l. Lub ntsiab yam tseem ceeb ntawm pob zeb shrinkage:
Kev siv dej hauv ib chav tsev ntawm pob zeb, muaj pes tsawg leeg ntawm pob zeb thiab xuab zeb, lub sijhawm pib ntub dej, thiab lwm yam xws li qhov loj me ntawm pob zeb, qhov sib xyaw ntawm cov khoom sib xyaw, thiab cov ntsiab lus slurry ntawm cov sib tov kuj tseem cuam tshuam rau cov khoom siv. drying shrinkage, thiab tag nrho qhov xav tau ntawm qhov sib tov Cov dej yog qhov tseem ceeb cuam tshuam rau kev ziab shrinkage.
① Feem ntau ntawm cov pob zeb hauv kev lag luam niaj hnub thiab kev tsim kho vaj tse muaj cov khoom ntawm cov khoom loj (loj-chaw) pob zeb, thiab yuav tsum tau them nyiaj rau qhov ntim ruaj khov (kub ntawm hydration thiab shrinkage). Cov pob zeb (xws li cov pob zeb sib xyaw nrog cov khoom sib txawv) feem ntau qhia me ntsis nthuav deformation hauv dej. Nyob rau hauv cov huab cua, nws feem ntau shrinks thiab deforms.
② Cov cement ntau dua, cov dej siv ntau dua, cov cement slurry ntau dua, qhov poob qis dua, thiab ntau dua qhov shrinkage; tsis txhob nchuav cov pob zeb hauv cov nag, thaum lub teeb los nag. Kev ntsuas dej nag yuav tsum tau ua thiab qhov sib piv ntawm cov dej-cement yuav tsum tau hloov kho (txo cov dej haus).
③ Qhov loj dua cov dej-cement piv, qhov ntau dua qhov qhuav shrinkage. Feem ntau, cov dej-cement piv ntawm cov pob zeb muaj zog yog qhov me me, uas muaj txiaj ntsig zoo los txo qis tom qab qhuav shrinkage. Txawm li cas los xij, vim muaj ntau cov cement slurry los yog cov ntaub ntawv cementitious thiab cov nyhuv ntawm cov dej ua kom muaj txiaj ntsig zoo Shrinkage loj dua li ntawm nruab nrab thiab qis zog pob zeb. Tsis tshua muaj dej-cement piv tsis zoo rau cov yas shrinkage thaum ntxov. Nws yog ib qho yooj yim los tsim kom qhuav shrinkage tawg thaum ntxov vim lub cev qhuav dej.
④ qhov loj ntawm thaj tsam ntawm txoj kev cua daj cua dub, qhov loj dua qhov shrinkage.
⑤ Lub shrinkage ntawm slag cement cement yog loj dua li ntawm cov zoo tib yam (PO) cement thiab composite (PC) cement, lub shrinkage ntawm ya tshauv cement me me, thiab shrinkage ntawm ceev hardening cement yog loj dua. Thaum tshav kub kub ntawm hydration ntawm cov cement sib xyaw yog qis dua li qhov qub (P .0) cement, yog li cov cement hom yuav tsum tau xaiv raws li qhov tuab, ntim thiab kev tsim kho ntawm cov pob zeb.
⑥ Sandstone aggregate shrinkage nce ntau. Nyias thiab nyias. Qhov ntau dua cov av nkos hauv cov aggregate (xuab zeb, pob zeb), qhov ntau dua qhov shrinkage, thiab qhov qis zog tensile, cov av nkos yuav tsum nruj me ntsis tswj:
⑦ Lub sijhawm ua kom ntxov ntxov thiab ntev dua (7-14 hnub), qhov me me qhov shrinkage. Moisturizing thiab kho kom tsis txhob qhuav qhuav tuaj yeem txo qis kev ntxhov siab. Ua tib zoo mloog rau kev vibration, tshwj xeeb tshaj yog nyob rau hauv kev sib tshuam ntawm kab teeb thiab slabs (los yog phab ntsa panels), tab sis tsis txhob over-vibrate los tiv thaiv kev sib cais thiab los ntshav loj. Tom qab lub hauv pem teb yog poured. Nws yuav txau sai sai. Ua cov txheej txheem thib ob nyob ze ntawm qhov chaw zaum kawg (tau txais cov ntaub so ntswg thiab sib tsoo), npog nrog cov hnab los yog cov quav cab, qhov thib ob calendering thiab ntxiv dag zog rau kev ntub dej yog qhov zoo heev los tswj cov kab nrib pleb.
⑧ Qhov ntau dua qhov ambient humidity, qhov me me qhov shrinkage: qhov siab dua qhov ambient kub. Qhov ntau qhuav qhov kev tawm dag zog, qhov ntau dua qhov shrinkage.
