Methyl cellulose ether nyob rau hauv chav tsev kub curing ultra-siab kev ua tau zoo pob zeb

Abstract: Los ntawm kev hloov cov ntsiab lus ntawm hydroxypropyl methylcellulose ether (HPMC) nyob rau hauv ib txwm kub curing ultra-high performance pob zeb (UHPC), cov nyhuv ntawm cellulose ether ntawm fluidity, teem sij hawm, compressive zog, thiab flexural zog ntawm UHPC tau kawm. , axial tensile lub zog thiab qhov kawg tensile tus nqi, thiab cov txiaj ntsig tau txheeb xyuas. Cov txiaj ntsig kev sim qhia tau hais tias: ntxiv tsis pub ntau tshaj 1.00% ntawm cov viscosity tsawg HPMC tsis cuam tshuam rau cov kua dej ntawm UHPC, tab sis txo qhov poob ntawm fluidity dhau sijhawm. , thiab ncua lub sijhawm teeb tsa, txhim kho kev tsim kho kev ua tau zoo; Thaum cov ntsiab lus tsawg dua 0.50%, qhov cuam tshuam ntawm compressive zog, flexural zog thiab axial tensile lub zog tsis tseem ceeb, thiab thaum cov ntsiab lus yog ntau tshaj 0.50%, nws cov neeg kho tshuab kev ua tau zoo yog txo los ntawm ntau tshaj 1/3. Xav txog ntau yam kev ua yeeb yam, qhov pom zoo noj ntawm HPMC yog 0.50%.

Cov lus tseem ceeb: ultra-siab kev ua tau zoo pob zeb; cellulose ether; ib txwm kub curing; compressive zog; flexural zog; tensile zog

0,Ua ntej

Nrog rau txoj kev loj hlob sai ntawm Tuam Tshoj txoj kev lag luam kev tsim kho, cov kev xav tau rau kev ua vaj tse pob zeb hauv qhov tseeb engineering kuj tau nce ntxiv, thiab ultra-siab kev ua tau zoo pob zeb (UHPC) tau tsim los teb rau qhov kev thov. Qhov kev pom zoo ntawm cov khoom uas muaj qhov sib txawv ntawm qhov ntau thiab tsawg yog theoretically tsim, thiab sib xyaw nrog cov hlau fiber ntau thiab cov dej ua haujlwm siab txo tus neeg sawv cev, nws muaj cov khoom zoo xws li ultra-siab compressive zog, siab toughness, siab poob siab ua hauj thiab muaj zog nws tus kheej zoo. muaj peev xwm ntawm micro-cracks. Kev ua tau zoo. Kev tshawb fawb thev naus laus zis txawv teb chaws ntawm UHPC yog qhov paub tab thiab tau siv rau ntau txoj haujlwm ua tau zoo. Piv nrog rau txawv teb chaws, kev tshawb fawb hauv tsev tsis tob txaus. Dong Jianmiao thiab lwm tus tau kawm txog kev sib koom ua ke ntawm fiber ntau los ntawm kev ntxiv ntau hom thiab ntau npaum li cas fibers. Lub zog mechanism thiab txoj cai ntawm pob zeb; Chen Jing et al. tau kawm txog kev cuam tshuam ntawm steel fiber ntau txoj kab uas hla ntawm kev ua haujlwm ntawm UHPC los ntawm kev xaiv steel fibers nrog 4 diameters. UHPC tsuas muaj qee qhov kev siv engineering hauv Suav teb, thiab nws tseem nyob rau theem ntawm kev tshawb fawb theoretical. Qhov kev ua tau zoo ntawm UHPC Superiority tau dhau los ua ib qho ntawm cov kev tshawb fawb ntawm kev txhim kho pob zeb, tab sis tseem muaj ntau yam teeb meem uas yuav tsum tau daws. Xws li cov kev xav tau siab rau cov khoom siv raw, cov nqi siab, cov txheej txheem kev npaj nyuaj, thiab lwm yam, txwv tsis pub UHPC ntau lawm technology. Ntawm lawv, kev siv lub tshuab hluav taws xob siab Kev kho ntawm UHPC ntawm qhov kub thiab txias tuaj yeem ua rau nws tau txais cov khoom siv hluav taws xob ntau dua thiab ua haujlwm ntev. Txawm li cas los xij, vim yog cov txheej txheem ua kom tsis muaj zog thiab cov khoom siv ntau lawm, kev siv cov ntaub ntawv tsuas yog txwv rau cov vaj tsev ua ntej, thiab kev tsim kho hauv qhov chaw tsis tuaj yeem nqa tawm. Yog li ntawd, nws tsis tsim nyog los siv cov txheej txheem thermal curing hauv cov haujlwm tiag tiag, thiab nws yog qhov tsim nyog los ua qhov kev tshawb fawb tob txog kev kho qhov kub thiab txias UHPC.

