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]
Trang 1Nghien CLFU sCe dung cat mjn lam
cot lieu nho cho be tong cap
cu'O'ng do 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
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 6 n g Ti&u c f i u i n Vl$t Nam TCVN 7570 : 2006
"Ceit lieu cho b6 tdng vS vCfa - Y6u c&u ky
t h u a t ' [1] phan cat d u n g cho bk t f l n g v^
vda ra t h ^ n h 2 n h 6 m : cdt t h 6 (cdn gpi la cat 3,3 va cat min c6 md d u n d o Idn tiS 0,7 d i n 2,0 Cung theo tiSu c h u i n nay thi cdt mm cd
m6 dun do idn tCr 0,7 tdi 1,0 chi du'dc d u n g
de che tao be t a n g m i e t d i 200 (cSp Bl 5), cat
mm c6 m d d u n d d Idn tCr 1,0 t d i 2,0 chl d\sac
d u n g de c h l tao be tong mac t d j 300 { d p B25)
Do trC luong cat vang cua ni/dc ta ft, phan b o khong d o n g deu d cac vCing m i l n
chuyen xa, gia thanh cao, t h i l u sU chCi d d n g
v l nguon cat de c h l tao b l t d n g Trong khi d d , cac t i n h d o n g bSng sdng CLTU Long, v i m g d d n g b i c , tgy bSc phia bdc Vi^t Nam c6 trCf lUdng cat m j n kha Idn, gia
t h ^ n h ha Vi v l y , n l u sCr d u n g duoc loai cat nay lam be t d n g thi se c6 t h i m ngudn cdt lieu nhd, m d rdng dUpc vi$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
va v l lau dai 0 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 thanh 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 min 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 6 - 93 (4) va ASTM C-33[5] cua My dua ra cac y^u cSu sau:
- c a t phai cd m d d u n d d Idn trong 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 khi cd bang
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
t u o n g t l / c} Chl dSn sd d u n g cat m j n va cat rSt min lam b d tdng m | t d d d n g va san bay [6]
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 ^ = 1 , 0 - 1 , 5 : X(PC40) = 3 6 0 - 4 0 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) = 3 6 0 - 4 0 0 kg; N/X = 0,42 - 0,45;
C a t = 6 0 0 - 7 0 0 kg;Oa = 1 1 0 0 - 1 0 0 0 k g
N h u vSy cd t h i thay, trong 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 trong 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 min
h o n cd t h i sd d u n g lam cdt lidu n h d cho bd
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
Trang 20.4 ae 1
Hinh 1 Bieu do phan bo thanh phan hat cua tro trau
2 4 0 10 » 4 0 6 0 100 2 0 0 4 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 3 0 0 4 0
Run r u m t
LS330 nuid Module
l6S6 3 n j i i l 2 O I 0
Group ID X i l o c a o T N
Run length 60 Seconds
Firmware 2 02 0
0 6 1 2
Volume Ste
from 0 375 iliti to 2,00
100%
10 59 \im
4 6 10 20 lO eo 100
D u o r ^ kinh hat - Particle Diameler (|jm)
bstics (Amhmelic) Xi lo cao TN 502
Oum
Hinh 2 Bleu do phan bo th^nh phan hat cua xl 16 cao hat hoa nghien rr
ai.Bdng 1
j g ^ j Q j
^M,98
Thanh phSn hoa ctja tro trau
0,73 0 ^
CaO 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 nay 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^; 0 6 min {luong
sdt tren sSng 75|am) 5,0%; Qo ddo tieu chuan
dfing ket: bSt d^u 95 phdt; k i t thuc 140 phut; Cudng d6 ch|U ndn: tuoi 3 ngay: 24,0 Mpa; tudi
28 ngay 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 min tro t h u dUoc Thanh phan hat, thanh phan hda cua tro trau dUOc Mdt sd tinh ch^t ky thuat cua tro trau duoc neu trong B^ng 2
- 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 min Thanh phan hat v^ thanh phan hda cCia xi 16 cao duac trinh bay tUOng dng tren Hinh 2 va Bang 3
3.2.3 Cdt
cat sd dung trong nghien cdu la cat min
sdng Hdng da dUOc phOi khd skng loai bd cac
Ld Thanh phan hat va tinh chat co ly cua cat
mm, cat vang dUoc ndu trong cac BSng 4 va 5
3.2.4 Cdt hfu Idn
Cdt l i l u Idn s d d u n g trong 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 trong Bang 6
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 min
quy hoach thuc nghiem bac hai tam xoay de nghien cdu Snh hUdng cOa cac yeu t o : t j Id N/
Trang 3Khdi lUdng t h i
tich (kg/m')
0,7
Khdi lU^ng
ridng {g/cm')
2,2
Kich thudc hgt trung binh (Mm)
e
0 0 hiit vdi (mg/g)
300
Chi s6 hogt tinh vdi xl mang, (%)
95
Bang 3 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 1 tich d trang thai bao hoa trong, khd
