Yeu cau ky thuat lUu giCT va van chuyen hon horp be tong tif len trong dieu kien thdi tiet khu viic Ha Noi
Technical requirements regarding the storage and transportstion process for self- compacting concrete mortar in the weather condition in the Hanoi region
Ngay nhan bai: 03/02/2017 Ngay sijfa bai: 20/3/2017 Ngay chap nhan dang: 5/4/2017
Ho Nggc Khoa, Nguyin Hung Cu'dng, Tran Hong Hai
T O M TAT:
Bai bao gidi thi^u ket qua nghien ciiu sU anh hildng cua phtlong phap, thdi gian liiu gifl hon hop be tong tU len, cung nhii dieu kien thc*i tiet mua khi hau khac nhau cua khu v\ic Hii Noi den cac th6ng so ky thuat dac trifng cho tinh eong tac cua hon h a p vi3a sau khi c h i tron. Tren ccf sd do, mflt s6 y^u cSu ky thuat IiIu giG va van chuyen dSm bao chSt ItJOng va tinh thi cflng cua hSn hop da duOc de xuat.
Tif khda: be tong tii len, tinh eong tac, do xoe, dp chay, ]„„g, Lbom V,un«.|.
ABSTRACT:
This article presents the empirical research results on the effects of storage time and methods as well as of the various weather condition in the Hanoi region on the unique technical parameters of the self-compacting concrete mortar's workablity.
As a result, some technical requirements regarding the storage and transportation for ensuring the workability of the self- compacting concrete mortar were discussed and recommended.
Keywords: Self-compacting concrete; workabiHty; slump flow;
fluidity; ]„n^Uox:Vjumd
Ho Ngoc Khoa, Nguyen Hung Cifdng, Tran H6ng Hai TrUdng Dai hoc Xay di^ng
I.OitvSnde
Tfnii cflng tac cixa. hdn hop be tong tif len (BTTL) duoc dac trifng bdi ba yeu t d : kha nang lap day, khS nang chSy xuyen qua, vS chdng phSn tang. Hon hop BTTL rat nhay cam vdi di4u kien khf hau bao gdm nhiet do, do I m , gi6 va bdcxa mat trdi. Trong dieu kien nhi§t do cao va do am thap tinh cdng tac cua hon hop suy giSm nhanh lam cho cSc uu diem thi c6ng cCia BTTL khong con gi^ trL
C^c nghi&n edu ngoai nUdfc d§ de cap d^n ir\h hu'dng cCia t? le cap phdi, thanh ph^n, ham lUOng v | t li^u vS cacyeu t d nhtit do d i n tinh cdng tac cCia hon hop va da dat dUOc nhieu ket qua cu t h i . 6 Vilt Nam, nhCIng nam gan dSy, BTTL da duoc sddung cho mot sd eong trinh xSy dung nha sieu cao tSng nhif toa nhS KeangNam, Lotte Center, Viettinbank Tower, The Landmark 81... Cong ngh# thi cdng BTTL la hoan toan mdi doi v6i ngSnh xSy dung Viet Nam. Oa c6 mot sd nghien ciiu co bSn ve BTTL, tuy nhien chua co nhCfng nghien ciJtu tdng the sif anh hudng (dinh tinh va dmh luong) cua thong sd thdi tiet khac nhau den cac tieu chi ky thuSt dac trung cCia tfnh eong tac hon hop BTTL.
Do dd, viec nghiln edu thifc nghiem sif suy gi^m tfnh eong tae eCia hon hop BTTL ket hop v6i cic nghien edu tdng quan ve I;;- luSn di \hm ro , m6t s6 ygu du ky thuat ve luu giO vS van chuyen hdn hop BTTL trong cac mua khi h^u cu the la can thiet, ed y nghTa ve mat khoa hoe va thUe tien.
