1.1Kev cuam tshuam ntawm HPMC ntawm kev luam tawm ntawm 3D luam ntawv mortars
1.1.1Cov nyhuv ntawm HPMC ntawm extrudability ntawm 3D luam ntawv mortars
Cov pab pawg dawb huv M-H0 yam tsis muaj HPMC thiab cov pab pawg xeem nrog HPMC cov ntsiab lus ntawm 0.05%, 0.10%, 0.20%, thiab 0.30% raug tso cai sawv ntsug rau lub sijhawm sib txawv, thiab tom qab ntawd cov fluidity raug kuaj. Nws tuaj yeem pom tau tias kev koom ua ke ntawm HPMC Nws yuav txo qhov fluidity ntawm mortar; Thaum cov ntsiab lus ntawm HPMC maj mam nce los ntawm 0% mus rau 0.30%, qhov pib fluidity ntawm mortar txo los ntawm 243 hli mus rau 206, 191, 167, thiab 160 hli, raws li. HPMC yog lub siab molecular polymer. Lawv tuaj yeem cuam tshuam nrog ib leeg los tsim cov qauv kev sib txuas, thiab kev sib koom ua ke ntawm cov cement slurry tuaj yeem nce ntxiv los ntawm cov khoom siv encapsulating xws li Ca(OH) 2. Macroscopically, cohesiveness ntawm mortar yog txhim kho. Nrog rau ncua sij hawm sawv ntsug, qhov degree ntawm hydration ntawm mortar nce. nce, fluidity poob lub sij hawm. Lub fluidity ntawm pab pawg neeg dawb paug M-H0 yam tsis muaj HPMC poob sai. Hauv pawg kev sim nrog 0.05%, 0.10%, 0.20% thiab 0.30% HPMC, qib ntawm kev txo qis hauv fluidity poob nrog lub sijhawm, thiab cov kua dej ntawm cov tshuaj khib tom qab sawv rau 60 min yog 180, 177, 164, thiab 155 hli, raws li. . Fluidity yog 87.3%, 92.7%, 98.2%, 96.8%. Kev sib koom ua ke ntawm HPMC tuaj yeem txhim kho qhov muaj peev xwm khaws cia ntawm mortar fluidity, uas yog vim muaj kev sib xyaw ntawm HPMC thiab dej molecules; Ntawm qhov tod tes, HPMC tuaj yeem tsim cov yeeb yaj kiab zoo sib xws Nws muaj cov qauv sib txuas thiab qhwv cov cement, uas ua rau txo cov volatilization ntawm cov dej hauv mortar thiab muaj qee yam dej tuav kev ua haujlwm. Nws yog ib qho tsim nyog sau cia tias thaum cov ntsiab lus ntawm HPMC yog 0.20%, lub peev xwm khaws cia ntawm cov tshuaj mortar fluidity mus txog qib siab tshaj.
Lub fluidity ntawm 3D luam ntawv mortar tov nrog ntau npaum li cas ntawm HPMC yog 160 ~ 206 hli. Vim muaj qhov sib txawv ntawm lub tshuab luam ntawv tsis sib xws, qhov kev pom zoo ntawm fluidity tau los ntawm cov kws tshawb fawb sib txawv txawv, xws li 150 ~ 190 mm, 160 ~ 170 mm. Los ntawm daim duab 3, nws tuaj yeem pom qhov xav tau Nws tuaj yeem pom tias qhov fluidity ntawm 3D luam ntawv mortar tov nrog HPMC feem ntau nyob rau hauv qhov kev pom zoo, tshwj xeeb tshaj yog thaum HPMC cov ntsiab lus yog 0.20%, fluidity ntawm mortar hauv 60 feeb yog nyob rau hauv qhov pom zoo ntau yam, uas txaus siab rau qhov tsim nyog fluidity thiab stackability. Yog li ntawd, txawm hais tias lub fluidity ntawm mortar nrog ib tug haum npaum li cas ntawm HPMC raug txo, uas ua rau kom ib tug txo nyob rau hauv extrudability, nws tseem muaj zoo extrudability, uas yog nyob rau hauv qhov kev pom zoo.
