KHOA HOC - CONG N G H I '
J 11/2018
Nghien cuu ung dung be tong cot spi thep phan tan trong khe co gian ban thep rang lupc
tren cau duong bp a Viet Nam
I TS. N G O V A N MINH - Trudng Dai hoc Giao thong van tai I KS. Q U i H Al TRUNG - Tong cue DUdng bg Viet Nam
I KS. T R A N M A N H CUdNG - Trung tam Khoa hgc cong nghe Xdy dUng va Giao thong
TOM TAT: Khi khe co gian rSng lupc b^n thep tren cau chiu t i l trgng trung phuc cOa banh xe ngng, ket hpp vdi dp cdng thay doi tCi lpp asphalt, phan be tpng khdng co ngdt cCia khe co gian co the xuat hi§n cac hu hdng nut va, i n h hudng trye fiep den an toan cua phupng tipn va fupi thp cua cdng trinh cau. Oe g i i m thieu tinh fr^ng tren, dong fhdi nang cao hieu q u i cCia viec sda chQa, thay the cac khe co gian b^n thep rang lupc hien tgi, bai bao tien hanh nghien cuu ung dung cilia be tong cot spi thep (BTCST) phan fan vpi ham lupng spi thep thich hpp de thay the vCra be tong khdng co ngdt dang dung.
TL/ KHOA: Khe co gian rang lupc ban thep, be tong cot spi, spi thep phan tan, vua be tong khong CO ngot.
ABSTRACT: Whensteel comb-plate expansion joint of a highway bndge is subjected repeated heavy loads combining with variant stiffness from asphalt layer to concrete block of the expansion joint, there will be occurrence of cracks on the concrete block This type of damage not only directly affects on vehiclespassing by but also the life of the bridge So to prevent this situation and to improve the effectiveness of repanng and replacing of the expansion joint, the paper carries out the study of application of steel dispersion fiber concrete with suitable content of fiber in taking the place of non-shnnk grout mix currently used for steel comb-plate expansion joint
KEYWORDS: Steel comb-plate expansion joint, fibre concrete, dispersion fiber, non-shnnk grout
I . O A T V A N O ^
Hidn nay, sau mdt thdi gian khai thic, sQ dung, cic khe CO g i i n b i n thep rang lUde d cae edng trinh eau d Viet Nam d i xuat hien nhldu hU hdng. Cic hu hdng nay
p h i t sinh ehu yeu do lUc xung kich eua tai banh xe khi di chuyen tQ mat cau b i n g be tdng asphalt sang Idp be tdng khdng co ngdt cua ket cau khe eo gian bang b i n thep, lam phan bd tdng nay bi vd, bong trde. Dang pha hoal nay ndu khdng dQdc xQ ly kip thdi se keo theo cac hu hdng khic cua khe co g i i n va cd the dan den hu hdng cho gdi cau. Dieu nay neu ra yeu cau can p h i i tang eUdng kha nang chiu luc cue bd va lUe va cham cua phan bd tdng cdt thep chuyen tiep giQa phan bd tdng asphalt va ban thep. Ben canh do, vide sQa ehUa, tang cUdng khe CO gian thQdng dupe thUe hien trong dieu kidn cau van eho phuong tien luu thdng, ndn i n h hUdng xung kich cua hoat t l i den bd tdng trong khe co gian thay the la dang ke.
Trdn the gidi, eae nghidn cdu ve viec Qng dung cua BTCST da dupe thuc hldn tQ nhieu nam qua. Cac spi thep vdi ty Id L/d (chieu dil/dudng kinh) tUdng thich dUdc dUa vao trong hon hdp be tdng, lam tang eUdng dp eung nhU Qng xQ cua bd tdng trong qua trinh hinh thanh cudng dp cung nhu khai thic. Do dd, vdi mong mudn tim ra dupe g i i l phap sUa chQa, thay the khe eo gian hieu qua hdn, vide nghien cQu kha nang Qng dung eua BTCST trong khe CO gian rang iQdc ban thep cho eau dudng bd dVlet Nam la rat can thiet va thUe tien.
2. NGHIEN CCfU <fNG DUNG BTCST P H A N T A N TRONG KHE CO G I A N R A N G Ll/CfC B A N THgP CHO cAu DUdNG B 6 6 V I £ T N A M
2.1 .T6ng quan ve ufng dung vat lieu BTCST phan tan BTCST la vat lieu hon hpp bd tdng xi m i n g bao gdm:
D i d i m , cdt lieu min (eat), ehi't kdt dinh (xi mang) va phy gia (neu cd) ket hpp vdi eae spi thep phan tan. Vat lieu spi thep thudng cd eUdng dp va md-dun dan hdi tUdng ddi cao, dUdc che tao de tranh bi an mdn do kiem cd the cd trong xi mang. De tang cUdng dinh bam eo hoc trong bd tdng, eie spi thep thudng dUdc che tao thanh cic neo d moi dau hoac lam bien dang t h i n h dang luon sdng.
