TAP c i i CONG TRirdNfi
GIAI PHAP XANH GIA CO NEN DlJCfNG BANG TRO x i NHA MAY NHIET DIEN VA RCfM RA
• LE THAI BINH - NGUYEN VIET TIEN
TOM TAT:
Nen da't yeu trong xd\ du'ng cdng trinh giao thong id van de can ddde nghien ci?u de tim gidi phdp giacd'. Tong hdp cdc giai phdp gia co'nen difdng d id da dddc thifc hien. bai bdo ddnh gia khd ndng sti dung tro \i cua nhd mdy nhiet dien va rdm ra de gia ed' n^n du'dng Id mgl gidi phdp xanh nhJlm tan dung khai thac nguon thai pha'm cdng-ndng nghiep hien nay de gdp phan bao ve mdi trifdng phal trien ben viTng. Trong dd, kha nang SIJ" dung ciia cdc Ioai vat lieu khi gia ed' nen dtfdng d l6 dtfdc chi rd cho mdt so'edng trinh khde nhau. Mdt khac, bai bdo ciing tdng hdp ty le thdi pham tro Xl Clia mgt so'nha mdy nhiel dien d Viet Nam va ty 16 khd'i hrdng ciia cac nguyen td'chinh trong rdm ra khi sifdung Iam vat lieu gia ed'.
Tuf khda: Tro xi. nha mdy nhiet dien, gia cd' nen difdng, Viet Nam.
I. Dat va'n de
Nen du'dng la bd phan ehii yeu cua edng trinh difdng Nhiem vu cua nd Id dam bao eu'dng do va dti dn dinh ciia kel ca'u mal du'dng. Cdc kieu nen difdng bao gom; Ndn dirdng da'p thdng thirdng;
Nen dirdng da'p ven sdng. Nen dirdng niia dao, nii'a dap; Nen du'dng ed tu'dng giif chdn (tu'dng chdn d ehan taluy). Nen du'dng ed tu'dng gii? d vai; Nen dddng xay dd; Nen du'dng cd tifdng chiin dd't; Nen difdng cd lu'dng chan; Nen du'dng dao: Nen du'dng dapbangeai|l](Hlnh 1.2).
Hinti 1: Nen dUdng dap thong thiJdng
Hinh 2: Nen difdng dap bang cat
Cde chi lieu ddnh gid cha'l lu'dng nen du'dng Ihtfdng diing: Chi tieu eO ly da't ddp nen du'dng;
Yen cau ve vat lieu ddp theo lieu ehua'n AASHTO;
He so'tdi xdp - He so'dam chdt [2, 5].
2. Mpt so'phi/dng phap gia co'nen di/dng 616 2,1, Cdc gidi phdp gia cdbang gia cong cd IIQC Khi cirdng do chdng ca't ciia nen da'l ye'u khdng dii de xay difng nen da'p theo giai doan hodc khi thdi gian cd'ke't qud dai so vdi thdi gian thi edng dif kie'n thi cd lhe dp dung cdc bien phdp nhdm tang do d'n dinh, giam kha ndng troi dS'lra hai ben bang each tang chieu rdng nen du'dng, lam be phan dp. Cd the ap dting bien phdp ddo bd mdt phan hoae loan bo ldp da't ye'u, Cd th^
giam trgng krdng ciia nen da'p tae dung Ien dai yeu bang hai each: Giam chieu cao nen dapd^n tri so'td'i thieu cho phep; Diing vat lieu nhe diip nen dudng. Dting phu'dng phdp gia tai tam thdi bdng viec dat mdt gia lai (thu'dng la 2-3m nen dap bd sung) trong vai thang rdi se Id'y di d thdi diem I ma d dd nen difdng se dat du'de do liin cuoi cung dif kien nhif iru'dng hdp vdi nen ddp khong gia tdi [1] (Hlnh 3).
