1. Qhov tsim nyog ntawm kev khaws dej
Txhua hom pob zeb uas xav tau cov tshuaj mortar rau kev tsim kho muaj qee qib ntawm kev nqus dej. Tom qab txheej hauv paus nqus cov dej hauv cov tshuaj mortar, qhov kev tsim kho ntawm cov tshuaj mortar yuav tsis zoo, thiab thaum muaj xwm txheej hnyav, cov khoom siv cementitious hauv cov tshuaj mortar yuav tsis tau hydrated tag nrho, ua rau lub zog qis, tshwj xeeb tshaj yog lub zog sib txuas ntawm cov tshuaj mortar tawv thiab txheej hauv paus, ua rau cov tshuaj mortar tawg thiab poob tawm. Yog tias cov tshuaj plastering muaj kev ua tau zoo ntawm kev khaws dej, nws tsis tsuas yog tuaj yeem txhim kho kev ua tau zoo ntawm cov tshuaj mortar, tab sis kuj ua rau cov dej hauv cov tshuaj mortar nyuaj rau nqus los ntawm txheej hauv paus thiab xyuas kom meej tias cov cement txaus hydrated.
2. Teeb meem nrog cov txheej txheem khaws dej ib txwm muaj
Cov kev daws teeb meem ib txwm yog kom dej rau hauv lub hauv paus, tab sis nws tsis yooj yim sua kom paub tseeb tias lub hauv paus tau ntub dej sib npaug. Lub hom phiaj zoo tshaj plaws ntawm cov cement mortar ntawm lub hauv paus yog tias cov khoom cement hydration nqus dej nrog rau lub hauv paus, nkag mus rau hauv lub hauv paus, thiab tsim ib qho "kev sib txuas tseem ceeb" nrog lub hauv paus, kom ua tiav lub zog sib txuas uas xav tau. Kev ywg dej ncaj qha rau ntawm qhov chaw ntawm lub hauv paus yuav ua rau muaj kev sib kis loj hauv kev nqus dej ntawm lub hauv paus vim qhov sib txawv ntawm qhov kub thiab txias, lub sijhawm ywg dej, thiab kev sib npaug ntawm kev ywg dej. Lub hauv paus muaj kev nqus dej tsawg dua thiab yuav txuas ntxiv nqus cov dej hauv cov mortar. Ua ntej cov cement hydration txuas ntxiv mus, cov dej raug nqus, uas cuam tshuam rau cov cement hydration thiab kev nkag mus ntawm cov khoom hydration rau hauv matrix; lub hauv paus muaj kev nqus dej loj, thiab cov dej hauv cov mortar ntws mus rau lub hauv paus. Qhov ceev nruab nrab yog qeeb, thiab txawm tias ib txheej nplua nuj dej tau tsim ntawm cov mortar thiab matrix, uas kuj cuam tshuam rau lub zog sib txuas. Yog li ntawd, kev siv txoj kev ywg dej rau hauv paus tsis yog tsuas yog daws tau qhov teeb meem ntawm kev nqus dej ntau ntawm lub hauv paus phab ntsa xwb, tab sis yuav cuam tshuam rau lub zog sib txuas ntawm cov mortar thiab lub hauv paus, ua rau muaj qhov thiab tawg.
3. Cov kev cai ntawm cov mortars sib txawv rau kev khaws dej
Cov hom phiaj ntawm kev khaws dej rau cov khoom siv plastering mortar siv rau hauv ib cheeb tsam thiab hauv cov cheeb tsam uas muaj qhov kub thiab txias zoo sib xws tau muab tso rau hauv qab no.
① Cov dej nqus dej siab heev rau cov khoom siv plastering mortar
Cov khoom siv uas nqus dej tau zoo uas muaj cov pob zeb ua los ntawm huab cua, suav nrog ntau yam khoom siv sib cais, cov blocks, thiab lwm yam, muaj cov yam ntxwv ntawm kev nqus dej tau zoo thiab siv tau ntev. Cov plastering mortar siv rau hom txheej txheem no yuav tsum muaj tus nqi khaws dej tsis pub tsawg dua 88%.
