KHOA HOC CONG NGHE
S6 01^2026
Nghien ciiu he sd gian no do nhiet cua be tong geopolymer tro bay SLT dung hoan toan cot lieu xi thep
• PGS. TS. OAO V A N O O N G ; ThS. NCS. TRINH H O A N G SON Trudng Dgi hoc Cdng n g h i Giao thdng vdn tdi
T 6 M TAT; Bai bao trinh bay ket q u i nghien cuu ve he s6 gi3n nd do nhiet dd thay doi (GTE) cOa bd tong geopolymer tro bay sd dung hoan t o i n cot lieu xl thep (GPCS) co cudng do cliiu nen d^c trung f'c = 25 MPa (GPCS25), 30 MPa (GPCS 30), 35 MPa (GPCS35). Ket q u i nay duoc so sanh vdi he s6 gian nd do nhiet dd thay doi cua be tong geopolymer tro bay (GPC 30) sO dyng cot li^u ty nU\er, (da dSm, cat sdng) v i be tong xi mSng truyen thdng c6 f'c = 3 0 MPa (OPC 30} Ket q u i cho thay, CTE cOa GPCS thu duoc dao dpng trong klioing 8,34 den 9,53 jie/°C Cudng dd be tong GPCS cang cao thi xu hudng cua he so gian nd nhiet CTE c i n g nhd Dong thai, tu ket q u i nghien cuu phucmg trinh hdi quy giCra CTE theo cuong dp ch|u n^n d$c trung cua GPCS dupc tl^iet lap Hon nQa, k i t q u i CTE cua GPCS 30 dat gia tn thap nhat la 8,65 jie/°C. Trong khi d6, CTE cua OPC 3 0 va GPC 30 khi sO dung cot lieu thong thuong la 10,42 v i 9,91 He/°C
T Q K H 6 A : Be t6ng geopolymer, cot lieu xi thep, he so gian nd do nhiet (CTE)
ABSTRACT: This paper presents the experimental results on coefficient of thermal expansion (CTE) of fly ash-based geopolymer concrete completely using steel slag aggregate (GPCS) with three grades of specific compressive strength, f c - 25 MPa {GPCS 25), 30 MPa (GPCS 30) and 35 MPa {GPCS 35). Then the results are compared with CTE of fly ash-based geopolymer concrete (GPC 30) using conventional aggregate (natural crushed stone, river sand), and traditional cement concrete that has f'c = 3 0 MPa (OPC 30). The goals showed that the CTE of GPCS obtained ranged from 8 34 to 9.53 ne/°C The higher the GPCS concrete strength, the smaller the trend of the CTE, Moreover, the regression equation about CTE according to the specific compressive strength of GPCS was obtained Additionally, CTE of GPCS 3 0 reached the lowest value of S 65 jie/°C At the same time, CTE of OPC 30 and GPC 3 0 using
conventional aggregate are 10.42 and 9.91 HE/^C.
respectively
KEYWORDS: Geopolymer concrete, Steel slag aggregate, coefficient of thermal expansion (CTE),
I.OATVANO^
Cie loai v i t lieu xiy dung thudng thay ddi kich thudc dan d i n thay ddi the tich khi chiu tie ddng cua n h i l t dd trong khi I p suit dupe glO khdng ddi. B l tdng xi m i n g cOng dien hinh eho sU co, nd t h i tieh khi n h i l t dd mdi trudng g i l m hole t i n g . H I sd gian nd n h i l t eua b l tdng dupe djnh nghia l i mot dai lupng v i t ly die trUng cho su thay ddi kich thudc khi cd q u i trinh trao d6i nhilt.
SU thay doi kich thudc khdng ddng d i u do nhiet se tao ra dng suat keo trong khdi b l tdng. Khi Lfng suit niy vupt q u i gidi han thi b l tdng se bi ndt. H I sd g i i n nd do n h i l t the hien dd doc ciia mdi quan he giCta b i l n dang theo v i n h i l t dd t i c ddng len b l tdng.