Sdi thep sQ dung trong be tdng cdt spi thudng ngIn, cd nhieu kich thudc v i hinh dang. Ty td glQa chieu dai va dudng kinh (L/d) thdng thudng tQ 20 ddn 100, trong do
45^
KHOA H O C - C d N G N G H g
ehieu dai cua spi tQ khoing 6.4mm den 100mm, Ty Id niy dupe quy Udc gpi la ty le be mat. Vdi eac hon hdp BTCST, ndu ty Id be mat qua Idn, eae sdl thep bl minh, khi trdn se cd xu hudng dan lai vdi nhau thanh tam hoac cudn lai, dan tdi hldn tupng vdn cue bd v i phan tan khdng ddu.
Ngupc lai, neu ty le be mat cua sdi thep q u i nhd sd iam giam hieu qua tang cUdng.
Bing 2.1. Bing t^le thanh phin vat lieu cua hai cap phSi be tong thi nghiem
Hinh 2.1: Mot so dang sgi thep s^dung trong BTCST Ham lupng spi thep phan t i n dupe dQa vao trong hdn hpp BTCST thdng thudng dupe tinh theo phan t r i m khdi lupng trdn tong khdi lUpng hon hop. Tuy theo muc dich sQ dung tang cQdng eho ket cau, h i m lupng spi thep theo khdi IQdng cd the len den 10%, nhung thdng thudng gia trj nay chi nam trong khoang t u 0.25% den 2.00%.
Tong hpp tQ cie nghidn cQu trdn the gidi, vdi ham iQpng spi thep hpp ly, BTCST phan tan mang lai cae Uu diem ndi trdi so vdi vat lieu bd tdng thdng thudng cung cic thinh phan cap phdi, cu the:
- Cudng dd chiu nen: Cudng dp chiu nen tdi han cd the tang den 30%;
- Cudng do chiu keo thang: Cd the tang den 30-40%;
- Kha nang chiu elt va xoan: Cd the tang pham vi chiu cat len ddn 30%;
- Kha n a n g e h j u u d n : V d i t h i n g h i e m u d n 3 d i e m , k h a n a n g e h j u u d n c d t h e t a n g 5 0 - 1 5 0 % ;
- Khi nang chiu tai trpng va dap: Tang ning lupng chiu phi hoai do va dap len 4 - 5 lan;
- Kha n a n g c h d n g m d i : SUe k h a n g m d i t a n g t Q 6 5 - 9 0 % ; - Hieu Qng eo n g d t , tQ b i e n : K h d n g a n h h u d n g d e n Qng xQ c o n g d t va tQ b i e n c u a vQa x l - m a n g ;
- Ma sit va sQc khang trucrt: SQc khang lan va truot cua BTCST cd the len ddn 15%.
2.1. Nghien cuTu de xuat ty le cap phoi hon hdp BTCST phan tan sit dung cho khe co gian rang lucre ban thep
2.1.1. Tyle thanh phan vat lieu va cdc phuong phdp thi nghiem
Trdn co sd nghien eUu ly thuyet ve ham lupng sol thep trong hdn hpp bd tdng, nhdm t i c gia tidn hanh nghidn cdu hai loai cap phdi dUa tren ty Id cap phdi thiet ke eho bd tdng cd / ' = 45MPa, thudng dupe dung lam be tdng cho eae dam BTCT dQ Ung luc. Loai da dam dupe sQ dung cd cap phdi nhd hon de thich hpp vdi vide thi edng khe co gian. Sol thep sQdung la soi thep Dramix sin xuat d Indonesia, Ham lupng thep dUa vao hai hdn hop be tdng bao gdm:
- Cap phdi 1 (CP1): Khdi lupng spi thep l i 35 kg/1 m^
bd tdng, tupng dUdng ham lupng 1,40%;
- Cap p h d i 2 (CP2): K h d i l u p n g spi t h e p la 5 0 k g / 1 m=
b e t d n g , t U d n g d U d n g h a m l u p n g 2.00%.
