So 05/2020
Nghien ciru thoi gian dong ket
va SLT phat trien cuong do nen theo thoi gian cua be tong geopolymer tro bay
su dung hoan toan cdt lieu xl thep
• ThS. NCS. TRjNH H O A N G SON; PGS. TS. D A O V A N £ > 6 N G Trudng Dqi hgc Cong nghe Giao thdng van tai
I PGS.TS. N G U Y § N Q U A N G PHCIC Trudng Dgi hgc Giao thong van tdi
TOM TAT: Bai bao trinh bay ket q u i nghien cuu ve thai gi3n dong ket va su phat tnen cuong do theo thoi gian cCia be tong geopolymer tro bay sd dgng hoan toan cot lieu xi thep (GPCS) so sanh vdi be tong geopolymer tro bay cot lieu tu nhien (GPC) va be tong xi m3ng truyen thdng (OPC) Thoi gian (bat dau, ket thuc) dong ket cus GPCS, GPC, OPC khong sd dung phg gia sieu dgo va lam cham mnh ket lan luot la (8h, 15h), (12h: 43h), (4,5h, 6h) tinh td liic bat dau trgn udt den khi cudng do khang xuyen d^t [3,5MPa, 27,6lv1Pa) tuong L/ng cho (bat dau, ket thuc) ddng ket Quy lu§t phat trien cuang dg nen ciia GPCS 25, GPCS 30, GPCS 35 co xu hudng tang deu d^n theo thdi gian hoan toan tuong tM nhu OPC Ty lg phat tnen cuong dp nen kha deu dan, lien tyc Xu huong tang cuong dp nen cua GPCS sau 28 ngay tudi con kha mgnh Trong ung xd nen quan sat thay cac dang pha ho?i cua GPCS 6 tudi mudn gan giong nhu cac dang pha hoai +ieu chuan doi vdi be tong cuong do cao Trong do, cac vet nirt di qua be tong, khong phan biet viing vua geopolymer va cot lieu, TL/ KHOA: Be tdng geopolymer, xi thep, thoi gian mnh ket, cuong dg chju nen
ABSTRACT: The paper presents the experimental results on setting time and compressive strength development of fly ash based geopolymer concrete completely using steel slag aggregate (GPCS) which compared with fly ash based geopolymer concrete (using natural aggregate) and traditional cement concrete (OPC). Setting time (beginning;
end) of GPCS, GPC, OPC) without additives are respectively (Sh; 15h), (12h, 43h), (4 5h, 6h) from the beginning of the wet mixing to the penetration resistance (3,5MPa, 27 6MPa) corresponding to
the (start, finish) setting. The strength development trend of GPCS 25, GPCS 30, GPCS 35 grades fends to increase steadily by the time similar to OPC. The growth rate of compressive strength ts quite gradually The trend of increasing compressive strength of GPCS after 28 days of age is sfill remarkable. In the compression behavior obsen/ed from the destructive forms of GPCS in late age are almost the same as that of high strength concrete The cracks passing concrete through regardless of geopolymer mortar and aggregate zone KEYWORDS: Geopolymer concrete, steel slag, setting time, compressive strength
I . D A T V A N O i
Hien nay, vdi sU phat trien eua nganh cdng nghiep vat lieu, xu hudng nghien cdu va dng dung cac loai vat lieu tien tien, vat lieu t h i n thien vdi mdi trudng eang dUpc quan tam, phit trien. Trong dd, be tdng geopolymer tro bay duac eoi la mdt loai be tdng xanh cd the thay the dugc be tdng xi mang truyen thdng trong tuong lai. Be tdng geopolymer tro bay la mpt loai be tdng thu dUOc tU hdn hpp tro bay, dung dich kiem kieh hoat, cdt lieu, nudc va phy gia (neu ed) sau khi ddng ran [7,11,2]. Theo eac nghien cdu eho thay, be tdng geopolymer tro bay cd cac dae tinh eo hpc tUPng tU nhU be tdng xi mang nhU:
cudng dd chju nen, cudng do chju keo udn, cudng dd ep ehe [2,15]. Tham ehi, cd mdt sd dae tinh vUpt trdi hon nhu: ben nhiet, ben sunfat, ben elorua hon, eo ngdt, t d bien thap hon [5,6], Sd dyng be tdng geopeolymer tro bay duac eho la mang lai nhdng hieu q u i ky thuat, kinh te va mdi trUdng do tan dung tro bay (thai pham cdng nghiep) va khdng diing xi mang (nen cat giam duoc iupng khi CO^ p h i t thai) [3,7].