Su hinh thanh v i phan bd trUdng nhiet dd, umg suit trong long khdi be tdng t r l n k i t eau rat phCrc tap. Q u i trinh niy phu thudc v i o eie y l u td n6i tai, eau true eua b l tdng eung nhu cic y l u to ben ngoii l i l n quan d i n mdi trudng va cdng nghe thi edng [2]. Cie y l u td ndi tai eua b l tdng cd the k l d i n , gdm: thdng sd v l n h i l t ciia vat lieu; loai va ham lUong chat k i t dinh; cie loai cdt lieu;
ti le t h i n h p h i n cap phoi; nhiet dd be tdng khi dd; n h i l t dung rilng eua be tdng; tde dp tda nhilt; hinh dang; kich thudc k i t eau. Cic y l u td ben ngoai bao gdm nhU: eie thdng so v l mdi trudng (nhiet dp, dp am, tde dd gid);
phuong phap b i o dUdng b l tdng; dieu k i l n cic be mat tiep xuc {vin khudn, n l n dat); nhiet do tai mat thoing eua khdi b l tong; h i sd trao ddi nhilt. He sd g i i n nd do n h i l t cua be tdng thudng rat nhd v l khd xic djnh.
Clu true cua b l tdng cd 3 pha, gdm cdt lieu, chat k i t dinh ddng rIn va Id rong. Ddi vdi b l tdng xi mang, cdt lieu thudng la d i d i m v i cit, nhCfng v i t lieu cd h i so g i i n nd nhiet thap. Nguoc lai, d l xi m i n g l i sin pham thuy hda ciia xi mang vdi nude, tao n l n cac sin pham chu yeu eua C-5-H, eiing vdi cau true 15 rong duoc cho l i k h i nhay c i m v l the tieh dUdi tie dpng ciia su thay ddi eiia n h i l t dd (1 ]. B l tdng geopolymer sir dyng l i xi t h i p mot mat cd quan he the tich - nhiet khic vdi d i d i m va
53
KHOA HOC CONG NGHE
SA 06.2020
cit. Ddng thai, chat k i t dinh geopotymer, do ed c l u true mach polymer ben vifng n l n cd nhilu khic b i l t so vdi cau true tinh t h i C-S-H trong da xi m i n g , dan tdi se cd dng xd the tieh do nhiet khic b i l t
Bii b l o nay trinh bay ve he sd g i i n r\d do n h i l t cua be tdng geopolymer tro bay sif dyng hoan t o i n cdt lilu xi t h i p vdi cle cap cudng do chju n l n khic nhau. Kit q u i thi n g h i l m duoc so sinh vdi h i sd g i i n nd do nhilt ciia be tdng gepolymer tro bay sif dung cdt tilu t u nhien ( d i d i m , c i t sdng) va be tdng xi mang truyin thdng.
2.CHUANBtMAuT>1ljrvATl£NHANHTHfNGHl|M H I sd gian nd n h i l t cua b l tdng (CTE) dupc xic djnh theo Tieu chuan AASHTO T336 [3]. Thilt bi chinh (Hinh 2.1) duoc SLf dung bao gdm: be nude dn djnh nhilt (nude trong b l cd the dupe thay ddi nhiet dp trong kholng tif 10°C d i n 5 0 ^ , vdl dp chinh xac 0,1 K.): LVDT de do b i l n dang, d i u do nhiet dd vdi dp chinh xac dat chuan do KYOWA ElECTRONIC INSTRUMENTS CO., LTD cung d p ; thiet bj thu tin h i l u da kenh UCAM 60B cung eie e l p k i t ndi chuyin dung; m i y tinh; khung gid m l u ( b i n m i t , b i n d i y v i thanh dd doc l i m b i n g thep).
M l u thi nghilm dupe ehe bj cho 3 loai be tdng, bao gdm: be tdng geopolymer tro bay sddung h o i n t o i n cdt lieu xi t h i p cd cudng dd chiu n l n die trung t h i l t k l l l n luot I I 25; 30; 35 MPa (GPCS 25; GPCS 30; GPCS 35); be tong geopolymer (GPC 30) sCf dyng cdt lieu t u nhiln ( d i d i m , c i t sdng) v i b l tdng xi m i n g truyin thdng (OPC 30) cd cung eudng dp chiu nen f'c = 30 MPa.
Cap phdi v i sd lupng mau thi nghilm cua cic loai b l tdng duac sd dung trong nghiin cuu duoc the h i l n d Bdng 2.1
Bing 2.1. Thinh phin cSp phdi vi sd lupng miu thinghiim cua cic lo^i t)e tong
n » * n h p h i a t f a h6n h q p OPCIO C K I C GPC5J0 G K S U G K S S S Xl m i n g PC ) 0 [ * ' i _ 2','i' j _ -
^ d l n i l k g l _ ^ 0 1 M 2 TJ56ft4 _ - ^ - C M f t g l aB6.«3 S9136 _ _ _ - -_
[Wufltdigl 1 6 7 . M ' J 6 3 0 i i S2_ 3S19 ?Q,W N*OH(kgl
D u n g d K h N j S ' O kg Tro t u y (kg) C A b ^ i Idn i l tMf> 4.75 - 1 9 mi C A iCu nh6 •< tti«p a i 5 - 4.75 n
n f t g l
• n f t g )
- 14J1 - , >2i4S -' 388.71
2I.9S 1 6 4 ^ 491.89 1670.90 716.10
l Z 4 a 171.99 4S2J4 167a9D 71&10
; i , i 3 1S3.59 S07J9[
1G70,90 716.10 ' S6 lupng m k i hinh tn.
