Cellulose ether akan yanayin ettringite na farko

An yi nazarin tasirin hydroxyethyl methyl cellulose ether da methyl cellulose ether akan yanayin ettringite a cikin farkon slurry na siminti ta hanyar duba na'urar microscopy ta lantarki (SEM). Sakamakon ya nuna cewa rabon tsawon-diamita na lu'ulu'u na ettringite a cikin slurry na hydroxyethyl methyl cellulose ether da aka gyara ya fi ƙanƙanta fiye da na slurry na yau da kullun, kuma yanayin lu'ulu'u na ettringite gajere ne kamar sanda. Rabon tsawon-diamita na lu'ulu'u na ettringite a cikin slurry na methyl cellulose ether da aka gyara ya fi girma fiye da na slurry na yau da kullun, kuma yanayin lu'ulu'u na ettringite sandar allura ce. Lu'ulu'u na ettringite a cikin slurry na siminti na yau da kullun suna da rabon al'amari a wani wuri a tsakanin. Ta hanyar binciken gwaji da ke sama, ya ƙara bayyana cewa bambancin nauyin kwayoyin halitta na nau'ikan cellulose ether guda biyu shine mafi mahimmancin abin da ke shafar yanayin ettringite.

Kalmomi masu mahimmanci:ettringite; Rabon tsayi-diamita; methyl cellulose ether; Hydroxyethyl methyl cellulose ether; yanayin halitta

Ettringite, a matsayin wani samfurin ruwa mai ɗan faɗaɗa, yana da tasiri mai mahimmanci akan aikin simintin siminti, kuma koyaushe shine wurin bincike na kayan da aka gina bisa siminti. Ettringite wani nau'in sinadarin calcium aluminate hydrate ne na trisulfide, tsarin sinadaransa shine [Ca3Al (OH)6·12H2O]2·(SO4)3·2H2O, ko kuma ana iya rubuta shi azaman 3CaO·Al2O3·3CaSO4·32H2O, wanda galibi ana taƙaita shi azaman AFt. A cikin tsarin siminti na Portland, ettringite galibi ana samar da shi ne ta hanyar amsawar gypsum tare da ma'adanai na aluminate ko ferric aluminate, wanda ke taka rawar jinkirta ruwa da ƙarfin siminti na farko. Samuwar ettringite da yanayinsa suna shafar abubuwa da yawa kamar zafin jiki, ƙimar pH da yawan ion. Tun farkon 1976, Metha et al. An yi amfani da na'urar daukar hoton lantarki ta hanyar amfani da na'urar daukar hoton lantarki don nazarin halayen halittar AFt, kuma an gano cewa yanayin irin waɗannan samfuran ruwa mai ɗan faɗaɗa ya ɗan bambanta lokacin da sararin girma ya yi girma sosai da kuma lokacin da sararin yake da iyaka. Na farko galibi siririn spherules ne masu siffar allura, yayin da na ƙarshe galibi gajerun prism ne mai siffar sanda. Binciken Yang Wenyan ya gano cewa siffofin AFt sun bambanta da yanayi daban-daban na warkarwa. Yanayin danshi zai jinkirta samar da AFt a cikin siminti mai faɗaɗawa kuma ya ƙara yuwuwar kumburi da fashewa. Muhalli daban-daban ba wai kawai yana shafar samuwar da ƙananan tsarin AFt ba, har ma da kwanciyar hankalin girmansa. Chen Huxing da sauransu sun gano cewa kwanciyar hankali na dogon lokaci na AFt ya ragu tare da ƙaruwar abun ciki na C3A. Clark da Monteiro da sauransu sun gano cewa tare da ƙaruwar matsin lamba na muhalli, tsarin lu'ulu'u na AFt ya canza daga tsari zuwa rashin tsari. Balonis da Glasser sun sake duba canje-canjen yawa na AFm da AFt. Renaudin da sauransu sun yi nazarin canje-canjen tsari na AFt kafin da bayan nutsewa cikin mafita da sigogin tsari na AFt a cikin bakan Raman. Kunther da sauransu. Sun yi nazarin tasirin hulɗar da ke tsakanin rabon CSH gel calcium-silicon da sulfate ion akan matsin lamba na AFt ta hanyar NMR. A lokaci guda, bisa ga amfani da AFt a cikin kayan da aka gina bisa siminti, Wenk da abokan aikinsa sun yi nazarin yanayin kristal na AFt na sashin siminti ta hanyar amfani da fasahar kammala X-ray diffraction. An binciki samuwar AFt a cikin siminti mai gauraye da kuma wurin bincike na ettringite. Dangane da jinkirin amsawar ettringite, wasu masana sun gudanar da bincike mai yawa kan dalilin matakin AFt.