1.1.2Cov nyhuv ntawm HPMC ntawm cov stackability ntawm 3D luam ntawv mortars
Nyob rau hauv cov ntaub ntawv ntawm tsis siv ib tug template, qhov luaj li cas ntawm cov duab tuav tus nqi nyob rau hauv nws tus kheej-yuag yog nyob ntawm qhov kev nyuaj siab ntawm cov khoom, uas yog muaj feem xyuam rau lub internal cohesion ntawm slurry thiab cov aggregate. Cov duab tuav ntawm 3D luam ntawv mortars nrog cov ntsiab lus HPMC sib txawv tau muab. Tus nqi hloov nrog lub sijhawm sawv. Tom qab ntxiv HPMC, cov duab tuav tus nqi ntawm mortar yog txhim kho, tshwj xeeb tshaj yog nyob rau theem pib thiab sawv rau 20 min. Txawm li cas los xij, nrog rau kev ncua sij hawm sawv ntsug, qhov kev txhim kho ntawm HPMC ntawm cov duab tuav tus nqi ntawm cov tshuaj khib nyiab maj mam tsis muaj zog, uas yog vim li cas tus nqi tuav tau nce ntau. Tom qab sawv ntsug rau 60 min, tsuas yog 0.20% thiab 0.30% HPMC tuaj yeem txhim kho cov duab tuav tus nqi ntawm mortar.
Cov txiaj ntsig kev nkag mus rau qhov kev ntsuas ntawm 3D luam ntawv mortar nrog cov ntsiab lus sib txawv ntawm HPMC tau pom hauv daim duab 5. Nws tuaj yeem pom los ntawm daim duab 5 tias qhov kev nkag mus tau feem ntau nce nrog qhov txuas ntxiv ntawm lub sijhawm sawv ntsug, uas feem ntau yog vim qhov ntws ntawm cov slurry thaum lub sij hawm cement hydration txheej txheem. Nws maj mam hloov zuj zus mus rau hauv cov khoom khov kho; Hauv thawj 80 min, kev koom ua ke ntawm HPMC nce qhov kev nkag mus tau zoo, thiab nrog kev nce ntawm cov ntsiab lus ntawm HPMC, kev nkag mus tau nce ntxiv. Qhov ntau dua qhov kev nkag mus, qhov deformation ntawm cov khoom vim yog siv load Qhov ntau dua qhov kev tiv thaiv ntawm HPMC yog, uas qhia tau hais tias HPMC tuaj yeem txhim kho cov stackability thaum ntxov ntawm 3D luam ntawv mortar. Txij li thaum cov hydroxyl thiab ether bonds ntawm cov polymer saw ntawm HPMC tau yooj yim ua ke nrog dej los ntawm hydrogen bonds, ua rau maj mam txo cov dej dawb thiab kev sib txuas ntawm cov khoom sib txuas, kev sib txhuam quab yuam nce, yog li qhov kev nkag mus thaum ntxov yuav loj dua. Tom qab sawv ntsug rau 80 feeb, vim yog cov dej ntawm cov cement, qhov nkag mus ntawm cov pab pawg dawb paug tsis muaj HPMC tau nce sai, thaum qhov kev nkag mus ntawm pawg xeem nrog HPMC nce Tus nqi tsis hloov pauv mus txog li 160 min ntawm kev sawv. Raws li Chen li al., qhov no feem ntau yog vim HPMC tsim cov yeeb yaj kiab tiv thaiv ib puag ncig cov cement, uas ua rau lub sijhawm teem sijhawm ntev; Pourchez et al. conjectured tias qhov no yog vim fiber ntau yooj yim ether degradation cov khoom (xws li carboxylates) los yog methoxyl pawg yuav ncua cov cement hydration los ntawm retarding tsim ntawm Ca(OH)2. Nws yog ib qho tsim nyog sau cia tias, txhawm rau tiv thaiv kev txhim kho ntawm kev nkag mus los ntawm kev cuam tshuam los ntawm evaporation ntawm cov dej nyob rau saum npoo ntawm cov qauv, Qhov kev sim no tau ua nyob rau hauv tib qhov kub thiab av noo. Ntawm tag nrho, HPMC tuaj yeem txhim kho lub stackability ntawm 3D luam ntawv mortar ntawm thawj theem, ncua lub coagulation, thiab ncua sij hawm luam tawm ntawm 3D luam ntawv mortar.