Nghien edu thuc nghiem dUoc thUe hien d ^ e u kien t u nhien eiia Ha Ndi, cd khi hau dac trUng cho khu vuc phia BSe Viet Nam vdi cac yeu t d gidi han la nhiet do va do am tUong ddi ciia khong khi trong eae mua khi hau khSe nhau
2.Mdt sd nghien edu ve tfnh cdng tdc hon hdp be tdng t i i l i n Tinh tiK nam 1986 khi Okamura d ^ xuat ^ tudng ve BTTL, den Hoi th^o qudcteRILEMve BTTL Ian 8 nam 2016 tai My, nhieu ket q u i n g h i l n edu da c h i l u \ii BTTL da dUOc cdng bd nhu ket q u i nghien eilu tdng quan ve xu hu'dng, tiem nang phat tnen BTTL cung nhu k h i nang va thUe te dng dung BTTL trong xay diing; cac phifong phap thf nghiem; cich thilc phan loai, ddnh gia ch^t lUong hon hop viJa va hudng dan sd dung; phuong phap va tdi Uu cap phdi, tinh chit ca 1^, eUdng dd chiu nen cua BTTL; tinh eong tic ciia hdn hop vCfa; qua trinh ddng ran va bao dUdng...
Theo [1 ], d nhiet do thSp tinh edng t^c cua BTTL suy g i i m nhanh.Bae biet trong di4u ki§n nhiet do thap ( s i 5°C) va lUu gidtrong d i l u k i l n Onh, tinh cdng tSc bi suy gidm nghiem trgng sau 30 phut. Nhiet dd <15°C \hm eho ehjit sieu d^o phSn tan kem dJln d i n khdng phdt huy tac dung keo d^i tinh cdng tdc. Nghien edu cung ehi ra d dieu kien n h i l t dd eao (>60°C) se day nhanh tdc do ddng k i t cua BTTL. K i t qui nghien cdu trong [2] cho rSng, h6n hop BTTLgidm tfnh cdng tac rat nhanh d nhiet do >75-80''C. 6 n h i l t do nay do chay xde SF trUdc khi van chuyen la 62.5cm nhung khi xa b l tdng xong SF chi dat 42,5cm
NhiSt dd vUa cung Snh hUdng dSng ke den do linh ddng ban dau cua hdn hop BTTL, khi nhiet do bien dong Idn, tinh cdng tac cua hdn hop can
04.2017 awni^iisi 35
phai danh gia lai Mdt nghien edu t r i n hon hop BTTL trong phong thi nghiem, duoc trdn vdi 3 dieu ki§n khde nhau. D i l u kien 1 tron be tdng bang nUdc thudng, nhiet do sau khi trdn cua hdn hop TBI=25"C, tUOng dng do xde SF=61cm, Tio=2s; Dieu k i l n 2 tron b l tdng bang nUdc lanh, TBr=7°C, SF=52,5cm, TM=SOS; Dieu kien 3 trdn b l tdng bang nUdc ndng, Ttn=32°C, SF=67,5cm. T;o=l s [3].
Ket quS mot n g h i l n c U u v I s U S n h hUdng eUa thdi gian lUu giCfden tinhcong tac eda hdn hop BTFL cho r3ng, hdn hop BTTL cd do Imh ddng ban dau tdt vdi T;iu=2,S3s; sau 90 phut lUu giaSF suy giam qui gia trj cho phep, Tjo vuot gia tri cho phep sau khoSng mot gid va Vfun.«i vuot gia tri cho p h i p sau 15 phUt. Tuy nhiSn d diy khdng ndi dieu k i l n thdi t i l t khi tien hanh thf nghiem [4].
6 d i l u kien phong t h i nghiem vdi T=28-30°C, SF eda hon hop BTTI suy giam sau 120 phdt khoSng 40-90mm. Tde do suy giam phu thudc nhieu vao luong xi mSng, xi mang cang nhieu tdc do suy giam cang nhanh. Hdn hop sd dung tro bay cho kha nang duy tri dd chiy xoe tdt hOn so vdi phuzolan thien nhien [5]. Trong dieu kien thdi tiet tif nhien khu vUc Ha Ndi, T^ig-SO^C, W=704-85%, toe .do va gia tri suy gi3m tinh cdng tac eua vufa BTTL phu thudc chu yeu vdo thdi gian luu giQ vCfa, sau 90 phut luu gid, tinh cdng tac va chat luong vda bj giam, nhieu tieu chf ky thuat qu^ gidi han eho phep, anh hUdng d i n khS nang tU l l n va d i l n day cda b§ tdng, g i d m c u d n g d d v d dd ben CLiabI tdng [6,7].