② Cov dej nqus dej tsawg tsawg
Cov khoom siv uas nqus dej tsawg uas yog cov pob zeb ua vaj tse uas raug pov rau hauv qhov chaw, suav nrog cov ntoo polystyrene rau kev rwb thaiv tsev sab nraud, thiab lwm yam, muaj kev nqus dej tsawg heev. Cov tshuaj pleev plastering uas siv rau cov khoom siv no yuav tsum muaj tus nqi khaws dej tsis pub tsawg dua 88%.
③Cov tshuaj nplaum nyias nyias
Kev pleev xim nyias nyias yog hais txog kev siv pleev xim nrog cov txheej pleev xim tuab ntawm 3 txog 8 hli. Hom kev pleev xim no yooj yim poob dej vim yog cov txheej pleev xim nyias nyias, uas cuam tshuam rau kev ua haujlwm thiab lub zog. Rau cov mortar siv rau hom kev pleev xim no, nws cov dej khaws cia tsis tsawg dua 99%.
④Cov tshuaj nplaum tuab tuab
Kev pleev xim tuab yog hais txog kev siv pleev xim uas qhov tuab ntawm ib txheej pleev xim yog ntawm 8 hli thiab 20 hli. Hom kev pleev xim no tsis yooj yim poob dej vim yog txheej pleev xim tuab, yog li tus nqi khaws dej ntawm cov tshuaj pleev xim yuav tsum tsis pub tsawg dua 88%.
⑤Cov dej tsis haum
Cov putty uas tiv taus dej yog siv ua cov khoom siv plastering nyias heev, thiab qhov tuab ntawm kev tsim kho yog ntawm 1 thiab 2 hli. Cov ntaub ntawv no xav tau cov khoom khaws dej siab heev kom ntseeg tau tias lawv ua haujlwm tau zoo thiab muaj zog sib txuas. Rau cov ntaub ntawv putty, nws tus nqi khaws dej yuav tsum tsis pub tsawg dua 99%, thiab tus nqi khaws dej ntawm putty rau phab ntsa sab nraud yuav tsum siab dua li ntawm putty rau phab ntsa sab hauv.
4. Hom khoom siv uas khaws dej tau
Cellulose ether
1) Methyl cellulose ether (MC)
2) Hydroxypropyl Methyl Cellulose Ether (HPMC)
3) Hydroxyethyl cellulose ether (HEC)
4) Carboxymethyl cellulose ether (CMC)
5) Hydroxyethyl Methyl Cellulose Ether (HEMC)
Hmoov txhuv nplej siab ether
1) Cov hmoov txhuv nplej hloov kho
2) Guar ether
Cov khoom siv ua kom cov dej ntxhia uas tau hloov kho kom ruaj khov (montmorillonite, bentonite, thiab lwm yam)
Tsib, cov hauv qab no tsom mus rau kev ua tau zoo ntawm ntau yam ntaub ntawv
1. Cellulose ether
1.1 Kev Txheeb Xyuas Txog Cellulose Ether
Cellulose ether yog ib lo lus dav dav rau cov khoom tsim los ntawm cov tshuaj tiv thaiv ntawm alkali cellulose thiab tus neeg sawv cev etherification nyob rau hauv qee qhov xwm txheej. Cov cellulose ethers sib txawv tau txais vim tias alkali fiber hloov los ntawm cov neeg sawv cev etherification sib txawv. Raws li cov khoom ionization ntawm nws cov substituents, cellulose ethers tuaj yeem faib ua ob pawg: ionic, xws li carboxymethyl cellulose (CMC), thiab nonionic, xws li methyl cellulose (MC).
Raws li cov hom substituents, cellulose ethers tuaj yeem muab faib ua monoethers, xws li methyl cellulose ether (MC), thiab cov ethers sib xyaw, xws li hydroxyethyl carboxymethyl cellulose ether (HECMC). Raws li cov kuab tshuaj sib txawv uas nws yaj, nws tuaj yeem muab faib ua ob hom: dej-soluble thiab organic solvent-soluble.
