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Trdn ca sd phan tich cac phuong trinh hdi quy thuc nghiem da lUa chpn dUpc mdt sd thanh phan bd tdng cat min, dd sut hdn hop bd tdng va cudng dd bd tdng cua cac thanh phln nay neu tr[r]
(1)Nghien CLFU sCe dung cat mjn lam cot lieu nho cho be tong cap
cu'O'ng tren B25
Ngo Van Toan
ABSTRACT
Met ^ a m standards TCVN 7570:2006 (Aggregates for concrete and mortar -Specification specified that sand with fineness modulus from 1.0 -^ 2.0 can be used only for concrete grade up to B25 (M300), while some of international standards and study results descriping in this paper show that fine sand in Viet Nam can be used for higher than B25 concrete grade Th.S Ng9 Van Toan
Vien Khoa hoc Cong nghe Xay dung Di dpng: 0903.457.433
1 Y«u ciu thi^c ti cda v i f c l A d ^ n g c i t i T ) f n d l c h J t a o b e t n g
Ti&u c f i u i n Vl$t Nam TCVN 7570 : 2006 "Ceit lieu cho b6 tdng vS vCfa - Y6u c&u ky t h u a t ' [1] phan cat d u n g cho bk t f l n g v^ vda t h ^ n h n h m : cdt t h (cdn gpi la cat vang) c6 mo d u n d Idn tCr Idn hon 2,0 d ^ n 3,3 va cat c6 md d u n d o Idn tiS 0,7 d i n 2,0 Cung theo tiSu c h u i n thi cdt mm cd m6 dun idn tCr 0,7 tdi 1,0 chi du'dc d u n g de che tao be t a n g m i e t d i 200 (cSp Bl 5), cat mm c6 m d d u n d d Idn tCr 1,0 t d i 2,0 chl d\sac d u n g de c h l tao be tong mac t d j 300 { d p B25)
Do trC luong cat vang cua ni/dc ta ft, phan b o khong d o n g deu d cac vCing m i l n nen nhieu noi phdi nhSp k h I u cat hoac van chuyen xa, gia cao, t h i l u sU chCi d d n g v l nguon cat de c h l tao b l t d n g
Trong d d , cac t i n h d o n g bSng sdng CLTU Long, v i m g d d n g b i c , tgy bSc phia bdc Vi^t Nam c6 trCf lUdng cat m j n kha Idn, gia t h ^ n h Vi v l y , n l u sCr d u n g duoc loai cat lam be t d n g thi se c6 t h i m ngudn cdt lieu nhd, m d rdng dUpc vi$c sCr d u n g tai n g u y i n thi^n n h i l n sSn cd, giai q u y l t duoc m d t ph3n khan hiem v l cat vang cho b& t d n g hi^n va v l lau dai m d t sd v u n g khan h i l m cat vang nhung sSn ngudn cat m i n gia r l h o n thi v i ^ sOr dung cat m i n thay cat vang cdn g d p phan lam giSm gia be t d n g
N h u vay, sif d y n g dUOc cat m j n m o d u n dd Idn t i f 1,0 d i n 2,0 d l c h l tao b6 tdng cSp tren B25 cd y nghia thyc tien Idn ddi vdi Vl^t Nam
2 Ti&u c h u i n q u d c t e v e siJr d u n g c i t m i n d l che t a o b l t d n g
cat duoc m p t s6 tieu chu^n ky thuSt tren t h i gidi quy dinh sCf d u n g nhU sau:
a) Cost 8736 - 93 [2] va Gost 26633 - S i [3]cija Nga quy dinh;
- Cat SLf d u n g cho b l t d n g phai cd m o d u n dp Idn t i f 1,5 den 3,25;
- Cat cd m d d u n d d Idn t i l 1,0 d i n 1,5 (vdi