3.Ket qud nghien cihi thiTc nghiim
3 . 1 . Ndi dung, phiiong phap v^ vdt lieu thf ngliiem Thf nghiem duoc thiic hien di danh gia sU thay ddi cic chi sd dac tning cua tfnh cdng tae hon hdp BTTL bao gdm: SF, Jnng, Tma, Vsumei, Lhn, eua hai cap phdi CPl, CP2 dudi s U i n h hudng eCia cac y l u td nhi§t dd ban' dau cda h6n hop, nhiet do va d d ^m moi trudng Va anh hudng cua sU thay doi tinh cdng tic den cu'dng do be tdng PhUong phap t h i nghiem ap dung theo tieu c h u i n cCia IWy v&>Chau Au. Ceic t h i nghiem dUoc thUe hien 6 Ha Ndi, trong d i l u k i f n t h d i t i l t t i t n h i l n ddc ttUng eCia khi hau mien Bic, bao gdm cac mua khi hau khac nhau, dc thong sd thdi tiet mdi trudng thi nghiem the hien d Bang 1,
Hon hop BTTL thi nghiem gdm-2 c^p phdi vdi thdnh phan vit li&u d Bang 2. CSp phdi 1 (CPl) co'dd chdy xde SF-710-730mm, dp phoi 2 (CP2) ed ddehdy xoe SF=650-680mm, nSm trong loai 2 theo each phan loai hdn hop BTTL theo t i l u chuan Chau Au.
3.2. Anh hir6ng d i l u Iden iuu giO'd^n tinh cdng tac hon hqrp BTTL Hdn hop h& tdng CPl, CP2 sau khi tron dui?c chia thanh hai phan, mdt phan hdn hop dUoc lUu gidtrong may trdn true nghieng cd g^n b i l n tan quay vdi tdc do cham, ph^n edn lai duoc luu giijrd thijng kin (han che bay hoi) trong dieu kien thdi tiet tU nhien. Dieu kien mdi trUdng thf nghiem cUa CPl la DK4, n^ng ndng mCia h i ; CP2 Id DK3, ndng ^m mua he, t h u . Ndi dung k i l m tra' d d chdy xde SF va Tsoo d eae thdi d l l m 0,30, 60,90,120 phut lUu gid. Ket qua thi nghl§m the h i l n d Bdng 3 vd Hinh 1.
Phan tfch ket qud thi nghiem cho thay hdn hop be tdng t i i len trong thiing chda tinh, cd be mat thoang bay hoi suy gidm SF vd dac biet TSM rSt nhanh. Sau hon 30 phUt lUu giCf SF khdng d^it tieu chi ky thuSt thi cdng theo tieu chuan Chau Au (650mm) vd sau hon 60 phut lUugiCrSF khdng
dat ca tieu chi ky thuat phdn loai (SSOmm); Tsoo eda CP2 sau 30 phdt, ciia CPl sau 50 phUt deu vUot qua tieu chi ky thuat thi cdng theo ti&u chuan Chdu Au Ids gidy.Trongkhidd, hdn h o p d u o c l i f u g i O t r o n g thdng tron kin, quay tdc do cham duy tri rat tdt tinh eong tac. SF cua ca hai cap phoi sau 60 phut lUu gifl van dat tieu ehi ky thuat phan loai la 650 mm, Tsoo trong gia tn cho phep la 5 gidy; tuy nhien lifu gitJT den 90 phut, SF tiem cgn den gidt han cCta tiSu chf thi cdng la 650, vd Tsoo cCia CP2 v U ^ qud gidi han eho ph^p.
Luu giCf hon hop BTTL trong thCing mdy tron tkfn) han ch^ sU mat nudc qua bay hoi, ngoai ra su quay cham cCia thung tic dung len phu gia s i l u deo, giup qua trinh tdc dung vdo cdc hat xi mdng vd phdn tdn tdt hon, ddng thdi chuyen ddng nay cd t h i cd tac dung keo dai vd tri hoan su ddng k i t cCia xi mang trong hon hop be tdng Tdng hop cac yeu td 36 lam duy tri tdt hOn tinh cdng tac cda hon hop.