3D luam ntawv mortar qhov chaw (ntev 200 mm × dav 20 mm × txheej thickness 8 mm): Cov pab pawg neeg dawb huv uas tsis muaj HPMC tau raug deformed hnyav, tawg thiab muaj teeb meem los ntshav thaum luam ntawv thib xya txheej; M-H0.20 pawg mortar muaj cov khoom zoo. Tom qab luam tawm 13 txheej, sab saum toj ntug dav yog 16.58 hli, hauv qab ntug dav yog 19.65 hli, thiab sab saum toj-rau-hauv qab piv (qhov piv ntawm sab saum toj dav dav rau hauv qab ntug dav) yog 0.84. Dimensional sib txawv me me. Yog li ntawd, nws tau raug txheeb xyuas los ntawm kev luam ntawv tias kev koom ua ke ntawm HPMC tuaj yeem txhim kho kev luam ntawv ntawm mortar. Mortar fluidity muaj zoo extrudability thiab stackability ntawm 160 ~ 170 hli; Cov duab tuav tus nqi tsawg dua 70% yog deformed loj thiab tsis tuaj yeem ua tau raws li cov kev cai luam ntawv.
1.2Kev cuam tshuam ntawm HPMC ntawm rheological zog ntawm 3D luam ntawv mortars
Qhov pom tseeb viscosity ntawm cov nqaij ntshiab nyob rau hauv cov ntsiab lus ntawm HPMC sib txawv yog muab: nrog rau qhov nce ntawm shear npaum li cas, qhov pom tseeb viscosity ntawm ntshiab pulp txo, thiab qhov tshwm sim ntawm shear thinning yog nyob rau hauv siab HPMC cov ntsiab lus. Nws yog qhov pom tseeb dua. HPMC cov saw hlau molecular tsis zoo thiab qhia tau tias muaj viscosity ntau dua ntawm qhov qis shear; tab sis ntawm qhov siab shear npaum li cas, HPMC molecules txav nyob rau hauv parallel thiab orderly raws lub shear kev taw qhia, ua rau cov molecules yooj yim rau swb, yog li lub rooj pom tseeb viscosity ntawm slurry yog kuj tsawg. Thaum tus nqi shear ntau dua 5.0 s-1, qhov pom tseeb viscosity ntawm P-H0 nyob rau hauv cov pab pawg neeg dawb paug yog nyob ruaj khov nyob rau hauv 5 Pa s; thaum pom meej viscosity ntawm slurry nce tom qab HPMC ntxiv, thiab nws yog tov nrog HPMC. Qhov sib ntxiv ntawm HPMC ua rau kom muaj kev sib txhuam sab hauv ntawm cov cement hais, uas ua rau kom pom tseeb viscosity ntawm cov muab tshuaj txhuam, thiab cov kev ua haujlwm macroscopic yog tias qhov extrudability ntawm 3D luam ntawv mortar txo qis.
Kev sib raug zoo ntawm kev ntxhov siab thiab kev sib tsoo ntawm cov slurry ntshiab hauv kev kuaj rheological tau sau tseg, thiab cov qauv Bingham tau siv los ua kom haum cov txiaj ntsig. Cov txiaj ntsig tau pom nyob rau hauv daim duab 8 thiab Table 3. Thaum cov ntsiab lus ntawm HPMC yog 0.30%, tus nqi shear thaum lub sij hawm kuaj tau ntau dua 32.5 Thaum lub viscosity ntawm slurry tshaj qhov ntau ntawm cov ntsuas ntawm s-1, cov ntaub ntawv sib thooj tsis tuaj yeem sau cov ntsiab lus. Feem ntau, thaj chaw uas nyob ze ntawm qhov nce thiab poob nkhaus nyob rau theem ruaj khov (10.0 ~ 50.0 s-1) yog siv los ua tus yam ntxwv ntawm thixotropy ntawm slurry [21, 33]. Thixotropy yog hais txog cov cuab yeej uas cov slurry muaj fluidity zoo nyob rau hauv qhov kev txiav txim ntawm sab nraud quab yuam shearing, thiab tuaj yeem rov qab mus rau nws qhov qub qub tom qab txiav txiav txiav. Tsim nyog thixotropy yog qhov tseem ceeb heev rau kev luam tawm ntawm cov tshuaj khib. Nws tuaj yeem pom los ntawm daim duab 8 tias thaj tsam thixotropic ntawm pawg dawb paug tsis muaj HPMC tsuas yog 116.55 Pa/s; Tom qab ntxiv 0.10% ntawm HPMC, thaj tsam thixotropic ntawm cov net muab tshuaj ntxiv tau nce ntxiv mus rau 1 800.38 Pa / s; Nrog rau qhov nce ntawm , thixotropic cheeb tsam ntawm cov muab tshuaj txo qis, tab sis nws tseem yog 10 npaug siab dua li ntawm cov pab pawg neeg dawb paug. Los ntawm qhov kev xav ntawm thixotropy, kev koom ua ke ntawm HPMC zoo heev txhim kho cov luam ntawv ntawm cov tshuaj khib.