\U(fng hat n h d h o n 0,16mm khdng qua 20% va biin-bui-s^t khdng qua 3%) dUdc phlpsA d u n g cho b l t d n g cSp chju n^n tdi 830, d p chiu k^o udn tdi B^^ 4,0 n l u qua n g h i l n ci]tJ t h l y rang b l t d n g d a m bdo cac tfnh nang Igi thuat y ^ u c l u va cd h i ^ u qua v l mat kinh t l
b) AASHTO M - 93 (4) va ASTM C-33[5] cua My dua cac y^u cSu sau:
- c a t phai cd m d d u n d d Idn gidi han 2,3 d i n 3,1 (sai lech cho p h t p ±0,2);
- c a t k h d n g dap uTig yeu d u v l mo dun d o Idn n h u t r ^ n duoc sd d u n g cd bang chdng rftng b d t d n g lam t d cat cd die tinh c h j t t i / o n g d u o n g bi tdng lam tir d t ddi chdng dupc lay tCr n g u d n da duoc chip thuan sd d u n g cho be tdng cda k i t d u t u o n g t l /
c} Chl dSn sd d u n g cat m j n va cat rSt lam b d tdng m | t d d d n g va san bay [6] cua Vi$n nghidn cdu D u d n g b d thupc Bd Xay d u n g giao t h d n g LB Nga cd k h u y i n d o t h a n h p h l n bd t d n g d l c h l tao I m ' mSt d u d n g b l t d n g vk san bay mac udn kdo 4,5 -5,0 / Mac chiu ndn 35 - 40 Mpa nhU sau:
+ C a t m m M ^ = , - , : X(PC40) = - 0 kg; N/X = 0,42 - 0,45; c a t = 500 - 600 kg; Da = 1200 -1100 kg;
-f c a t m i n M ^ = 1,5-2,0, X{PC40) = - 0 kg; N/X = 0,42 - 0,45; C a t = 0 - 0 kg;Oa = 1 0 - 0 k g
N h u vSy cd t h i thay, cac tidu chuan va chl dSn ky t h u ^ t cCia m d t sfi nddc trdn the gidl, v i l e sCr d u n g cat m j n d u ^ c dat xu h u d n g md T i l u chulin cua Nga cho p h i p sfl' d u n g cat m j n m d d u n d d Idn t d i 1,5 Cat h o n cd t h i sd d u n g lam cdt lidu n h d cho bd t d n g cac c5p t d i B30 cd c l c k i t q u i thi n g h i l m m i n h c h d n g rSng b l tdng dSm b i o tinh nang k^ thuSt va viec d i i n g chdng mang lai hieu qua kinh t l
3 M d t stf k ^ q u i n g h i d n c i h i c h l tao be t d n g d t m j n c£p cudmg d o B60 t a i Vidt Nam 3.1 Muc ti£u nghiin c i h i : Minh chUtis khd nang ch4tqo be tong cdt mjn cSp B60
(2)Tich lily < Tlic licli - (^uiulliitn'e Volinue
0.4 ae
Hinh Bieu phan bo phan hat cua tro trau
2 10 » 100 0 0 Diioiutkiiililift-PiirticlcDi^iielci (|jm)
C a U L T E r ^
L S P a r t i c l e S i z e A n a l y z e r 0
Run r u m t
LS330 nuid Module l6S6 n j i i l O I
Group ID X i l o c a o T N
Run length 60 Seconds
Firmware 02
0
Volume Ste
from 375 iliti to 2,00 100% 10 59 \im
4 10 20 lO eo 100 D u o r ^ kinh hat - Particle Diameler (|jm)
bstics (Amhmelic) Xi lo cao TN 502
Oum
Hinh Bleu phan bo th^nh phan hat cua xl 16 cao hat hoa nghien rr
ai.Bdng j g ^ j Q j ^M,98
Thanh phSn hoa ctja tro trau 0,73 ^
CaO 1/40
Na^O 0,11
KsO 2,46
WlqO 0,57 5,14
trln casdcdc nguyin Hiu Wet Nam vdphu gia
siiu dio
3.2 Nguyin vdt liia sCf dung Trong nghien ciJu cac nguyen vat lieu sau day da duoc sif dung:
3.2.1.Xlmang:)i\ mang podc lang PC40 But Son; Khoi lUOng r i l n g 3,1 g/cm^; {luong sdt tren sSng 75|am) 5,0%; Qo ddo tieu chuan 29,0%; dn dmh t h i tich 1,0mm; Thdi gian dfing ket: bSt d^u 95 phdt; k i t thuc 140 phut; Cudng d6 ch|U ndn: tuoi ngay: 24,0 Mpa; tudi 28 50,2 Mpa
3 2.2 Pliu gia fdioang
- Tro trdu.'Tro trau dUoc chuan bj bang cdch dot trau va n g h l l n tro t h u dUoc Thanh phan hat, phan hda cua tro trau dUOc trinh bay tuong Ung tren Hinh va Bang Mdt sd tinh ch^t ky thuat cua tro trau duoc neu B^ng
- Xi id cao hat hda: Xi 16 cao sd dung la xi 16 cao hat hoa cda nha may gang thep Thai Nguyen da duoc say kho va n g h i l n Thanh phan hat v^ phan hda cCia xi 16 cao duac trinh bay tUOng dng tren Hinh va Bang
3.2.3 Cdt
cat sd dung nghien cdu la cat sdng Hdng da dUOc phOi khd skng loai bd cac hat trdn m m va cdt doi chdng la cat vang sdng Ld Thanh phan hat va tinh chat co ly cua cat mm, cat vang dUoc ndu cac BSng va
3.2.4 Cdt hfu Idn
Cdt l i l u Idn s d d u n g nghidn cdu la da dam cd Dmax 20 dUOc sSn xuSt tir md da bazan Odng Ao - Ha Nam Mgt sd tfnh chat co I'j/ cda da dam duoc trinh bay Bang
3.2.5 Phu gia siiu dio vd nudc Trong nghien cdu n j y da sd dung phu gia sidu ddo gdc polycarboxylate cOa hang BASF Vidt Nam, CO t i n thuong pham la Glenium ACE388 SureTec vh nudc may Ha Ndi
3.3 Ket qud thi nghiim
3.3 J K i t qud th!nghiim be tdng vdi cdt Da che tao 31 cap phdi be tdng lap theo quy hoach thuc nghiem bac hai tam xoay de nghien cdu Snh hUdng cOa cac yeu t o : t j Id N/
(3)Bang Mot sd tinh chat ky thuSt cij Khdi lUdng t h i
tich (kg/m') 0,7
Khdi lU^ng ridng {g/cm')
2,2 tro trau
Kich thudc hgt trung binh (Mm)
e
0 hiit vdi (mg/g)
300
Chi s6 hogt tinh vdi xl mang, (%)
95
Bang Thanh phan hda hgc SiOj
34,2 FejOj
0.64 Ali03
13,7 CaO 42.6
ua xl Id MgO
6,9
cao hat h6a Thai Nguyen Na^O
0,08 K J O
0,24 SO3 0,07
MnO 0,81
TIO; 0,13
S^ 1,23
Bang 4.Thanh phin hat va tinh ch^t coly cda cat vdng sdng Ld
Kich thudc mSt sang, m m Lugng sdt tich luy, (%1 Khdi lucjnq ridnq, q / c m ^
Khdi lUdng t h tich d trang thai bao hoa trong, khd matysscfg/cm')
Khdi luonq the tich d trang thai khd yvk, (q/cm^) hut nudc, (%)
Od $m (sau phoi khd t u nhidn),% H a m l u o n g b u i , sdt, (%) Tap chat hUu co, (so vdi mau chuSn) Md dun Idn
5
2,5 7,7
1.25 17,2
0,63 45,1
0.315 78.7
0.14 96,3 2,65 2,63 2,61 0,6 0,1 1,0 Sanq ban
2.7
Bang 5.Thanh phan hat va tinh chat co ly cua cat mm sdng Hong
Kich thudc mSt sSng, m m Luong sdt tich luy, (%} Khdi luonq rieng, g / c m '
Khoi l u o n g t h e tich d t r a n g t h a i b a o h o a trong, khd matYiso,(q/cm')
Khoi luong the tich d tranq thai kho y,i„ (g/cm^) Od hut nudc, {%)
Od am (sau phoi khd t u nhidn),% Ham luong bui, s i t (%) Tap chat hdu cO, (so vdi mau chuan) Md dun dd Idn
5
2,5
1,25
0,63 23,4
0,315 50,5
0,14 82,3 2,64 2,58 2,51 0.7 0.1 1.0 sang han
1,6