1.2 Cov hom cellulose tseem ceeb
Carboxymethylcellulose (CMC), qib kev hloov pauv: 0.4-1.4; tus neeg sawv cev etherification, monooxyacetic acid; cov kuab tshuaj yaj, dej;
Carboxymethyl hydroxyethyl cellulose (CMHEC), qib kev hloov pauv: 0.7-1.0; tus neeg sawv cev etherification, monooxyacetic acid, ethylene oxide; cov kuab tshuaj yaj, dej;
Methylcellulose (MC), qib kev hloov pauv: 1.5-2.4; tus neeg sawv cev etherification, methyl chloride; cov kuab tshuaj yaj, dej;
Hydroxyethyl cellulose (HEC), qib kev hloov pauv: 1.3-3.0; tus neeg sawv cev etherification, ethylene oxide; cov kuab tshuaj yaj, dej;
Hydroxyethyl methylcellulose (HEMC), qib kev hloov pauv: 1.5-2.0; tus neeg sawv cev etherification, ethylene oxide, methyl chloride; cov kuab tshuaj yaj, dej;
Hydroxypropyl cellulose (HPC), qib kev hloov pauv: 2.5-3.5; tus neeg sawv cev etherification, propylene oxide; cov kuab tshuaj yaj, dej;
Hydroxypropyl methylcellulose (HPMC), qib kev hloov pauv: 1.5-2.0; tus neeg sawv cev etherification, propylene oxide, methyl chloride; cov kuab tshuaj yaj, dej;
Ethyl cellulose (EC), qib kev hloov pauv: 2.3-2.6; tus neeg sawv cev etherification, monochloroethane; cov kuab tshuaj yaj, cov kuab tshuaj organic;
Ethyl hydroxyethyl cellulose (EHEC), qib kev hloov pauv: 2.4-2.8; tus neeg sawv cev etherification, monochloroethane, ethylene oxide; cov kuab tshuaj yaj, cov kuab tshuaj organic;
1.3 Cov khoom ntawm cellulose
1.3.1 Methyl cellulose ether (MC)
①Methylcellulose yaj tau hauv dej txias, thiab nws yuav nyuaj rau yaj hauv dej kub. Nws cov kua dej ruaj khov heev hauv PH = 3-12. Nws muaj kev sib raug zoo nrog cov hmoov txhuv nplej siab, cov roj hmab guar, thiab lwm yam thiab ntau yam surfactants. Thaum qhov kub ncav cuag qhov kub gelation, gelation tshwm sim.
② Qhov kev khaws dej ntawm methylcellulose nyob ntawm nws qhov ntxiv ntau npaum li cas, viscosity, qhov zoo ntawm cov khoom me me thiab qhov nrawm ntawm kev yaj. Feem ntau, yog tias qhov ntxiv ntau npaum li cas, qhov zoo me me, thiab qhov viscosity loj, qhov khaws dej siab. Ntawm lawv, qhov ntau npaum li cas ntawm kev ntxiv muaj qhov cuam tshuam loj tshaj plaws rau kev khaws dej, thiab qhov viscosity qis tshaj plaws tsis ncaj qha rau qib kev khaws dej. Qhov nrawm ntawm kev yaj feem ntau nyob ntawm qib kev hloov pauv ntawm qhov chaw ntawm cov khoom me me cellulose thiab qhov zoo ntawm cov khoom me me. Ntawm cov cellulose ethers, methyl cellulose muaj qhov nrawm ntawm kev khaws dej siab dua.
③Qhov kev hloov pauv ntawm qhov kub thiab txias yuav cuam tshuam loj heev rau qhov ceev ntawm methyl cellulose khaws dej. Feem ntau, qhov kub siab dua, qhov kev khaws dej phem dua. Yog tias qhov kub ntawm lub mortar tshaj 40 ° C, qhov kev khaws dej ntawm methyl cellulose yuav tsis zoo heev, uas yuav cuam tshuam loj heev rau kev tsim kho ntawm lub mortar.
④ Methyl cellulose muaj feem cuam tshuam loj heev rau kev tsim kho thiab kev nplaum ntawm cov mortar. Qhov "kev nplaum" ntawm no yog hais txog lub zog nplaum uas hnov ntawm tus neeg ua haujlwm lub cuab yeej thov thiab phab ntsa substrate, uas yog, qhov kev tiv thaiv shear ntawm cov mortar. Qhov kev nplaum yog siab, qhov kev tiv thaiv shear ntawm cov mortar yog loj, thiab cov neeg ua haujlwm xav tau ntau lub zog thaum siv, thiab kev ua haujlwm ntawm cov mortar ua tsis zoo. Methyl cellulose adhesion yog nyob rau theem nruab nrab hauv cov khoom cellulose ether.
