t t t t t KHOA HOC - C O N G N G H E
KHAO SAT ANH HUdNG CUA DO AM
VA CONG DAM NEN TOI CU0NG DO CUA CAP PHOI DA DAM GIA CO XI MANG TRONG CONG TAC XAY DUNG DUOING 0 TO
ThS. NGd LAM Cgc gidm dinh chit li/Q'ng BO Xdy Di,rng,
PGS.TS. Bill PHU DOANH
Khoa xay dyng C^u Di/6'ng, Trud-ng Bgi hpc Xay di^ng
J6m tat- Bai bao gi&i thi^u nOi dung cac thi nghidm kh^o sat anh having cua d0 Sm va cdng dam ndn tin cifOng dQ ndn, cuong dO ep chd cua cap phoi dd ddm gia c6 xi mdng trong cdng ldc xdy di^mg mdng duong 6 to cdp cao tir dd co nhung nhdn dinh ban dau de tang cuong cong tdc dam hdochM iuvng trong qud trinti thi cdng.
TCr khoa- Cdp phdi dd dam gia c6 xi mang: Cuimg dd ndn: cuong dd dp che
Abstract- The paper presents experiments' results on impacts of moistnjre and compression rammer work to compression strength and splitting tensile strength of Cement Treated Aggregate Bases in high-level road foundation construction and introduces initial suggestions for quality control enhancement during road construction process
Keywords: Cement Treated Aggregate Bases; Compression strength: Splitting tensile stren0h;
1 . eidl THlEU CHUNG
Trong khoang vai chgc ndm g^n ddy o nhieu nu'd'c tren the gia"] ngifd'i ta dd dCing cdc l<et cSu mdt du'dng m6i c6 cdc ldp mdng .ldm bdng vdt li^u dd gia cd cdc chit lidn kdt vd ca nhir xi mdng, xl 16 cao, tro bay, puzfflan v.v...Ct Vi$t Nam trong nhOng ndm qua, do si.r tdng dOt bidn vd luu luQ'ng giao thdng ca vd quy md l l n tai tnjng ndn trdn nhidu tuydn dudng Qudc Id xudt hidn v0t lun bdnh xe Idm mdt du'dng bj hu hdng dan ddn vide khai thdc vd ddm bao an todn giao thdng gdp khd khdn. Mdt du'dng BTXM theo quy trinh 22TCN-223-95 khi thidt kd cho phdp ddt trdn Idp mdng cdp phdi dd ddm thdng thudng dd dyptc thidt kd vd tridn khai thi cdng d^i trd tuy nhien cdc dogndudng dd thi cdng dua vdo khai thdc xudt hidn nhidu hu hong khdng dam bdo tudi thg theo thidt kd cua cdng trinh. Dk khdc phuc cdc hidn tuqvng hu hong ciJa mdt dudng BTXM, Bd GTVT dd tidn hdnh soat xdt, bd sung vd ban hdnh quy djnh tgm thdi theo quydt dinh sd 3230/QO-BGTVT ngdy 14 thdng 12 ndm 2012 ve thidt kd mdt dudng BTXM thdng thudng cd khe ndi trong cdng trinh xdy dung giao thdng. Quy dinh t^m thdi ndy thay thd cho 22TCN-223- 95 vd ydu cdu cu thd ddi vdi mdng do difdng ciing phdi dung mdng gia cd Id cap phdi dd ddm gia cd xi mdng. Mdt khdc, tinh hinh sdn xudt xi mdng trong nudc hidn nay cho thdy ngudn xi mdng san xudt trong nudc cd thd ddp i/ng duo'c tdt cd nhu cdu vd xdy dyng kd ca xdy di/ng cdng trinh giao
thdng. Nhu vdy vide tdng cudng su dyng san phdm xi mdng trong kdt cau do dudng d td ngodi vifc gidm lucng nhya nhdp khdu cho BTN cdn tdng dn dinh cho nin kinh td, dam bdo phdt tridn bin vung vd ndng cao khd ndng chiu lyc cua kdt cdu do dudng. M|t, mdng dydng cdp phdi da gia c6 xi mdng ngodi yu didm c6 dO ci>ng cao, cd tinh lidn khdi tdt, dam bao phdn bd ddu tdi trgng trdn nin ddt, dam bdo dd bdn vd dd 6n dinh cho Idp mdt phia trdn vd la mdt kdt cdu do dydng thich h(»p vdi dieu kidn giao thdng hien 3ai (iyu lygng xe ch^y idn vd nhieu xe tai ndng). Cdn cd yu didm tdng tudi thg cho kdt cdu do dydng, dl ca gidi hda thi cdng vd dd gidng kidm sodt chdt lypng. Mde du mdt dydng dd gia cd xi mdng Id mOt tidn bd trong xdy dyng dudng.
