thiab txias tam sim ntawd tuaj yeem ua rau muaj kev nce qib ntawm kev txwv sab hauv thiab sab nraud. Txawm hais tias nws yog ib qho qauv tswj hwm los ntawm cov kev txwv sab nraud lossis cov qauv tswj hwm los ntawm cov kev txwv sab hauv, sab nraud thermal rwb thaiv tsev thiab sab hauv qhov qis qis tuaj yeem zam thiab txo cov pob zeb tawg.
Raws li cov ntsiab lus, nws tuaj yeem pom tau tias txawm tias qhov ntsuas kub ntawm qhov nruab nrab, uas yog hais tias, txawm hais tias qhov kub sab nraud yog siab lossis qis hauv lub caij nplooj ntoo hlav, lub caij ntuj sov, caij nplooj zeeg thiab lub caij ntuj no, lub thermal rwb thaiv tsev thiab kev saib xyuas ntawm cov pob zeb tsis yog tsuas yog ua rau lub caij nplooj ntoo hlav. qhov kub thiab txias ntawm cov pob zeb, tab sis kuj ua rau qhov kub thiab txias hauv cov pob zeb. Nws txo qhov kub ntawm qhov sib txawv ntawm sab hauv thiab sab nraud thiab qhov sib txawv ntawm qhov kub thiab txias ntawm qhov sib txawv ntawm qhov chaw ua vaj tse thiab qhov chaw atmospheric. Vim li no, txoj kev kho ntawm "sab nraud thermal rwb thaiv tsev thiab sab hauv qis qis" tuaj yeem tiv thaiv thiab txo qhov tawg ntawm pob zeb.
8. Tsis yog raws li qhov xwm txheej tiag tiag ntawm cov pob zeb, cov kev cai yog nruj me ntsis txav
Txhawm rau tiv thaiv qhov tshwm sim ntawm cov kab nrib pleb thaum ntxov hauv cov pob zeb, tib neeg feem ntau tswj cov kev ntsuas kev ntsuas xws li qhov kub siab tshaj plaws ntawm cov pob zeb, qhov kub sib txawv ntawm sab hauv thiab sab nraud, qhov kub sib txawv ntawm qhov chaw thiab ib puag ncig, qhov kub thiab txias. tus nqi. Qhov kub sib txawv nrog cov huab cua puag ncig yuav tsum tsis txhob siab tshaj 20 degree. Txawm li cas los xij, muaj qee qhov tsis sib xws hauv daim ntawv thov ntawm cov kev qhia yav dhau los hauv qhov tseeb engineering. Qee tus ntseeg tias yuav tsum tsis txhob siab tshaj 25 degree; ib txhia ntseeg hais tias nws yuav tsum tsis txhob siab tshaj 30 degree; ib txhia ntseeg hais tias nws yuav tsum tsis txhob siab tshaj 15 degree; Qhov ntsuas kub tam sim no tshwm sim los ntawm kev txau dej thiab tshem tawm pwm yuav tsum tsis pub tshaj 15 degree. Kev xyaum ua vaj tse tau ua pov thawj tias hauv qee qhov haujlwm, qhov kub ntawm qhov sib txawv ntawm sab hauv thiab sab nraud ntawm pob zeb yog ntau dua 25 degree, tab sis cov qauv tsis tawg; thaum nyob hauv qee qhov haujlwm, qhov kub sib txawv ntawm sab hauv thiab sab nraud yog tsawg dua 20 degree, tab sis cov pob zeb tawg. Los ntawm qhov no, nws kuj tuaj yeem piav qhia tau tias qhov hloov kho "Quality Specification" tsis ua cov kev cai nruj rau qhov no.
Tib lub sijhawm, cov ntsuas ntsuas ntawm qhov ntsuas cua txias txhua hnub kuj txawv. Qee tus neeg xav tias qhov cua txias txhua hnub yuav tsum tsis txhob siab tshaj 3 degree, qee qhov xav tias nws yuav tsum tsis txhob siab tshaj 2 degree, thiab qee tus txawm xav tias nws yuav tsum tsis txhob siab tshaj 1.5 degree.
Qhov tshwm sim ntawm qhov sib txawv ntawm cov ntaub ntawv qhia saum toj no yog qhov ua tau zoo heev. Txawm hais tias qee cov ntaub ntawv tau teev tseg los ntawm cov lus qhia tshwj xeeb, nws tsis tuaj yeem ua rau muaj kev tsis ntseeg txog qhov tshwj xeeb. Vim lub randomness, ntau haiv neeg thiab heterogeneity ntawm cov muaj pes tsawg leeg ntawm cov khoom ua vaj tse, raws li zoo raws li lub heterogeneity ntawm pob zeb thiab qhov sib txawv nyob rau hauv kev tsim kho zoo, nws tsis yog xav tsis thoob tias cov ntaub ntawv qhia yog txawv. Xav txog kev tswj qhov kub thiab txias, qee qhov kev cai tsis tuaj yeem muab luam tawm los ntawm mechanically.