31
KHOA HOC CONG NGHE
So 05/2020
Mat khac, khi nganh vat lieu xay dung p h i t trien ddi hdi nhu cau ve cdt lieu tang len trong khi cdt lieu t u nhien ngay cang khan hiem. Viee sd dyng vat lieu nhan tao thay the cot lieu k h o i n g t u nhien la xu hudng tat yeu, Ben canh dd, chat thai edng nghiep dang gia tang dang ke dan den nhieu chii de moi trudng trong trudng hop khdng cd phuong phap xd l y h a p l y . V i d y , t a i V i e t Nam, udc tinh cd hang trieu tan xi thep duoc thai ra moi n i m v i ehu yeu duoc dem di chdn lap. Vl vay, neu xi thep dupe sddyng de thay the cho edt lieu khoang t u nhien trong xay dUng, dd se l i mdt g i i i phap hieu qua. Vdi mdt sd tinh chat vUOt trdi nhu hinh khdi, gdc eanh nhieu, thd rap, dd rong Idn, be mat rd lam cie hat cd the chen mdc vao nhau, dn dmh cao neu duoc dam chat; ham lupng tap chat hdu CP va hat thoi det thap, do mai mdn Los-Angeles, dp nen dap trong xi-lanh deu ri't tdt, xi thep ( t h i i pham cCia q u i trinh luyen thep} cd the diing thay the cho
; cot lieu da dam. Cac ket q u i nghien edu bude d i u eua cie t i c g i i tren the gidi nhu Ashadi H.W [12], Nitendra Palanka [14], M.S.H, Khan [13] va chinh nhdm t i c gia 6 Vi^t Nam [9,10,8] da eho thay viec sd dung xi thep lam cdt lieu cho be tdng geopolymer la hoan toan k h i thi. Tuy nhien, de ed the dUa be tdng geopolymer edt
• lieu xi thep vao dng dung trong eie cdng trinh thue te thi can p h i i cd nhieu nghien cUu sau hon nda ve cae dng xd cO hoe va dae tinh ky t h u i t eua nd, Mdt trong
^ sd dd, thdi gian ninh ket va phat tnen eudng dd eiia be tdng la hai yeu td can dupe xem xet va danh gia, vi day chinh la yeu td ky t h u i t quyet dmh den eic bien
!phap t d ehUc thi cdng va thdi gian khai t h i e (ddi vdi dng dyng cho ket cau dudng).
2.CHU^NB!MAUTHiyvATiiNHANHTHfNGHl£M Dexaedinh thdi thdi gian ddng ket mau thddupe [lay dai dien tU hon hop be tdng geopolymer sd dyng Ihoan toan edt lieu xi thep theo quy djnh trong Tieu chuan TCVN 3105:1993. Trong q u i trinh trdn, ghi lai thdi diem khi b i t dau trdn dung dieh kiem kich hoat vdl tro bay va hdn hpp cdt lieu xi thep. Hon hpp be tong geopolymer dupe sang qua sing tieu ehuan m i t trdn cd dUdng kinh 5mm de t i c h phan vQa len mat khay khdng hut nude. Trdn ky lai bang tay phan vufa geopolymer thu dupe tren mat khay. Xic djnh nhiet do cua vda b i n g each e i m nhiet ke sau vao vUa t d 5em tdi 7em va ghi lai nhiet dd cua vQa khi nhiet do dat g i i tri tdi da, Xuc vda vao 3 khudn ehda, moi khudn mdt lan l i m thanh mdt Idp. 0am c h i t mau vda trong khudn ehda v i lam p h i n g be mat. Khudn chUa phai chac c h i n , kin nUdc, khdng hap thu nude, khdng dinh d i u md va ed tiet dien trdn, vudng hoic chd n h i t song dudng kinh hoac canh cua tiet dien p h i i khdng nhd hon 150mm va chieu eao khudn it nhat la 150mm. Dien tich be mat vda p h i i du eho 10 lan t h d xuyen ngau nhien vdi khoang each gida eic vi tri e i m kim xuyen v i o vda. Dam chat mau cho den khi hd geopolymer ndi deu len be mat mau.Tien hanh
thi nghiem xae djnh thdi gian ninh ket cua hdn hpp be tdng geopolymer sir dung hoan toan cdt lieu xi thep dugc thuc hien theo TCVN 9338-2012 dua tren nguyen t i c do lue c i n cua vda geopolymer chdng lai su xuyen cua cie kim tieu chuan sau nhdng thdi gian nhatdmh.Thdi gian b i t dau va ket thue ddng ketdUOc xie dinh co sd khi eudng do khang xuyen dat tUOng Ung 3,5MPa va 27,6MPa.