⑨ Lub coarser lub aggregate (xuab zeb, pob zeb) particle loj, qhov me me qhov shrinkage: qhov me me ntawm aggregate particle loj, qhov siab dua cov xuab zeb (uas yog, ntau xuab zeb thiab tsawg pob zeb), thiab qhov loj dua qhov shrinkage.
⑩Qhov siab dua cov cement kev ua haujlwm, qhov zoo dua cov khoom, qhov loj ntawm qhov chaw tshwj xeeb, thiab qhov loj dua qhov shrinkage; qhov siab dua qhov ambient kub thiab cement kub. Qhov loj dua qhov shrinkage, lub Hoobkas cement nrog kub siab yuav tsum tau zam kom siv ncaj qha rau hauv kev tsim vaj tsev, thiab cov cement yuav tsum tau txias ua ntej siv.
11) qhov loj dua qhov sib piv, qhov me me ntawm qhov shrinkage, thiab loj heev (coarse) reinforcement yuav ua rau lub tensile kev nyuaj siab ntawm cov pob zeb: lub reinforcement yuav tsum nyias thiab ntom, tsis tuab thiab nyias. Them mloog mus ntxiv dag zog rau cov qauv kev txhawb nqa nyob rau hauv lub shrinkage stress concentration cheeb tsam, thiab ntxiv dag zog rau lub non-prestressed reinforcement nyob rau hauv lub prestressed qauv.
12) Qhov cua nrawm dua, qhov ntau dua qhov shrinkage. Ua tib zoo saib rau qhov siab-siab cam khwb cia-hauv-qhov chaw pob zeb. Tsis txhob tso lub hnub ci ncaj qha rau ntawm qhov chaw tshiab uas tau nchuav rau hauv cov cua qhuav thiab lub caij kub, uas yog, kom tsis txhob poob dej sai hauv cov pob zeb: lub formwork yuav tsum tau ntim nruj nreem kom tsis txhob muaj dej to (cement slurry), thiab cov formwork yuav tsum tau drenched. .
13) Kev xaiv tsis raug ntawm cov khoom siv sib xyaw thiab cov khoom sib xyaw ua ke yuav ua rau kom muaj kev sib tw. Xaiv qhov tsim nyog los txo qhov shrinkage, tshwj xeeb tshaj yog thaum sawv ntxov shrinkage.
14) Qhov siab dua qhov chaw thiab qhov kub thiab txias, qhov shrinkage ntau dua, thiab lub sij hawm raug kaw ntev dua, qhov shrinkage ntau dua.
15) Lub Shrinkage thiab ib puag ncig txias tshwm sim nyob rau tib lub sijhawm, tshwj xeeb tshaj yog qhov kub thiab txias thiab kub hloov pauv, thiab cua tsis zoo rau qhov project.
16) Rov qab cov av kom sai li sai tau, cov av yog qhov zoo tshaj plaws kho nruab nrab rau pob zeb. Kaw thiab pleev xim lub tsev thaum ntxov yog qhov zoo rau kev txo qis.
17) Qhov ntau dua los ntshav, qhov siab dua cov ntsiab lus ntawm cov dej ntawm cov pob zeb. Ua kom lub ntsej muag thaum ntxov: Txawm li cas los xij, lub cev qhuav dej thaum ntxov ntawm cov pob zeb yuav tsum raug zam kom ua kom lub ntsws loj dua, vim tias qhov me me ntawm cov ntshav thiab txhim kho cov dej ntub dej kom zoo kom txo tau cov kab nrib pleb hauv pob zeb.
18) Qib nruab nrab thiab qis-zog qib cement nrog me me. Cov pob zeb uas tsis tshua muaj dej-cement piv (tsawg dua cov dej sib tov yog xav tau) thiab cov slump me me yuav siv li ib xyoos los ua kom tiav feem ntau ntawm cov shrinkage; tus nqi ntawm cov cement yog qhov loj. Cov av tshauv kuj loj thiab cov slump loj. Lub sijhawm ua tiav ntawm feem ntau ntawm cov shrinkage ntawm pob zeb nrog qib siab zog yog li 2 xyoos; qhov kawg shrinkage lub sij hawm ntawm pob zeb yog hais txog 20 xyoo. Lub shrinkage qeeb ntawm cov pob zeb yuav tsis tsim cov kab nrib pleb loj, tab sis cov kab nrib pleb thaum ntxov tshwm sim los ntawm kev tsim kho thiab kev saib xyuas yuav tsum raug zam (lub sijhawm no, lub pob zeb tsis tuaj yeem tiv taus qhov kev ntxhov siab shrinkage). Kev kho thiab kho me ntsis shrinkage tawg tsis yog "kev raug mob zoo".