Ngoai ra, edn sii" dung nhifng bien phdp cdi igo dieu kien dn dinh \a bien dang cua nen da'l yeu nhu" lam ldp dem eat hay lam Idp dem da, soi.
Dap da'l tren be lam bang tre. gd hoae edc b6 canh cay la mgt trong nhii'ng phu'dng phdp xdy
lUANTRI-qUAIIiy
Hlnh 3: M^t Irong nhOng giai phap gla co bang gla cong cd ht?c
_L
dtfng lau ddi, da tifng siif dung thanh cdng trong
\ay difng de dap. Khi chieu day eua Idp da't ye'u ra't day hodc khi dd tha'm ciia da't ra't nho, td'c dd cd'keiiif nhien ciia nen da'l yeu cd the cham, Mdt so' bien phdp cd hieu qua de tang Id'c do cd' ke't la bo' iri trong da't yeu cdc thie't hi ihodt mfdc dirdi dang dtfdng tha'm th^ng du'ng hodc cae ranh Iha'm.
Dau the ky XVill, d Ha Lan da xay di/ng nhieu doan du'dng qua dam lay bdng each gia cd' nen da't ye'u bdng he Ihd'ng cae cgc gd. O nu'dc ta nhieu n^n mdng nhd cu'a vd cdng trinh lam trdn nen da't ye'u da difdc xii" ly bdng each ddng egc Ire (d mien Biic) hodc cgc tram (d mi^n Nam).
Phifdng phap cd' ke't ddng do Louis Menard de xud'l lif ndm 1970, nguyan ly cdban ciia nd la lac dung eac Itfc xung kich ndng lifdng Idn tren be mdl eiia dd't ye'u de'cdi thien cdc dac trifng cd hgc ciia dd't theo chieu sdu.
2.2, Gia cd nen difdng sii dung chd't lien icet vdcd
Kel qud nghien ciJu tien hanh d Lien Xd cu, nay la nifdc Nga (Vien Nghien cii'u khoa hoc Difdng bg Lien Xd). d Cdng hda Nhan dan Ba Lan. Cdng hda Nhan dan Rumani cung nhif d My.
ngtrdi ta da ehiJng minh rang, cilng vdi vdi, ne'u irgn them vao da'l cat va a cdt cdc loai tro bay khde nhau hodc cdc cha'l dien phan th) da't cd the dai eu'dng dp cao [6). Phirdng phap giacd'dd't bang vdi cd them cdc cha't khde dd ddde lhi nghiem trong phdng vd kiem nghiem trong san xuat bdng cdch trdn them vdi vd silicat natri cung nhd vdi va sdt sunfat. Viec gia cd' da'l bdng vdi va chd't phu gia iro bay lie'n hdnh d cdc nifdc cho Iha'y rang, eac loai tro bay kel hdp vdi mgt il phu gia vdi Id mgt vai lidu Id'l de gia cd cdc loai da't, trong dd bao gdm ca d cdt \a cat it dinh. T.Yu.Liubi-mova va K.P.Brddxka da chi ra kha ndng siJ dung tro khi cho them \o'\ vao tro mdt each bat bude, de tao thdnh cha't lien ketiro-vdi. Ddc diem ciia cha't lien ke't nay id hoal tinh (eifdng dp) lu'dng dd'i khdng ldn \a qud trinh hlnh thanh ca'u tnic xay ra cham.
Sii dung cic dung dich chd'l dien phan khac nhau
(NaiCO,, KOH....) nhdm mue dich tang nhanh ede qua trinh hinh thanh ca'u tnie \a tao dieu kien de dam bao nhan difde ca'u true ed cddng do vd tinh dn dinh nu'dc cao.
Gia cd' tdng hdp \di vd chd't phu gia iro bay dt/dc sti dung rdng rai d .My. Khi gia ed' tdng hdp dat bdng v6i va tro phai het sifc bao dam sir tid'p xuc chdl che giifa cdc hat da't \di tro va vdi.