"_ ~^~.—^, , r
' - - r -
X '
/ • - ^
—-
•
- i - Cp; SUnung ihua —K—SF^Bi lun mm - •-CPl,T5(»»ianlrtn - • - C P l rsOD-inungchua - - * - CP3-TSKI-l>iilogliAn A - CP2,T5IKMhii,o cniij
Hinh 1. Anh hudng phuong phdp luu giif den dd xoe (SF) vd d d nhdt (TSOO) cua ho hop BTTL
3.3. Anh hudng cua dieu kien thdi tiet den tinh cdng tac cua hon hdp BTTL va cudng dd be tong
Thi n g h i l m thUe h i l n t r I n hai cap phdi CPl, CP2 trong eac dieu Wen thdi tiet khde nhau, dac trUng khi hau mien Bae nhU trong Bang 1. Cac mau thf n g h i l m difoc lay t d hon hop be tdng d ede thdi diem 0,30,60, 90,120 phUt luu giCr, bdo dudng am d d i 4 u kien tieu chuan, n I n xde dmh cudng do d tudi 28 ngay. Ndi dung k i l m tra: do ehdy xde SF, Tsoo, Li™, Vfunffii, Jring dcac thdi d i l m luu gidtUdng dng. Hdn hap be tong duoe bao qudn trong thung trdn quay tdc do cham, tuong t u d i l u kien van chuyen bang xe bdn. Ket qud t h i nghiem the hien d cac Bdng 4,5; Hinh 2,3,4,5,6.
Bdng 1. Thdng sd thdi t i l t mdi trudng t h i nghiem K^ hif u
eKi DK2 BK3 OK4
Bitu kien thi nghUm (MCia khi hiu) Am ifiM, n6m (mfia xuSn) Kh6 hanh (mCia aflng) N6nq im (mCia hfe, thu) NSng ndng (mita hi)
Nhl«t (16 khdng khi
•C 15-30 18-30 28-36 28-40
06 dm tiro-ng ddi ' khdng khi
%
70*96 40*65 65-85 40-66
T6c dd gid m/s 1 * 2 1-2,5 1-2,5 2 - 2 , 5
Bang 2. Bdng thiet ke thanjijihan cap phdi hon hop BTTL thinghieri 1 XM PC40 " ~ T r o bay 1 (kg) (kg) Ky hi«u
c^p p l i d l
Cdt Dd P G S i e u (kg) I (0,5x1) d«o
PG tao NirdK
\ n h M (kg)
J ikgL__
' 0 195 185,9
0,195 197
Jdng 3. Suy gidm tinh cdng tae eUa hon hop be tdng t u len trong hai dieu kien bao qudn klnsc nhau
Thdii gian (phut)
0 30 60 90 120
ThCing t r d n , q u a y tdc d d chdm SF
CP1/CP2, m m 710/670 720/680 700/670 690/660 680/610
TMO CP1/CP2, qiav
3,7/4,2 3,5/4,32 3,7/4,85
ThCing SF CP1/CP2, qiay
710/670 680/660 650/600 3.9/5,3 1 500/S3S 4,2/8,9 j
chCFa
CP1/CP2, qidy 3,7/4,2 4,6/5,8 5,3/12,6 34,8/29,3
i
thi nghiem d d i l u k i ^ n thdi tiet DK1 (ndm am Cdp pnoi
C P l (N/B=0,35)
CP2 (N/B=0,3)
Chi ti£u d o
SF TsM Vfunn.1
Lbo.