Faɗaɗar girma da samuwar ettringite ke haifarwa wani lokacin yana da kyau, kuma yana iya aiki a matsayin "faɗaɗawa" kamar wakilin faɗaɗa magnesium oxide don kiyaye daidaiton girma na kayan da aka gina da siminti. Ƙarawar polymer emulsion da foda emulsion mai sake rarrabawa yana canza halayen macroscopic na kayan da aka gina da siminti saboda tasirinsu mai mahimmanci akan ƙananan tsarin kayan da aka gina da siminti. Duk da haka, ba kamar foda emulsion mai sake rarrabawa wanda galibi yana haɓaka haƙƙin haɗin turmi mai tauri ba, cellulose ether mai narkewa cikin ruwa (CE) yana ba sabon turmi gauraye kyakkyawan riƙe ruwa da tasirin kauri, don haka inganta aikin aiki. Ana amfani da CE mara ionic akai-akai, gami da methyl cellulose (MC), hydroxyethyl cellulose (HEC), hydroxypropyl methyl cellulose (HPMC),hydroxyethyl methyl cellulose (HEMC), da sauransu, kuma CE tana taka rawa a cikin sabon turmi da aka gauraya amma kuma tana shafar tsarin ruwa na slurry na siminti. Bincike ya nuna cewa HEMC yana canza adadin AFt da aka samar a matsayin samfurin ruwa. Duk da haka, babu wani bincike da ya kwatanta tasirin CE akan ƙananan siffofin AFt, don haka wannan takarda ta bincika bambancin tasirin HEMC da MC akan ƙananan siffofin ettringham a farkon (kwana 1) slurry na siminti ta hanyar nazarin hoto da kwatantawa.

1. Gwaji

1.1 Kayan Danye

An zaɓi simintin P·II 52.5R na Portland wanda Anhui Conch Cement Co., LTD ta samar a matsayin siminti a cikin gwajin. Kwayoyin cellulose guda biyu sune hydroxyethyl methylcellulose (HEMC) da methylcellulose (methylcellulose, Shanghai Sinopath Group) bi da bi. MC); Ruwan da ake haɗawa shine ruwan famfo.

1.2 Hanyoyin Gwaji

Rabon ruwa da siminti na samfurin manna siminti shine 0.4 (rabon taro na ruwa da siminti), kuma abun da ke cikin cellulose ether shine 1% na nauyin siminti. An gudanar da shirye-shiryen samfurin bisa ga GB1346-2011 "Hanyar Gwaji don Amfani da Ruwa, Lokacin Saitawa da Daidaito na Daidaito na Siminti". Bayan ƙirƙirar samfurin, an lulluɓe fim ɗin filastik a saman mold ɗin don hana fitar da ruwa da carbonization, kuma an sanya samfurin a cikin ɗakin da ke da zafin jiki na (20±2)℃ da ɗanɗanon dangi na (60±5)%. Bayan kwana 1, an cire mold ɗin, kuma an karye samfurin, sannan aka ɗauki ƙaramin samfur daga tsakiya aka jiƙa shi da ethanol mai hana ruwa don dakatar da ruwa, kuma an fitar da samfurin kuma an busar da shi kafin a gwada. An manne samfuran busassun a kan teburin samfurin tare da manne mai gefe biyu, kuma an fesa wani Layer na fim ɗin zinare a saman ta amfani da kayan aikin Cressington 108auto automatic ion sputtering. Wutar lantarki ta sputtering ita ce 20 mA kuma lokacin sputtering shine daƙiƙa 60. An yi amfani da FEI QUANTAFEG 650 Environmental Scanning electron Microscope (ESEM) don lura da halayen AFt akan sashin samfurin. An yi amfani da yanayin electron na biyu mai ƙarfi don lura da AFT. Ƙarfin wutar lantarki mai sauri shine 15 kV, diamita na tabo na katako shine 3.0 nm, kuma an sarrafa nisan aiki a kusan mm 10.