1.3.2 Hydroxypropyl Methyl Cellulose Ether (HPMC)
Hydroxypropyl methylcellulose yog cov khoom siv fiber uas nws cov zis thiab kev noj haus tau nce sai sai hauv xyoo tas los no.
Nws yog cov cellulose sib xyaw ether uas tsis yog ionic ua los ntawm paj rwb zoo tom qab alkalization, siv propylene oxide thiab methyl chloride ua cov neeg sawv cev etherification, thiab los ntawm ntau yam kev tshuaj tiv thaiv. Qib ntawm kev hloov pauv feem ntau yog 1.5-2.0. Nws cov khoom sib txawv vim yog qhov sib txawv ntawm cov ntsiab lus methoxyl thiab cov ntsiab lus hydroxypropyl. Cov ntsiab lus methoxyl siab thiab cov ntsiab lus hydroxypropyl qis, qhov kev ua tau zoo ze rau methyl cellulose; cov ntsiab lus methoxyl qis thiab cov ntsiab lus hydroxypropyl siab, qhov kev ua tau zoo ze rau hydroxypropyl cellulose.
①Hydroxypropyl methylcellulose yooj yim yaj hauv dej txias, thiab nws yuav nyuaj rau yaj hauv dej kub. Tab sis nws qhov kub gelation hauv dej kub siab dua li ntawm methyl cellulose. Qhov solubility hauv dej txias kuj zoo dua piv rau methyl cellulose.
② Qhov viscosity ntawm hydroxypropyl methylcellulose muaj feem cuam tshuam nrog nws qhov hnyav molecular, thiab qhov siab dua qhov hnyav molecular, qhov siab dua qhov viscosity. Kub kuj cuam tshuam rau nws qhov viscosity, thaum kub nce, viscosity txo qis. Tab sis nws qhov viscosity tsis cuam tshuam los ntawm kub dua li methyl cellulose. Nws cov kua ruaj khov thaum khaws cia rau hauv chav sov.
③Qhov dej khaws cia ntawm hydroxypropyl methylcellulose nyob ntawm nws qhov ntxiv, viscosity, thiab lwm yam, thiab nws qhov dej khaws cia tus nqi nyob rau hauv tib qho ntxiv yog siab dua li ntawm methyl cellulose.
④Hydroxypropyl methylcellulose ruaj khov rau cov kua qaub thiab alkali, thiab nws cov kua dej ruaj khov heev hauv PH = 2-12. Caustic soda thiab dej txiv qaub tsis muaj feem cuam tshuam rau nws cov kev ua tau zoo, tab sis alkali tuaj yeem ua kom nws cov yaj sai dua thiab ua rau nws cov viscosity me ntsis. Hydroxypropyl methylcellulose ruaj khov rau cov ntsev feem ntau, tab sis thaum cov ntsev concentration siab, cov viscosity ntawm hydroxypropyl methylcellulose kua feem ntau nce.
⑤Hydroxypropyl methylcellulose tuaj yeem sib xyaw nrog cov polymers uas yaj tau hauv dej los ua cov tshuaj sib xws thiab pob tshab nrog viscosity siab dua. Xws li polyvinyl cawv, hmoov txhuv nplej siab ether, zaub gum, thiab lwm yam.
⑥ Hydroxypropyl methylcellulose muaj kev tiv thaiv enzyme zoo dua li methylcellulose, thiab nws cov kua tsis tshua muaj peev xwm raug rhuav tshem los ntawm cov enzymes dua li methylcellulose.
⑦Qhov kev nplaum ntawm hydroxypropyl methylcellulose rau kev tsim kho mortar siab dua li ntawm methylcellulose.
1.3.3 Hydroxyethyl cellulose ether (HEC)
Nws yog ua los ntawm paj rwb zoo, kho nrog alkali, thiab reacted nrog ethylene oxide ua tus neeg sawv cev etherification nyob rau hauv lub xub ntiag ntawm acetone. Qib ntawm kev hloov pauv feem ntau yog 1.5-2.0. Nws muaj hydrophilicity muaj zog thiab yooj yim rau nqus dej noo.
①Hydroxyethyl cellulose yaj tau hauv dej txias, tab sis nyuaj rau yaj hauv dej kub. Nws cov kua ruaj khov ntawm qhov kub siab tsis muaj gelling. Nws tuaj yeem siv tau ntev hauv qhov kub siab hauv mortar, tab sis nws cov dej khaws cia qis dua li ntawm methyl cellulose.
