Chuyen de Be Tong Chiu Nhiet-V2

TRNG I HC XY DNG

GVHD: PGS. TS. V MINH C CHNG 1: M U

I.1. Tnh cp thit v ngha ca ti. Trong thc t, nhng cng trnh, kt cu chu nhit, cc thit b nhit, cc kt cu bo n cho cc thit b nhit c ch to t b tng chu nhit lm vic trong iu kin nhit cao lu di, nhit thay i, vi mc chnh lch nhit cao b ph hoi, h hng nhanh, tui th thp l thc t lm gim cht lng cng trnh, gim hiu qu kinh t ca cng trnh, nn vic nng cao tui th, bn lu cng trnh, kt cu v thit b nhit c ngha to ln, mang ngha v kinh t k thut su sc. Vic s dng cc loi b tng thng thng, s dng cc loi cht kt dnh nh xi mng poc lng hay xi mng poc lng hn hp thng thng khng t c hiu qu cao, do trong qu trnh lm vic nhit cao, chng b bin i cc tnh cht c l v b ph hu hon ton. Nguyn nhn l do s mt nc lin kt ha hc ca cc sn phm thy ha, trong c thnh phn Ca(OH)2 mt nc to nn CaO, Sau CaO li hp th hi nc trong mi trng khng kh, tin hnh thy ha ln hai, gy trng n th tch, to ng sut ph hoi cu trc ca vt liu, lm gim bn, kh nng lm vic, gim tui th ca vt liu, v th: vic tm ra cc loi vt liu c cht lng cao hn, c bn cao hn, tui th cao hn cho cng trnh, kt cu v thit b nhit lm vic trong cc iu kin nhit khc nhit l ht sc cn thit. khc phc s ph hoi do tc ng ca nhit i vi cc cng trnh, kt cu v thit b sn xut t b tng chu nhit, ta cn nng cao kh nng lm vic trong iu kin nhit cao ca cc thnh phn cu to nn b tng, bao gm c ct liu v cht kt dnh, nhng trong thc t: cc loi ct liu c s dng l cc mnh v snh s, bn thn chng c nung n kt khi, kh nng chu ng ca chng nhit cao l rt tt, nn mc ch ca vic nng cao kh nng chu nhit ca b tng chu nhit l: nng cao kh nng chu nhit ca cht kt dnh hay ca cht kt dnh s dng ch to b tng chu nhit. thc hin mc tiu ny, chng ta c th s dng cc loi cht kt dnh chu nhit, c to thnh t ph gia khong nghin mn v xi mng poc lng. Vic nghin cu ch to cht kt dnh chu nhit c kh nng chu nhit cao, lm vic trong iu kin nhit khc nhit t cc loi xi mng poc lng a phng cng c ngha kinh t k thut cao v thit thc. - V mt khoa hc k thut: y l hng nhin cu v pht trin mi trong khoa hc k thut v vt liu chu nhit-cch nhit dn dn thay th cc vt liu cch nhit truyn thng nh vermiculit, pclit, iatmt B tng chu nhit - cch nhit c cng ngh sn xut n gin hn cc vt liu cch nhit khc, khng phi tri qua giai on sy nung phc tp, c th ch

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GVHD: PGS. TS. V MINH C

to vi bloock ln hnh dng bt k gip cho qu trnh thi cng cc cng trnh nhanh chng v t hiu qu cao. - V mt kinh t: V nguyn liu s dng l nguyn liu a phng: xi mng, cc ph gia v khng phi tri qua giai on sy nung nn gim chi ph cho qu trnh sn xut tit kim nng lng, tit kim vt liu qu him, tn dng c ngun nguyn liu a phng, gim gi thnh sn phm, nng cao hiu qu kinh t. - V mt mi trng v x hi: Vic nghin cu v a b tng chu nhit- cch. nhit vo thc tin sn xut tn dng c ngun nguyn liu a phng, gii quyt vn mi trng, to cng n vic lm cho ngi lao ng gip xo i gim ngho, ngn chn cc t nn x hi. I.2 Mc ch v ni dung nghin cu. Mc tiu: Thc hin nghin cu nng cao kh nng chu nhit ca cht kt dnh chu nhit c to thnh t vic phi hp xi mng poc lng PC40 Bt Sn v PCB40 Phc Sn vi cc loi ph gia l: Samt v gch . Vi cc nhim v sau: - Kho st tnh cht ca cc nguyn liu thnh phn ch to cht kt dnh chu nhit: xi mng poc lng PC40 Bt Sn, xi mng poc lng hn hp PCB40 Phc Sn, ph gia samt, v ph gia gch . - Kho st, nghin cu tnh cht ca cht kt dnh chu nhit dng xi mng poc lng PC40 Bt Sn v cc ph gia cc t l pha trn khc nhau cc cp nhit khc nhau. - Kho st, nghin cu tnh cht ca cht kt dnh chu nhit dng xi mng poc lng hn hp PCB40 Phc Sn v cc ph gia cc t l pha trn khc nhau cc cp nhit khc nhau. - Thc hin: Quy hoch thc nghim ti u tm ra cp phi b tng ti u 800oC v 1000oC. - Nghin cu v thit lp s cng ngh ch to b tng chu nhit-cch nhit dng cht kt dnh chu nhit t xi mng PC40 Bt Sn, PCB40 Phc Sn v cc ph gia.

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CHNG 2: TNG QUAN II.1 Tnh hnh nghin cu b tng chu nhit nng, nh. Hin nay, vi s pht trin mnh m ca cc ngnh cng nghip: nng lng, luyn kim, ha du, ha cht.., b tng c s dng ngy cng nhiu trong cc kt cu xy dng chu tc ng lu di ca nhit cao v bin ng, lm gim kh nng chu lc ca b tng, tng vng ca cc kt cu v cng trnh, c th ph hy hon ton vt liu v cu kin. Trn th gii c nhiu nghin cu v b tng chu nhit (BTCN) cc loi p ng cho nhu cu xy dng ca cc ngnh cng nghip. Nga (Lin X c) vic nghin cu b tng v b tng ct thp chu nhit bt u t nm 1942, ti Trung tm nghin cu khoa hc cc trng i hc, Vin nghin cu cc cng trnh cng nghip v Vin nghin cu khoa hc b tng v b tng ct thp. Trn c s nghin cu thc nghim tin hnh kho st cc loi BTCN khc nhau vi nhit lm vic t 200oC n 1800oC. BTCN l loi nhn to khng nung, c cc tnh cht c l ch yu c bo ton di tc dng lu di nhit 250oC tr ln. Bn thn n va mang tnh cht ca b tng va mang tnh cht ca vt liu chu la, v l s kt hp ca b tng v vt liu chu la. l kh nng d ch to, c th thi cng ton khi hoc lp ghp, y nhanh tc thi cng xy dng, tng kh nng lm vic ca cng trnh, c kh nng chu mhit cao (c th ti 1800oC) lu di v thay i, s dng nguyn vt liu a phng v khng phi qua khu nung. Do khi ch to v nhit thp n l vt liu b tng, nhng khi lm vic nhit cao s xy ra cc phn ng pha rn, to ra cc khong mi, cc khong ny c bn nhit cao. B tng chu nhit c th s dng nhiu loi cht kt dnh khc nhau, ty thuc vo yu cu mc chu nhit. Khi s dng xi mng poc lng lm cht kt dnh th nhit cao, b tng s b ph hy do cc khong thy ha ca xi mng khng bn nhit. Nm 1952-1954 V.V.Contunov tin hnh nghin cu nh hng ca nhit cao i vi cc khong ring bit ca clanhke xi mng poc lng khi rn chc, nh hng ca nhit n s ph hy ca C3S, C2S, C4AF, C3A. cng vi V.V.Contunov cn c cc nh nghin cu khc tin hnh nghin cu tc ng ca nhit n cc tinh cht ca xi mng nh: S A.Myronov, L.A.Malynhina, N.A.Mosanski, G.D.Salmanov, V.A.Kynd v S D.OCorokov, A.E.Xeikin Qua nghin cu nh hng ca nhit cao n cc tnh cht ca clanhke xi mng poc lng vi cc thnh phn khong ha khc nhau, C.D.Nhecrasov, V V Contunov v cc tc gi khc cho thy: Di tc dng ca nhit cao bn ca xi mng sau khi t nng, ph thuc vo thnh phn khong ca n v b tng khng nn s dng lu di nhit ln hn 250oC.