2. Sakamako da tattaunawa

Hotunan SEM na ettringite a cikin simintin da aka gyara da HEMC sun nuna cewa ci gaban da aka samu a cikin simintin da aka gyara da HEMC ya nuna cewa ci gaban Ca (OH)2(CH) mai layi a bayyane yake, kuma AFt ya nuna tarin AFt mai kama da sandar gajere ba bisa ƙa'ida ba, kuma an rufe wasu gajerun AFT mai kama da sandar gajere da tsarin membrane na HEMC. Zhang Dongfang da sauransu sun kuma sami AFt mai kama da sandar gajere lokacin da suka lura da canje-canjen tsarin microstructure na simintin da aka gyara na HEMC ta hanyar ESEM. Sun yi imanin cewa simintin siminti na yau da kullun yana amsawa da sauri bayan sun haɗu da ruwa, don haka lu'ulu'u na AFt ya yi siriri, kuma tsawaita shekarun ruwa ya haifar da ci gaba da ƙaruwar rabon tsayi-diamita. Duk da haka, HEMC ya ƙara ɗanko na maganin, ya rage ƙimar ɗaurewar ions a cikin maganin kuma ya jinkirta isowar ruwa akan saman ƙwayoyin clinker, don haka rabon tsayi-diamita na AFt ya ƙaru a cikin yanayin rauni kuma halayensa na siffar sun nuna siffar sandar gajere. Idan aka kwatanta da AFt a cikin simintin siminti na yau da kullun na wannan zamani, an tabbatar da wannan ka'idar kaɗan, amma ba a yi amfani da shi ba don bayyana canje-canjen siffar AFt a cikin simintin da aka gyara na MC. Hotunan SEM na ettridite a cikin slurry na siminti mai tauri na MC na kwana 1 suma sun nuna ci gaban da aka tsara na Ca(OH)2 mai layi, wasu saman AFt kuma an rufe su da tsarin fim na MC, kuma AFt ya nuna halayen siffar girma na gungu. Duk da haka, idan aka kwatanta, lu'ulu'u na AFt a cikin slurry na siminti mai gyara na MC yana da babban rabo na tsawon-diamita da sirara, yana nuna yanayin acicular na yau da kullun.