Qhov kub thiab txias kho UHPC yog nyob rau theem tshawb fawb hauv Suav teb, thiab nws cov dej-rau-binder piv yog qhov tsawg heev, thiab nws yog qhov ua rau lub cev qhuav dej sai sai ntawm qhov chaw thaum tsim kho. Txhawm rau txhim kho qhov tshwm sim ntawm lub cev qhuav dej zoo, cov ntaub ntawv cement-based feem ntau ntxiv qee cov dej tuav cov thickeners rau cov khoom. Tus neeg saib xyuas tshuaj tiv thaiv kev sib cais thiab los ntshav ntawm cov ntaub ntawv, txhim khu cov dej tuav thiab cohesion, txhim kho kev tsim kho, thiab tseem txhim kho cov khoom siv ntawm cov khoom siv cement. Hydroxypropyl methyl cellulose ether (HPMC) ua cov polymer Thickener, uas muaj peev xwm faib tau cov polymer gelled slurry thiab cov ntaub ntawv nyob rau hauv cov cement-raws li cov ntaub ntawv tusyees, thiab cov dej dawb hauv slurry yuav dhau los ua cov dej khi, kom nws tsis yooj yim poob los ntawm cov slurry thiab txhim kho cov dej tuav kev ua tau zoo ntawm cov pob zeb .Yuav kom txo qhov cuam tshuam ntawm cellulose ether ntawm fluidity ntawm UHPC, low-viscosity cellulose ether raug xaiv rau kev kuaj.

Hauv cov ntsiab lus, txhawm rau txhim kho kev tsim kho kev ua haujlwm raws li kev ua kom ntseeg tau cov khoom siv ntawm qhov qub-kub kho UHPC, daim ntawv no kawm txog cov txiaj ntsig ntawm cov viscosity cellulose ether cov ntsiab lus ntawm qhov kub thiab txias raws li cov khoom siv tshuaj ntawm cellulose ether. thiab nws cov txheej txheem ntawm kev ua haujlwm hauv UHPC slurry. Lub zog ntawm fluidity, coagulation lub sij hawm, compressive zog, flexural zog, axial tensile lub zog thiab qhov kawg tensile tus nqi ntawm UHPC los txiav txim qhov tsim nyog npaum li cas ntawm cellulose ether.

1. Kev npaj xeem

1.1 Ntsuas cov ntaub ntawv raw thiab sib tov piv

Cov ntaub ntawv raw rau qhov kev xeem no yog:

1) Cement: P·O 52.5 zoo tib yam Portland cement ua nyob rau hauv Liuzhou.

2) Fly tshauv: ya tshauv tsim nyob rau hauv Liuzhou.

3) Slag hmoov: S95 granulated moj tej tawg rauv slag hmoov ua nyob rau hauv Liuzhou.

4) Silica fume: semi-encrypted silica fume, grey hmoov, SiO2 cov ntsiab lus≥92%, tshwj xeeb thaj chaw 23 m²/g.

5) Quartz xuab zeb: 20 ~ 40 mesh (0.833 ~ 0.350 mm).

6) Dej reducer: polycarboxylate dej reducer, hmoov dawb, dej txo tus nqi≥30%.

7) Latex hmoov: redispersible latex hmoov.