J™,g Nhiet d d vOa Nhiet d d M T D d a m MT R2S SF Tsoo VtuxM
Lbo<
Jnrn Nhi§t d d vOa N h i e l d d M T DoJiv'm
R2B Dofn
mm qiSv
mm
"C
"C
%
liflPa mm
mm
°C OC
%
MPa mua xuan) va
0 QKI 1_720 3.75 7,91 0,93 6 0 24 7 23,6 68,0 51,0 680 3 1 11,7 0,89 9,0 25 6 23,4 81,0 56,6
0K2 730 2,43 6.72 0.84 8.0 29.7 30.0 51.0 S1.5 680 3.7 8.1 0.94 9.0 30.5 30.8 50.0 64.0
DIQ (khd hanh mua ddng) Thd'i gian 30 OKI 730 3.50 7,06 0.97 8.0 24.2 23.1 68,0 50,3 710 3.66 10.8 0.90 7.0 24,7 23,2 82,0 55,1
DK2 700 2,69 6 59 0.87 9.5 29.0 30.7
so.b
59.0 700 3.28 10.3 0.93 9.5 30.0 30.7 49.0 57.4
6 OKI 720 3,85 8,22 0,95 9,0 2Z3_
23,2 71 45,7 700 3.7 11,0 0,87 _9J_
23.8 23.1 82,0 51.2
do (phut) 0 9
0K2 OKI "
0 OKZ 680 705 \ 670 3.75 3 91 ^ 5,57 10.1 9,30 1 17,3 0 84 0,94 0 83 13,0 9 5 18,0
1 120 DK1 700
pyio
9,70 0,93 11,0 28 2 23.4 28.1 23,2 29.2
50.0 57.5 670 4.25 11 6 0.88 14.0 30 4
23 0 75 43,9 670 4.72 12,4 0,66 10,0 23,5 30 5 22,9 48.0 83,0 52,8 50,1
29,8 52,0 55,8 650 6,34 16.7 0.73 19,0 29.1 29.4 51.0 49.2
23,1 80 38.9 ("665 4,73 13,0 0,85 11,0 23,4 22,8 83 44,4
DK2 650 5,85 19.3 0 79 23,0 28.0 29.0 52.0 52.0 eoo 7,53 20,5 0.66 20,0 29.8 30.3 57 0 43,0
Bdng 5. Sd lieu thf nghi§m d dieu ki§n thdi t i l t DK3 (ndng &m mua he, thu) va DK4 [nSng ndng mUa he) c a p phdi
C P l {N/B=0,35)
CP2 (N/B=0.3)
Chi tieu do
SF Tsoo Vfunn.1
LEK»
Jong Nhifet d d vOa Nhifel d d M T D d l m l v i T
Raa SF Taw VlWw,!
Lbo.
Jnno NhiStdflvOa Nhi§t dd MT D d am MT
R2a D e n
v!
mm
fliay
mm OC OC
%
MPa mm qiSv giay
mm
"C OC
%
MPa 0 DK3 700 2,84 5,28 0,94 9.0 32,4 31,8 74,0 49,0 670 3,68 10,9 0,94 8.0 31,3 31.0 75,0 61.0
0K4 730 2.1 5,791 0,95 9.2 40.6 43.6 31.0 49.0 680 3.4 9.2 0.88 7.0 40.5 43.1 43 58,0
Thd'i qian 30 DK3 715 2,35 5,37 0,93 9,4 32,2 32,1 70,0 54,0 680 2,8 11.9 0,93 6.0 29.2 33,0 72,0 62,3
0K4 700 2.25 6.28 0.9 9.5 39.8 47.5 29,0 50,0 670 2.75 13,0 0.87 9.0 46.3 46.5 41.0 63.0
d o (phiit) 60 1 9 0K3
"680"
2 75 5,91 0,91 9,6 32,9 31,7 70,0 51,0 680 3,0 14,4 0,9 8.0 28.4 32,0 72,0 60,0
DK4 0K3
" 6 0 5 1 6"70 "
4.78 4 32 0
" D K T
520 13.6 1 0 6 i 6 91 33,2 0,6 0 82 14,0 \ 11,0 38 9 32,1 44.6 31,4
| 3 2 , 0 48.0 eoo' 3.91 17.1 0.67 11,0 43.2 43.8 35.0 55 0
72,0 47,0 670 3.4 21,3 0.89 12,0 27,6 31,0 74,0 53,0
36.0 38.0 44.0 30.0 42.5 500 5,4 34.2 0,5 15,0 37.1 43.0 33.0 47.0
120 0K3 660 4,80 7,69
DK4
0,81 16,0 32.1 31.2 71.0 42,0 610 3,81 30,9 0,86 16,0 27.3 31.0 73.0 46,0
— • — B K H M m i n —•—CMJinft hann A BKl^nlngnong - ' - T c h i p h t n l o a l F n n - Hinli2 Suygiamdocliai)TOeSFCP2 theo flieukisn thin tiet
ChauAu 1^ 12s sau 60 phut lull giu'dGK2]did hanh v^DK4nSng ndng, khi do am tUong ddi ciia khdng khi trong khoSng 45-65%. Dac bi§t sau 90 phijt liiu giCf Viunnei eda CP1 va CP2 giSm hon mdc t i l u chi phan lo^i 1^
35s.Sau 60 phijtlUu giCTsooeda CPl giSm dUditi§u ehisddung S s dOK4;
sau 75 phut liru giCi TEDD ciia CPl d DK3 va Tsoo cOa CP2 d DK2,0K4 deu giSm ducfl t i l u chf sCt dung (BSng 4,5; Hinh 3).