46
V i t I l 6 u
X i m i n Q - P C 4 0 Cat - s o n g L 6 D a [ 1 x 2 c m ) - H J N a m NUdc sach C o t s o i D r a m t x a S / O S P h u g i a g i a m n u d c 8 7 1 3
T d n g
O t f n v i
k g k g k g lit k g lit k g
C P 1 K h f i l l i W n g
• i M 7 9 0 1 0 2 0 163
35 7 3 5 2 5 0 5 , 3 5
C P 2 Khtf 1 luong
4 9 0 7 9 0 1 0 0 5 163 5 0 7 3 5 2 5 0 5 . 3 5
Cac m a u eua hai loai c a p p h d i d u o c t i e n h a n h thi n g h i e m tai V i e n Khoa h p c C d n g n g h e x a y d u n g - Vidn c h u y e n n g a n h b e t d n g (IBST/ICT). Cae t h i n g h i e m b a o g d m : - Thi nghiem dd sut cua hon hdp bd tdng: Phuong phapTCVN 3016:1993;
- Thi nghiem cudng do nen: PhUdng phap TCVN 3105:1993, TCVN 3118:1993;
-Thi nghiem cQdng do keo khi udn: PhQdng phip TCVN 3105:1993;TCVN 3119:1993.
Cie thidt bi thi nghldm va xuat xQ:
- (Vlay t r d n b d t d n g - V i e t N a m ; b d c d n thCf d p s u t - V i e t N a m ;
- IVlay n e n 2 0 0 0 k N - A D S 2 0 0 / E L - U n i t t e s t - Malaysia;
- M a y n e n 3 0 0 0 k N - U T 3 0 0 / 5 0 E L - U n i t t e s t - Malaysia;
- M a y n d n , u d n 10OkN - A m s l e r - T h u y Sy.
2.1.2. Ket qua thi nghiem
Vdi mdi loai mau, nhdm tac gia tien hanh xac dinh thude tinh ciia be tdng d cac tuoi 1 ngiy, 3 ngay va 7 ngay tudi, de xac dinh Qng xQcua be tdng khe co gian khi chju t i l trong banh xe trong q u i trinh hinh thanh cUdng dp.
* Kef quo thi nghiem cua CP I
Dd sut eua hdn hpp bd tdng sau khi trdn l i 19.0em.
Ket q u i thi nghiem xae dmh cudng dp nen va cQdng dd keo khi udn dQpc the hldn lan lUpt trong cic Bdng2.2, Bang 2.3, Hinh 2.2. Hinh 2.3.
Bing 2.2. Kit qui thi nghiem cudng do nen cua CPl
'0/3/2017 33/3/2017 N g i y t h i n g h i t m
; i « / 2 0 1 7
u^
[ IngJy) K I c h t h u M
[mm)
D150XH3CIO LUC p h i hoai
IN) 431 3 458 B 446 2
c u d n g ttf nin m i u t n i T £ m g v i t n
( M P . I 24 4 26 0 25 3
(MPa)
35 2
D15OXH30O
D150iH3O0 9900 1000 0 1020 0 11300 11200 11000
56.6 57 7 6 4 0 63,4 6 2 J
56 B
63.2
Bing 2.3. Kit qua thi nghiem cudng do keo khi udn cua CPl N g i y t h i
nghiAm
21/3/2017 T i j 6 l m J u
( r g i y l KfchthUdc
(mm)
,..»,..™
Li/c p h i
(Nl 174 )S4 176 29 0
c u d n g d $ k i o khi u6n Tung vi£n
(MPa) 55 S3 55 9 1
Trung binh
20:3/2017 23/3/2017
KHOA HOC-CONG NGHE So 11/2018
Tudi be tong (ngay) Hinh 2.4: Cudng do chiu nen thi nghiem CP2
Hinh 2.3: Cudng dp chju kio khi uSh CP 1
*Ketqua thi nghiem cua CP2
Dp sut eda hon hop bd tdng sau khi trpn la 18.5cm, Ket q u i thi nghiem xac djnh eUdng dp nen va cUdng dp keo khi udn dupe the hldn lan lUdt trong Bang 2.4, Bdng 2.5, Hinh 2.4, Hinh 2.5.