Txhawm rau kom cov mortar tuav nws cov duab tom qab extrusion thiab tiv thaiv lub nra ntawm cov txheej txheem extruded, cov tshuaj khib yuav tsum muaj kev ntxhov siab ntau dua. Nws tuaj yeem pom los ntawm Table 3 tias cov txiaj ntsig kev ntxhov siab τ0 ntawm net slurry yog qhov zoo dua tom qab HPMC ntxiv, thiab nws zoo ib yam li HPMC. Cov ntsiab lus ntawm HPMC muaj kev sib raug zoo; thaum cov ntsiab lus ntawm HPMC yog 0.10%, 0.20%, thiab 0.30%, qhov kev ntxhov siab ntawm cov net paste nce mus rau 8.6, 23.7, thiab 31.8 npaug ntawm pawg dawb paug, feem; cov yas viscosity μ kuj nce ntxiv nrog kev nce ntawm cov ntsiab lus ntawm HPMC. 3D Printing xav kom cov yas viscosity ntawm mortar yuav tsum tsis txhob me dhau, txwv tsis pub deformation tom qab extrusion yuav loj; Nyob rau tib lub sijhawm, cov yas viscosity tsim nyog yuav tsum tau tswj xyuas kom ntseeg tau qhov sib xws ntawm cov khoom siv extrusion. Hauv cov ntsiab lus, los ntawm qhov pom ntawm rheology, HPMC's Incorporation muaj txiaj ntsig zoo rau kev txhim kho stackability ntawm 3D luam ntawv mortar. Tom qab koom nrog HPMC, cov tshuaj dawb huv tseem ua raws li Bingham rheological qauv, thiab qhov zoo ntawm haum R2 tsis qis dua 0.99.
1.3Cov nyhuv ntawm HPMC rau cov khoom siv kho tshuab ntawm 3D luam ntawv mortar
28d compressive zog thiab flexural zog ntawm 3D luam ntawv mortar. Nrog rau qhov nce ntawm HPMC cov ntsiab lus, 28 d compressive thiab flexural zog ntawm 3D luam ntawv mortar txo; Thaum cov ntsiab lus ntawm HPMC mus txog 0.30%, 28 d compressive zog thiab flexural zog yog 30.3 thiab 7.3 MPa, feem. Cov kev tshawb fawb tau pom tias HPMC muaj qee yam huab cua nkag mus, thiab yog tias nws cov ntsiab lus siab dhau lawm, qhov porosity sab hauv ntawm lub mortar yuav nce ntxiv; Lub diffusion kuj nce thiab nws yog qhov nyuaj rau tso tawm tag nrho. Yog li ntawd, qhov nce ntawm porosity yuav yog vim li cas rau qhov txo qis ntawm lub zog ntawm 3D luam ntawv mortar tshwm sim los ntawm HPMC.