Gia cd' long hdp dat bdng xi mang ed cho them nhu ti/dng bitum hay viTa vdi-bitum se cd the dam bao cho da't cat. a cdt va d set nhir gia cdxi mang trd nen cd tinh ky nddc. do dd ndng eao tinh bien dang vd dn dinh nhiet. Vien Nghien cii'u Dirdng bg Lien Xd (cu) da nghien cdu cdc phu'dng phdp ehe lao da't xi mang va vifa vdi bitum (nhfl lu'dng bitum), ciing vdi cac tinh eha't eua da't xi mang bitum. Hoat tinh hda - ty ciia bg phan hat min cdc Ioai dat dinh. dae biet la set trong nhieu tnfdng hdp lai cd hai. Nd lam tdng lu'dng lieu hao chd'l lien kel. lam ha cifdng do da't gia ed khi bao hda nu'dc va khi ldng nhidt do. Ddng thdi cac nghien ciTu da qua kinh nghiem san xud't thiJ nghiem, ehiing td rdng, mdt lu'dng nhd cha't phu gia vdi khodng 2 - 4% trpng lu'dng da'l gia co bittum se eho ta mdt hon hdp dd't bittum cd chd't liTdng vdi cdc tinh cha't ea'u tnic cd hgc djnh trUdc.
Gia cd' nen da't ye'u bdng tru da't-xi mdng: Cpc da'l-ximang (D-XM) la mot trong nhu'ng gidi phdp xir ly nen da't ye'u vdi kha nang ii'ng dung lu'dng do'i rpng rdi. Uudiem la kha nangxuTly sau (de'n 50m), thich hdp vdi cdc loai dat ye'u (lir cdt thd cho de'n biin ye'u), dii cdng dirdc ca irong dieu kien nen ngap sdu trong mfdc hodc dieu kien hien tnfdng chat hep, U-ong nhieu tnfdng hdp da difa Iai hieu qua kmh te rd ret so vdi cac giai phdp \.d !y khde (Hlnh 4).
Hinh 4: Cong nghe thi cong cgc 0-Xt\A^
- Mgt ftong nhiJng giai phap gia co sit dung chdt lien ket vo cd
So 7 - T h a n g 4/2020 185
TAP Cll mt TRIIIING
3. Giai phap sU dung phu phdm cong-nong nghiep gia co' nen difffng 6 to
3.1. Gidi phdp xanh khi si? dung phu phdm edng nghidp: Tro xi cua cdc nhd mdy nhiet dien
Tro xi la san pham phu (chat thai) ciia cac nha may nhiet dien sifdung nhien lieu rdn la than. Tro xi du'de thai ra d ddy Id thu'dng difde ggi id tro ddy hode xi than, tro xi difdc thu bdng bd lpc bui tinh dien kich thu'dc nho va ddng deu du'de gpi la tro bay (Hlnh 5-6). Tuy thuge vao edng nghe dot. Ioai than sii dung lu'dng tro ba> chie'm khoang 65 - 807f. lu'dng tro ddy chie'm khoang 20 - 35%.
Hinh 5: Hinh anh cua tro ddy
Troxi ia hdn hdp min bao gdm cac hat hinh eau
\a cae hat hlnh gde eanh (than chu'a ehay he't).
Kieh cd hat ldn nhd't ciia tro bay thu'dng nho hdn 100pm {cS biet 200pm). tro dd\ cd kich cd hat ldn nhd't thifdng nhd hdn 2-5mm (cd biel 30mm).
Mau siie ciia tro \f phu ihude \ao thanh phin hda hoc, cu the la phu thupc \ a o ham liTdng ck bon chu'a chay het, loai than nhieu lieu diing d^' ddt vd cdc phu phd'm khac, tif mau \ang sangd^n xam den. Tro xi cd ham li/dng cdc bon ehifa doi he't cao (hdm lifdng CaO nhd). cd mdu sdm, tro xi cd ham Iifdng cdc bon thiJa nho (ham li/dng v6i eao) cd mau sdng [7].
