Tasirin ether cellulose akan zafi na hydration na siminti daban-daban da ma'adinai guda ɗaya

Sakamakon cellulose ether akan hydration zafi na Portland ciminti, sulfoaluminate ciminti, tricalcium silicate da tricalcium aluminate a cikin 72h aka kwatanta da isothermal calorimetry gwajin. Sakamakon ya nuna cewa ether cellulose na iya rage yawan hydration da zafi na saki na Portland ciminti da tricalcium silicate, da kuma raguwar sakamako a kan hydration da zafi saki kudi na tricalcium silicate ya fi muhimmanci. Tasirin ether cellulose akan rage yawan sakin zafi na hydration na ciminti sulfoaluminate yana da rauni sosai, amma yana da tasiri mai rauni akan inganta yanayin sakin zafi na hydration na tricalcium aluminate. Cellulose ether za a adsorbed da wasu kayayyakin hydration, don haka jinkirta crystallization na hydration kayayyakin, sa'an nan kuma rinjayar hydration zafi saki siminti da kuma guda tama.

Mabuɗin kalmomi:ether cellulose; Siminti; Ma'ada guda ɗaya; Zafin hydration; adsorption

1. Gabatarwa

Cellulose ether muhimmin wakili ne mai kauri da mai riƙe da ruwa a cikin busasshiyar turmi gauraye, siminti mai haɗa kai da sauran sabbin kayan tushen siminti. Duk da haka, ether cellulose zai kuma jinkirta ciminti hydration, wanda yake da amfani don inganta lokacin aiki na kayan aikin siminti, inganta daidaiton turmi da kuma asarar lokaci na kankare, amma kuma yana iya jinkirta ci gaban ginin. Musamman, zai yi mummunan tasiri akan turmi da kankare da aka yi amfani da shi a cikin yanayin yanayin ƙananan zafin jiki. Saboda haka, yana da matukar muhimmanci a fahimci ka'idar cellulose ether akan ciminti hydration kinetics.

OU da Pourchez sun yi nazari akai-akai game da tasirin sifofin kwayoyin halitta irin su nauyin kwayoyin halitta na cellulose ether, nau'in maye gurbin ko digiri na maye gurbin a kan ciminti hydration motsin rai, kuma sun kusantar da mahimmanci mai mahimmanci: Ikon hydroxyethyl cellulose ether (HEC) don jinkirta hydration na siminti yawanci yana da ƙarfi fiye da na methyl cellulose ether (HPMC), hydroxymethyl ethyl cellulose ether (HEMC) da methyl cellulose ether (MC). A cikin ether cellulose dauke da methyl, ƙananan abun ciki na methyl, ƙarfin ƙarfin jinkirta jinkirin ciminti; Ƙananan nauyin kwayoyin halitta na cellulose ether, mafi ƙarfin ikon jinkirta jinkirin ciminti. Waɗannan ƙaddamarwa suna ba da tushen kimiyya don zaɓar ether cellulose daidai.

Ga sassa daban-daban na siminti, tasirin ether cellulose akan ciminti hydration motsin rai shima matsala ce mai matukar damuwa a aikace-aikacen injiniya. Duk da haka, babu wani bincike kan wannan bangare. A cikin wannan takarda, an yi nazarin tasirin cellulose ether akan hydration kinetics na simintin Portland na yau da kullun, C3S (tricalcium silicate), C3A (tricalcium aluminate) da cimintin sulfoaluminate (SAC) ta hanyar gwajin isothermal calorimetry, don ƙarin fahimtar hulɗar da juna. na ciki tsarin tsakanin cellulose ether da siminti hydration kayayyakin. Yana ba da ƙarin tushen kimiyya don amfani da hankali na ether cellulose a cikin kayan tushen siminti kuma yana ba da tushen bincike don hulɗar tsakanin sauran abubuwan haɓakawa da samfuran hydration na siminti.

2. Gwaji

2.1 Raw Materials

(1) siminti na Portland na yau da kullun (P·0). Kerarre ta Wuhan Huaxin Cement Co., LTD., da ƙayyadaddun ne P · 042.5 (GB 175-2007), ƙaddara da zango watsawa-nau'in X-ray fluorescence spectrometer (AXIOS Advanced, PANalytical Co., LTD.). Dangane da nazarin software na JADE 5.0, baya ga siminti clinker ma'adanai C3S, C2s, C3A, C4AF da gypsum, albarkatun siminti kuma sun haɗa da calcium carbonate.

(2) sulfoaluminate ciminti (SAC). Simintin sulfoaluminate mai ƙarfi mai sauri wanda Zhengzhou Wang Lou Cement Industry Co., Ltd ya samar shine R.Star 42.5 (GB 20472-2006). Babban kungiyoyinsa sune calcium sulfoaluminate da dicalcium silicate.