€)e nghien cdu quy luat phat trien eudng dp cua be tdng geopolymer tro bay cdt lieu xi thep theo thdi gian, tien hanh che bi mau be tdng GPCS hinh try 15x30cm cho eie cap phdi da thiet ke cho GPCS 25, GPCS 30 va GPCS 35, Cac mau dUOc dUdng hd d dieu kien nhiet dp phdng thi nghiem t - 22+4°C, do am w = 60±20%.
Cudng dp chju nen eiia eic mau GPCS dUOc xic djnh theo ASTM C39 d cac ngay tudi 3, 7,14, 28, 56, 365 ngay tuoi. Sd luong mau thd va ke hoach thi nghiem dUpe the hien 6 Bang 2.1.
Hinh 2.1: Thi nghiem xuyin tren miu hon hpp be tdng geopolymer hoan toan coi lieu xi thep
32
Bing^. i. Ki hoach thi nghiem va sd'lupng mau thi nghidm
>h[ n g h i d m
Z,T^
cu&ng as n^
. h c g i a n GPCS 2S
«
GPCS 30
s GPCS 35
45 GPC 30
3 OPC 30
3 Ghi chii OVCtkhdiigsif dvng phu gia lam chom ranh Aft) nghrem d nhiet d6:
3, 7. H.56.36S 1 <15 miu), 28 ngdy
(30 mau)
3. KET QUA THI NGHIEM VA THAO LUAN Qua bieu do d Hinh 3.1 eho thay, thdi gian (bat dau; ket thuc) ddng ket eua cie hon hop geopolymer tro bay cdt lieu xi thep (GPCS); be tdng tro bay edt lieu t u nhien (GPC) va be tdng xi mang truyen thdng khdng sddung phu gia sieu deo v i lam c h i m ninh ket (OPC) l i n lupt la (8h; 15h), (12h; 43h), (4,5h; 6h) tinh t d luc b i t dau trdn udt den khi eudng dd khang xuyen dat (3,5MPa; 27,6(VlPa) tuong dng eho ( b i t dau; ket thuc) ddng ket.
Nhu vay, khi sif dung cdt lieu xi thep thay the da d i m va cat vang trong be tdng geopolymer, thdi gian ddng ket cua hon hop be tdng tuoi da g i i m va c i i thien di rd ret ma khdng p h i i dudng hd nhiet d 60"C trong 24h nhu be tdng geopolymer tro bay cdt lieu tU nhien giup giam thieu duoc chi phi va tien dp thi edng. Tuy nhi^n, thdi gian ninh ket cua GPCS lai Idn hon dang ke so vdi thdi gian mnh ket cua hon hop OPC khdng sd dung phu gia sieu deo lam cham ninh ket nhung GPCS v^n dat dupe cudng dd thiet ke d tudi 28 ngiy. Day cd the la nhuoe diem ddl vdi nhdng edng trinh ddi hdi tien do thi cdng nhung eung cd the la Uu diem doi vdi nhdng cdng trinh dxa tram trdn p h i i m i t thdi gian de di chuyen ma khdng phai them phu gia cham ninh ket de duy tri tinh cdng t i c phu eho viec thi cdng va dam len. Ddi vdi be tdng xi mang thdng thudng khi sddung phu gia sieu deo cham ninh ket thi theo thdi gian nmh ket cd the keo dai den hon 12h,
Dae biet, t r i i nguoc vdi OPC, GPCS khi che tao xong thi khdng can bao dUdng am nhu be tdng xi mang, mdt so nghien cUu chi ra rang nhiet dp cang cao thi phan Ung geopolymer hda dien ra eang nhanh. Thdi gian ddng ket cang nhanh phu hpp thi cdng cho cae cdng trinh d cac viing ed khi hau nang ndng nhu thi cdng vao mua he va vung ven bien bien gidi h i i dao.
Dieu nay cd the dugc g i i i thieh thdng qua co che cua chat ket dinh, edt lieu va cau true cua be tong. Theo nghien cull da cdng bd ve vi eau true cua GPCS [)], cac thanh phan khoang vat tren be mat eua cot lieu xi thep d i tuong tac hda hpc vdi ehat ket dinh geopolymer tro bay tao nen d i thuc day toe dd p h i n dng nhanh va tao hen ket manh me hon so vdi be tdng geopolymer tro bay sd dung cdt lieu t u nhien. Hoat tinh be mat ciia cac hat tro bay tuong ddi tro hon so vdi cie hat elinke xi mang ri't nhay va hao nudc nen d nhiet dp thdng thudng phai mat mdt thdi gian lau hon thi dung djch kiem mdi kich hoat dUOc tro bay phin u'ng, Ciing hoan toan tUOng ddng vdi khuyen eio eiia ACI
So 05/2020 2 n 4 R - 0 8 n h u ddi vdl be tdng xi mang sddung tro bay l i m phy gia khoang thi ngay tuoi chuan de danh g i i va nghiem thu chat luong ciia be tdng la 56 ngay.