10Omm v l thitu ao 200 m m
t W u l i * ! b i o * ) * > £ [ _ _ l l l i l i _ i l L _ 1?! ' ^ i .
()) Sau khi thao khudn. tien hinh imam trong nude d dHu kien phong den 28 ngiy tuoi.
(2) Khi due mau xong. sau 1 ngiy nen hanh dudng hp nhipt 6 6ff'C/24h. sau do thao khudn va luu b dieu kien phong Thi r\ghiem den 28 ngay tuoi:
(3): Mau sau khi ttiao khudn dupc luu dieu kien phdng ttv nghiem ddn 28 ngiy tudi
Mau trudc khi thi nghilm dupc dem di m i t p h l n g sao cho cic m i t e l t song song vdi nhau. Mau dupe n g i m trong mdt be chCra nude d 23 ± 2''C ft nhit 48h.Tlln hanh vdt m l u , lau khd be m i t mau, de khd rIo b i n ngoii. Sau dd, d i t mau v i o trong be dn dinh nhiet do.
D i t nhi|t do be chiJa I I 10°C, duy tri n h i l t dd nay trong 1h d l dat ducK c i n b i n g nhiet trong m l u . Cin b i n g n h i l t trong mau dUOc gia dinh I I khi thu dupe g i l
54
tri LVDT khdr>g ddi sau khi ghi l i l n tue eO 10 phut mdt l i n trong kholng thdi gian l,5h. Ghi lai sd dpc n h i l t dd tif (cac) e l m bien chinh xic d i n O . l t ! Ghi lai LVDT dpc chinh xac den 0,00025 mm.
Sau dd, t i n g n h i l t be d i n 5 0 ^ q u i trinh t i n g n h i l t dp tdi t h i l u kholng 2h, sau dd duy tri nhiet dd trong b l kholng 1 h eho d i n khi dat trang t h i i c i n b i n g trong m l u v i ghi lai k i t q u i tucmg t u nhu q u i trinh tren.
Lai ha nhiet dd trong b l xudng 10°Cdl m l u dat c i n b i n g n h i l t va ghi lai cac g i l tn LVDT tUong t u nhU tren.
Cic g i i tri CTE, thu dupe khi n h i l t dd tang t u 10°C d i n 5 0 ^ trong khi cic CTE^ thu dupe khi n h i l t dp g i l m tif 50°C den 1 0 ^ . Sau dd, k i l m tra su khic b i | t gida cic g i i tn CTE, v i CTEj trong hai q u i trinh t i n g v i giam nhiet dd tren. N l u chinh lech g i i ^ hai g i i tri CTE n i y nhd hem 0,3 \im/°C thi g i i tri CTE cua mau thCt la g i l tn trung binh cua hai g i l tn CTE, v i CTEj. N l u chinh l i c h giita c i e CTE, va CTEj Idn hon 0,3 |jm/"C, p h i p t h d 6uac l i p lai eho d i n khi ehenh lich n i m trong pham vi sai sd.
H I sd g i i n nd nhilt cua b l tdng (CTE) duoc xie dinh theo cdng thdc sau:
CTE=(ML„)AT
Trong dd: AL - Chieu d i i thay ddi m l u do; L^ - Chilu dai ban dau do dUOc cua mau do; AT - Su c h i n h lich n h i l t dd.
NWi 2.2: DO^u M 6 > d^ng theo nhiit do duoc ghi lai trin miy tirOt ItSng phin mim ciia UCAM60
KHOA HOC CONG NGHE
5dO&'2026 3. K ^ QuA THr NGHI$M VA THAO L U A N
Kit q u i thi nghilm thu duoc h i l u chuan vdi cle d i u do b i l n dang, d i u do n h i l t dp v i tien h i n h loai bd sai so thd theo ASTM El 78 [9]. Chi t i l t cic k i t q u i dUpc tdng hpp 6 Bdng 3.1 v i Hinh 3.1, Hinh 3.3.
