Plaster - ib tug pov thawj cov ntaub ntawv uas rau centuries

Heev feem ntau, nyob rau hauv ntau yam finishing ua hauj lwm siv ib cov khoom xws li gypsum plaster. Txawm cov neeg uas nyob deb ntawm cov kho thiab tsim, paub lub npe. Rau ntau centuries, nws yog tus zoo tagnrho cov ntaub ntawv uas rau lub reconstruction thiab kho vaj tse.

Heev finely av gypsum plaster tsis tsim ib tug sib txawv ntawm cov tshiab thiab cov laus txheej phab ntsa thiab ceilings. Nws muaj ib tug zoo qauv thiab nws tsis keej. Ua hauj lwm nrog plaster pib los ntawm nws cov nws nrog dej. Nrog zoo sib xws ntawm cov khoom txig nyob rau tej kab nrib pleb thiab yuav siv sij hawm rau hauv daim ntawv ntawm txawm me me kom paub meej.

Plaster muaj ib tug ntxeem tau qauv, yog li ntawd tag nrho cov txee kho nrog no cov ntaub ntawv uas, zoo peev xwm ntawm absorbing suab tsis, li no kom ntseeg tau suab rwb thaiv tsev ntawm lub chav tsev. Cov dawb xim ntawm cov khoom no yuav ua rau nws tau siv nws tsis muaj ntxiv uas tseg tau qhov twg tsim nyog zoo tagnrho dawb coatings.

Yuav ua li cas yog lub tuam tsev no cov ntaub ntawv uas? Ntuj gypsum, muaj ib tug crystalline qauv, yog kho nyob rau high school kub. Yog li muaj yog tsis ¾ ntawm cov dej muaj nyob rau ntawd, thiab hloov dua siab tshiab rau hauv mineral nws tus kheej hemihydrate uas, thaum tov nrog dej dua tau txais ib tug natural pob zeb qauv. Vim tsis muaj ntau tshaj li 1% ntawm cov gypsum ntxiv mus rau lwm yam organic khoom siv ntawm tej yam ntuj tso tshuaj, nws yog environmentally kev ruaj ntseg rau cov tib neeg thiab tej tsiaj txhu. Qhov no tsev ntaub ntawm refractories, yog li ntawd ib qho tseem ceeb luag hauj lwm nyob rau hauv kev tiv thaiv vaj tse los ntawm hluav taws. Nyob rau hauv tas li ntawd rau tag nrho cov zog, nws muaj peev xwm mus nqus tshaj noo noo nyob rau hauv qhov chaw zov thaum lub sij hawm nws raising thiab tej muab dej nyob rau hauv nws qib.

Gypsum ua ob peb ntau yam. Common siv cov khoom siv rau manufacturing gypsum vaj tse thiab gypsum khoom, plaster boards, panels thiab muab faib phiaj, gypsum-txiv qaub plaster daws teeb meem. High gypsum pwm yog ua los ntawm tshwj xeeb cov neeg kho tshuab kev txhim kho cov pa siv cov ntaub ntawv uas los ntawm subjecting nws mus rau ib tug ntxiv purification thiab milled. Vim hais tias nws ua rau cov stucco thiab lwm yam hniav cov khoom rau interiors thiab facades. Plaster sib cais los ntawm lub sij hawm uas nws curing: 2-15 feeb - ceev chaw; 6-30 feeb - qub chaw; ntau tshaj 20 feeb - qeeb-chaw.

Lub zog ntawm cov khoom no yog txiav txim los ntawm cov qhab nia, uas yog cov sib txawv nyob rau hauv nws compressive zog (F-2, 3, 4, 5, 6, 7, 15, 10, 19, 16, 22, 25). Gypsum hom G-10, 16, 15 yog tias tau txoj kev ua. Tej ntaub ntawv uas yog tshuam free ntawm impurities thiab ib tug siab zog.

Thaum ua hauj lwm nrog cov khoom no yuav tsum tau nco ntsoov hais tias hais tias nws sai sai freezes, li ntawd, tsis txhob cia li noj ib tug loj npaum li cas ntawm diluted plaster. Tus nqi ntawm cov dej yuav tsum tau tsim ib tug sib tov ntawm txwm taub hau, yog feem ntau 50-80% (rau kev tsim kho ua hauj lwm) thiab 35-45% rau cov creation ntawm ntau yam khoom. Ntev li dej yuav nyob twj ywm nyob rau hauv lub pores ntawm lub hardened cov ntaub ntawv uas, whereupon nws suab. Raws li ib tug tshwm sim, lub porosity ntawm plaster yuav kwv yees li 50-60%. Nws yog ib qho tseem ceeb yuav tau nco ntsoov hais tias cov dej tsawg siv rau dilution ntawm gypsum, lub denser yuav ua qhov kawg khoom los yog txheej, thiab lub ntau dua nws durability. Raising los yog tej lub kub heev muaj feem xyuam rau lub zog ntawm cov solidified khoom. Yuav kom nce lub dag lub zog ntawm gypsum plaster yog tej zaum ntxiv thereto txog 5% slaked txiv qaub.

Rau kev kho mob siv thiaj li hu ua polymer ua gypsum, uas yog yooj yim thov mus rau ib qho raug mob neeg mob lub cev los ntawm cov ntaub qhwv. Nws txig raws li cov nkhaus thiab muaj ib tug high elongation. Qhov no cov ntaub ntawv uas muaj high porosity, ces tus tib neeg daim tawv nqaij tseem ua pa dawb do, uas tiv thaiv qhov tshwm sim ntawm khaus. Tej zaum cov ntaub nplaum yog thov li ntawd cov neeg mob yuav tau ua ib co zog. Qhov no cov ntaub ntawv uas tsis cuam tshuam nrog kev kho mob cov txheej txheem thiab cov kev siv ntawm ib tug X-ray xeem.