Qhov tshwj xeeb lamination molding txheej txheem ntawm 3D luam ntawv ua rau muaj qhov tsis muaj zog hauv cov qauv thiab cov khoom siv kho tshuab ntawm cov khaubncaws sab nraud povtseg, thiab lub zog sib txuas ntawm cov khaubncaws sab nraud povtseg muaj kev cuam tshuam zoo rau tag nrho lub zog ntawm cov khoom luam tawm. Rau 3D luam ntawv mortar cov qauv sib xyaw nrog 0.20% HPMC M-H0.20 raug txiav, thiab lub zog interlayer tau raug kuaj los ntawm txoj kev sib cais. Lub interlayer daim ntawv cog lus lub zog ntawm peb qhov chaw yog siab tshaj 1.3 MPa; thiab thaum tus naj npawb ntawm cov khaubncaws sab nraud povtseg tsawg, lub interlayer bond zog yog me ntsis siab dua. Yog vim li cas tej zaum yuav yog tias, ntawm ib sab, lub ntiajteb txawj nqus ntawm cov txheej sab sauv ua rau cov txheej txheem qis dua densely bonded; Ntawm qhov tod tes, qhov saum npoo ntawm cov mortar yuav muaj cov dej noo ntau dua thaum luam tawm cov txheej txheem qis, thaum cov av noo ntawm cov mortar txo qis vim evaporation thiab hydration thaum luam ntawv cov txheej sab saud, yog li cov kev sib txuas ntawm cov txheej hauv qab yuav muaj zog dua.
1.4Cov nyhuv ntawm HPMC ntawm Micromorphology ntawm 3D Printing Mortar
Cov duab SEM ntawm M-H0 thiab M-H0.20 cov qauv ntawm 3 d hnub nyoog qhia tias qhov pores saum npoo ntawm M-H0.20 cov qauv tau nce ntxiv tom qab ntxiv 0.20% HPMC, thiab qhov pore loj dua li ntawm pab pawg dawb. Qhov no Ntawm ib sab, nws yog vim hais tias HPMC muaj cov huab cua-entraining nyhuv, uas qhia txog uniform thiab zoo pores; Ntawm qhov tod tes, nws yuav yog tias qhov sib ntxiv ntawm HPMC nce viscosity ntawm slurry, yog li ua kom cov pa tawm ntawm huab cua hauv slurry. Qhov nce tuaj yeem yog qhov laj thawj tseem ceeb rau kev txo qis hauv cov khoom ntawm cov tshuaj khib nyiab. Txhawm rau ua kom tiav, txhawm rau ua kom lub zog ntawm 3D luam ntawv mortar, cov ntsiab lus ntawm HPMC yuav tsum tsis txhob loj dhau (≤ 0.20%).
Hauv kev xaus
(1) Hydroxypropyl methylcellulose HPMC txhim kho kev luam tawm ntawm cov tshuaj khib. Nrog rau qhov nce ntawm cov ntsiab lus ntawm HPMC, lub extrudability ntawm lub mortar txo, tab sis tseem muaj zoo extrudability, lub stackability yog zoo dua, thiab cov printable lub sij hawm ntev. Nws tau raug txheeb xyuas los ntawm kev luam ntawv tias qhov deformation ntawm cov txheej hauv qab ntawm cov mortar txo qis tom qab ntxiv HPMC, thiab qhov sib piv saum toj-hauv qab yog 0.84 thaum HPMC cov ntsiab lus yog 0.20%.
(2) HPMC txhim kho cov khoom rheological ntawm 3D luam ntawv mortar. Nrog rau qhov nce ntawm HPMC cov ntsiab lus, qhov pom tseeb viscosity, yield stress thiab yas viscosity ntawm slurry nce; thixotropy thawj zaug nce thiab tom qab ntawd txo qis, thiab cov ntawv luam tawm tau txais. Kev txhim kho. Los ntawm qhov kev xav ntawm rheology, ntxiv HPMC tuaj yeem txhim kho kev luam tawm ntawm cov tshuaj khib nyiab. Tom qab ntxiv HPMC, cov slurry tseem ua raws li Bingham rheological qauv, thiab qhov zoo ntawm haum R2≥0.99.
(3) Tom qab ntxiv HPMC, microstructure thiab pores ntawm cov khoom nce. Nws raug pom zoo tias cov ntsiab lus ntawm HPMC yuav tsum tsis pub tshaj 0.20%, txwv tsis pub nws yuav muaj kev cuam tshuam zoo rau cov khoom siv ntawm cov tshuaj khib nyiab. Lub zog sib txuas ntawm cov khaubncaws sab nraud povtseg ntawm 3D tshuab luam ntawv mortar yog qhov sib txawv me ntsis, thiab cov txheej txheem ntawm cov txheej txheem thaum nws qis dua, lub zog ntawm cov khoom sib txawv ntawm cov mortar ntau dua.
Post lub sij hawm: Sep-27-2022