Bing 3.1. Bing tdng hop kit qui thinghiim CTE cua cic loai bi t6ng
Loai ' t n j n g b i n h ' _ ,
|OPC30 10,42 GPC30 9,91 1GPCS30 8,65
| G P C S 2 5 1 9,53 GPCS35 ' 8,34
M2
\iErx.
10.26 1 10,92 9,72 9,65 8,42 1 8,58 9,68 i 9,97 8.16 8.23
«3
|ic/<>C
10,08 10,36 8,95 8,94 8,63
c h u j n p h i n t i n .
0,44 4,24 1 0.39 3,95 i 0.27 3,14 0,53 1 5,57 0,25 , 3,04 1
: 1 ! ! : "
111'
Hinh 3.1: Bliu dd quan hi glQa blin d^ng theo rAiitd6 cua cic loai bi tdng 'GPCS25, GPCS30. CPCS35 Vdi 3 hdn hop b l tdng geopolymer dang xet GKS25, GPCS30, GPCS35, k i t q u i CTE thu dUpc dao ddng trong kholng 8,34 d i n 9,53 pe/'C Cudng dp be tdng GPCS cing cao thi xu hudng cua he so g i i n nd n h i l t CTE cing nhd nhutig ehUa rd ret vl eudng dp chju n l n die tn/ng GPCS chinh nhau khdng nhilu.Tuy nhiln, de nghiin cufu rd hon nifa ve van 64 n i y thi can khio sit vdi pham vi nghiin cdu rpng hOn v i kholng chinh giura c i c d p b l tdng can Idn han de n h i n thay rd sU khie biet.
Phuong trinh hdi quy thue nghiem giCfa he so g i i n nd nhilt (CTE) vdi cudng dp chju n l n d i e trUng thue nghilm GPS 25 (f'c = 27,29 MPa); GPS 30 (f'c = 32.50 MPa);
GPS 35 (f'c = 37,06 MPa) [7,8.6] eiia be tdng geopolymer tro bay sir dung h o i n toan cdt lieu xi t h i p dUpc the h i l n nhu phuong trinh (1) va Hinh 3.2.
CTE = 40.51 f'e-°" vdi R^ = 0.7137 (1)
Caing Of ck|i mtu (Strn) Hinh 3,2: Bi^ dd quan hi giOa CT£
vi cudng d6 chiu nin cda tii tong GPCS
l " f
Hinh 3.3: Bieu do quan hi gida blin d^ng theo nhl$t d^
c6a cic toai bi tong GPCS30. GPC30. 0PC30 hfinh 3.3 cung the h i l n quan h | b i l n dang theo nhiet dp eua b l tdng gepolymer tro bay cdt lieu t u nhien (GPC 30) v l b l tdng xi m i n g truyen thdng (OPC 30) ciing d p . Kit q u i eho thay, CTE cua GPC30 cung g i n tUong t u vdi OPC30. K i t q u i n i y eung tUOng ddng vdi cic k i t l u i n cua eie t i e g i i Hajito, Davidoit, Rangan [5,4,10]. K i t q u i CTE eCia (GPCS 30) sir dung cdt l i l u xi t h i p dat g i i tri t h i p nhat la 8,65 \XE/°C. CTE eua (OPC 30) v l (GPC 30) khi sd dyng cdt lieu thdng thudng l l n lupt l i 10,42 v i 9,9lM£/°C. Nguyin n h i n cd the do sCf dyng cdt l i l u xl t h i p da lam g i i m dp gian nd. D i l u niy phij hpp vdi k i t q u i nghien cOXi cua t i c g i l nhu Neville v i Brooks [12].
Nghien cdu da chi ra h i sd CTE phy thudc v i o loai cdt lieu, thdi gian x i c i^nh, 6\4u kiln mdi trudng v i chu trinh thay ddi n h i l t dp. Do cdt lieu chiem mot p h i n d i n g ke theo t h i tich trong t h i n h p h i n hdn hpp b l tdng, n l n mde dp thay ddi h i m lupng, tinh c h i t v i t l i l u cua cdt l i l u s i I n h hudng nhilu den sU bien dang do nhilt ciia be tdng. Tir eie nghiin ciJu [11] da ch( ra mdi quan he t u y l n tinh gida lupng diing cdt lieu Idn v i h i sd CTE, h i m luong va loai cdt lieu i n h hudng Idn d i n CTE. Do sU b i l n thien cua CTE phy thupe vao nhieu v i o loai v i t l i l u SLf dyng m i chu y l u l i do cot lilu.