(3) tricalcium silicate (C3S). Latsa Ca (OH) 2, SiO2, Co2O3 da H2O a 3: 1: 0.08: Matsakaicin taro na 10 an gauraye shi daidai kuma an danna shi a ƙarƙashin matsa lamba na 60MPa akai-akai don yin billet mai cylindrical. An yi lissafin billet ɗin a 1400 ℃ na 1.5 ~ 2 h a cikin sandar silicon-molybdenum high zafin wutar lantarki tanderu, sa'an nan kuma koma cikin microwave tanda don ƙarin dumama microwave na 40min. Bayan fitar da billet ɗin, an kwantar da shi ba zato ba tsammani kuma an karye shi akai-akai kuma an lissafta shi har sai abin da ke cikin CaO kyauta a cikin samfurin da aka gama bai wuce 1.0% ba.

(4) tricalcium aluminate (c3A). CaO da A12O3 an gauraye su daidai, an ƙididdige su a 1450 ℃ na 4 h a cikin tanderun lantarki na silicon-molybdenum, ƙasa a cikin foda, kuma ana maimaita su akai-akai har sai abun ciki na CaO na kyauta bai wuce 1.0% ba, kuma kololuwar C12A7 da CA sun kasance. watsi.

(5) cellulose ether. Aikin da ya gabata ya kwatanta tasirin nau'ikan ethers na cellulose guda 16 akan hydration da yanayin sakin zafi na siminti na Portland na yau da kullun, kuma ya gano cewa nau'ikan ethers na cellulose daban-daban suna da bambance-bambance masu mahimmanci akan ka'idar hydration da sakin zafi na siminti, kuma yayi nazarin tsarin ciki. na wannan gagarumin bambanci. Dangane da sakamakon binciken da ya gabata, an zaɓi nau'ikan cellulose ether guda uku waɗanda ke da tasirin ja da baya a zahiri akan simintin Portland na yau da kullun. Waɗannan sun haɗa da hydroxyethyl cellulose ether (HEC), hydroxypropyl methyl cellulose ether (HPMC), da hydroxyethyl methyl cellulose ether (HEMC). An auna dankon ether na cellulose ta na'urar na'ura mai jujjuyawa tare da gwajin gwaji na 2%, zazzabi na 20 ℃ da saurin juyawa na 12 r/min. An auna dankon ether na cellulose ta na'urar na'ura mai jujjuyawa tare da gwajin gwaji na 2%, zazzabi na 20 ℃ da saurin juyawa na 12 r/min. Matsakaicin maye gurbin molar cellulose ether yana samarwa ta masana'anta.

(6) Ruwa. Yi amfani da ruwa mai tsafta na biyu.

2.2 Hanyar gwaji

Zafin ruwa. TAM Air 8-tashar isothermal calorimeter wanda Kamfanin Kayan Kayan Aikin TA ya samar. Dukkanin albarkatun kasa an kiyaye yawan zafin jiki don gwada zafin jiki (kamar (20± 0.5) ℃) kafin gwajin. Da fari dai, an ƙara 3 g siminti da 18 MG cellulose ether foda a cikin calorimeter (matsakaicin adadin cellulose ether zuwa kayan cemellative shine 0.6%). Bayan cikakken hadawa, an ƙara ruwa mai gauraye (ruwa na biyu na distilled) bisa ga ƙayyadaddun rabo na siminti na ruwa kuma yana motsawa daidai. Sa'an nan kuma, an saka shi da sauri a cikin calorimeter don gwaji. Matsakaicin mai ɗaure ruwa na c3A shine 1.1, kuma rabon mai ɗaure ruwa na sauran kayan siminti guda uku shine 0.45.

3. Sakamako da tattaunawa

3.1 Sakamakon gwaji

Sakamakon HEC, HPMC da HEMC akan ƙimar sakin zafi na hydration da ƙimar sakin zafi na simintin Portland na yau da kullun, C3S da C3A a cikin sa'o'i 72, da tasirin HEC akan ƙimar sakin zafi mai zafi da ƙimar sakin zafi na sulfoaluminate ciminti. a cikin 72 h, HEC shine ether cellulose tare da tasirin jinkiri mafi ƙarfi akan hydration na sauran siminti da ma'adinai guda ɗaya. Haɗuwa da tasirin guda biyu, ana iya gano cewa tare da canjin simintin kayan aikin siminti, ether cellulose yana da tasiri daban-daban akan ƙimar sakin zafi na hydration da sakin zafi mai tarawa. The zaba cellulose ether iya muhimmanci rage hydration da zafi saki kudi na talakawa Portland ciminti da C, S, yafi tsawanta lokacin shigar da lokaci, jinkirta bayyanar hydration da zafi saki ganiya, daga cikin abin da cellulose ether zuwa C, S hydration da kuma Jinkirin sakin zafi ya fi bayyane fiye da na yau da kullun na simintin Portland da jinkirin sakin zafi; Cellulose ether kuma na iya jinkirta yawan sakin zafi na sulfoaluminate ciminti hydration, amma jinkirin iyawar yana da rauni sosai, kuma galibi jinkirta hydration bayan sa'o'i 2; Don ƙimar sakin zafi na C3A hydration, ether cellulose yana da rauni mai saurin haɓakawa.