Trong thdnh phan hda hge cua tro \i bao g6m tdi hang chue nguyen to hda hgc (hdn 30 nguy6n id) khac nhau, tdn tai ehu \'eu d cdc dang dxit SiO,, AKOi, CaO, MgO, Fe.O^, FeO, TiO^, CriOj, Vibj. MnO, SOl, Na.O, KiO, BiO,.., frong'cdc dxit iren thi SiO,, AUO,, CaO, MgO difde coi lil thdnh phan chii ye'u vl ehung cd ham lifdng ldn vil quye't dinh dS'n edc tinh chat cd ban ciia tro xi.
Cd'u triic tro \ i gdm 3 nhdm vat eha'l Id ihuy tinh, kel tinh vd cdc lap chat, hodc du'de qui tu vd 2 loai pha la cdc pha vd djnh hlnh vd cdc cd'u tu' ke't tinh. Hoal linh ciia tro xi la cd khd ndng ldc dung vdi sdn pham thuy hda xi mdng d dieu kifin thu'dng (cd hodc khdng cd cha'l boat tinh hod), hodc d dieu kign nhiet dp cao (gia cdng nhiel am).
Tinh cha't va thanh ph^n hda hgc ciia tro xi trong cdc nhd mdy nhiet dien phu thude vao cdng nghe dd't than, phy phtim cdng nghe, nhien li?u than dau vao va cdng nghe thu gom XIJ: Iy tro xi.
Slf hlnh thdnh tro bay va tro day Id tdng hdp ciia nhieu qua trinh hda hpc khde nhau. Cac thdnh phan cua tro bie'n ddi khi tie'p xue vdi mdi tru'dng ^m, qud Irinh dien bien xay ra tuy thupc vao Ihdi gian, nhiel dp... Sif phdc tap trong thanh phan tro bay vii iro day anh hu'dng den tinh cha't sii" dung va dinh hu'dng xd ly cdc yeu to cd hai,
Trong cdc nha mdy nhiet dien Viet Nam liTdng tro day thu'dng chiem 27-30%, Itfdng tro bay Ihu'dng chie'm 70-73%. (Bang 1)
Bang 1. So lieu thong ke lUcJng tro bay va tro ddy dUcfc thdi ra tqi cdc nha mdy nhi§tdi^n
Nha may Tro day Tro bay
Pha Ial1 27%
73%
Pha lai 2 27%
73%
Ninh Binh 27%
73%
Uong Bl 29%
7 1 % Cao Ng?n 30% 70%
Tiiy theo IhSi gian xay diTng ihifftng s!l dung cic day chuyen cong nghe khac nhau. ben canh il6 thi nguon nguyan lieu than ciing khac nhau: s i dung nguon than non true Hep tai dia phi/Ong. mua than
186 So 7 - Thang 4/2020
QUANTRj QUANLY
lir cdc mo than ciia Tilp doan Than va Khoang san Viet Nam hode nhap than li^ mfdc ngodi. Dieu nay dan de'n thanh phan hda hoc vd dac tinh cua tro xi ciia moi nha mdy Id khde nhau.
Theo khao sdt ciia Ngdn hang Hdp ldc quo'e te' Nhat Ban (JBIC). cdc nhd mdy nhiel dien thai ra binh quan 428 la'n tro xi moi nam u'ng vdi mdi Megawau (MW) dien. {Bang 2)
lignin va cac cha't trong le bao: cha'l beo, dau. nhi/a, photpholipit. glyconlipit- .xeioit., Ke't qua phan tich nguyen td trong rdm ra nhu' Bang 3 [8].
Rdm, ra du'de su" dung lam nguyen lieu Irdng nam, lam ihdc dn ehdn nudi. li phan bdn vi sinh.
lam nhien lieu sinh hgc. Nen epde lai che nguyen lieu rdm ra thdnh vat lieu dun na'u cho ngifdi dan thdng qua nen thanh \ien de ihay the than to ong.