8) Fiber ether: hydroxypropyl methylcellulose METHOCEL ua nyob rau hauv Tebchaws Meskas, viscosity 400 MPa s.

9) Hlau fiber ntau: ncaj tooj liab-plated microwire steel fiber, txoj kab uas hlaφ yog 0.22 hli, ntev yog 13 hli, tensile zog yog 2 000 MPa.

Tom qab kev sim ntau yam kev tshawb fawb nyob rau theem pib, nws tuaj yeem txiav txim siab tias qhov sib xyaw ua ke ntawm ib txwm kub kho ultra-siab kev ua tau zoo yog cement: ya tshauv: ntxhia hmoov: silica fume: xuab zeb: dej txo tus neeg sawv cev: latex hmoov: dej = 860: 42: 83: 110: 980: 11: 2: 210, steel fiber ntau cov ntsiab lus yog 2%. Ntxiv 0, 0.25%, 0.50%, 0.75%, 1.00% HPMC ntawm cellulose ether (HPMC) cov ntsiab lus ntawm qhov kev sib xyaw ua ke no Teeb tsa cov kev sim sib piv raws li.

1.2 Test method

Ntsuas cov hmoov qhuav raw cov ntaub ntawv raws li qhov sib tov sib xyaw thiab muab tso rau hauv HJW-60 ib leeg-kab rov tav ncej yuam cov pob zeb sib tov. Pib lub tov khoom kom txog thaum sib tov, ntxiv dej thiab sib tov rau 3 feeb, tua lub tov khoom, ntxiv cov hnyav hlau fiber ntau thiab rov pib lub tov khoom rau 2 feeb. Ua rau UHPC slurry.

Cov khoom kuaj muaj xws li fluidity, teem sij hawm, compressive zog, flexural zog, axial tensile zog thiab qhov kawg tensile tus nqi. Qhov kev ntsuas fluidity yog txiav txim siab raws li JC / T986-2018 "Cement-based Grouting Materials". Kev ntsuas lub sij hawm yog raws li GB / T 1346—2011 "Cement Standard Consistency Water Consumption and Setting Time Test Method". Lub zog flexural xeem yog txiav txim siab raws li GB / T50081-2002 "Standard for Test Methods of Mechanical Properties of Ordinary Concrete". Compressive zog xeem, axial tensile lub zog thiab qhov kawg tensile tus nqi xeem yog txiav txim raws li DLT5150-2001 "Hydraulic Concrete Test Regulations".

2. Cov ntawv xeem

2.1 Liquidity

Cov txiaj ntsig kev ntsuas dej tau qhia pom qhov cuam tshuam ntawm HPMC cov ntsiab lus ntawm qhov poob ntawm UHPC fluidity dhau sijhawm. Nws tau pom los ntawm qhov kev sim tshwm sim tias tom qab cov slurry tsis muaj cellulose ether yog nplawm tusyees, qhov saum npoo yog qhov ua rau lub cev qhuav dej thiab crusting, thiab cov dej ntws sai sai. , thiab kev ua haujlwm tsis zoo. Tom qab ntxiv cellulose ether, tsis muaj tawv nqaij ntawm qhov chaw, qhov poob ntawm fluidity nyob rau lub sijhawm me me, thiab kev ua haujlwm tau zoo. Nyob rau hauv qhov kev xeem, qhov tsawg kawg nkaus poob ntawm fluidity yog 5 hli hauv 60 feeb. Kev soj ntsuam ntawm cov ntaub ntawv ntsuam xyuas qhia tau hais tias, Tus nqi qis-viscosity cellulose ether muaj kev cuam tshuam me ntsis ntawm qhov pib fluidity ntawm UHPC, tab sis muaj kev cuam tshuam ntau dua rau qhov poob ntawm fluidity lub sijhawm. Thaum tsis muaj cellulose ether ntxiv, fluidity poob ntawm UHPC yog 15 hli; Nrog rau qhov nce ntawm HPMC, qhov fluidity poob ntawm mortar txo; thaum qhov ntau npaum li cas yog 0.75%, qhov fluidity poob ntawm UHPC yog qhov tsawg tshaj plaws nrog lub sijhawm, uas yog 5 hli; Tom qab ntawd, nrog nce ntawm HPMC, qhov fluidity poob ntawm UHPC nrog lub sij hawm yuav luag tsis hloov.