3.2 Nazari da tattaunawa

Hanyar cellulosic ether jinkirta ciminti hydration. Silva et al. hasashe cewa ether cellulosic ya karu da danko na maganin pore kuma ya hana yawan motsi na ionic, don haka jinkirta ciminti hydration. Duk da haka, yawancin wallafe-wallafen sun yi shakkar wannan zato, kamar yadda gwaje-gwajen su sun gano cewa ethers cellulose tare da ƙananan danko suna da ƙarfin da zai iya jinkirta ciminti hydration. A gaskiya ma, lokacin motsi ko ƙaura yana da ɗan gajeren lokaci wanda a fili ba zai iya kwatanta da lokacin jinkirin ciminti ba. An yi la'akari da adsorption tsakanin ether cellulose da siminti hydration kayayyakin a matsayin ainihin dalilin jinkirta ciminti hydration ta cellulose ether. Cellulose ether yana da sauƙin adsorbed zuwa saman samfuran hydration irin su calcium hydroxide, CSH gel da calcium aluminate hydrate, amma ba shi da sauƙi a yi amfani da shi ta hanyar ettringite da unhydrated lokaci, kuma ƙarfin adsorption na cellulose ether akan calcium hydroxide ya fi girma fiye da CSH gel. Don haka, ga samfuran siminti na Portland na yau da kullun, ether cellulose yana da jinkiri mafi ƙarfi akan calcium hydroxide, jinkiri mafi ƙarfi akan calcium, jinkiri na biyu akan gel CSH, kuma mafi raunin jinkiri akan ettringite.

Nazarin da suka gabata sun nuna cewa adsorption tsakanin non-ionic polysaccharide da ma'adinai lokaci yafi hada hydrogen bonding da sinadaran hadaddun, kuma wadannan biyu effects faruwa a tsakanin hydroxyl kungiyar polysaccharide da karfe hydroxide a kan ma'adinai surface. Liu et al. ya kara rarraba adsorption tsakanin polysaccharides da ƙarfe hydroxides azaman hulɗar tushen acid, tare da polysaccharides azaman acid da hydroxides na ƙarfe azaman tushe. Don polysaccharide da aka ba, alkalinity na ma'adinan ma'adinai yana ƙayyade ƙarfin hulɗar tsakanin polysaccharides da ma'adanai. Daga cikin nau'ikan gelling guda huɗu da aka yi nazari a cikin wannan takarda, babban ƙarfe ko abubuwan da ba na ƙarfe ba sun haɗa da Ca, Al da Si. Dangane da tsarin aikin karfe, alkalinity na hydroxides shine Ca (OH) 2> Al (OH3> Si (OH) 4. A gaskiya ma, Si (OH) 4 maganin acidic ne kuma baya adsorb cellulose ether. abun ciki na Ca (OH) 2 a saman samfuran hydration na ciminti yana ƙayyade ƙarfin adsorption na samfuran hydration da ether cellulose Saboda calcium hydroxide, gel CSH (3CaO · 2SiO2 · 3H20), ettringite (3CaO · Al2O3 · 3CaSO4 · 32H2O). da calcium aluminate hydrate (3CaO · Al2O3 · 6H2O) a cikin abun ciki na inorganic oxides na CaO shine 100%, 58.33%, 49.56% da 62 .2%. aluminate> CSH gel> ettringite, wanda ya dace da sakamakon a cikin wallafe-wallafe.

Abubuwan hydration na c3S sun hada da Ca (OH) da gel csH, kuma ether cellulose yana da tasiri mai kyau akan su. Saboda haka, ether cellulose yana da jinkirin jinkiri sosai akan C3s hydration. Bayan c3S, siminti na Portland na yau da kullun ya haɗa da hydration na C2s wanda ke da hankali, wanda ke sa tasirin ether na cellulose ba a bayyane yake ba a farkon matakin. Samfuran hydration na silicate na yau da kullun sun haɗa da ettringite, kuma sakamakon jinkiri na ether cellulose ba shi da kyau. Saboda haka, jinkirin iyawar cellulose ether zuwa c3s ya fi ƙarfin siminti na Portland na yau da kullum da aka gani a gwajin.