@IKJ@
S4 11 nam 2014 IKHOA H O C - C O N G NGHE # # # # J
cung dd cfi nhilu nghien ci>u dup^c thye hiOn tuy nhien efing nghO ndy v§n cfin ehua du^c ung dyng rpng rai tgi ViOt Nam;
vgn dyng ky thugt moi ndy vao thye t6 xay dyng duo-ng cua ViOt Nam nhu the ndo la mOt van de khfing don gian, c i n phai cfi cae nghidn ci>u, cde thye nghiOm va cJin duQ-e dau tu thich dang. B§c biOt trong giai dogn hiOn nay khi mong dufi-ng cap phoi dd dam gia c6 xi mdng dd dup-e thi cong then khai 6- nhieu dy dn thye te, viOc dam bdo ehit iup-ng thi cfing vd hgn che nhung nhan t6 anh hufi-ng d^n qua trinh thi cong Id hit sue cap bach.
2. TONG QUAN CAC VAN DE NGHIEN CIJU
Cdc nghidn cuu cua cdc tae gid 6' Wpt Nam, vd trdn t h i gifi-i da tien hdnh nghien cuu, sudyng logi hinh vgt liOu elp phli dd ddm eo gia e l xi mdng lam mfing, mgt duong o tfi cap cao. dufi-ng bdng sdn bay.
Du6i day la mOt so nghien ciru dnh huong cua cdc nhdn td toi chit luQ'ng cua h6n hp'p cap phoi dd ddm gia eo xi mdng.
+ Anh hud'ng cua hdm luong xi mang doi vfifi cuo'ng dp cua hon hgrp: Theo giao su J.Bonnot thi cufirng ao chju nen vd ham luyng XI mdng trong hon hp-p da gia co xi mdng cfi quan hO tuyen tinh it nhat tnsng pham vi vdi phan tram xung quanh ham lugrng xi mang su dung, anh huo'ng cua hdm lup'ng XI mdng doi vfifi mfi dun dan hoi vd cuong dO chju keo {dp ehe) cua vat liOu da gia eo xi mang eung tuong ty (1], [2].
+ Cfing tdc lu len efi tdc dung trye tiep din viec tang giam dp chat cua mgt duo'ng da gia c l xi mdng, do dfi anh huong rat ifi-n d i n cuo-ng dp cua ket eau mat duo'ng, theo so liOu cua Vien LCPC (Phap) khi dO chat giam tu 100% xuong 95% dp chat lo'n nhat theo tidu ehuan Proctor thi cuo'ng dO chju nen se giam 50%.
+ Anh hud'ng eua hdm lug-ng nuo'c: Hdm lug-ng nuo'c cho cuo'ng dO cao nhat nho han 1%
hdm lup'ng nuo'c tot nhit cho dung trpng kho eao nhat (ung vfi-i cong dam nen eua coi Proctor cai tiln)
+ Anh hud'ng cua thanh phan
hat: Khi thay doi thanh phan cap phoi theo duo'ng eong o ngoai pham vi d p phoi tot nhat eua Roobin thi cuong dp chju ndn cua hfin hp'p da gia co xi mang ehi giam xuong khoang 15%.