Dukansu HEMC da MC sun jinkirta farkon tsarin ruwa na siminti kuma sun ƙara danko na maganin, amma bambance-bambancen halayen AFt da suka haifar har yanzu suna da mahimmanci. Za a iya ƙara bayani game da abubuwan da ke sama daga hangen tsarin kwayoyin halitta na cellulose ether da tsarin lu'ulu'u na AFt. Renaudin et al. sun jiƙa AFt ɗin da aka haɗa a cikin maganin alkali da aka shirya don samun "jikin AFt", sannan suka cire shi kaɗan suka busar da shi a saman maganin CaCl2 mai cike (danshi 35% na dangi) don samun "bushewar AFt". Bayan nazarin gyaran tsari ta hanyar Raman spectroscopy da diffraction na foda na X-ray, an gano cewa babu wani bambanci tsakanin tsarin biyu, kawai alkiblar samuwar lu'ulu'u na ƙwayoyin halitta sun canza a cikin tsarin bushewa, wato, a cikin tsarin canjin muhalli daga "jike" zuwa "bushe", lu'ulu'u na AFt sun samar da ƙwayoyin halitta tare da alkiblar al'ada ta ƙara a hankali. Lu'ulu'u na AFt tare da alkiblar al'ada ta c sun zama ƙasa da ƙasa. Mafi mahimmancin sashin sarari mai girma uku ya ƙunshi layi na al'ada, layin al'ada na b da layin al'ada na c waɗanda ke tsaye da juna. Idan aka gyara al'amuran b, lu'ulu'u na AFt sun haɗu tare da al'ada, wanda ke haifar da faɗaɗa sashin giciye na tantanin halitta a cikin matakin ab normals. Don haka, idan HEMC ta "ajiye" ruwa fiye da MC, yanayi "bushewa" na iya faruwa a yankin da ke kusa, yana ƙarfafa haɗuwa a gefe da haɓaka lu'ulu'u na AFt. Patural et al. sun gano cewa ga CE kanta, mafi girman matakin polymerization (ko girman nauyin kwayoyin halitta), mafi girman danko na CE kuma mafi kyawun aikin riƙe ruwa. Tsarin kwayoyin halitta na HEMCs da MCS yana goyan bayan wannan hasashe, tare da ƙungiyar hydroxyethyl tana da nauyin kwayoyin halitta mafi girma fiye da ƙungiyar hydrogen.

Gabaɗaya, lu'ulu'u na AFt za su samar kuma su zube ne kawai lokacin da ions masu dacewa suka kai wani takamaiman cika a cikin tsarin mafita. Saboda haka, abubuwa kamar yawan ion, zafin jiki, ƙimar pH da sararin samarwa a cikin maganin amsawar na iya yin tasiri sosai ga yanayin lu'ulu'u na AFt, kuma canje-canje a cikin yanayin haɗakar wucin gadi na iya canza yanayin lu'ulu'u na AFt. Saboda haka, rabon lu'ulu'u na AFt a cikin ruwan siminti na yau da kullun tsakanin su biyun na iya faruwa ne ta hanyar abu ɗaya na amfani da ruwa a farkon ruwan siminti. Duk da haka, bambancin yanayin lu'ulu'u na AFt da HEMC da MC ke haifarwa ya kamata ya zama saboda tsarin riƙe ruwa na musamman. Hemcs da MCS suna ƙirƙirar "rufe madauki" na jigilar ruwa a cikin ƙaramin yanki na ruwan siminti na sabo, wanda ke ba da damar "ɗan gajeren lokaci" wanda ruwa yake "sauƙin shiga kuma yana da wahalar fita." Duk da haka, a wannan lokacin, yanayin matakin ruwa a cikin da kusa da ƙaramin yanki shima yana canzawa. Abubuwa kamar yawan ion, pH, da sauransu, Canjin yanayin girma yana ƙara bayyana a cikin halayen siffar lu'ulu'u na AFt. Wannan "rufe madauki" na jigilar ruwa yayi kama da tsarin aikin da Pourchez da abokan aikinsa suka bayyana. HPMC suna taka rawa wajen riƙe ruwa.

3. Kammalawa

(1) Ƙara sinadarin hydroxyethyl methyl cellulose ether (HEMC) da methyl cellulose ether (MC) na iya canza yanayin sinadarin ettringite a farkon (kwana 1) simintin da aka saba amfani da shi.

(2) Tsawon da diamita na lu'ulu'u na ettringite a cikin simintin HEMC da aka gyara ƙanana ne kuma gajere; Rabon tsayi da diamita na lu'ulu'u na ettringite a cikin simintin MC da aka gyara babba ne, wanda shine siffar sandar allura. Lu'ulu'u na ettringite a cikin simintin siminti na yau da kullun suna da rabon al'amari tsakanin waɗannan biyun.

(3) Bambancin tasirin ethers guda biyu na cellulose akan yanayin ettringite ya faru ne saboda bambancin nauyin kwayoyin halitta.