Bang Mot so tinh chat ca ly cua da dam
Kich thudc mat sang, (mm) Ldonq sdt tren sSnq {%)
Khdi luonq rieng d tranq thai khd yk (g/cm') Khoi l u o n g t h i tich d trang thai bao hoa trong, khdmatyssD, (q/cm')
Khdi luonq t h i tich d trang thai khd^vk (g/cm^) D d hut nudc, (%)
D n l n dap xi lanh,%
Cd hat 5-10 100
10
Cd hat 10-20 10 100
20 2,70 2,68 2,66 0,8 12
2,65 2,60 0,75 10,8
CKD, ham luong tro trJu, bhm lu^ng xi Id cao, va ham luong phu gia sidu ddo tdi dd sut cOa hdn hqp bd long va cUdng dd be tdng
Sau khl xd ly sd li$u thuc nghilm da xac dmh duoc mfl hinh thdng kd thyc nghidm md ta anh hudng cua cac y l u td ndu trdn tdi dd sut va cudng dd cua bd tdng cat mm Cac md hinh thdng kd thuc nghidm n^y dupc trinh bay chi t i l t tai lidu [7]
Trdn ca sd phan tich cac phuong trinh hdi quy thuc nghiem da lUa chpn dUpc mdt sd phan bd tdng cat min, dd sut hdn hop bd tdng va cudng dd bd tdng cua cac phln neu cac Bdng 7,8,9
3.3.2 So $dnh bi tdng cdt vin be tong cdt vdng
De so sanh be tdng cat v& bd tdng cat vang da c h l tao hai cSp phdi bd tdng cd ciing ty Id N/CKD, lUong diing nUdc va phu gia sidu ddo Ham luong cat cdt lifu d thJnh phjn bd tdng cat la 28%, cdn d bd tdng cat thd la 41% Thanh phan va tinh chSt cua hai cSp phdi be tdng dUdc trinh bay Bang 10 va 11
3.3.3 Nhdn xit kSt qud thi nghiim a) Kit qua thi nghidm da cho thay.Tdxi mang PC40, tro trSu, xi nghiln va phu gia sidu dio, sddung c6t lidu nhd la cat mm c6 md dun dd Idn 1,6 cd t h i che tao duoc bd tdng dd sut 16 -18 cm, cudng dd ndn tdii 800 Mpa (be tdng cap B60)
b) So vdi be tdng cSt v^ng, bd tdng cat mjn {Mdl= 1,6), cd cung lupng phu gia silu d i a cung lupng chat kit dinh (xi mang + tro trftj + xi nghien) nhU Idpng xi mang cCia be t6ng cat vang, dat dupc dd sut, cUdng d tudi 28 ngay, md dun dan hdi tucjng tit nhu bd tdng cat vang Tdc suy giam dd syt d ca hai loai be tdng cat mjn va cat vang d i u cham nhd dac tinh cua phy gia sidu d i o gdc polycarboxylate Bl tdng cSt nhd phu gta mjn tro trSu, xF nghiln han c h l dupc dd thcim clo giup nang cao kha nang chdng an mdn cho cdt thdp b l tdng
(4)sang 7, Thanh p h a n v a t l i d u sir dung cho m^ bd tdng cat n' K^ hidu c^p
phdi CPI CP2 CP3 CP4 CP5 XM (kg) 266 339 308 321 309 XLC (kg) 193 128 172 140 141 TT[kg) 92 83 70 89 99 N (lit) 138 154 170 187 203 SD (kg) 5,5 4,4 3.3 3.3 3.3
cat (kg) 488 478 467 453 440 Oadam.[kq) 10-20 853 836 817 792 769 5-10 401 393 384 373 362
Bang Sy suy giSm d d sut cua cac hdn hop b l tdng cat mm theo thdi gian Sd TT Ky hidu c5p phoi CPI CP2 CP3 CP4 CP5 N/CKD 0.25 0,28 0,31 0,34 0,37
Dd sut (cm), tai cac thdi d i l m O p h u t
18,0 18,5 18,0 18.5 17,5 30 phut 16,5 17,5 17,0 17,5 16,5 60 phut 14,5 16,0 15,5 15,0 14,5 Bang Cudng d d ndn ciia be tong theo thdi gian