Tom qabHPMCyog tov nrog UHPC, nws cuam tshuam rau lub rheological zog ntawm UHPC los ntawm ob yam: ib tug yog hais tias ywj siab micro- npuas yog coj mus rau hauv tus txheej txheem nplawm, uas ua rau cov aggregate thiab ya tshauv thiab lwm yam ntaub ntawv tsim ib tug "pob nyhuv", uas ua rau kom lub aggregate thiab ya tshauv thiab lwm yam ntaub ntawv tsim ib tug "pob nyhuv", uas yuav ua rau kom lub stagnation ntawm cov khoom. Nyob rau tib lub sijhawm, ntau cov khoom siv cementitious tuaj yeem qhwv cov khoom sib sau ua ke, kom cov khoom sib xyaw ua ke tuaj yeem sib npaug "tshem tawm" hauv slurry, thiab tuaj yeem txav tau yooj yim, kev sib txhuam ntawm cov khoom sib xyaw yog txo, thiab cov fluidity yog nce; Qhov thib ob yog ua kom lub UHPC lub zog cohesive txo cov fluidity. Txij li thaum qhov kev ntsuam xyuas siv cov viscosity tsawg HPMC, thawj nam yog sib npaug rau qhov thib ob, thiab qhov pib fluidity tsis hloov ntau, tab sis qhov poob ntawm fluidity nyob rau lub sij hawm yuav raug txo. Raws li kev soj ntsuam ntawm cov txiaj ntsig kev xeem, nws tuaj yeem paub tias ntxiv qhov tsim nyog ntawm HPMC rau UHPC tuaj yeem txhim kho kev tsim kho ntawm UHPC zoo heev.

2.2 Teem sijhawm

Los ntawm qhov kev hloov pauv ntawm lub sijhawm teeb tsa ntawm UHPC cuam tshuam los ntawm tus nqi ntawm HPMC, nws tuaj yeem pom tias HPMC ua lub luag haujlwm tsis zoo hauv UHPC. Qhov loj dua tus nqi yog, qhov pom tseeb dua cov nyhuv retarding yog. Thaum tus nqi yog 0.50%, lub sij hawm teem ntawm lub mortar yog 55min. Piv nrog rau pawg tswj hwm (40 min), nws nce los ntawm 37.5%, thiab qhov nce tseem tsis pom tseeb. Thaum qhov ntau npaum li cas yog 1.00%, lub sijhawm teeb tsa ntawm lub mortar yog 100 min, uas yog 150% siab dua li ntawm pawg tswj hwm (40 min).

Cov qauv molecular yam ntxwv ntawm cellulose ether cuam tshuam nws cov nyhuv retarding. Cov qauv molecular tseem ceeb hauv cellulose ether, uas yog, lub nplhaib anhydroglucose tuaj yeem hnov ​​​​mob nrog calcium ions los tsim cov suab thaj-calcium molecular tebchaw, txo lub sij hawm induction ntawm cement clinker hydration cov tshuaj tiv thaiv cov concentration ntawm calcium ions tsawg, tiv thaiv ntxiv nag lossis daus. Ca (OH) 2, txo qhov ceev ntawm cov cement hydration cov tshuaj tiv thaiv, yog li ncua kev teeb tsa ntawm cov cement.

2.3 Compressive zog

Los ntawm kev sib raug zoo ntawm lub zog compressive ntawm UHPC cov qauv ntawm 7 hnub thiab 28 hnub thiab cov ntsiab lus ntawm HMPC, nws tuaj yeem pom tseeb tias qhov sib ntxiv ntawm HPMC maj mam txo qis hauv compressive zog ntawm UHPC. 0.25% HPMC, lub zog compressive ntawm UHPC txo me ntsis, thiab compressive zog piv yog 96%. Ntxiv 0.50% HPMC tsis muaj kev cuam tshuam rau lub zog compressive piv ntawm UHPC. Txuas ntxiv mus ntxiv HPMC hauv qhov kev siv, UHPC's Lub zog compressive poob qis heev. Thaum cov ntsiab lus ntawm HPMC nce mus rau 1.00%, lub zog compressive piv tau poob mus rau 66%, thiab lub zog poob tau loj heev. Raws li cov ntaub ntawv txheeb xyuas, nws tsim nyog ntxiv 0.50% HPMC, thiab qhov poob ntawm compressive zog yog me me.