②Hydroxyethyl cellulose ruaj khov rau cov kua qaub thiab alkali. Alkali tuaj yeem ua kom nws cov yaj sai dua thiab ua rau nws cov viscosity me ntsis. Nws cov dispersibility hauv dej yog qhov phem dua li ntawm methyl cellulose thiab hydroxypropyl methyl cellulose.
③Hydroxyethyl cellulose muaj kev ua tau zoo tiv thaiv kev qaug zog rau cov mortar, tab sis nws muaj lub sijhawm ntev dua rau cov cement.
④Kev ua tau zoo ntawm hydroxyethyl cellulose uas tsim los ntawm qee lub tuam txhab hauv tsev yog qhov qis dua li ntawm methyl cellulose vim nws cov dej ntau thiab cov tshauv ntau.
1.3.4 Carboxymethyl cellulose ether (CMC) yog ua los ntawm cov fiber ntuj (paj rwb, hemp, thiab lwm yam) tom qab kev kho alkali, siv sodium monochloroacetate ua tus neeg sawv cev etherification, thiab dhau los ntawm ntau yam kev kho mob tshuaj tiv thaiv los ua ionic cellulose ether. Qhov degree ntawm kev hloov pauv feem ntau yog 0.4-1.4, thiab nws cov kev ua tau zoo cuam tshuam loj heev los ntawm qhov degree ntawm kev hloov pauv.
①Carboxymethyl cellulose yog hygroscopic heev, thiab nws yuav muaj dej ntau thaum khaws cia rau hauv cov xwm txheej dav dav.
②Hydroxymethyl cellulose aqueous solution yuav tsis tsim gel, thiab qhov viscosity yuav txo qis nrog rau qhov kub nce. Thaum qhov kub tshaj 50 ℃, qhov viscosity tsis rov qab tau.
③ Nws qhov kev ruaj khov raug cuam tshuam los ntawm pH. Feem ntau, nws tuaj yeem siv rau hauv gypsum-based mortar, tab sis tsis yog rau hauv cement-based mortar. Thaum alkaline heev, nws poob viscosity.
④ Nws cov dej khaws cia qis dua li ntawm methyl cellulose. Nws muaj cov nyhuv qeeb rau gypsum-based mortar thiab txo nws lub zog. Txawm li cas los xij, tus nqi ntawm carboxymethyl cellulose qis dua li ntawm methyl cellulose.
2. Cov hmoov txhuv nplej hloov kho
Cov hmoov txhuv nplej siab ethers feem ntau siv rau hauv cov mortars yog hloov kho los ntawm cov polymers ntuj ntawm qee cov polysaccharides. Xws li qos yaj ywm, pob kws, cassava, taum guar, thiab lwm yam yog hloov kho rau hauv ntau yam hloov kho hmoov txhuv nplej siab ethers. Cov hmoov txhuv nplej siab ethers feem ntau siv rau hauv mortar yog hydroxypropyl hmoov txhuv nplej siab ether, hydroxymethyl hmoov txhuv nplej siab ether, thiab lwm yam.
Feem ntau, cov hmoov txhuv nplej siab hloov kho los ntawm qos yaj ywm, pob kws, thiab cassava muaj cov dej khaws cia qis dua li cov cellulose ethers. Vim nws qhov sib txawv ntawm kev hloov kho, nws qhia txog kev ruaj khov sib txawv rau cov kua qaub thiab alkali. Qee cov khoom tsim nyog rau kev siv hauv gypsum-based mortars, thaum lwm tus tsis tuaj yeem siv rau hauv cement-based mortars. Kev siv cov hmoov txhuv nplej siab ether hauv mortar feem ntau yog siv ua cov khoom tuab kom txhim kho cov khoom tiv thaiv kev sagging ntawm mortar, txo qhov kev nplaum ntawm cov mortar ntub, thiab ntev lub sijhawm qhib.
Cov hmoov txhuv nplej siab feem ntau siv ua ke nrog cellulose, ua rau muaj cov khoom sib txuas thiab qhov zoo ntawm ob yam khoom. Vim tias cov khoom hmoov txhuv nplej siab pheej yig dua li cellulose ether, kev siv cov hmoov txhuv nplej siab hauv cov tshuaj khib yuav ua rau tus nqi ntawm cov tshuaj khib txo qis.