Bing2.4. Ketqui thinghiem cudng dp nen ciia CP2
N g i y d i i c m l u
20/3/2017 N g i y t h i nghi£m
21/3/2017
iziiar^yi
27filia\7
T &l 1 Kfch thudc I n g M
1
3
7 (mm)
O15OxH3O0
D150XH3OO
D150lH30a
toa?*
(N)
c u d n g d d n^n mSu t r u
(MPa) 585.6 1 33,2 590.6 1 33 4 5925 1160,0 1220 0 1200.0 1390.0 1430.0 13200
33 5 65.7 69,1 67.9 7 8 7 B1.0 74.7
Trung b i n h IMPa)
33 4
6 7 *
781
Hinh Z.5- Cudng do chiu keo khi udn CP2
*So sanh ket qua thinghiem trung binh giCfa 2 cap phoi - Ve dp sut cua hon hpp be tdng: Hai cap phdi cd do sytxapxi nhu nhau;
- Ve cudng dp chiu nen: CP2 (vdi ham lUpng spi 2.00%) ed cudng dp ehju nen Idn hon rat nhieu so vdi cQdng do nen cua CPl (ham lUdng sOi 1.40%) {Hinh2.6);
- Cudng dp chju keo khi udn: Dp ehdnh Idch vd cUdngddkeokhi udn cua CP2 vdi CPl tang dan theo thdi gian hinh thanh cudng dp cua bd tdng (Hinh 2.7).
Bing 2.5. Ket qui thinghiem cudng dp keo khi uon c6a CP2 Hinh 2.6: So sanh cudng dp chiu nen
m t u
30/3/3O17 N g l y t h I n g h l f m
21/3/2017
23/3/2017
27/3/2017 T u J J m l u
I n g i y i
1
3
7 Kich thudc
(mm)
IOO)'IOO«400
100^100.1400
100x100x400 h o f i
IN) 18.4 188 186 350 306
454 52 S 514
CUdng d d k i o U i t u D n TUngvHn
(MPa) 5.8 5 9 59 110 9 6 106 14,3 166 16,2
Trung binh IMPi)
5.9
104
IS 7
Hinh 2.7: So sanh cudng dp chiu keo khi uon
47
KHOA H O C - C O N G N G H e
So 11/2018
va (2) khe co gian sQdung BTCST, dudi eung mdt sd vdng lap t i i trpng (Hinh 2.12 va Hinh 2.13).
Hinh 2.12: Bien dang cua be tong khe co gian vda be tong khdng co ngdt
Hmh 2 13 Bien dang cua be tdng khe co gian sCrdung BTCST Ket qua cho thay, dUdl tac dung eua tai trpng lap cua banh xe, bd tdng cdt spi trong khe eo gian cd bien dang tich luy nhd hdn, the hien sut vd khdng dang ke khi so sanh vdi vide sQ dung vQa bd tdng khdng co ngdt thdng thudng. Nguyen nhan la do gidi han chju keo da dupe cai thldn dang ke.
3. K^T L U A N V A K I E N N G H ;
Kdt hop giQa p h i n tich ly thuydt va thi nghiem, nghien cQu ehi ra cac Uu diem cua viee sQ dyng BTCST p h i n t i n trong khe co gian b i n thep ring iQoe cho edng trinh eau dudng bd dVidt Nam.
Ket qua thf nghiem, phan tich dupe ndu ra trong b i l cung chi ra, vdi ham lUdng khdi lupng spi thep sQ dyng b i n g 2.00%, cie thudc tinh chju lye cua bd tdng trong khe CO gian rang lupc ban thep dupe tang cUdng dang ke.Trong khi do, hdn hpp BTCST phan tan hoan t o i n d i m b i o chat lupng ydu eau trong q u i trinh thi cdng, ehd tao.
Do do, BTCST hoan toan cd the i p dung de nang eao hieu q u i trong sQa chQa, thay the khe co gian b i n thep rang lupe cho c l u dudng bd d Viet Nam.
Tai lieu tham khiio
[1]. ACI 544.1 R-96 (reapproved 2002), State-of-the- art Report on Fiber Reinforced Concrete.
[2]. FHWA Publication No: FHWA-HRT-14-084: Design and Construction of Field-Cast UHPC Connections.
[3]. K. Sobolev, I. Flores, L M. Torres-Martinez, P L.
Valdez, E. Zarazua, E, L (2009), Cuellar, Engineering ofSi02 Nanoparticles for Optimal Performance in Nano Cement- Based Materials. Nanotechnology in Construction 3, pp.139-148.
[4]. TCVN 6016:2011, Xi mang: PhUdng phdp thCfvd xac dinh cudng do.
[5]. BS EN 196-1:2005, Methods of testing cement.
Detemination of strength.
[6]. TCVN 5906:2007, Dqc tinh hinh hgc cua san pham, dung soi hinh hgc, dung soi hinh dgng, hudng, vi tri va do dao.
f7]. ASTM C496, Test for splitting tensile strength of concrete.
[8]. ASTM C496, Standard Test Method for Static Modulus of Elasticity and Poisson's Ratio of Concrete in Compression.
Ngay nhin bai: 25/9/2018 Ngay chap nhan clang: 10/10/2018 NgUdi phSn bi&n: TS. NguySn HQuThuin
TS. Le Ba Anh