HPMC muaj qee yam huab cua nkag mus. Qhov sib ntxiv ntawm HPMC yuav ua rau muaj qee qhov microbubbles hauv UHPC, uas yuav txo qhov ntom ntom ntawm cov khoom sib xyaw tshiab ntawm UHPC. Tom qab cov slurry yog hardened, lub porosity yuav maj mam nce thiab lub compactness kuj yuav txo, tshwj xeeb tshaj yog cov ntsiab lus HPMC. Siab dua. Tsis tas li ntawd, nrog rau qhov nce ntawm cov nyiaj HPMC qhia, tseem muaj ntau yam hloov pauv tau polymers nyob rau hauv qhov pores ntawm UHPC, uas tsis tuaj yeem ua lub luag haujlwm tseem ceeb hauv kev ua haujlwm zoo thiab kev txhawb nqa thaum lub matrix ntawm cov cementitious composite yog compressed. .Yog li ntawd, qhov sib ntxiv ntawm HPMC zoo heev txo cov compressive zog ntawm UHPC.

2.4 Flexural zog

Los ntawm kev sib raug zoo ntawm lub zog flexural ntawm UHPC cov qauv ntawm 7 hnub thiab 28 hnub thiab cov ntsiab lus ntawm HMPC, nws tuaj yeem pom tias qhov kev hloov pauv ntawm lub zog flexural thiab compressive zog zoo sib xws, thiab kev hloov ntawm flexural zog ntawm 0 thiab 0.50%. ntawm HMPC tsis zoo ib yam. Raws li qhov sib ntxiv ntawm HPMC txuas ntxiv, lub zog flexural ntawm UHPC cov qauv txo qis heev.

Cov nyhuv ntawm HPMC ntawm lub zog flexural ntawm UHPC feem ntau yog nyob rau hauv peb yam: cellulose ether muaj retarding thiab air-entraining los, uas txo cov flexural zog ntawm UHPC; thiab qhov thib peb nam yog cov hloov tau yooj yim polymer uas ua los ntawm cellulose ether, Txo cov rigidity ntawm cov hnoos qeev slows qhov txo qis ntawm lub zog flexural ntawm cov qauv me ntsis. Kev muaj nyob ib txhij ntawm peb yam no txo ​​cov compressive zog ntawm UHPC cov qauv thiab kuj txo cov flexural zog.

2.5 Axial tensile lub zog thiab qhov kawg tensile tus nqi

Kev sib raug zoo ntawm lub zog tensile ntawm UHPC cov qauv ntawm 7 d thiab 28 d thiab cov ntsiab lus ntawm HMPC. Nrog rau qhov nce ntawm cov ntsiab lus ntawm HPMC, lub zog tensile ntawm UHPC cov qauv ua ntej hloov me ntsis thiab tom qab ntawd poob sai. Lub tensile lub zog nkhaus qhia tau hais tias thaum cov ntsiab lus ntawm HPMC nyob rau hauv cov qauv mus txog 0.50%, axial tensile lub zog tus nqi ntawm UHPC specimen yog 12.2MPa, thiab tensile zog piv yog 103%. Nrog rau kev nce ntxiv ntawm HPMC cov ntsiab lus ntawm cov qauv, axial Lub hauv paus tensile zog tus nqi pib poob qis. Thaum HPMC cov ntsiab lus ntawm cov qauv yog 0.75% thiab 1.00%, lub zog tensile piv yog 94% thiab 78%, feem, uas qis dua lub zog tensile ntawm UHPC tsis muaj HPMC.