3. Guar gum ether
Guar gum ether yog ib hom polysaccharide etherified nrog cov khoom tshwj xeeb, uas tau hloov kho los ntawm cov taum guar ntuj. Feem ntau los ntawm kev sib xyaw ua ke ntawm guar gum thiab acrylic functional groups, ib qho qauv uas muaj 2-hydroxypropyl functional groups tau tsim, uas yog cov qauv polygalactomannose.
①Piv nrog cellulose ether, guar gum ether yooj yim dua rau yaj hauv dej. PH yeej tsis muaj kev cuam tshuam rau kev ua haujlwm ntawm guar gum ether.
②Raws li cov xwm txheej ntawm viscosity qis thiab cov koob tshuaj tsawg, guar gum tuaj yeem hloov cellulose ether hauv qhov sib npaug, thiab muaj cov dej khaws cia zoo sib xws. Tab sis qhov sib xws, tiv thaiv kev qaug zog, thixotropy thiab lwm yam tau pom tseeb zoo dua.
③Nyob rau hauv cov xwm txheej ntawm viscosity siab thiab ntau koob tshuaj, guar gum tsis tuaj yeem hloov cellulose ether, thiab kev siv sib xyaw ntawm ob qho yuav ua rau muaj kev ua tau zoo dua.
④ Kev siv cov roj hmab guar hauv cov gypsum-based mortar tuaj yeem txo qhov kev nplaum thaum lub sijhawm tsim kho thiab ua rau kev tsim kho du. Nws tsis muaj kev cuam tshuam tsis zoo rau lub sijhawm teeb tsa thiab lub zog ntawm gypsum mortar.
⑤ Thaum siv cov roj hmab guar rau cov cement-based masonry thiab plastering mortar, nws tuaj yeem hloov cellulose ether hauv qhov sib npaug, thiab ua rau cov mortar muaj kev tiv thaiv sagging zoo dua, thixotropy thiab du ntawm kev tsim kho.
⑥Hauv cov mortar uas muaj viscosity siab thiab cov ntsiab lus siab ntawm cov neeg sawv cev khaws dej, guar gum thiab cellulose ether yuav ua haujlwm ua ke kom ua tiav cov txiaj ntsig zoo heev.
⑦ Guar gum kuj tseem siv tau rau hauv cov khoom xws li cov nplaum rau pobzeb, cov tshuaj pleev av uas ua rau nws tus kheej sib npaug, cov putty uas tiv taus dej, thiab cov polymer mortar rau kev rwb thaiv tsev phab ntsa.
4. Cov khoom siv ua kom cov dej ntxhia uas tau hloov kho tshiab
Cov tshuaj ua kom dej noo uas ua los ntawm cov zaub mov ntuj tsim los ntawm kev hloov kho thiab sib xyaw tau siv rau hauv Suav teb. Cov zaub mov tseem ceeb uas siv los ua cov tshuaj ua kom dej noo yog: sepiolite, bentonite, montmorillonite, kaolin, thiab lwm yam. Cov zaub mov no muaj qee yam khoom ua kom dej noo thiab ua kom tuab los ntawm kev hloov kho xws li cov neeg sawv cev sib txuas. Hom tshuaj ua kom dej noo no siv rau hauv cov pob zeb muaj cov yam ntxwv hauv qab no.
① Nws tuaj yeem txhim kho qhov kev ua tau zoo ntawm cov mortar ib txwm muaj, thiab daws cov teeb meem ntawm kev ua haujlwm tsis zoo ntawm cov cement mortar, lub zog qis ntawm cov mortar sib xyaw, thiab kev tiv thaiv dej tsis zoo.
② Cov khoom siv mortar nrog ntau qib zog rau cov tsev lag luam dav dav thiab pej xeem tuaj yeem tsim tau.
③Tus nqi khoom siv qis.
④ Qhov kev khaws cia dej qis dua li ntawm cov neeg sawv cev khaws cia dej organic, thiab tus nqi qhuav ntawm cov mortar npaj tau loj heev, thiab qhov sib koom ua ke txo qis.
Lub sijhawm tshaj tawm: Lub Peb Hlis-03-2023