Bang TSn nha may Cong suSt (MW) LU(?ng tro (Tein/nam)
2. So lieu thd'ng ke tro xT duoc thai ra Phi Lal 1
400 188.000
P h a U I 2 600 249,000
Ninh BInh 100 37.000
iit c a c nhd Uong Bl
100 39.000
m a y nhiet dien Uong Bl md rOng
300 124,600
long so
637.600
Bang 3. Ket qua phdn tich nguyen to trong rdm rg Nguyen to
Thanh phin (% khoi ItiOng) C 53.94
0 39,20
H 5,84
N 1,02
s
0,02
Nhrrng ndm gan diiy va'n de tai sCr dung tro xi tai Vi^t Nam da du'de sif quan tam chii y eiia Chinh phu vd nhieu ngdnh khde nhau. Dd'i vdi xay ddng du'dng 0 td tai Viet Nam dd va dang cd nhffng cdng trinh nghien cu'u sii dung tro xi nhiet dien nhdm c;ic mue dich sau: giam gia thanh trong viec xdy d(rng mdt dirdng (thay the mot phan cha't ke't dinh xi mdng); tdng chat IUdng vdt lieu dia phffdng dam bdo dii chd'l Iffdng dilng de xay dffng nen mat dffdng (gia cd' dd't, dd bdng tro bay cung cac phu gia khde); xff ly nen da't ye'u...
3.2. Gidi plidp xanh khi sd dijing phu phdm nong nghidp: Rum rg
Viel Nam la mgt nffde ndng nghiep lua nffdc, ngudn rdm ra la ra't ddi dao vdi sdn Iffdng khoang 30 tri^u ta'n/nam va chiing chii ye'u dffdc xff li bang cdch dot de la'y tro bdn cho ddng rudng. Tuy nhidn.
vi^c dd't irffc tie'p rdm ra tren cdnh ddng dd gay d nhiem Iram trpng ddi vdi mdi trffdng nhff tao khdi.
bui ddng thdi phdt thai ra mdt Iffdng ra't ldn khi CO^.
CO vd CHj gay anh hffdng hieu dng nhd kinh.
Rdm ra cd ngudn gdc thffc vat la san pham cua qud Irinh quang hda Iff cdc ihanh phan cd sdn trong khdng khi: COi. nffdc vd dnh sang. Thdng qua qua tlinh quang hdp, chlorophyll trong thffc vat ddng vai trd nhff mdt cha'l xtic tac quang ha'p thu dnh ndng mat trdi thffc hien qua trinh chuyen hda khi COi trong khdng khi \a H,0 tao thdnh cacbonhydrat d dang (CH20)x. Rdm ra co thanh phan bao gdm cac chd't cau lao nen thanh te bdo: xeniulozd, hemixenlulozd.
Rdm ra dffdc xem Id nguon dinh dffdng quan trpng lam gia ldng ndng sud't liia (0,4 la'n/ha/vu khi rdm ra dffdc viii vao trong da't) va lam gia ldng dp mdu md ciia dd't iheo Ihdi gian.
Trong imh vffc \ay dffng va ha tang Ihl rdm, ra dffdc nghien cffu ii'ng dung nhdm Idng ctfdng sff dn dinh Clia mdi la luy, dieu che xenlulo de Iam vat lieu, sff dung lam nguyen lieu san xua'l vdn dp.