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S gim cng v ph hoi b tng khi tng nhit d mt nc lin kt, ph hoi cu trc ca b tng, ng thi do s thy ha ln 2 ca CaO ( do phn ng phn hy Ca(OH)2 to ra cao t do) bng hi nc trong khng kh. Nghin cu qu trnh thy ha ln hai ca Cao trong xi mng poc lng sau khi t nng, G.M.Ruxue kin ngh a vo trong xi mng poc lng cc ph gia khong khc nhau.V.M.Moskvin, V.V.Contunov nm 1957 cng nghin cu tng tnh cht chu nhit ca xi mng poc lng bng cch s dng cc loi ph gia khong khc nhau. Khi a ph gia khong nghin mn vo xi mng poc lng, ngi ta c hn hp cht kt dnh chu .nhit (CKDCN). Ty thuc vo ph gia, c th nhn c CKDCN vi cc tnh cht chu nhit khc nhau. Y.U.Bt nghin cu s dng ct quc v iatmt nghin mn lin kt CaO thy ha ca xi mng khi gi mu trong iu kin tiu chun v sau khi chng p. Trong qu trnh chng p, ct quc v iatomt nghin mn s lin kt vi CaO t do. Theo Y.E.Gurvytr v M.C.Agaphnp phn ng gia xyt Silic v nh hnh v CaO t do trng rn xy ra mnh nhit 500oC-600oC; cn i vi quc tinh th, n ch bt u 600oC. Theo P.P.Budnhicop, V.Pa.Zuravlev phn ng pha rn gia xyt Silic v xyt Can xi (khi t l 1 : 1 ) xy ra qua hp cht trung gian khng bn 2CaO.SiO2 v 3CaO.SiO2 n hp cht cui cng l CaO.SiO2, tuy nhin khi t nng SiO2 c s bin i th hnh khng n nh th tch, nn khng s dng n vi tnh cht ph gia cho XMPL vi tinh cht chu nhit. V. V. Contunov v Z.M.Larionov nghin cu tc ng ca cc khong xi mng ch yu vi cc ph gia sa mt mn, cho thy: lng ph gia a vo cng ln th kh nng lin kt vi CaO t do xy ra hon ton dn ti tng bn ca xi mng sau khi t nng 1200oC. iu ni ln rng khng cn CaO t do trong xi mng sinh ra khi t nng xi mng, chng c lin kt hon ton vi SiO2 v Al2O3 ca sa mt mn, hnh thnh dng khong mi l silicat v aluminat khan. Tuy nhin khi tng lng ph gia s nh hng n cc tnh cht khc ca xi mng nh t l nc/hn hp cht kt dnh chu nhit, cng nn Tuy nhin t l xi mng vi ph gia cn cha c nghin cu c th. Khi s dng x l cao lm ph gia trong xi mng poc lng, ngi ta thy rng: khi nhit cao t 750 : 800 oC, kh nng lin kt vi CaO ln hn 600oC v s lin kt ca x nh hn ca sa mt. tng cc tnh cht chu la ca xi mng poc lng, G.D.Salmanov s dng ph gia nghin mn crmmit, ph gia ny khi a vo s lin kt t do vi xyt can xi t do ca XMPL, tng chu la v nhit bin dng di ti trng 2kG/cm2 ca xi mng. Ngoi b tng nng cn c b tng nh chu nhit, theo B.G.Skramtaep, ct liu tt nht s dng cho b tng nh chu nhit l vt liu xp: x, peclit, x bt, tp, keramzit, vemiculit. Cc HVTH: NGUYN HONG T Page 4

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tc gi C.D.Nhecrasov, S.C.Lisenco nghin cu b tng kh chu nhit (b tng chu nhit-cch nhit) dng XMPL vi cc ph gia mn khc nhau l: sa mt, x l cao, tro x, keramzit, trn c s dng ph gia mn lin kt vi xyt can xi t do. Nm 1966- 1968 Trung tm nghin cu khoa hc xy dng (ca CHLB Nga-VNYYS) tin hnh nghin cu b tng nh chu nhit dng XMPL vi ph gia samt nghin mn v ct liu l si keramzit, dm aglporit. c bit trong cc nm gn y c cc cng trnh nghin cu v b tng nh chu nhit dng ct liu xp nhn to v cc loi ph gia khc nhau. Hin nay Trung tm nghin cu b tng v b tng ct thp (ca CHLB Nga -NYYZB) v ang nghin cu BTCN dng cht kt dnh phi pht vi cc ct liu alumsilicat khc nhau: mnh vn sa mt, sa mt v sa mt cao lanh. Ngoi cc loi cht kt dnh trn, ngi ta cn nghin cu cc loi cht kt dnh t thy tinh lng v ph gia c cha silicat mt can xi ch to B'TCN. nng cao tnh chu la ca cht kt dnh ngi ta s dng mt s loi cc ph gia mn: sa mt, manhezi, vt liu chu la cao nhm. mt s nc khc: Trung Quc, Anh, CHLB c u s dng xi mng alumin ,caoalumin vi lng Al2O3 ln Xy dng cc cng trnh chu tc ng ca nhit Vit Nam, vic nghin cu BTCN cng bt u c tin hnh: Nm 1977, B mn Cng ngh vt liu xy dng-trng i hc Xy dng v Vin k thut xy dng H Ni tin hnh nghin cu th nghim BTCN dng XMPL vi ph gia nghin mn samt. Nm 1988- 1991 , B mn Cng ngh vt liu tin hnh, nghin cu ch to BTCN s dng ph gia x nhit in v hn hp ph gia samt-x nhit in ch to cht kt dnh chu nhit; tin hnh nghin cu tnh ton thnh phn ht ct liu dng cho b tng chu nhit. Nm 1993, B mn Cng ngh vt liu tin hnh nghin cu ch to b tng kh chu nhit (loi b tng chu nhit-cch nhit) dng xi mng poc lng vi cc ph hia samt, x nhit in. Nm 19961998, B mn cng ngh vt liu tin hnh nghin cu ch to b tng nh chu nhit dng XMPL vi ph gia keramzit, gch v v ct liu rng keramzit. Nm 2005-2006, B mn Cng ngh vt liu tin hnh nghin cu ch to va (b tng ht nh) chu nhit, chng chy s dng ct liu sa mt, gch v vi cht kt dnh xi mng poc lng hn hp v thu c cc kt qu kh kh quan. II.2. Tnh hnh s dng b tng chu nhit nng, nh. B tng chu nhit c s dng ngy cng rng ri xy dng cc cng trnh chu tc ng ca nhit cao. Vic s ng b tng thay th cc vt liu chu la c nhiu u im, mang li hiu qu kinh t cao, l: cho php xy dng cng trnh theo hng cng nghip ha HVTH: NGUYN HONG T Page 5

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ton khi hoc lp ghp t cc cu kin kch thc ln ch to sn cc nh my b tng, tng kh nng lm vic ca cc cng trnh nh gim s mch xy, khng phi qua khu gia cng nhit, . . . Cc cng trnh BTCN c th ton khi hay lp ghp c s dng rng ri trong cc ngnh cng nghip khc nhau: Luyn kim en, mu; cng nghip ha cht; cng nghip vt liu xy dng, cng nghip nng lng, ch bin du m, . . . II.2.1. Tinh hnh s dng b tng chu nhit trn th gii. 1 B tng chu nhit dng trong cng nghip luyn kim en. a. Lm thp t nng khng kh. Nm 1958 ln u tin trn th gii v Nga, khu lin hip luyn kim Kuznhexe xy dng cng trnh thp t nng khng kh ca l cao t cc mc c ln bng BTCN v BTCNCN vi lp trong cng l BTCN, lp tip theo bn ngoi l BTCN-CN. Cc block xy dng thp t nng khng kh s dng xi mng poc lng vi ph gia sa mt v ct liu sa mt. Nhit s dng ln nht l 1200oC. Ngoi ra ngi ta cn s dng BTCN dng kt cu n tm, dng XMPL vi ph gia sa mt lm vm che ca l t nng, c nhit s dng 650850oC. Kt cu vm l ny lm vic c 1 8 thng, trong khi nu lm t gch sa mt thi gian s dng.ch c c 3 thng. Tip Khc, nm 1965 tin hnh nghin cu v s dng BTCN. (nng v nh) trong xy dng cc thit b nhit. BTCN c s dng xy dng cc l bung t c y l di ng, c s dng lm tm che, ca chn, ng khi, knh dn. Nhit ln nht c bit ca l l 1050oC. B tng chu nhit s dng xi mng poc lng vi ph gia v ct liu sa mt, b tng nh chu nhit s dng ct liu peclit phng trng, BTCN-CN s dng xi mng poc lng vi ph gia x l cao. b. Lm nn mng l cao,ng khi v knh dn. Vic nghin cu cc kt cu ca mng l cao dng BTCN c bt u t nm 1949 Nga, n nm 1951 a vo s dng v chng minh c s bn vng v n nh ca n trong qu trnh lm vic. B tng chu nhit c s dng rng ri lm ng khi v knh dn. Vic xy dng cc ng khi rt nng nhc nn vic c gii ha c mt ngha quan trng. Nm 1966 , nh my luyn kim Caragandiski (Nga) thit k v xy dng ng khi bng BTCN vi cht kt dnh l xi mng poc lng vi ph gia, ct liu keramzit. Nhit s dng nht l 700oC. BTCN cn c s dng lm knh dn kh nng, bao gm cc block cao 2,5m, rng 1,5 - l,8m. Tip