Co su tuong ddng trong anh hUdng cCia ^ e u kien thdi tiet d i n do linh dong, khA nang tif chay, chSy qua eCia hon hop BTTL qua eac tidu chf Lbo. va Jfing nhif ddi vdi do nhdt cua hdn hop Lbo, vi JHHJ suy giam ro r^
nhat dDK2 khd hanh va DK4 nSng ndng. U=< cua CPl, CP2 suy giam dudi tieu chf sd dung IS 0,8 sau 45 phiit lUu gid;va sau 75 phijt lifu giLfCP2d DK2. Sau 45 philt lUu g i f l d B i Q vi DK4,75 phut luu giQdBK3, J^., ci hai cap phdi C P l , C P 2 d l u g i 3 m dUcfi mdc tieu chf s d d u n g la 10mm (BSng 4,5; Hinh 4).
> ^ ; ^ :
H)nh4 Khi nang ch^y qua, do linh dong Uava khd nang tirdiayJ,r9CP2 theo dieu kien thcil tiet Yeu t d do am tUong ddi cua khdng khi (W) cd Jnh hudng rd ret hon yeu t d nhiet dd den sif suy giSm dd nhdt eua hdn hop qua hai chi tieu Vrunnsi va Tsno V(„™i ciJa CPl va CPl gi^m qua tieu chi sd dung theo TC
BK3-<10ng im GK4-nan9 no
BO aSOph aeOph ngOph [ii120ph Hinh 5 Anh hUSng ciia dieu ki^n thdi tift vS th&i gian lu\i giiJhon hpp BTTL den Ra (CPl)
Kinh 3. Bien d« dii so do nhdt Tmva VteniCPl theo dieu kien thcif tiet Ket qua t h i n g i l m cho thay nhi§t dd va dd am khdng khi cd inh hiJdngrd n i t d i n tfnh cdng cac ciia hdn hop BTTL d e l hat cap phdi CPl, CP2, hon hpp duy tri tdt dd ch^y xde sau 90 phut liAi gifl d eae dieu k i l n thdi tiet ndm a m D K l , k h d hanhDK2 va ndng I m DK3. Sau 9 0 p h i j t l i i u giu' dDK2, SF ciia dp phoi CP2 gi^m dUdi mflc tieu ehf ky thuat sCl dung (650 mm) Ri§ng d dieu kien nang ndng flK4, ca CPl va CP2 d l u suy giam SF dudi miJc tieu chi phan loai sau 45 phut luU giu' va du'di mile tieu chi sddung sau 75 phut IUugiij'{B3ng 4,5; Hinh2).
n o [330ph E]]60ph D90ph n120ph
Hinh 6. Anh huftng cua dieu kien ihoi liet va thoi gian luu giij'hon hup BTTL d^n Ru (CPZ) Nhan thay rSng d OK2 khd hanh, co sif giam Eljs cua be tdng sau 30 phut luu giCf, thOi diem nay chUa cd sU suy giam dang k l tinh cdng tcic cua hon hop, ket qu3 t h i n g h i l m chua dii de giai thieh hien tflcmg n^y. d DK3, DK4 dd chiy xde SF ciia hon hop tang sau 30 phGt cd t h i la nguyen nhan lam tang cu'dng dd b§ tdng Sau 30 phut luu giCrban dSu, Rjociia b l tdng giiim khi thdi gian luu gifl vfla tang len, dJic biet gi3m manh khi thdi gian Iflu gifl qua 90 d i n 120 philt. d d^y the hien rd 3nh hu'dng ciia tinh edng tac, dgiai doan nay cae tieu chi ky thuat ciia tfnh edng tac deu gi^m manh, vitot qua cae tieu chuan thi cdng cho phep (83ng 4,5, Hinh 5,6).