C3A zai narke kuma ya yi ruwa da sauri lokacin da ya hadu da ruwa, kuma samfuran hydration yawanci C2AH8 da c4AH13 ne, kuma za a saki zafi na hydration. Lokacin da bayani na C2AH8 da c4AH13 ya kai jikewa, za a samar da crystallization na C2AH8 da C4AH13 hexagonal sheet hydrate, kuma za a rage yawan amsawa da zafi na hydration a lokaci guda. Saboda adsorption na cellulose ether zuwa saman calcium aluminate hydrate (CxAHy), kasancewar cellulose ether zai jinkirta crystallization na C2AH8 da C4AH13 hexagonal-farantin hydrate, sakamakon rage yawan dauki da hydration zafi saki kudi fiye da haka. na C3A mai tsabta, wanda ke nuna cewa ether cellulose yana da raunin hanzarin hanzari zuwa C3A hydration. Ya kamata a lura cewa a cikin wannan gwajin, ether cellulose yana da rauni mai saurin haɓakawa zuwa hydration na c3A mai tsabta. Koyaya, a cikin siminti na Portland na yau da kullun, saboda c3A zai amsa tare da gypsum don samar da ettringite, saboda tasirin ma'aunin ca2 + a cikin slurry bayani, ether cellulose zai jinkirta samuwar ettringite, don haka jinkirta hydration na c3A.

Daga illar HEC, HPMC da HEMC akan hydration da zafin sakin zafi da tarawar zafi na simintin Portland na yau da kullun, C3S da C3A a cikin sa'o'i 72, da tasirin HEC akan ƙimar hydration da sakin zafi da tarawar zafi na sulfoaluminate siminti a cikin sa'o'i 72, ana iya ganin cewa daga cikin ethers cellulose guda uku da aka zaɓa, Ƙarfin jinkirin jinkiri na c3s da simintin Portland ya fi karfi a HEC, sannan HEMC, kuma mafi rauni a cikin HPMC. Dangane da C3A, ikon ethers uku na cellulose don hanzarta hydration shima yana cikin tsari iri ɗaya, wato HEC shine mafi ƙarfi, HEMC shine na biyu, HPMC shine mafi rauni kuma mafi ƙarfi. Wannan tare da tabbatar da cewa ether cellulose ya jinkirta samar da samfuran hydration na kayan gelling.

Babban samfuran hydration na ciminti sulfoaluminate sune ettringite da Al (OH) 3 gel. C2S a cikin simintin sulfoaluminate shima zai yi ruwa daban don samar da Ca (OH) 2 da gel cSH. Saboda ana iya watsi da adsorption na cellulose ether da ettringite, kuma hydration na sulfoaluminate yana da sauri sosai, sabili da haka, a farkon matakin hydration, ether cellulose yana da ɗan tasiri akan ƙimar sakin zafi na sulfoaluminate ciminti. Amma zuwa wani lokaci na hydration, saboda c2s za su raba hydrate don samar da Ca (OH) 2 da gel CSH, waɗannan samfuran hydration guda biyu za a jinkirta su ta hanyar ether cellulose. Sabili da haka, an lura cewa ether cellulose ya jinkirta jinkirin ciminti sulfoaluminate bayan sa'o'i 2.

4. Kammalawa

A cikin wannan takarda, ta hanyar gwajin calorimetry na isothermal, dokar tasiri da tsarin samuwar cellulose ether akan zafi mai zafi na simintin Portland na yau da kullun, c3s, c3A, ciminti sulfoaluminate da sauran sassa daban-daban da ma'adinai guda a cikin 72 h an kwatanta. Babban abin da aka kammala shi ne kamar haka:

(1) Cellulose ether iya muhimmanci rage hydration zafi saki kudi na talakawa Portland ciminti da tricalcium silicate, da kuma sakamakon rage hydration zafi saki kudi na tricalcium silicate ne mafi muhimmanci; Sakamakon ether na cellulose akan rage yawan sakin zafi na ciminti sulfoaluminate yana da rauni sosai, amma yana da tasiri mai rauni akan inganta yanayin sakin zafi na tricalcium aluminate.

(2) cellulose ether za a adsorbed da wasu kayayyakin hydration, don haka jinkirta crystallization na hydration kayayyakin, shafi zafi saki kudi na siminti hydration. Nau'i da adadin samfuran hydration sun bambanta don sassa daban-daban na simintin lissafin tama, don haka tasirin ether na cellulose akan zafin ruwan su ba iri ɗaya bane.