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Khc, cc knh dn kh thi ca l c lm t BTCN c nhit s dng l 620 oC, sau 15 thng vn hot ng tt. Phn xng cn thp ca khu lin hp luyn kim Magnhitogoski, tng ca knh dn kh nng c lm t cc block chu nhit, vi cht kt dnh l XMPL, ph gia ,ct liu crommit, focsterit. Qua 2,5 thng, hao mn ca block l 10mm, cn khi dng gch thut l 1,5-2 thng. CHLB c, nh my thy tinh Ainkhait-thnh ph Vaisvase tin hnh th nghim ch to cc knh dn khi t BTCN dng XMPL vi ph gia v ct liu samt c nhit s dng n 900oC kt qu cho thy bn vng, tui th, hiu qu s dng hn hn gch samt. Ba lan, BTCN cng c s dng tt trong trong cc knh dn kh nng, kh thi v ng khi vi nhit lm vic l 900oC, thi gian s dng t 8 n 10 nm. c. Bung lng x v bung tch nhit ca l Mc tanh. Ngi ta s dng BTCN-CN ng vai tr vt liu cch nhit trong bung lng x v bung tch nhit ca l Mc tanh. iu ny cho php ch to cc cu kin cch nhit bng phng php cng nghip, tng tui th ca cng trnh cng nh t c hiu qu kinh t cao so vi vic s dng vt liu n chic l iatmit. 2.B tng chu nhit dng trong cng nghip luyn nhm. Nh my luyn nhm Cadalacski (Nga) tin hnh thc nghim thay th cc vng kim loi ca l in phn bng BTCN lp ghp t XMPL vi phu gia, ct liu samt, cho php gim chi ph thp, gim gi thnh do tng mc lp ghp cc canh ca l in phn. Ngoi ra nh my luyn nhm Vongagrad tin hnh nghin cu s dng BTCN lm y l in phn luyn nhm. 3.B tng chu nhit dng trong cng nghip ch bin du m. a. Thit b t nng ng. L bung dng t nng ng ,ch bin nguyn liu du m. Ln u tin l dc xy dng bng BTCN cc nh my ch bin du m Angarse (CHLB Nga) vi nhit lm vic l 760oC. Cc knh dn, tng, vm, nn l u c lm t BTCN dng XMPL vi ph gia v ct liu l sa mt, dng xi mng alumin vi ct liu sa mt v dng cht kt dnh silicat vi ct liu sa mt. b. Lo chy bc x nhit. "

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BTCN dng XMPL vi ph gia v ct liu sa mt v ang c s dng xy cc l bc x nhit, ng vai.tr lp lt v lp chu lc Nvquybsav, Grozenski, Vongagrad v cc nh my ch bin du khc Nga. Ngoi ra cn c mt s nh my ch bin du m c s dng cc loi BTCN khc nhau xy dng l ng chu p lc vi nhit s dng t 600- 1200oC. phn trn ca l c nhit t 600-1200oC, c xy bng BTCN dng XMPL vi ct liu agloporit v BTCN dng XMPL vi ph gia v ct liu sa mt, phn di l c nhit 1000 oC c xy bng BTCN dng XMPL vi ph gia v ct liu sa mt. 4. S dng trong ch to my. Nm 1959, phn xng rn nh my Kirovski Xanh Peterbua (CHLB Nga) xy dng l gia cng nhit cc chi tit. L c xy dng t cc block BTCN sn xut t XMPL vi ph gia v ct liu samt, c nhit lm vic n 1200oC. Vic s BTCN cho cc l c ch lm vic gin on l rt hp l v chng lm vic khng km g so vi lm t vt liu chu la n chic. Tip Khc, BTCN cn c s dng lm cc khun c gang vi nhit lm vic l 1230oC trong thi gian 1 pht, s dng c 10 chu k. 5. Dng trong cng nghip nng lng. Nm 1958, c bt u nghin cu v s dng BTCN trong cc thit b ni hi ca trm ln Trattendorph. Ba ni hi c lt bng cc tm BTCN ch to t XMPL vi ct liu samt, chu c nhit t 800- 1000oC . Nm 1959, trm pht in Biolen (c) cng s dng cc block BTCN lt lp b mt t nng ni hi s 6. Cc block BTCN dng XMPL vi ct liu sa mt nhit lm vic 600 oC, thi gian s dng sau 17 thng vn khng c vt nt. Vic s dng cc block BTCN ny rt ngn c 25% thi gian xy dng. 6.Trong cng ngh vt liu xy dng. a. Lm l tuynen nung gch: Nm 1959 nh my gch Nov-mantiski, nh my Ustikamenogorski, nh my thc nghim Glebtrevski(nga) xy dng l tuynen nung gch t cc cu kin b tng ct thp chu nhit lp ghp, nhit nung l 970 oC. Cc panen, cc block lm tng, vm, nn dng BTCN t XMPL vi ph gia v ct liu sa mt. Ngoi ra BTCN cn c s dng lm lp lt cho ton b va gng ca cc l trn.

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b. Lm l nung gch: Nh my gch Nov-mantiski, Ziminski (Nga) s dng BTCN t XMPL vi ph gia tro thi, ct liu samt lm 18 bung ca l vng nung gch t st, nhit t 850-970oC. Tip Khc, Ba lan BTCN dng XMPL vi ct liu sa mt c nhit lm vic t 9001000oC cng c s dng xy l vng nung gch. II.2. Tnh hnh hnh s dng b tng chu nhit nng, nh Vit Nam. Vit Nam vic s dng BTCN hy cn nhng hn ch, bi v vic nghin cu cn cha c y v ton din. mt s ni s dng BTCN nh : nh my nhit in Ph Li dng xi mng alumin vi ct liu sa mt. Nh my knh p Cu s dng BTCN t XMPL vi ph gia xi l cao v ct liu sa mt. B mn Cng ngh vt liu xy dng-trng HXD v Vin k thut xy dng H Ni nghin cu BTCN dng XMPL vi ph gia v ct liu samt, xy knh kh nng l tuy nen nh my gch Phc Thnh H Ni. B mn Cng ngh vt liu xy dng - trng HXD v nh my s Thanh Tr H Ni nghin cu ch to BTCN lm lp lt va gng nung s dng XMPL vi ph gia samt, x v hn hp samt-x, ct liu sa mt. B mn Cng ngh vt liu xy dng - trng HXD v nh my xi mng H Dng -Ninh Bnh nghin cu ch to v s dng b tng ct thp chu nhit dng XMPL vi ph gia v ct liu sa mt lm chp l ng nung clanhke xi mng lm vic 1000oC. B mn Cng ngh Vlxd-trng HXD v Cng ty sn xut kinh doanh vt liu xy dng thnh ph Thi Bnh nghin cu ch to BTCN dng XMPL xy cc b phn ca l tuy nen nung gch: knh dn kh nng, ng rt nhin liu, lp lt va gng nung. Nhn chung cc vn nghin cu v s dng BTCN t cc nguyn liu trong nc, ti cc c im cng ngh sn xut trong iu kin ca nc ta c ngha to ln v cp thit.