+ Anh huong eua phuang phap thi efing: Theo gido su XIavutxki, phuong phdp trpn vgt liOu anh huo'ng rat td'n den cufi-ng dO chju nen cua mgt dufi-ng da gia c6 xi mang, khi trOn tai duong bdng mdy san ty hanh D-144, cuo'ng dO chju nen cua vgt lipu giam xuong 50% so voi khi trOn trong thiet bj va chi bdng 33%
cuong dp cua mau che tgo trong phong thi nghigm.
De thye hiOn hfia cac anh hudng cua eae nhdn t l tren td'i qud trinh thi efing edp phli da dam gia c l xi mang tdc gia da tien hdnh nghien cuu anh hud'ng cua dp am vd cfing dam nen tfi'i cuong dp cua cap phoi da ddm gia CO xi mang de kien nghi eho qua trinh thi cfing thye t l Id'p mdng tren cua duo'ng fi tfi, thuOe dy dn ndng cap cai tgo quoc 10 I.
Bang 1: To hgp miu vd nhom miu khao sat
TT
1
III
Oieu kifn tlii nghifm Of am h o n h ^ 3%-7%
6%
Him lufngxi
ming 5%
5%
So It/fng ti hfp mlu
(3 mau)
30
e
6 6
Nfi dung kiem tra KiSm tra cwng
df chiu nen R7, R14, R28 Nl Nt Nt
Kiem tra cirong df ep ctie R7. R14, R28 nt nt nl
So tiif u mau
UI 1 - Ml. 90 Ml 37 Ml 54 Mill 1 Mill 18 MIII.19 ' MIII.36
Ghi chu
Thay doi do am 1 lop 56 chay 1 lop 45 chay 1 lOp 30 chay
I s 6 l 1 nam 2014
Si& m&
V # # # KHOA HOC - C O N G NGHE
Dja diem vd v$t lieu diu vao Cdc thi nghiOm dup'c tiln hanh tgi phong thi nghiOm LAS - XD 164 thuoc Cfing ty C l phan tap dodn Truo'ng Thinh d' hiOn truo'ng Dy dn Mfi- rOng QLIA tu Thdnh phi Ofing Hd din thj xa Quang Trj.
d p phoi dd ddm lay tgi mfi da Olu Mau - huyOn Cam LO - tinh Qudng Trj.
Dung logi xi mdng PCB30 - Thd'i gian bit diu nmh kit Id:
132 phut;
- Thd'i gian kit thuc ninh ket Id:
231 phut;
- Dp nghien mm 2795 em'/g;
Dp deo tieu chuan N/X:
23,54%.
Thd'i gian thi nghiOm tu ngay 24/3/2013 din ngdy 22/6/2013
Hinh 1: Thi cong cSp phSi da ddm gia c6 xi mang tinh 1^ 293
Bac Giang - Tay Yen Tie
3. KHAO SAT ANH H U A N G CIJA
0 0 AM OEN CUdNG DO HON HOP OA DAM GIA CO XI MANG
DO am la mOt ehi tieu quan trpng, quyet djnh tdi chit lup'ng cua hon hi?p d p phoi da dam gia CO xi mdng. O l nghien cuu dup'c mue dO anh hud'ng cua dp am tdi cudng dO tde gia tiln hanh cac t l mau MI.1 den MI.90. Thi nghipm dup'c thuc hiOn thdng qua kit qua thi nghiOm dam nen thu theo dO
am a%, a% + 1%, a% + 2%, a%
+ 3%, a% + 4% {a = 3%), ung vdi ham lup'ng xi mdng 5% (Bang 1)
Mfii chi tieu dup'c thi nghiOm 9 mau d cde ngdy tuli 7, 14, 28. Cdc mau due diu dup'c ghi ngdy vd ky hieu trdn mat mau nhdm tranh viOe sai xfit trong thi nghiem xac djnh dup'c cdc chi tidu can thilt.
Thi nghiOm xdc djnh cdc chi tieu cudng dO chju ndn (R^) theo phuong phdp TCVN 3118-1993, chi tieu cudng dO ep che (R^) theo phuang phdp TCVN 8862-2011.
Mdu dup'c che bj theo phuang phap thi nghiOm neu tren efi kieh thudc D= 152mm; h = 117mm.