Los ntawm kev sib raug zoo ntawm qhov kawg tensile qhov tseem ceeb ntawm UHPC cov qauv ntawm 7 hnub thiab 28 hnub thiab cov ntsiab lus ntawm HMPC, nws tuaj yeem pom tias qhov kawg tensile qhov tseem ceeb yuav luag tsis hloov nrog qhov nce ntawm cellulose ether thaum pib, thiab thaum cov ntsiab lus ntawm cellulose ether nce mus txog 0.50% thiab tom qab ntawd pib poob sai.

Cov txiaj ntsig ntawm qhov sib ntxiv ntawm HPMC ntawm lub zog tensile axial thiab qhov kawg tensile tus nqi ntawm UHPC cov qauv qhia tau hais tias tus qauv ntawm yuav luag tsis hloov thiab tom qab ntawd txo qis. Qhov laj thawj tseem ceeb yog tias HPMC tuaj yeem tsim ncaj qha ntawm hydrated cement particles Ib txheej ntawm cov dej tsis muaj dej polymer sealing zaj duab xis plays lub luag haujlwm ntawm kev sib khi, kom muaj qee qhov dej khaws cia hauv UHPC, uas muab cov dej tsim nyog rau kev txhim kho txuas ntxiv hydration. ntawm cov cement, yog li txhim kho lub zog ntawm cov cement. Qhov sib ntxiv ntawm HPMC txhim kho lub cohesiveness ntawm UHPC endows slurry nrog saj zawg zog, uas ua rau UHPC tag nrho hloov mus rau lub shrinkage thiab deformation ntawm lub hauv paus khoom, thiab me ntsis txhim kho lub tensile lub zog ntawm UHPC. Txawm li cas los xij, thaum cov ntsiab lus ntawm HPMC tshaj qhov tseem ceeb, cov huab cua nkag tau cuam tshuam rau lub zog ntawm cov qauv. Cov teebmeem tsis zoo maj mam ua lub luag haujlwm tseem ceeb, thiab axial tensile lub zog thiab qhov kawg tensile tus nqi ntawm cov qauv pib txo qis.

3. Cov lus xaus

1) HPMC tuaj yeem txhim kho kev ua haujlwm ntawm kev kho qhov kub thiab txias UHPC, ua kom nws lub sijhawm coagulation thiab txo cov kua dej tsis zoo ntawm cov khoom sib xyaw tshiab ntawm UHPC lub sijhawm.

2) Qhov sib ntxiv ntawm HPMC qhia txog qee yam ntawm cov npuas me me thaum lub sijhawm nplawm ntawm cov slurry. Yog tias tus nqi ntau dhau lawm, cov npuas yuav sib sau ntau dhau thiab tsim cov npuas loj dua. Lub slurry yog cohesive heev, thiab cov npuas tsis tuaj yeem dhau thiab tawg. Lub pores ntawm hardened UHPC txo; Tsis tas li ntawd, cov ntaub ntawv hloov pauv tau tsim los ntawm HPMC tsis tuaj yeem muab kev txhawb nqa nruj thaum nws nyob rau hauv siab, thiab cov compressive thiab flexural zog tau txo qis heev.

3) Qhov sib ntxiv ntawm HPMC ua rau UHPC yas thiab hloov tau. Lub zog tensile axial thiab qhov kawg tensile tus nqi ntawm UHPC cov qauv tsis tshua hloov nrog qhov nce ntawm HPMC cov ntsiab lus, tab sis thaum HPMC cov ntsiab lus siab tshaj ib qho nqi, Lub zog tensile axial thiab qhov kawg tensile qhov tseem ceeb txo qis heev.

4) Thaum npaj qhov kub thiab txias kho UHPC, qhov ntau npaum ntawm HPMC yuav tsum tau tswj nruj me ntsis. Thaum qhov ntau npaum li cas yog 0.50%, kev sib raug zoo ntawm kev ua haujlwm ntawm kev ua haujlwm thiab cov khoom siv kho qhov muag ntawm qhov kub thiab txias UHPC tuaj yeem ua haujlwm zoo.