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CHNG 3: C S L LUN KHOA HC NGHIN CU B TNG CHU NHIT - CCH NHIT B tng chu nhit- cch nhit hin nay c to ln bi cc nguyn vt liu ch yu sau: - Cht kt dnh chu nhit: lm cht kt dnh chu nhit c th s dng nhiu loi nh xi mng ngc lng, xi mng ngc lng hn hp vi cc ph gia chu nhit, thu tinh lng, cc loi xi mng c bit c kh nng chu nhit nh xi mng alumin, xi mng periclazo. . . - Cht to rng: Tu theo phng php cng ngh, cht to rng trong b tng chu nhitcch nhit c th l cht to kh hoc cht to bt. Cht to kh c th dng l H2O2; bt nhm(Al), v hin nay thng dng nht l bt nhm. Cc loi cht to bt c th dng l x phng- keo nha thng, huyt thu phn v cc cht to bt tng hp khc. - Nc v cc ph gia khc: Nc sn xut b tng chu nhit-cch nhit cng ging nh i vi b tng thng tc l cng phi m bo cc yu cu v pH, hm lng mui sun pht, ngoi ra khi ch to c th s dng ph gia nh ph gia rn nhanh. . .yu cu vi cc loi ph gia l khng to ra hp cht km bn di tc dng ca nhit cao v ko di. Nh vy, nguyn vt liu s dng cho b tng chu nhit cch nhit rt a dng tu thuc theo iu kin c th v cc yu cu thc t m la chn nguyn vt liu cho ph hp, nhm mang li hiu qu kinh t k thut cao nht. III.1 Cht kt dnh chu nhit s dng cho b tng chu nhit-cch nhit. lm cht kt dnh chu nhit chng ta c th s dng nhiu loi vt liu khc nhau phi hp li m thnh, v ph bin nht hin nay l s dng xi mng poc lng, bi xi mng poc lng l cht kt dnh hidrat c kh nng ng kt rn chc, pht trin cng trong mi trng nc v khng kh. Thnh phn ha ca xi mng ch yu gm 4 xyt chnh l CaO, SiO 2, Al2O3 , Fe2O3 , cc xyt ny c hm lng: 95 - 98% trong klanke xi mng, ngoi ra cn cc xyt khc nh: Na2O, K2O, TiO2... vi hm lng nh v hu ht c nh hng ti n cc tnh cht ca xi mng, nhng nu hm lng chng qu ln s lm gim cng ca xi mng Thnh phn khong ca xi mng ch yu gm cc khong : Siiicat can xi (hm lng 70-80 %), cc khong Aluminat Canxi, Alumo ferit can xi. - Khong Alt ( 3CaO.SiO2 - k hiu C3S ): chim 45-60%. y l khong quan trng nht ca xi mng, to cho xi mng c cng cao, ng kt rn chn nhanh v c nh hng nhiu n tnh cht ca xi mng. HVTH: NGUYN HONG T Page 10

TRNG I HC XY DNG


- Khong Blt (2CaO.SiO2 - k hiu C2S ): chim khong. 20-30% khi lng clanke. y l thnh phn khong quan trng, c c tnh ng kt chm nhng cng cui cng tng i cao, l dung dch rn ca 2CaO.SiO2 vi mt lng nh (l-3%) cc xt khc nh Al2O3; Fe2O3; Cr2O3 n tn ti trong clanke xi mng poc lng 4 dng th hnh -C 2S; -C2S; -C2S; C2S nhng ch yu dng -C2S. Ngoi ra, trong xi mng poc lng cn c cc pha khc nh: pha canxialumferit, can xi aluminat, pha thy tinh v mt lng CaO v MgO t do. Khi b t nng nhit cao, thnh phn pha v cu trc ca xi mng pooclng b bin i: - Khi t nng t: 100 - 200oC mu xi mng poc lng: tng cng do s "t chung hp ca cc khong xi mng poc lng. - Khi t nng trn: 200oC th cng bt u gim do s mt nc l hc, khi tip tc tng nhit t 400 : 500oC, xy ra s t tch nc ca hydroxyt can xi to ra CaO gy ra ph v cu trc v gim cng . - Khi t nng t: 600 - 900oC: th xi mng b ph hy hon ton sau khi gi chng trong khng kh, do s thy ha ln hai ca CaO. - Khi t nng nhit cao hn mu b ph hy hon ton. Trong qu trnh t nng xi mng poc lng xy ra hin tng co ngt, ph thuc vo thnh phn khong m co t n 1% v cao hn. III.2. C s l thuyt - thc nghim nghin cu cht kt dnh chu nhit: Nh trn phn tch v s ph hy cu trc ca xi mng poc lng di tc dng ca nhit cao, xy ra qu trnh tch nc ca hydroxit can xi to ra CaO t do v qu trnh thy ha ln hai ca CaO t do trong xi mng poc lng. Mc ch s dng ph gia khong nghin mn ch to cht kt dnh chu nhit l: lm gim s co ngt ca xi mng khi t nng, lin kt vi thnh phn khong thy ha ca xi mng, lin kt vi CaO t do hnh thnh cc hp cht c kh nng chu nhit cao hn. Bng kt qu thc nghim G.M.Ruxuk xc nh c nhit ta ra ca xi mng poc lng tinh khit v hn hp xi mng poc lng vi cc ph gia nghin mn khc (x t st, trepel. . .) di tc dng ca nhit cao. Ruxuk cho thy qu trnh thy ha ln hai ca CaO trong XMPL tinh khit v hn hp xi mng poc lng vi cc ph gia nghin mn khc xy ra khc nhau: Trong xi mng poc lng tinh khit, nhit ta ra tng theo mc tng nhit t nng,

HVTH: NGUYN HONG T

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TRNG I HC XY DNG -


Trong hn hp xi mng poc lng - ph gia nghin mn, nhit ta ra ln nht cho thy c khi t nng n 300 - 400oC, sau gim dn, c bit s ta nhit thp nht r rt 800 - 900oC .

-

i vi mt s xi mng vi ph gia nghin mn khc, khng thy c trng ta nhit trong khong 500 - 600oC, iu chng t hm lng ca CaO thy ha thp.

G.M.Ruxuk ch ra rng Ca(OH)2 tch ta khi xi mng thy ha c th c lin kt trong qu trnh t nng vi cc ph gia nghin mn khc nhau. B.M.Moskvyn v B.B.Kuraev nhn thy rng, tng tnh chu nhit ca xi mng poc lng v b tng c th s dng mt s loi ph gia khc nhau. a ph gia nghin mn vo trong xi mng poc lng dn ti gim lng cht nng chy trong mt n v th tch (n khng cn qu ln gy bin dng ca vt liu v khng qu nh lm chm phn ng ca pha rn v s kt khi). Ngoi ra cn tng lc ma st bn trong gia cc phn ca vt liu do nht ca cc cht kt dnh tng ln, tng nhit mm di ti trng cng nh chu la cht kt dnh. Ph gia khong nghin mn a vo trong xi mng poc lng lm gim tng i khi lng pha lng v tng chu la, tng nhit bin dng di ti trng ca b tng Do vy chng phi tha mn cc yu cu: - Tng tc vi cc thnh phn khong thy ha ca XMPL v lin kt vi oxit can xi t do nhit cao to thnh cc hp cht mi c chu la cao. - Ha tan khng ng k pha lng v khng to thnh nhng hp cht c im tecti thp khi tng tc vi cc khong ca xi mng poc lng. - Khng lm tng co ngt ca xi mng poc lng trong qu trnh t nng. - Khng lm gim hot tnh ca xi mng poc lng. Ph gia a vo trong b tng theo mt t l nht nh so vi xi mng, khi hn hp xi mng poc lng v ph gia c gi l cht kt dnh chu nhit (CKDCN) v b tng c gi l b tng chu nhit. Tnh cht ca BTCN ph thuc vo CKDCN. Khi nghin cu BTCN cn phi bit s thay i cng v cc tnh cht khc ca CKDCN khi t nng, cc tnh cht ca nguyn liu s dng. Cng ca CKDCN trong qu trnh t nng thay i ph thuc vo cc yu t: loi ph gia nghin mn, lng dng ph gia, nghin mn ca ph gia, t l nc v cht kt dnh . . . III.3 Phng php to rng cho b tng chu nhit cch nhit: i vi cc vt liu chu nhit cch nhit cu trc rng rng l rng kn, c ng knh nh, th tch l rng ln, cc l rng phn b u trong vt liu, nhng vn m bo nhng c tnh k thut ca vt liu: bn HVTH: NGUYN HONG T Page 12

TRNG I HC XY DNG


Cu trc rng t ong ca vt liu cch nhit bao gm cc l rng t ong (l rng ln) v cc l rng trong cc vch ngn gia cc l rng ln (l rng b). Vic nghin cu ch to vt liu cch nhit c lng l rng ln, m vn m bo cc tnh nng ca vt liu cng nh cc ch tiu v kinh t k thut ca vt liu l ht sc cn thit. Theo kt qu thc nghim, cc nh khoa hc thy cu trc rng l tng ca vt liu cch nhit chu nhit c xc nh theo cng thc sau: Rto = 0.812*(d/D+)3*100 (%) Vi: Rto D : rng ca vt liu : ng knh trung bnh ca l rng : Chiu dy trung bnh vch ngn l rng.

Ngoi l rng t ong trong vt liu chu nhit cch nhit cn c ,t lng l rng mao qun v l rng gel, v cc l rng trn tnh ton c theo cng thc: L rng mao qun: Rmq = 0.001*(N-Wi*a*X) (%) Vi: N X Wi a L rng gel: Rgel = 0.01*j*a*X (%) Vi: j : Th tch nc lin kt gel hp ph. : Lng dng nc trong 1m3 vt liu : Lng dng xi mng trong 1m3 vt liu : Lng nc lin kt ho hc, vt l ca cc gel : Mc thu ho.