0 4 8 12 16 20 24 28 32 36 40 44 Thffi gian (Gio') Hinh 3.1: Bieu do quan hi giUa cudng dp khing xuyen
theo thai gian
?0
& 60
1 40 '-§• 30 1 30
10 0 •
!^y
f 1
o?cs L "
Rii
„
= 116liiCt)
^
- 4 . 8
J 'O-L 1
-• L_| :GPCS;S)
112 140 168 196 224 2_-2 2S0 jQS 336 364 Tbolgiaii (ngay tuoi)
Hinh 3.2. Mdi quan he gida cuong do chiu a theo thdi gian 1 cua GPCS Qua bieu dd d Hinh 3.2 cho thiy, cudng dp cua be tdng geopolymer tro bay cot lieu xi thep dng vdi cie cap phdi GPCS 25, GPCS 30, GPCS 35 ed xu hudng t i n g deu dan theo thdi gian va hoan toan tuong t u nhu BTXM truyen thdng, Ty le phat trien eUdng dp nen kha deu d i n va lien tyc, Tuy nhien, xu hudng tang eudng do nen ciia GPCS sau 28 ngay tudi cdn kha manh. Dieu nay cho phep du kien chOng dat duac eudng dd cao d tuoi mudn, ket qua eho thay tai 365 ngay tuoi cudng dd nen cua GPCS 25 tang 47,67%; GPCS 30 tang 57,22%; GPCS 30 t i n g 56,32% so vdi eudng do nen tai 28 ngay tudi.
Td mdi quan he do rut ra cac phuang trinh hdi quy eudng dp ciia be tdng geopolymer tro bay edt lieu xi thep theo thdi gian Ung vdi cac cap be tdng tUong dng 25,30,35MPa-
GPS 25 (cap 25): R„ - 8,5 ln(t) + 3,7 (MPa); R' - 0,97 GPS 30 (cap 30): R^ = 10,5ln(t) + 3,4 (IVIPa); R^ = 0,98 GPS 35 (cap 35): R" - 11,6!n(t) + 4,8 (MPa); R' = 0,97 Trong Ung xd nen quan sat thay cac dang p h i hoai ciia be tdng geopolymer tro bay sd dyng cdt lieu xi thep d tudi mudn gan giong nhU eic dang pha hoai tieu chuan ddi vdi be tdng cudng dp eao, eae vet nut di qua
33
KHOA HOC CONG NGHE
5605/2020
khdng p h i n biet vimg vda va edt lieu the hien d Hinh 3.3 den Hinh 3.5.
Dieu nay cd the dUOc ly g i i i la do da ed tUong tac hda hoe tren be mat cot lieu xi thep vdi ehat ket dinh gepolymer tro bay giup eho lien ket trd nen manh me hon v i vung ehuyen tiep gan nhU khdng phan biet dupe, npi dung n i y da dUoc nghien cdu va trinh bay chi tiet d edng bd trUde [1], Hoan toan trai nguoc, ddi vdi BTXM thdng thudng thi viing chuyen tiep gida ho xi mang va cdt lieu cd cau true ket tinh, rong nhieu hon, cae mat ndt, vet ndt va cudng dp nhd hPn vung vda xi m i n g , chieu day eua ldp ehuyen tiep nay la t d 20-^100 pm.
Hinh 3.3: Vet ndt cda bi tdng cudng dd cao [4]
\ /
\ / / \ X
/ \
1
1 1
A
/ \ / N 1 A /
/
A
/ \ / \
/ / /
c) - Cone and Shear d) Shear e) - Columnar Hinh 3.4: Cac dang phi hoat mau thd chuan
Hinh 3.5: Dang pha hoat mau GPCS
4. KET L U A N VA K|£N NGHI
TU eac ket qua thye nghiem trong nghien eUu nay, eie ket l u i n va kien nghi sau cd the dupe riit ra:
- Thdi gian (bat dau; ket thuc) ddng ket eiia cie hon hpp geopolymer tro bay edt lieu xi thep (GPCS); be tdng tro bay cdt lieu t u nhien (GPC) va be tdng xi mang truyen thdng khdng sddung phu gia sieu deo va lam chim ninh ket (OPC) lan lupt la (8h; 15h), (12h; 43h}, (4,5h; 6h) tinh t d luc b i t dau trdn Udt den khi cUdng 6g khing xuyen dat (3,5IVIPa;
27,6IVlPa) tuong Ung eho (bat dau; ket thiic) ddng ket.
