1. Vim li cas PP Hollow Formwork tsis xav tau tus neeg sawv cev tso tawm
Ntoo formwork yuav tsum tau coated nrog tso tawm neeg sawv cev vim ntoo nto muaj capillary pores. Cov cement slurry los ntawm cov pob zeb nkag mus rau cov pores thiab cov ntaub ntawv "txhim kho kev sib tshuam." Yog tsis muaj tus neeg sawv cev tso tawm, lub formwork sticks khov kho thiab tsis tuaj yeem raug tshem tawm.
Nyob rau hauv sib piv, nto ntawm PP hollow yas formwork yog ib tug du, ntom, tsis yog -polar polymer qauv, tsim ib tug natural "chemical cais txheej" ntawm formwork thiab pob zeb:
Tsis tshua muaj zog saum npoo: Lub zog saum npoo ntawm cov khoom siv PP yog kwv yees li 30mN / m, qis dua li ntawm cov pob zeb slurry (kwv yees li 70mN / m). Cov cement slurry tsis tuaj yeem ntub lossis nkag mus rau saum npoo, zoo li cov dej ntws tawm ntawm nplooj nplooj. Qhob tsuas tsis tuaj yeem "suav" lub formwork nto.
Chemical Inertness: PP yog saturated hydrocarbon compound uas tsis chemically hnov mob nrog alkaline tshuaj hauv pob zeb xws li calcium hydroxide thiab silicates. Tsis muaj "chemical bonding."
Tsis muaj Capillary Pores: Cov yas saum npoo tsis muaj cov qauv microporous pom hauv cov ntoo, yog li cov cement slurry tsis tuaj yeem embed nws tus kheej los tsim cov khoom siv sib cuam tshuam.
Xaus: Thov tso tawm tus neeg sawv cev tsis yog qhov tsim nyog xwb tab sis yuav ua rau lub ntsej muag du ntawm PP, ua rau nws yooj yim dua rau kev siv tom ntej.
2. Yog vim li cas nws thiaj "Tswj Detach"
Qhov no siv lub hauv paus ntsiab lus ntawm thermal expansion coefficient sib txawv:
Thermal Expansion Coefficient ntawm PP: Kwv yees li 100-150 × 10⁻⁶ / degree
Thermal Expansion Coefficient of Concrete: Kwv yees li 10-14 × 10⁻⁶ / degree
Qhov sib txawv ntawm ob yog ze li ntawm 10 npaug. Thaum pouring, pob zeb hydration tso cua sov thiab kub nce. PP formwork nthuav dav ntau dua li cov pob zeb, tsim kom muaj qhov sib txawv me me ntawm lawv. Thaum lub sij hawm tom qab kho, raws li qhov kub thiab txias, PP cog lus ntau dua, ntxiv qhov sib txawv.
Qhov tshwm sim: Ib qho ntuj "sib cais" cov ntaub ntawv ntawm cov formwork thiab pob zeb. Lub formwork tuaj yeem raug tshem tawm tag nrho yam tsis muaj hammering lossis tsuas yog siv lub teeb kais. Lub sij hawm demolding yam tsawg kawg nkaus tsuas yog 1/4 ntawm qhov uas yuav tsum tau rau cov ntoo formwork.