Theo kt qu nghin cu cc nh khoa hc thy rng: trong b tng t ong cch nhit th tch l rng mao qun chim khong: 5 12% th tch l rng vt liu v th tch l rng gel chim khong 1.5 2.5% th tch l rng vt liu. Khi mt trung bnh ca b tng cng cao hay chiu dy vch ngn gia cc l rng ln cc ln v lng dng nc trong mt mt khi vt liu cng tng th l rng mao qun v l rng gel cng tng tuy nhin khi l rng t ong ca vt liu li gim v gim rt ln. ng thi cu trc rng ca vt liu c th hin qua cc c trng: HVTH: NGUYN HONG T Page 13

TRNG I HC XY DNG -


S phn b ca cc l rng trong vt liu: ng u hay khng ng u Chiu dy cc vch ngn gia cc l rng Mt vch ngn gia cc l rng Hnh dng l rng c im b mt bn trong ca l rng S ng kn ca cu trc t ong.

Khi ch to cu trc rng cho vt liu chu nhit cch nhit cn c bin php m bo cc c trng ny. Phng php to rng cho vt liu chu nhit cch nhit c la chn tu theo phng php cng ngh, cht to rng trong b tng chu nhit-cch nhit c th l cht to kh hoc cht to bt. Cht to kh c th dng l H2O2 hay bt kim loi nhm (Al), nhng hin nay thng dng nht l bt nhm kim loi. to ra b tng chu nhit - cch nhit s dng cht to kh th qu trnh tch kh to rng trong b tng c th sy ra do cc nguyn nhn sau: - Tc dng ln nhau gia cc cht to kh (v d: bt nhm) vi cc sn phm thu ho ca cht kt dnh gii phng hyr: 2Al + 3Ca(OH)2 +6H2O -> 3CaO.Al2O3.6H2O + 3H2 - Phn ng to kh ca cc cht khng n nh. Trong cng ngh ch to b tng.kh, cht to kh s dng ph bin nht l bt nhm. Bt nhm s dng c mn rt ln 4000 - 6000 cm2/g. mn cng ln, bt nhm cng phn b u trong hn hp, tng hiu qu to kh, do gim c lng dng bt nhm, ng thi to ra l rng b phn b ng u hn lm tng cng . Hin nay sn xut b tng kh thng s dng bt nhm do Lin X c sn xut. C 4 mc khc nhau t: nAK1 n nAK4. Trong sn xut b tng kh s dng hp l nht l loi: nAK2 v nAK3 . Khi sn xut bt nhm c bao bc bi mt mng parafin mng trnh s xy ho. Trc khi s dng, bt nhm cn c gia cng s b tch mng bc parafin.

HVTH: NGUYN HONG T

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TRNG I HC XY DNG C

GVHD: PGS. TS. V MINH

CHNG 4. CC PHNG PHP NGHIN CU IV.1. Cc phng php nghin cu cc tnh cht ca cht kt dnh chu nhit. Cc ch tiu nh khi lng ring, khi lng th tch, mn, lng nc tiu chun, thi gian ninh kt, tnh n nh th tch c xc nh theo TCVN 2682-1992. Xc nh co th tch ca cht kt dnh chu nhit: TCVN 201 - 1986. chu la ca CKDCN c xc nh theo tiu chun TCVN 1 79- 1 996.

- Phn tch nhit DTA DTG - Phng php phn tch nhiu x R nghen nghin cu s hnh thnh cc hp cht mi, l cc khong mi to thnh nh phn ng vt cht trng thi rn trong qu trnh t nng. ng thi gii thch s hnh thnh ca cc khong mi bn nhit, nng cao tnh chu nhit cho vt liu. - Phn tch thch hc bng phng php chp vi in t, phn tch cu trc trn c s s hnh thnh cu trc ca cc mu cc cp nhit khc nhau v cu trc ca cc khong bn nhit mi c to ra, t gii thch bn cht cc tnh cht c l v tnh cht chu nhit ca nguyn vt liu nghin cu. IV.2. Phng php nghin cu hn hp b tng chu nhit cch nhit: IV.2.1 Tnh ton cp phi b tng ch nhit cch nhit: Tnh: Lng dng xi mng: Pxm = Trong : Pxm: 0bt

0 BT xVK cx (1 + C )

(kg)

lng dng xi mng, kg : KLTT b tng trng thi kh, g/cm3 Th tch 1m3 m trn H s tng khi lng vt cht kh do lng nc lin kt trong qu trnh rn chc ca b tng (Kcx = 1,1) T l lng ph gia pha trn vi XMPL, t l ny ph thuc vo loi PG v nhit s dng

V: Kcx: C:

Tnh: Lng dng nc: Pn = (Pxm + PPG ). Trong : PPG: Lng dng ph gia khong nghin mn, kgN , kg R

HVTH: NGUYN HONG T

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TRNG I HC XY DNG CN : R


T l lng dng nc vi khi lng cht rn

Tnh: rng: r r=1Vi: :

0Kc

( +

N ) R

Khi lng ring tuyt i ca th tch hn hp kh, (l/kg) = ahh1

a =Trong : axm

axm x aPG AXM aPG + APG axm

: Khi lng ring ca xi mng, g/cm3. Hm lng xi mng trong hn hp CKD : Khi lng ring ca ph gia, g/cm3. Hm lng ca ph gia trong hn hp CKDV (kg) k .

Axm:aPG

APG:

Tnh: Lng dng cht to kh Pk = r. Trong : : K: H s s dng cht to kh ( = 0.75 0.8) Sn lng to kh ca mt n v cht to kh, theo l thuyt k = 1390l/kg, thc t: k = 1350l/kg. IV.2.2. Cc phng php xc nh tnh cht ca hn hp b tng v b tng chu nhit cch nhit: chy ca va b tng kh c xc nh nh sau: Dng c s dng gm mt hnh tr bng ng hoc ng thau ng knh trong 5cm, chiu cao 10 cm v tm thu tinh c kch thc mi cnh l 40cm. Trn tm thu tinh qua mi 0,5cm vch mt ng trn xung quanh tm vi ng knh ln nht l 40cm. Quy trnh th nghim: t tm thu tinh nm ngang, cn hnh tr tm cc vng trn ng tm. va trn trc vi bt nhm vo hnh tr, sau nhc hnh tr ln theo phng thng ng. Va s c chy loang trn tm thu tinh do tc dng ca trng lng bn thn. Xc nh co th tch v khi lng th tch. xc nh cc ch tiu ny, trc v sau khi nung mu cn tin hnh o kch thc v cn khi lng mu. T tnh c cc gi tr nh sau: HVTH: NGUYN HONG T Page 16

TRNG I HC XY DNG C + co th tch : V = (V1- V2)*100/V1, %. + Khi lng th tch: = m/V2, g/cm3. Trong : V1: Th tch mu trc khi nung, cm3. V2: Th tch mu sau khi nung, cm3. m: Khi lng mu sau khi nung, g. Xc nh cng nn.


xc nh cng nn, tin hnh c mu lp phng kch thc 10x10x10cm. Sau dng h trong iu kin t nhin vi thi gian 7 ngy. Sau mu c em i nn, xc nh cng 25oC. Khi xc nh cng nn sau sy, mu c gia cng v sy 100oC n khi lng khng i, sau c em i xc nh cng . Khi xc nh cng nn ca vt liu cc cp nhit khc nhau, mu sau khi c gia cng, sy 100oC, sau c em nung nhit cn xc nh cng , v c hng nhit nhit trong khong 2h, sau mu c lm ngui n nhit thng v xc nh cng nn Rtn. Xc nh bn nhit Ch to mu, bo dng theo quy nh. Sau t nng mu n 800 oC, sau ly mu ra lm ngui trong khng kh bng cch thi kh lnh. Sau khi lm ngui n nhit phng, em mu vo cn v kim tra s hnh thnh cc vt nt, sau li a mu vo t nng. Mi ln t nng v lm ngui nh vy l mt ln trao i nhit. Kt qu th nghim l s ln trao i nhit n khi mt 20% khi lng ban u hoc s xut hin vt nt, khi : bn nhit ca vt liu l s chu k vt liu thc hin trao i nhit m khng xut hin vt nt hoc cha mt 20% khi lng.

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CHNG 5. KT QU NGHIN CU. V.1. Cc kt qu nghin cu v cht kt dnh chu nhit. V.1.1. Kt qu kho st nguyn vt liu: Trong ti ny chng ti s dng cht kt dnh l xi mng pooclng PC40-Bt Sn v PCB40-Phc Sn, k hiu ln lt l: PC40BS v PCB40PS. Bng 1: Thnh phn ho ca xi mng PCB40 - Bt Sn v PCB40 Phc Sn.

[[

STT 1 2 3 4 5 6 7 8 9

Thnh phn ha oxit CaO SiO2 Al2O3 Fe2O3 MgO SO3 K2O Na2O MKN

Loi oxit PC40BS (%) 62,84 20,65 5,42 8,43 2,01 0,47 0,74 0,16 1,14 PCB40PS(%) 6365,2 22,224,6 5,26,2 2,23,1 2,22,5 1,21,8 0,30,6 0,180,21 1,121,2

Bng 2: Thnh phn khong ca xi mng PCB40 - Bt Sn v PCB40 Phc Sn.