4.Ket luan
Ket qu5 nghien cflu cho ph^p d l xuat mdt so y l u du ky thuEit Iflu giu' vh van e h u y i n hdn hop vCta BTTL trong dieu k i l n thdi tiet khu vUe Ha N^i va cae vung tflong ddng d mien BSc V i l t Nam, nhU sau:
- Thdng sd n h i l t do va d d Sw tUong ddi ciia khdng khi eua eac miia thdi tiet khae nhau khu vuC Ha Ndi (inh hfldng l^m suy gidm tinh cdng tac
3 8 i n D n i [ | H « 04.2017
va chat Iflong hdn hap BTTL sau khi che trdn.
- Thdi gian Iflu gifl va van chuyen vfla tr^n cae phuong tien khdng chuyen dung hoac thu cdng khdng nen qud 30 phiit sau khi che trdn.
- Phflong tien Iflu giflvavSn chuyen tdt nhat ddi vdi hon hop BTTL la xe bdn 6 che dd thCing quay chSm, thdi gian Iflu g i f l va vSn chuyen k h u y l n c a o n h u s a u '
+ khdng Idn hon 120 phut ddi vdi d i l u kien thdi t i l t ndm am miia xuan (T=l S-SO^C; W-70^-9S%).
+ khdng Idn hOn 60 phut - khd hanh miia ddng (T=18-30''C, W=70-r95%) va ndng am mfla he, thu (T=28-;-35''C; W=65-=-8S%); vdi hon hop cd SF>700mm, thdi gian luu giQ va via ehuyin cd the tang, nhflng khdng Idn hon 90 phiit
+ khdng Idn hOn 30 phut - nang ndng mua h i {T=28-40°C, W=40v6S%); vdi hdn hop cd SF>700mm, thdi gian luu gifl va van chuyen ed t h i tang, nhflng khdng idn hon 90 phut.
- Keo dai thdi gian luU gifl va van chuyen hon hop ISm giam cfldng do n^n RzB ciia be tdng. Rze cfla be tdng tao hinh tfl hdn hop vfla Iflu gifl 90 phdt giam den 13,8% so vdi b§ tdng tao hinh ngay sau khi c h i trdn;
tuong tirthdi gian luxi g i f l 120 phut - R;a gidm den 24,8%. Do dd can phai ap dung bien phSp ky thuat nghiem ng^t de kiem tra va dSm bao eUdng dd thiet ke cfla be tdng trong qua trinh thi cdng.
TAI Lieu THAM KHAO
1. W P Tsai, H.J Chen, H S.Peng and C H Huang, Research on the engineering properties of Self-Compacting Concrete, Department of Civil Engineering, National Chung-Hsing University, Taiwan.
2. Jo^nW.Henault.P.E(2(n4),Self-Consolidatlng Concrete. A Synthesis of Research Findings and Best Practices, Report No.CT-22S5-F-12-4,
J. BulentErkmen,CatherineE.Wolfgfam French,Carol K.Shidd (2005), Development of Self- Consolidating Concrete for Bndge Girders and Evaluation of Its Fresh Properties, Proceedings of the 2005 Mid-Continent Transportation Research Symposium, Iowa State Univeisity,
4. flbhishek S. Shethji and C Vipulanandan (2004), Flow Properties of Self Consolidating Concrete with Time, Vipufanandan Center for Innovative Grouting Matenal and Technology (CIGMAT),Engineenng University of Houston, Texas
5. Hoang Plid Uyen (2012), Hoan thien eong nghe che lao va thi rang BTIL trong XOG Thiiy
\(A, Bao ciio de lai NCKH, TrUfng m Thiiy \g\.
6. Ho Ngoc Khoa (2015) Anh hi/cing cfia thcii gian li/u giO den tinh eong tac BTTL, Tap chi Xay d(lng-BXO, so'1-2015, HS Noi
7. Hd Ngoc Khoa (2015), Anh hudng ciia tinh eong t k h o n hop BTTL den chat luang be tong.
Tap chiXay dung - Bo Xay dung, 50 4-2015, Ha Noi
04.2017EWn[E[|BS9ll39