Vi viy, cic k i t q u i thi nghiem dupe trinh b i y d t r l n d i cho thay i n h hudng cua loai cdt lilu, loai chat k i t dinh, eudng dp chiu nen d i n he sd g i i n nd nhilt cua be tdng. D i l u nay se gdp phan hieu q u i cho viec tinh t o l n kich thudc hinh hpc cua c l u kiln, g i l m dupe vet niJt do nhiet va t i n g tuoi thp cdng trinh.
4 . K^T L U A N V A K I ^ N NGH!
Tif c i c k i t q u i thUc nghilm dat dUOc v l he sd g i i n nd n h i l t CLia b l tdng geopolymer sd dung h o l n t o i n cdt lieu xi thep khi so sinh vdi cic loai b l tdng ddi chiimg khic trong nghiin cdu niy, cle k i t l u i n va k i l n nghi sau cd the 6uac nit ra:
- Kit q u i CTE cua {GPCS 30) sddung cdt l i l u xi t h i p dat g i l tri thap nhat la 8,65 ye/'C. CTE ciia {OPC 30) v i (GPC 30) khi SLf dyng cot lieu thdng thudng l i 10,42 v i 9,91 ME/"C.
- Cudng dd b l tdng GPCS cang eao thi xu hudng cua he sd g i l n nd n h i l t CTE cang nhd. Tuy nhiln, d l nghiin
55
KHOA HOC CONG NGHE
SA Ob 2020
cdu rd hon nCta v l v i n d l nay thi d n khao sat voi pham vi r>ghtln euu rdr>g hon va kholr>g ehenh giCta cac d p be tdng d n Idn han 64 nhan thay rd su khac biet
- Phuang trinh hdi quy thue nghiem giOa he sd g i l n nd nhiet iCTE) vdi cu6r>g dp chju nen die trung cua be tdr>g geopolymer tro bay sd dyr>g hoan t o i n edt lieu xi t t i l p trong pham vi nghien cdu duoc rut ra:
CTE = 40J1 f ' c * " v 6 i R ' = 07137 T l i lieu tham khao
[ l i . Pham Duy HCfu va Dao Van Dong (20091, Vdtliiu xdy dung mdi. NXB. GTVT, Ha Ndi.
[2]. Hd Ngoc Khoa v l Vu Chi Cong (2012), Phdn tich tn/dng nhidt do va ung suat nhiet trong be tong khdi Idn bdng phuang phdp phdn td hOu han. Tap chi Khoa hpc Cdng nghe Xiy dung (14 12), tr 17-27.
[3]. AASHTO, T336Coefficienf of Thermo/Efpomron of Hydraulic Cement Concrete.
[4]. D. Hardjito, DMJ. Suma)ouw and B.V Rangan (2014), Development of Fly ash based Geopolymer Concrete. Conference of Construction matenals. India.
[5]. J. Davidovrts (2008), Gec^xVymcr Chemistry and App//car/onj,lnstitutGeopolymere.Saint-Quentin. France.
[6]. Dong Van Dao va cic edng sU (2019), Artificial Intelligence Apprcxiches for Prediction of Compressive Strength of Geopolymer Concrete. MDPI Journal of Materials, Special Issue New Advances in Self- Compacting Concrete and Geopolymer Concrete. voJ.l 2.
SCIE, IF 2.217.
[7]. Dong Van Dao and Son Hoang Trinh (2019), Mechanical properties of fiy ash txised geopolymer concrete using only steel siag as aggregate. Springer Nature Singapore Pte Ltd. 2020; C. Ha-Minh et aL (eds.), CIGOS 2019, Innovation for Sustainable Infrastructure, Lecture Notes m Civil Engineering 54.
[8]. Dong Van Dao and Son Hoang Trinh (2019), Prediction of Compressive Strength of Geopolymer Concrete Using Entirely Steel Slag Aggregates: Novel Hybrid Ariificial Intelligence Approaches, MDPI Journal of Applied Sciences, Special issue Soft Computing Techniques in Structural Engineering and Materials, vol.9. SOE, IF 2J17.
[9]. ASTM El 78 [2016), Standard Practice for Dealing With Outlying Observations, chii biln, American Society for Testing and Matenals.
[10]. D. Hardjito v i eie cdng sU (2004), On the development of fiy ash-t>ased geopctlymer concrete, ACI Materials Journal 101,tr.467-472.
[11], A. M Neville (1995), Properties of Concrete 4th edn. Longman.
[12]. A. M. Neville (2000), Properties of Concrete (Fourth and Final ed.).
Hgiy n h i n b i i : 19/3/2020 Ngiy chip n h i n d i n g : 29/4/2020 NgUdi phin biln: TS. Nguyen Thi Thu N g l
T5. Nguyen Thiiy Anh