STT 1 2 3 4

Thnh phn khong C3S C2S C3A C4AF

Loi oxit PC40BS 45,2647,5 24,4126,3 6,367,5 10,3411,8 PCB40PS 46 49 17,0 21 69 12 14

Cc ch tiu c l ca xi mng c xc nh theo tiu chun TCVN 2682-92, kt qu thu c ph hp vi quy phm.

HVTH: NGUYN HONG T

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TRNG I HC XY DNG C


Bng 3: Cc tnh cht c l ca xi mng PCB40 - Bt Sn v PCB40 Phc Sn.Ch tiu Nc tiu chun Lng st sng N008 n nh V Thi gian ng kt Bt u Kt thc Khi lng ring (a) Khi lng th tch (o) Cng nn 28 ngy n v tnh % % mm Pht Pht Pht g/cm3 g/cm3 kG/cm2 90.00 150.00 3.16 1.09 381.50 105.00 172.00 3.07 1.08 480.25 PC40BS 29.00 2.50 1.50 PCB40PS 28.50 2.80 1.80

Ph gia khong s dng cho cht kt dnh chu nhit l samt (S) v gch (G). Di y l thnh phn ha v cc tnh cht c l ca ph gia S v G: Bng 4: Thnh phn ha ca ph gia S v GThnh phn ha SiO2 Al2O3 Fe2O3 CaO MgO SO3 R2O MKN PG Sa mt 57.80 38.57 5.00 1.20 1.08 1.56 PG gch v 67.82 17.53 9.82 1.18 1.84 1.05 -

Bng 5: Cc tnh cht ca ph gia S v GCh tiu Khi lng ring Khi lng th tch ht nc chu la mn (St sng N008) n v g/cm3 g/cm3 % oC % Sa mt 2.652.89 11301260 58 16501750 30.00 Gch v 2.62.7 8501100 1215.2 11501180 30.00

Cht hot ho: C thnh phn l cc cht kim. HVTH: NGUYN HONG T Page 19

TRNG I HC XY DNG C


Ph gia to rng: Dng bt nhm c kch thc 20-50m, tng ng mn: 4000 6000cm2/g, c bc parafin chng xi ho. V.1.2. Kt qu nghin cu cht kt dnh chu nhit: Bng 6: Lng nc tiu chun ca hn hp cht kt dnh STT 1 2 3 4 5 6 7 8 9 T l X:PG 100:0 90:10 80:20 75:25 70:30 65:35 60:40 55:45 50:50 Nc tiu chun, (%) PC40BS PCB40PS Ph gia S Ph gia G Ph gia S Ph gia G 29 29 28.5 28.5 29.25 29.5 28.75 29 29.5 29.75 29 29.25 29.75 30 29.25 29.5 30 30.5 29.5 30 30.25 30.75 29.75 30.25 30.75 31.5 30.22 30.75 31.5 31.75 30.5 31.5 32 32 31 32

Bng 7: Thi gian ng kt ca hn hp cht kt dnh Thi gian ng kt, pht/gi TT T l X:PG PC40BS PCB40PS

PG S PG G PG S PG G PG S PG G PG S PG G Bt u Kt thc Bt u Kt thc Bt u Kt thc Bt u Kt thc 90 1h50 2h05 2h15 2h28 2h42 2h55 3h08 3h12 150 2h45 2h58 3h15 3h30 3h42 3h52 4h07 4h15 90 1h45 2h00 2h10 2h25 2h35 2h47 2h58 3h05 150 2h40 2h52 3h15 3h22 3h35 3h46 3h58 4h07 1h45 2h00 2h12 2h20 2h33 2h48 2h58 3h12 3h20 2h55 3h05 3h15 3h24 3h42 3h47 3h58 4h10 4h20 1h45 1h55 2h08 2h08 2h20 2h45 2h55 3h05 3h12 2h55 3h02 3h12 3h48 3h28 3h42 3h55 4h07 4h15

1 2 3 4 5 6 7 8 9

100:0 90:10 80:20 75:25 70:30 65:35 60:40 55:45 50:50

HVTH: NGUYN HONG T

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TRNG I HC XY DNG C Nhn xt:


- Ta thy khi tng hm lng ph gia sa mt hay ph gia gch th lng nc tiu chun tng dn (ng thi ln hn lng nc tiu chun ca xi mng). Nguyn nhn ca hin tng ny l do ph gia nm dng bt mn phn b u trong hn hp cht kt dnh, cc ph gia ny ht nc vo trong bn thn chng, do vy lm lng nc tiu chun ca hn hp cht kt dnh tng ln. - So snh hai loi ph gia sa mt v gch th thy lng nc tiu chun khi dng ph gia S vi cng t l v loi xi mng th cao hn khi dng ph gia G, v S c ht nc cao hn G. nh hng ca loi v lng dng ph gia n cng nn ca CKD CN. Vi PC40 Bt Sn: Rn ca CKDNC cc cp to ; kG/cm2 / % Loi CKD PC40 BS T l X : PG 100 : 0 R25 481.50 67.98 90 : 10 472.00 70.70 80 : 20 444.00 70.76 75 : 25 403.50 66.89 CKD s dng PG : S 70 : 30 369.00 64.15 65 : 35 324.00 59.75 60 : 40 306.50 59.43 55 : 45 290.75 58.86 50 : 50 276.40 56.92 R100 708.25 100.00 667.00 100.00 627.50 100.00 603.00 100.00 575.25 100.00 542.75 100.00 515.75 100.00 494.00 100.00 485.60 100.00 R200 835.75 118.00 809.50 121.36 790.75 126.02 762.75 126.49 737.75 128.25 700.00 128.97 687.75 133.35 662.50 134.11 640.80 131.96 R400 734.75 103.74 765.75 114.81 734.50 117.05 714.00 118.41 692.75 120.43 675.25 124.41 653.73 126.75 628.75 127.28 598.50 123.25 R600 470.00 66.36 528.25 79.20 562.00 89.56 537.50 89.14 490.75 85.31 492.50 90.74 482.50 93.55 465.00 94.13 450.80 92.83 R800 242.00 50.26 347.00 52.02 423.25 67.45 438.00 72.64 453.30 78.80 425.00 78.30 425.00 82.40 390.75 79.10 368.80 75.95 R1000 95.75 19.89 153.25 22.98 165.75 26.41 184.50 30.60 209.50 36.42 234.50 43.21 235.50 45.66 272.00 55.06 261.50 53.85 Page 21

HVTH: NGUYN HONG T

TRNG I HC XY DNG C 453.25 69.70 80 : 20 432.50 69.34 75 : 25 350.75 61.45 CKD s dng PG: G 70 : 30 334.50 60.79 65 : 35 312.00 60.35 60 : 40 287.75 37.80 55 : 45 268.25 56.83 50 : 50 255.80 54.17 650.25 100.00 623.75 100.00 570.75 100.00 550.25 100.00 517.00 100.00 503.00 100.00 472.00 100.00 450.00 100.00 805.00 123.80 753.75 120.84 720.25 126.19 714.50 129.85 667.00 129.01 660.75 131.36 628.25 133.10 622.25 138.28 754.50 116.03 714.00 114.47 700.25 122.69 666.25 121.08 640.75 123.94 623.75 124.01 597.00 126.48 596.75 132.61


90 : 10

530.75 81.62 490.75 78.68 513.25 89.93 530.00 96.32 500.75 96.86 519.00 103.18 492.50 104.34 460.20 102.27

334.50 51.44 414.50 66.45 424.50 74.38 422.00 76.69 422.00 81.62 456.50 90.76 392.00 83.05 360.00 80.00

148.25 22.80 179.50 28.78 182.75 32.02 203.50 36.98 208.00 40.23 224.80 44.69 225.00 47.67 232.50 51.67

*Ch thch: T s ghi gi tr cng nn; Mu s l % cng cn li so vi cng nn 100oC T s liu ca bng kt qu th nghim trn ta c ca biu sau:

HVTH: NGUYN HONG T

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TRNG I HC XY DNG C


Biu 1: Cng nn ca mu vi hm lng ph thay i 100oC; 400oC; 1000oC.Nhn xt:

-

i vi c hai loi ph gia: s bin i cng nn ca cht kt dnh u din ra theo quy lut: 200oC: c s tng t bin. Sau cng nn suy gim t 400 1000oC (i vi c hai loi ph gia).

-

i vi xi mng khng c ph gia 400 1000 oC : cng nn suy gim nhanh, hu

nh khng c cng , v khi a ra ngoi khng kh, th b mn ra. Ty theo ph gia m s suy gim cng nn l nhanh hay chm.