- Cie phuong trinh hdi quy eUdng do eua be tdng geopolymer tro bay cot lieu xi thep theo thdi gian dng vdi eac cap be tdng tUOng dng 25, 30, 35Mpa:
GPS 25 (cap 25): R^ - 8,5 ln(t) + 3,7 (MPa); R' - 0,97 GPS 30 (cap 30): R^ - 10,5ln(t) + 3,4 (MPa); R' - 0,98 GPS 35 (cap 35): R„ - 11,6ln(t) + 4,8 (MPa); R' - 0,97 - Trong Ung xd nen quan sit thay eie dang p h i hoai ciia be tdng geopolymer tro bay sd dung edt lieu xi thep d tudi mudn gan gidng nhu eac dang p h i hoaitieu chuan ddi vdi be tdng cudng dd cao, cac vet nut di qua khdng p h i n biet vung vda va cdt lieu
Ldi cam d n : Nghien cdu sinh duoc hd trp bdi ehuong trinh hpc bdng d i o tao tien sT trong nUdc eda Quy Doi mdi sing taoVingroup.
Tai lieu tham khio
[1], Dao Vin Ddng va Trjnh Hoang Son (2020), Nghien cdu vi cdu true cua be tong geopolymer tro bay sCf dung hoan todn cot lieu xithep, Tap chi GTVT
[2]. Dao Van Ddng (2010), Nghien cdu mgt so tinh chdt ca hoc cua be tong polymer vo ca. Tap chi GTVT.
[3]. Dao Van Ddng (2009), Vat lieu "xanh" va ben vOng - xu hudng dephdt trien xay dung. Tap chi Khoa hoe cdng nghe Xay dUng.
34
cudng dg eao vd be tong chat lugng cao. NXB. GTVT, Hi Ndi.
[5]. Concrete Institute of Australia (2011), Recommended practice Geopolymer concrete.
[6]. D, Hardjito, D.M.J, Sumajouw va B.V, Rangan (2014), Development of Fly ash based Geopolymer Concrete, Conference of Construction materials, India.
[7]. J. Davidovits (2008), Geopolymer Chemistry and Applications, Institut Geopolymere, Saint-Quentin, France.
[8]. Dong Van Dao va eac edng sU (2019), Artificial Intelligence Approaches for Prediction of Compressive Strength of Geopolymer Concrete. MDPI Journal of Materials, Special Issue New Advances in Self- Compacting Concrete and Geopolymer Concrete, vol.12.
SCIE, IF 2.217.
[9]. Dong Van Dao and Son Hoang Trinh (2019), fi/Jechanical properties of fly ash based geopolymer concrete using only steel slag as aggregate. Springer Nature Singapore Pte Ltd. 2020; C. Ha-Minh et al, (eds,), CIGQS 2019, Innovation for Sustainable Infrastructure, Lecture Notes in Civil Engineering 54,
[10], Dong Van Dao va Son Hoang Tnnh (2019), Prediction of Compressive Strength of Geopolymer Concrete Using Entirely Steel Stag Aggregates: Novel Hybrid Artificial Intelligence Approaches. MDPI Journal of Applied Sciences, Special Issue Soft Computing Techniques in Structural Engineering and Materials, vol.9. SCIE, IF 2,217.
[11], P Duxson va eae cpng sU (2007), Geopolymer technology:The current state of the art, iourna\ of Mater\a\s Science, 42(9), tr.2917-2933,
[12],HenkiWibowoAshadi(Apnl2015),fffecfsofsfee/
slag substitution in geopolymer concrete on compressive strength and crrosion rate of steel reinforcement in seawater and an acid rain enviroment, International Journal of Technology.
[13]. M.S.H. Khana va cac cdng su (2016), Uf/7;saf/on of steel furnace slag coarse aggregate in a lov\/caleiumflyash geopolymer concrete. Cement and Concrete Research, 89, tr.220-229,
[14], Nitendra Palankar va A.U. Ravi Shankar & B.M Mithun (2015), Investigations on Alkali-Activated Slag/
Fly Ash Concrete with steel slag coarse aggregate for pavement structures, International Journal of Pavement Engineering,
[15]. B. V. Rangan (2008), Fly Ash Based Geopolymer Concrete. Research Report GC4, Curtin University of Technology, Perth, Australia,
Ngay nhan bai: 01/3/2020 Ngay chiip nhan dang: 19/3/2020 NgUori phdn bien: TS.TranVanQuan
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