4. Danh gia
Tren the gidi da nghien cffu va sff dung hau nhff loan bp Iffdng tro xi thai vao nhieu ITnh vffc, trong dd cd dung de xay dffng dffdng d td. O Viet Nam, theo quy hoaeh phdt trien nang Iffdng ihl sd Iffdng nha mdy nhiet dien dd't than ngay cdng tang. Khdi Iffdng iro xi thai ra ra't ldn. irong khi mffe dp tdi sff dung cdn tha'p, ehiem nhieu dien tich chdn lap va gay d nhiem moi trffdng,
Ben canh do khdi Iffdng rdm ra chiem ty trpng ldn trong nhffng phu pham ndng nghiep, Lffdng phal sinh hdng nam sau mdi miia thu hoaeh la rat ldn va hau nhff bj dd't bo ma ehffa dffdc nghien cffu tai su' dijng triet de'. Dieu dd vffa lang phi lai nguyen, vifa gay d nhiem mdi trffdng.
Nhu cau ve xay dffng cdc cdng trinh giao thdng dffdng bg d nffdc ta la rd't nhieu, trong khi ngudn vyl lieu iff nhien ngay eang can {\i du nhff cat) va eha't Iffdng cdn nhieu han che. VI vay, nghien cffu sir dung tro xi vd rdm ra Idm vat lieu lai eho phue vu \ a \ dffng nen dffdng Id ra'l thu'c le nhdm gop phan xu'ly mdi irffdng \a phdt trien bdn vffng •
So 7 - T h a n g 4/2020 187
TAP CIJ CONB TRirONG
TAI LIEU T R W ! KHAO:
\. Nguyen Quang Ch'jeu. La'v in Ch!im{200&).-Xdy dung nen dudng Old". NXB Giao diong \ an tai. Hd Ngi.
2. Tieu chuan Viet Nam 12005), TC\ N 4054-2(X)5 -Tieu chudn iliiei ke dudng 6 td ~. \'iei Nam.
3. Do Minh Toan (2013), 'Dat dd xdy dUngva phueyng phdp cCii tgo",'^'X^Y.^LV d\fn%.\i^ Npi.
4 Tieuchuan Viet Xam (1993). TCVN 5747-1993: f)d>-vay dirtj^-P/ja/i/oHJ.
5. Tieu chuan AASHTO: T99: T193; Til;T89: T90.
6. V M Bezruk, A.X. Elenoviis (1981), 'ko difdng bhng ddt gia cd" - Ban dich lieng Viet ttf tieng Nga. NXB Khoa hoc va ky thual. Ha Ndi.
7 Michsel Rafalowski (2003), 'Fly Ash Facts for Highway Engineer". American Coal Ash Association. USA.
8. Pham Thi Thu Giang (2015). "Nghien cdu long hop he .xuc Idc bieu qua cbo qud irinh sdn .uid't nbien /tpi/ .sinh bgc id ram rg". Luan an Tien si hda hgc. Ha Noi
Ngay nhdn bai: 10/3/2020
Ngay phan bi^n danh gia va sufa chfla: 20/3/2020 Ngay cha'p nh§n dang bai: 30/3/2020
Thdng I'm ldc gtd:
ThS. LE THAI BINH ThS. N G U Y I : N VIET TIEN
Khoa X5y dffng - Trffdng Dai hgc Di?n lUc
GREEN SOLUTION FOR REINFORCING THE ROADBED BY USING ASH AND SLAG FROM THERMAL POWER PLANTS AND STRAW
• Master. LE THAI BINH
Faculty of Construction, Electric Power University
• Master, NGUYEN VIET TIEN Faculty of Construction, Electric Power University
ABSTRACT:
The weak ground in the construction of transport works is a problem that needs to be studied lo find reinforcement solutions. By summarizing roadbed reinforcement measures which have been implemented, this ardcle assesses the possibility of using slag and ash from thermal power plants and straw to reinforce the ground of roads for vehicles. This measure is considered a green solution to take advantage of industrial and agricultural waste, contributing to the environment protection.
In diis article, the possibilitj' of using different materials to reinforce the roadbed is specified for different constructions. On the other hand, this article also summarizes the ash and slag waste ratio of some thermal power plants in Vietnam and the weight ratio of the main elements in straw when the\ are used as reinforcement material.
Keywords: A-^h. thermal power plants, roadbed reinforcement, Vietnam.