-

Vi CKD s dng ph gia S: cng t l ph gia, cng nhit t nng, th CKD s dng ph gia S c cng nn cao hn so vi ph gia G. Vi cht kt dnh c s dng ph gia, nhit cao, mc suy gim cng l thp hn so vi xi mng khng dng ph gia. Nhit t 400 - 600oC: Cng nn ca CKD a s l gim, tuy nhin c mt s cp phi gn nh khng gim m c xu hng tng. Khi t nng n 800 - 1000oC th cng tip tc gim v t mc 1000oC, cng nn sau t nng ph thuc vo: Loi xi mng. Lng ph gia. Loi ph gia.

-

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TRNG I HC XY DNG C-


V th la chn lng s dng ti u ph gia cho CKD cng nh cho BTCN, cn xc nh m hnh ha xc nh gi tr ti u.

Hm hi quy ca cng nn theo t l dng ph gia cc nhit 800oC v 1000oC: 800oC:

Y Y 1000oC:

Rn-S

= 452.85 16.0 X2 = 454.77 25.04 X2

Rn-G

Y Y

Rn-S

= 272.16 2.56 X2 = 230.95 4.26 X2

Rn-G

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TRNG I HC XY DNG C Vi PCB40 Phc Sn:


Loi CKD

T l X:PG 100 : 0 90 : 10 80 : 20 75 : 25

Cng nn ca CKD cc cp nhit ; Rn - kG/cm2 / % Rn25 408.25 65.30 460.50 66.67 432.25 64.78 420.00 64.07 405.00 62.13 386.50 61.01 368.75 59.74 350.00 58.87 334.25 58.38 458.50 64.58 432.75 62.40 417.50 62.06 401.25 61.87 382.00 60.63 365.50 60.07 348.50 59.70 330.25 58.63 Rn100 735.5 100.00 690.75 100.00 675.00 100.00 655.50 100.00 652.25 100.00 633.50 100.00 617.25 100.00 594.50 100.00 572.50 100.00 710.00 100.00 693.50 100.00 672.75 100.00 648.50 100.00 630.00 100.00 608.50 100.00 583.75 100.00 563.25 100.00 Rn200 792.50 107.75 750.25 108.61 725.50 107.48 710.25 108.35 695.75 106.67 675.00 106.55 640.75 103.81 622.50 104.71 604.05 105.51 770.00 108.45 745.25 107.46 726.50 107.99 700.25 107.98 680.25 107.98 659.50 108.38 638.50 109.38 622.25 110.47 Rn400 777.75 105.74 745.50 107.93 717.25 106.26 690.75 105.38 668.50 102.49 652.75 103.04 631.50 102.31 597.50 100.50 580.75 101.44 750.00 105.63 733.25 105.73 709.50 105.46 683.75 105.44 660.00 104.76 631.25 103.74 620.00 106.21 599.20 106.38 Rn600 512.50 69.68 540.50 78.25 598.75 88.70 575.00 87.72 550.25 84.36 527.50 83.27 505.25 81.86 490.00 82.42 475.00 82.97 663.25 93.42 680.00 98.05 640.25 95.17 625.50 96.45 610.75 96.94 597.25 98.15 580.40 99.43 550.75 97.78 Rn800 240.75 32.73 298.50 43.21 346.50 51.33 430.00 65.60 388.00 59.49 415.00 65.51 367.50 59.54 367.50 61.82 322.50 56.33 280.50 39.51 363.25 52.38 435.25 64.70 473.75 73.05 453.40 71.97 451.50 74.20 420.50 72.03 398.50 70.75 Rn1000 80.00 10.88 108.50 15.71 122.50 18.15 144.25 22.01 164.50 25.22 132.50 20.92 152.50 24.71 183.50 30.87 174.00 30.39 105.25 14.82 124.75 17.99 138.75 20.62 105.50 16.27 167.00 26.51 178.75 29.38 200.25 34.30 232.75 41.32

CKD s dng PG : S 70 : 30 65 : 35 60 : 40 55 : 45 50 : 50 90 : 10 80 : 20 75 : 25 CKD s dng PG: G 70 : 30 65 : 35 60 : 40 55 : 45 50 : 50Nhn xt:

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TRNG I HC XY DNG C


Qua kho st s dng ph gia cc cp nhit , thy c quy lut nh sau: Khi tng hm lng ph gia: cng nn nhit thng: gim dn. Khi nhit tng t 100 200oC th cng nn caCKD tng. Khi nhit tng t 200 400oC th cng nn ca CKD i vi xi mng khng c ph gia gim dn v gim nhanh. Vi CKD chu nhit: RnCKD t gi tr ln nht 200oC v n 400oC th Rn bt u gim. T 400 600oC: cng nn ca CKD gim, tc suy gim ph thuc vo lng ph gia v loi ph gia. Khi nhit tng t 600 800oC th cng nn ca CKD tc suy gim l ln nht. n nhit 1000oC th cng nn ca mu l nh nht. Nhit trn 1000oC th cng nn ca mu c xu hng tng. RnCKD ph thuc vo loi xi mng ban u: Vi xi mng PC ph gia a vo c tc Nu s dng PCB cn kho st k ngun gc, tnh cht ph gia a vo xi mng ngay Hm lng cc khong ph gia cng nh hng n RnCKD . Nu hm lng khong

Kt lun: suy gim, cng nn thp hn hay cng n nh hn. t ban u. ph gia cacbonnat thp ta vn c th dng c. V theo kt qu nghin cu lng dng cc khong cacbonnat nh hn 10% l rt tt v lng ph gia cacbonnat ny khng c vt qua lng CaO t do trong xi mng. Nhng: tt nht l khng nn dng cc khong cacbonnat. tng cng nn cho CKDCN v gim s suy gim cng nn ny, khong nhit 200 400oC chng l nhng ph gia nhit hay ph gia hot tnh c tcdng lm tng cng nn ca CKD nh: puzolan, x, tro c thnh phn hm lng SiO2 t do cao.

nhit t: 200 600oC, ngi ta s dng ph gia hn hp.Chng c tc dng:

-

Chng c kh nng lin kt vi cc khang khc to thnh cc hp cht CS. Chng khi b t nng: c tc dng lm gim co ngt v nn cht cu trc lm tng cng nn, do gim tc suy gim cng ca CKD. m bo khng b phn hy nhit cao, hay c bn nhit cao.

Vi ph gia S c kh nng to ra CKDCN tt hn ph gia G v s suy gim cng

nn ca CKD cng nh hn.

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Theo cc bng s liu trn, ta lp c hm hi quy ca cng nn theo t l dng ph gia cc nhit 800 v 1000oC: 800oC: 1000oC:

Y Y

Rn-S

= 181.87 3.968 X2 = 236.33 27.04 X2

Rn-G

Y Y

Rn-S

= 181.87 3.968 X2 = 236.33 27.04 X2

Rn-G

Nhn xt: Theo cc phng trnh hi quy thu c trn ta thy: Vi xi mng PC40 Bt Sn: 800oC: S suy gim cng ca CKD s dng ph gia Samt ln hn so vi CKD s dng ph gi gch v. 1000oC: S suy gim cng ca CKD s dng ph gia Samt t hn so vi CKD s dng ph gi gch v. Vi xi mng PCB40 Phc Sn: c hai cp nhit ny cht kt dinh u c s suy gim cng ln hn so vi xi mng PC Bt Sn. 3. Kt qu nghin cu b tng chu nhit cch nhit: Thc hin quy hoch quy hoch thc nghim vi cc tnh cht khc ca b tng chu nhit cch nhit, ta c kt qu nh sau: 3.1. Nghin cu th cht hn hp b tng cch nhit chu nhit: chy ca hn hp b tng: Bng m ha vi mu th 800oC Mc quy hoch thc nghip Nhn t N / CKDCN PG/XM Bin X1 X2 -1.414 0.822 0.29 -1 0.83 0.33 0 0.85 0.43 +1 0.87 0.53 +1,414 0.878 0.57

Bng m ha vi mu th nhit 1000oC Mc quy hoch thc nghip Nhn t N / CKDCN PG/XM Bin X1 X2 -1.414 0.822 0.609 -1 0.83 0.67 0 0.85 0.82 +1 0.87 0.97 +1,414 0.878 1.032

Kt qu th nghim chy ca hn hp BTCN CN HVTH: NGUYN HONG T Page 27

TRNG I HC XY DNG C im QH STT 1 2 3 4 5 6 7 8 9 10 11 12 13 X1 +1 +1 -1 -1 + 1,414 - 1,414 0 0 0 0 0 0 0 X2 +1 -1 +1 -1 0 0 +1,414 -1,414 0 0 0 0 0


chy (D;cm) Vi mu th Vi mu th 800oC 47.0 48.0 48.5 48.0 48.5 49.5 48.0 48.0 48.0 48.0 48.5 48.0 48.0 1000oC 48.5 50.0 49.5 51.5 51.0 50.5 49.5 50.0 49.5 49.5 49.5 49.5 49.5