Ky hidu cap phdi CPI CP2 CP3 CP4 CP5
Cudng dd ndn MPa nqay 41,4 41,2 37,1 35,6 33.0 nqay 68,1 67,6 61,0 58,6 54,3 nqay 78,3 77,6 70,1 67,3 62,4 28 nqay 92,0 91,3 82.5 79.2 73,4 Bang 10 Ky hieu CP2 CPCV
Cap phdi be t d n g cat m m (CP2 XM (kq) 339 550 XLC (kg) 128 TT (kg) 83
va be t6ng cat vang (CPCV) SD (kg) 4,4 4,4 N (lit) 154 154 C (kq) 478 724
Di dam, (kq) 5-10 393
10-20 836 333 708
Bang 11 Kyhidu
CPCV
So sanh t i n h chat cua be tdng cat va be t d n g cat vang sut,
cm
20
Cudng d d d tudi 28 ngay, MPa Chiu udn 16,5 Chiu ndn 82,5 76,0
Md dun dan hdi, CPa 66,9 63,5
Didn luong truyen qua mau, Cu Idng
179 1238
4 Ket luan vi k i l n n g h j
Nghidn cdu da chdng t d , d i l u kien cua Viet Nam, cd t h i s d d u n g cat thay cho cat thd d l che tao be t d n g cudng dd cao c^p cudng d o ndn tdi B60 Be dat dupc cap cudng d6 nay, mdt cac bidn phap co t h i duoc ip dung la sCrdung xi mang PC40 k i t h p p hdn hop phu gia: sieu ddo, tro tr^u - xl 16 cao va dCing phSn be tdng cd mdc ngam cat hpp ly
Dua trdn k i t qua nghidn cdu thuc nghiem va mdt sd t i l u c h u i n qudc t l v l sd dung cat mm lam cdt lieu nhd cho b l t d n g cd t h e k i l n nghj:
- N^n soat s i t lai TCVN 7570 ; 2006 theo hudng ndl Idng chl tieu Mdl cda cat, cho phdp cat cd Mdl ttf 1,5 t r d Idn dUoc d i i n g de c h l tao be tdng cSc cap cudng d d ; cat c6 Mdl t d 1,0 d i n
1,5 dupc phep ap dung cho b l tdng d p chju ndn tdi B30, c i p chju kdo udn tdi Bku 4,0 n l u qua n g h l l n cUu thay rSng bd tdng dam bao cac tinh chat y l u cau va cd hieu qua ve mat kinh te
- Nen CO d l tai nghidn cdu toan dien vide ii'ng dung cat mm, dac bidt la cat ddng bSng sdng Cdu Long de l^m be tong cac loai,cac cap t r l n B25, dd tap trung vao mdt sd b i l n phap d o n giSn nang cao hieu qua s d d u n g cat m m bd tdng nhU: Xd ly biin, bui set cao cat m m ; Thd hda cat bSng phdi trdn cat mjn vdi cat xay hoac da mat; Sd dung xi mang ho?t hoa Phu gia, t;^ Id C/D hpp ly cap phdi b l t d n g ; Bidn p h i p t h i cdng bd t d n g , dac bidt be t d n g b o m d i l u kidn Vidt Nam
TAI Lieu THAM KHAO
1.TCVN 7570 2006 Cot lieu Clio be tong uavfla-Yeu cau ky thual rOCT 8736 - 93 necoKfiJW cipoHTWiHbix pa6or - TexHiwecKiie ycnoBMB
3 rOCT 26633 91 EeTOHHbie Te*enbie H MenKoaepHwcTbie -TexKHiecKHeycnoBMfi
4 AASHT0M6-93 Fine Aggregate for Portland cement concrete ASTM C-31 Standaid Specification for Conaete Aggregates 6, MeTOflimecKiie peKOMeHnaiinii no npuMeHeKnio r^emwx H OMeHb MeriKHH necKOB B 6eT0He ana cTpoHienbCTBa ueMeHTofieroHHWH noupbrmii aBTOMofimibHWH flopor H ajpoilpoiiiDB Coi033AOpHHM., M., 1984
7 HgoVanTo^n,°Ngliien(i)usi}dungcatinmvah6nticrppliugia khoang tro trau - xi 16 cao de ch^ tao b l tong cUcing cao", Luan van thac sy ky thuat - Qai hoc Xay difng, 2D10