Dab tsi yog Pob Zeb Slump
Apr 29, 2024
Qhov poob ntawm cov pob zeb feem ntau yog hais txog plasticity thiab pumpability ntawm cov pob zeb. Cov yam ntxwv cuam tshuam rau qhov poob ntawm cov pob zeb feem ntau suav nrog kev hloov pauv hauv kev muab qhab nia, cov ntsiab lus dej, ntsuas qhov sib txawv ntawm cov nplai, thiab cov khoom siv ntxiv. Feem ntau overlooked yam tseem muaj xws li qhov kub thiab txias ntawm cov cement. Slump yog ib qho qhia txog kev ua haujlwm ntawm cov pob zeb, uas tshwj xeeb ua kom muaj kev txhim kho ntawm kev tsim kho. Qhov no suav nrog kev tuav dej, fluidity, thiab cohesiveness ntawm cov pob zeb.
Kev ua haujlwm tau hais txog seb lub pob zeb puas yooj yim los lis thiab ua tiav kev sib sau ua ke, suav nrog kev ua haujlwm zoo suav nrog kev ua kom dej, cohesiveness, thiab tuav dej. Cov yam ntxwv cuam tshuam rau kev ua haujlwm feem ntau suav nrog cov dej siv, dej-rau-cement piv, cov ntsiab lus ntawm cov xuab zeb, thiab cov khoom xws li cov cement hom, aggregate condition, time, temperature, thiab additives.
Lub slump ntawm cov pob zeb yuav tsum tau txiav txim siab raws li cov txheej txheem hla ntu ntawm lub tsev, cov ntsiab lus rebar, kev thauj mus los deb, txoj kev pouring, hom kev thauj mus los, muaj peev xwm compaction, thiab huab cua puag. Thaum xaiv qhov sib xyaw ua ke, cov yam ntxwv no yuav tsum tau txiav txim siab zoo, thiab feem ntau yuav tsum tau siv me me.
Txoj Kev Xeem
Slump Test Method:Cov txheej txheem no siv lub khob ntim nrog lub taub sab saum toj ntawm 100mm, hauv qab txoj kab uas hla ntawm 200mm, thiab qhov siab ntawm 300mm. Lub pob zeb yog nchuav rau hauv lub khob hliav qab hauv peb txheej, nrog rau txhua txheej compacted los ntawm uniformly tawm tsam sab nraud ntawm lub khob hliav qab 25 zaug nrog ib tug tamper. Tom qab compaction, nto yog leveled. Lub khob hliav qab yog lifted, thiab vim nws qhov hnyav, lub pob zeb yuav slump. Qhov kev poob qis yog ntsuas raws li qhov sib txawv ntawm qhov siab ntawm lub khob hliav qab (300mm) thiab qhov siab tshaj plaws ntawm cov pob zeb tawg. Piv txwv li, yog tias qhov sib txawv yog 100 hli, qhov poob qis yog 100 hli.
Slump Classification
| Qib | Lub npe | Qhov siab (mm) |
|---|---|---|
| T1 | Tsawg Plasticity Qhob | 10-40 |
| T2 | Yas Pob Zeb | 50-90 |
| T3 | Cov kua nplaum | 100-150 |
| T4 | Cov kua nplaum ua kua | Ntau tshaj los yog sib npaug rau 160 |
Slump Spread MethodTxoj kev no yog tsim rau cov pob zeb sib xyaw uas qhov siab tshaj plaws sib sau ua ke tsis tshaj 40 mm thiab qhov poob qis tsis tsawg dua 10 mm. Nws yog siv los txiav txim qhov sib xws ntawm cov pob zeb sib xyaw.
Tam sim no, tsis muaj txoj hauv kev uas qhia txog kev ua haujlwm ntawm cov pob zeb sib tov. Hauv cov chaw tsim kho thiab hauv chaw kuaj mob, qhov kev ntsuas slump feem ntau yog ua los ntsuas qhov fluidity ntawm qhov sib tov, ntxiv los ntawm kev pom kev los ntsuas kev cohesiveness thiab tuav dej.
Cov txheej txheem rau kev ntsuas qhov poob qis suav nrog sau lub khob ntim nrog cov pob zeb sib xyaw, ua kom nws tawm, thiab tom qab ntawd nqa lub khob hliav qab mus rau sab saud thiab txav mus rau sab. Vim lub ntiajteb txawj nqus, lub pob zeb sib tov yuav slump. Qhov ntsuas ntawm qhov kev poob qis (hauv mm) ua haujlwm raws li qhov ntsuas ntawm fluidity-qhov loj dua qhov poob, qhov zoo dua qhov fluidity.
Thaum lub slump tshaj 220 hli, nws tsis yog qhia meej txog qhov fluidity ntawm cov pob zeb. Nyob rau hauv cov ntaub ntawv no, qhov nruab nrab txoj kab uas hla ntawm cov pob zeb sib kis, hu ua slump kis, yog siv los ua ib qho kev qhia ntawm fluidity.
Thaum lub sij hawm slump test, lub cohesiveness thiab dej tuav ntawm cov pob zeb sib tov yuav tsum tau soj ntsuam xyuas kom meej nws workability.
Kev Ntsuam Xyuas Cohesiveness:Qhov no yog soj ntsuam los ntawm maj mam tapping rau sab ntawm lub pob zeb tawg lub khob hliav qab nrog ib tug pas nrig. Yog hais tias lub khob hliav qab maj mam poob, nws qhia tau hais tias zoo cohesiveness. Yog hais tias lub khob hliav qab, ib feem crumbles, los yog cais, nws qhia tias tsis zoo cohesiveness.
Kev ntsuas dej ruaj khov:Qhov no yog ntsuas los ntawm qib ntawm dilute cement paste uas cais tawm ntawm cov pob zeb sib xyaw. Tom qab lifting lub slump cone, yog hais tias ib tug loj npaum li cas ntawm dilute cement paste cais los ntawm lub hauv qab thiab cov pob zeb sib tov poob paste exposing lub aggregate, nws qhia tau hais tias cov dej tsis zoo. Yog tias tsis muaj lossis tsuas yog ib qho me me ntawm cov cement paste cais tawm hauv qab tom qab nqa lub khob hliav qab, nws qhia tau tias dej tuav tau zoo ntawm cov pob zeb sib xyaw.