3.2. Nghin cu tnh cht b tng cch nhit chu nhit: Khi lng th tch ca b tng cch nhit chu nhit Kt qu nghin cu tnh cht ca BTCN CN Bin QH STT X1 1 2 3 4 5 6 7 8 9 10 11 12 13 +1 +1 -1 -1 + 1,414 - 1,414 0 0 0 0 0 0 0 X2 +1 -1 +1 -1 0 0 +1,414 -1,414 0 0 0 0 0 KQ khi lng th tch 800oC / (o, g/cm3) Vi mu th Vi mu th 100oC 382 383 385 387 387 389 385 388 380 378 378 379 381 1000oC 348 347 351 350 352 347 348 348 345 347 344 343 346 KQ khi lng th tch 1000oC / (o, g/cm3) Vi mu Vi mu th th 100oC 375 378 379 380 381 378 373 374 372 370 368 365 367 1000oC 342 342 343 347 350 348 345 343 340 337 338 341 338

Gii ma trn thu c: HVTH: NGUYN HONG T Page 28

TRNG I HC XY DNG C


Y Y

KLTT-800

= 344,99 - 0,2198X1 - 0,25X2 + 2,188X12 + 1,937X22 = 338.8 0.5216 X1 0.0215 X2 + 0.25 X1X2 + 4.538 X12 + 2.037X22

KLTT-1000

co ton phn ca b tng cch nhit chu nhit: Kho st co ca BTCN CN 800oC v 1000oC STT 1 2 3 4 5 6 7 8 9 10 11 12 13 Bin QH X1 +1 +1 -1 -1 + 1,414 - 1,414 0 0 0 0 0 0 0 X2 +1 -1 +1 -1 0 0 +1,414 -1,414 0 0 0 0 0 co ca BTCN - CN, % Vi mu th 800oC Vi mu th 1000oC 2.82 2.85 2.8 2.87 2.78 2.88 2.82 2.86 2.84 2.88 2.84 2.86 2.82 2.84 2.81 2.84 2.76 2.8 2.77 2.79 2.78 2.81 2.75 2.78 2.79 2.79

Gii ma trn thu c cc phng trnh hi quy:

Y Y

co TP - 800

= 2.77 + 0.0025X1 0.0007 X2 + 0.015 X1X2 + 0.0294 X12 + 0.0169 X22 = 2.79 + 0.001 X1 -0.015 X1X2 + 0.0405 X12 + 0.0255 X22

co TP - 1000

Nhn xt: Gi tr co ca b tng ny kh ln. Nguyn nhn ca co: l do hin tng mt nc lm co gel CKD, do qu trnh phn ng pha rn gy co ngt, qu trnh co to thnh l rng lm gim o KLTT ca b tng. Nhng: qu trnh co khng gy ra ng sut nn khng to vt nt trong b tng. Qu trnh co ph thuc vo: T l N/CKD Page 29

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TRNG I HC XY DNG C


Khi lng ph gia tng khin co gim hay n ph thuc vo ph gia/ xi

mng. H s gin nhit ca b tng cch nhit chu nhit: Bin QH STT 1 2 3 4 5 6 7 8 9 10 11 12 13 X1 +1 +1 -1 -1 + 1,414 - 1,414 0 0 0 0 0 0 0 X2 +1 -1 +1 -1 0 0 +1,414 -1,414 0 0 0 0 0 H s gin nhit (Kcal/moCh) Vi mu th Vi mu th 800oC 0.0750 0.0753 0.0762 0.0756 0.0762 0.0748 0.0752 0.0750 0.0740 0.0748 0.0736 0.0733 0.0744 1000oC 0.0729 0.0734 0.0741 0.0748 0.0759 0.0749 0.0740 0.0733 0.0723 0.0710 0.0716 0.0726 0.0714

Theo kt qa thc nghim trn, ta thy: Cc sn phm tha mn c kh nng dn nhit. bn nhit ca b tng cch nhit chu nhit Kh nng ca b tng chu s dao ng nhit m khng b ph hu. iu ny c ngha rt ln i vi vt liu cch nhit, bi v phn ln vt liu cch nhit khi nhit cao chng phi cch nhit cho cc thit b v cng trnh vi s chnh lch v nhit ln, dn ti gradient nhit gia lp bn trong v lp bn ngoi, chng gy ra cc ng sut nhit lm pht sinh cc lc ko, nn gia cc lp dn ti vt liu b nt v hay ph hu, c bit i vi vt liu c cu trc rng xp, khi thi gian s dng ca chng ngn do chu k t nng v lm ngui thp v vy i vi b tng chu nhit - cch nhit cn xc nh kh nng bn nhit ca chng, Tin hnh nghin cu bn nhit theo phng php mm: Tin hnh t nng mu 8000C, hng nhit >2 gi, sau lm ngui nhanh trong HVTH: NGUYN HONG T Page 30

TRNG I HC XY DNG C


dng khng kh lnh n t=2020C, sau li tip tc t nng lp li, s ln chu k t nng v lm ngui cho n khi mu xut hin vt nt >1mm v mt 20% khi lng c nh gi l bn nhit n nh. Tuy nhin trong thc t th t khi xy ra qu trnh t nng v lm ngui t ngt. Kt qu nghin cu v 13 cp phi b tng chu nhit - cch nhit chng t c bn nhit t 7-10 ln dao ng nhit v vy tui th ca vt liu ny ln hn so vi cc vt liu thng thng. Vi yu cu: bn nhit khng nh hn 5 ln, thng qua vic kho st nh gi s mt khi lng v xut hin vt nt, kt qu thu c: Vi CKD l xi mng v ph gia: S hay G th XLBTCN CN c cht lng cao. II. Cng ngh ch to ca b tng cch nhit chu nhit: Nguyn liu s dng ch to gm cc loi sau: Xi mng Ph gia (S/G) Cht to xp ( Bt Al) Cht hot ha. Qua s cng ngh ta thy, cng ngh khng ging nh i vi b tng thng, ch khc l c cng on sy (sy bung hoc sy tuynel), khi sy s lm tng cng v gim co ngt.

c b tr theo s cng ngh sau:

HVTH: NGUYN HONG T

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TRNG I HC XY DNG C


Kho XM nh lng

Kho PGK mn nh lng Nghin bi Gu nng Bunke nh lng

Kho bt Al nh lng

Kho cht hot ho nh lng

Nc

My khuy Trn khun Tnh nh (4-5h) Ct sn phm Tho khun Dng h (7 ngy trong mi trng m) Sy v t nng (100oC) Kho SP

III. Kt lun - Kin ngh: Vic ch to b tng chu nhit cch nhit trn th gii c nghin cu v s dng kh rng di, tuy nhin Vit Nam vic nghin cu v ng dng loi b tng ny vn cn kh mi m, hin nay mi ch thc hin ch yu trong phng th nghim, vic nghin cu s dng cht kt dnh xi mng pooClng PC40 v PCB40 c ngha v cng to ln v mt kinh t, k thut cng nh v mt x hi. T kt qu nghin cu trn ta nhn thy rng:

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- Vi cht kt dnh chu nhit l xi mng pooClng PC40 Bt Sn v xi mng PCB40 Bt Sn trn vi ph gia Sa mt v gch v vi t l khc nhau th + Lng nc tiu chun tng khi tng hm lng ph gia t 0 n 50%. XM PC40 Ph gia S tng t 29.0% n 32% Ph gia G tng t 29% n 32.25% XM PCB40 Ph gia S tng t 28.5% n 31% Ph gia G tng t 28.5 n 32% Lng nc tiu chun ca XM PC40 ln hn so vi XM PCB40 - Thi gian ninh kt ca cht kt dnh chu nhit. Khi tng hm lng ph gia th thi gian ng kt ca cht kt dnh chu nhit tng dn, vi PG G th thi gian ng kt ln hn so vi PG S. - Cng ca CKD chu nhit s dng PG S v PG G cc t l khc nhau vi cc cp nhit khc nhau. Khi tng nhit t nhit thng ( y xt l 250C) n 2000C th cng tng dn tt c cc t l ph gia khc nhau, v trong cng mt cp nhit ( y l 25 0C, 1000C, 2000C) th khi tng t l ph gia th cng gim dn. Khi nhit ln hn 2000C ( y xt 4000C, 6000C, 8000C, 10000C) th cng cc t l khc nhau u gim dn - V khi lng th tch ca b tng chu nhit cch nhit, vi cng mt cp phi th khi lng th tch nhit 10000C nh hn 8000C v nh hn 1000C 0 0 0

1000

c

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