matysscfg/cm')
Khdi luonq the tich d trang thai khd yvk, (q/cm^)
0 6 hut nudc, (%)
Od $m (sau phoi khd t u nhidn),%
H a m l u o n g b u i , sdt, (%)
Tap chat hUu co, (so vdi mau chuSn)
Md dun do Idn
5
0 2,5 7,7 1.25 17,2 0,63 45,1 0.315 78.7 0.14 96,3 2,65 2,63 2,61 0,6 1,0
Sanq ban
2.7
Bang 5.Thanh phan hat va tinh chat co ly cua cat mm sdng Hong
Kich thudc mSt sSng, m m
Luong sdt tich luy, (%}
Khdi luonq rieng, g / c m '
Khoi l u o n g t h e tich d t r a n g t h a i b a o h o a trong, khd
matYiso,(q/cm')
Khoi luong the tich d tranq thai kho y,i„ (g/cm^)
Od hut nudc, {%)
Od am (sau phoi khd t u nhidn),%
Ham luong bui, s i t (%)
Tap chat hdu cO, (so vdi mau chuan)
Md dun dd Idn
5
0 2,5
0 1,25
0 0,63 23,4 0,315 50,5 0,14 82,3 2,64 2,58 2,51 0.7 1.0 sang han 1,6
Bang 6 Mot so tinh chat ca ly cua da dam
Kich thudc mat sang, (mm)
Ldonq sdt tren sSnq {%)
Khdi luonq rieng d tranq thai khd yk (g/cm')
Khoi l u o n g t h i tich d trang thai bao hoa trong,
khdmatyssD, (q/cm')
Khdi luonq t h i tich d trang thai khd^vk (g/cm^)
D d hut nudc, (%)
D 6 n l n dap trong xi lanh,%
Cd hat 5-10
5
100
10
0
Cd hat 10-20
10
100
20
0 2,70 2,68 2,66 0,8
12
2,65 2,60 0,75 10,8
CKD, ham luong tro trJu, bhm lu^ng xi Id cao,
va ham luong phu gia sidu ddo tdi dd sut cOa hdn hqp bd long va cUdng dd be tdng Sau khl xd ly sd li$u thuc nghilm da xac dmh duoc mfl hinh thdng kd thyc nghidm md
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 trong tai lidu [7]
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 trong cac Bdng 7,8,9
3.3.2 So $dnh bi tdng cdt min vin be tong cdt vdng
De so sanh be tdng cat min v& bd tdng cat vang da c h l tao hai cSp phdi bd tdng cd ciing ddo Ham luong cat trong cdt lifu d thJnh phjn
bd tdng cat min la 28%, cdn d bd tdng cat thd la 41% Thanh phan va tinh chSt cua hai cSp phdi
be tdng dUdc trinh bay trong 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, khi 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), khi 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 do d tudi 28 cat vang Tdc do suy giam dd syt d ca hai loai
be tdng cat mjn va cat vang d i u cham nhd dac
Bl tdng cSt min nhd phu gta mjn tro trSu, xF nghiln con han c h l dupc dd thcim clo giup trong b l tdng
Trang 4K^ hidu c^p
phdi
CPI
CP2
CP4
XM (kg)
266
308
309
XLC (kg)
193
172
141
TT[kg)
92
70
99
N (lit)
138
170
187
203
SD (kg) 5,5 3.3 3.3
cat min (kg)
488
467
440
Oadam.[kq) 10-20
853
817
769
5-10
401
384
362
Bang 8 Sy suy giSm d d sut cua cac hdn hop b l tdng cat mm theo thdi gian
Sd
1
3
5
Ky hidu
c5p phoi
CPI
CP2
CP4
N/CKD
0.25
0,31
0,34
0,37
Dd sut (cm), tai cac thdi d i l m
O p h u t 18,0 18,0 17,5
30 phut 16,5 17,0 16,5
60 phut 14,5 15,5 14,5 Bang 9 Cudng d d ndn ciia be tong theo thdi gian
Ky hidu cap phdi
CPI
CP2
CP4
Cudng dd ndn MPa
1 nqay
41,4
37,1
35,6
3 nqay 68,1 61,0 58,6 54,3
7 nqay 78,3 70,1 62,4
28 nqay 92,0 82.5 73,4
Bang 10
Ky hieu
CP2
CPCV
Cap phdi be t d n g cat m m (CP2
XM
(kq)
550
XLC
(kg)
0
TT (kg)
83
0
va be t6ng cat vang (CPCV)
SD (kg) 4,4
N (lit)
154
C (kq)
724
Di dam, (kq)
5-10
393 10-20
836
333 1 708
Bang 11
Kyhidu
CPCV
So sanh t i n h chat cua be tdng cat min va be t d n g cat vang
0 6 sut,
cm
20
Cudng d d d tudi 28 ngay,
MPa Chiu udn
16,5
Chiu ndn 82,5
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 , trong d i l u kien
cua Viet Nam, cd t h i s d d u n g cat min thay cho
cudng d o ndn tdi B60 Be dat dupc cap cudng
d6 nay, mdt trong 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
thanh 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
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 min ddng bSng sdng Cdu Long de l^m be tong cac loai,cac cap t r l n B25, trong 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 trong bd tdng nhU: Xd ly biin, 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 trong cap phdi b l t d n g ; Bidn p h i p t h i cdng Vidt Nam
TAI Lieu THAM KHAO
1.TCVN 7570 2006 Cot lieu Clio be tong uavfla-Yeu cau ky thual
2 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
5 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 do cao", Luan van thac sy ky thuat - Qai hoc Xay difng, 2D10