• Gid trj cudng dO khang ndn dup'c xae djnh theo cong thue:
R. = P™/F (1) Trong 66:
P^. lyc tde dyng len mdu;
F: DiOn tich mgt mau.
* Gid trj cudng dO chiu ep che dup'c xdc djnh theo efing thuc:
R^^ = (2xP)/(Dxhxn) (2) Trong dd:
P: lye tac dyng len mau.
F: DiOn tich mgt mlu;
D: Dudng kinh mau;
h: Chilu eao mlu Kit qud thi nghiOm cudng dp chju nen, eudng dp ep che hon hp'p cap phoi da ddm gia c l xi mang theo cac dieu kien khac nhau d cac ngay tuli khac nhau dup'c tong hp'p nhu sau:
3.1 Quan he giQa cUdng do chju nen (RJ vdi dp am hon hdp:
Qua kit qua thi nghipm cho
thay cudng dO chju ndn RJ, R^14, R^28 eua cde mdu thay ddi theo dO am dup'c t h i hiOn Bang 2~4, tren ca sd s l liOu dfi ede tac gia dd tien hanh ve bilu do m6i quan hO cudng dp chju nen cua hon hp'p vdl dp am dup'c t h i hifn tren bieu do hinh 2.
Bang 2: Ket qua th/ nghidm cuong dip c/)/u n&} tiieo dg am hon hgp b 7 ngdy tuoi
STT
1 2 3 TB
Ciro'ng d f chju ndn Rn7 (kG/cm') 3%
59,78 59.78 59,25 59,80
4V.
74.60 75,12 74.07 74,60
5%
79,36 80,42 79,36 79,71
6%
73,01 74,07 73,01 73,36
711 61.90 62.43 6t,90 62,01 Bang 3: Ket qua thi nghidm cuxmg dg chiu nen theo dg m hon hgp & 14 ngdy tuoi
1 2 3 TB
Cudng d f cliju nen 1^14 (kG/cm^
3%
85,71 79,36 85,71 83,59
4%
107,40 99,46 107,40 104,75
5%
114,80 105,81 114,80 111,80
S%
105,81 97,34 105,81 102,99
7% 89.41 82,53 89,41 87,12] Bang 4: Ket qua tiii nghiem cuong dg chju nen theo do am hon /)op o*
28 ngdy tuoi
sn
1 2 3 TB
Cifdng df chju nen Rn28 (kG/cm') 3%
9311 89Alj 95,23 92,58
4%
123,80 123,80 132,26 126,62
S!4 132.26 132,26 141,26 135,26
6%
121,68 121.68 130.15 124,50
711 10316 103,16 110.04 10S,4S
1 ^ m^ S6 11 nam 2014 |
KHOAHOC-CONGNGHE ####J
Theo ket qud t h i hiOn tren bieu do ta thay cudng dO chiu nen cua hon hp'p tang d i n theo ngdy tuli vd gid trj thay d l i theo dfi am, gid tn dgt cyc trj tgi Idn egn d dO I m 5%. Nhu vgy rfi rang dO am cfi anh hudng rit Idn din cudng dp hin hp'p, d dO am tot nhit gid trj cudng dO gip 1,46 lln so vdi cudng dO tgi dO am nho nhit.
3.2 Quan he giCfa cUdng do ep chl (R^) vdi dp am hon hdp:
Tuong ty nhu tren ta cfi kit qud cua Rec, t h i hiOn tren eac bdng 5-7 vd hinh 3.
Bang 5: Kit qud thi nghigm ctrimg do ep che theo do am hon hgp & 7 ngdy tuoi
STT 1 2 3 TB
Circmg df chju n6n Rec7 (KG/cm') 3%
4,02 3,65 4,38 4,02
4%
5,48 5,11 5,84 5,48
5%
6.21 6,21 6,58 6,33
6%
5,48 5,48 5,84 5,60
7%
4,02 4.38 4,38 4,26 Bang 6: Ket qui thi nghi$m ctrdmg dg ep che theo dg am hon htj/p d* 14 ngiy tuoi
STT
1 2 3 TB
Cirimg df chiu nin Rec14 (kG/cm^
3%
6,94 6,58 7,31 6,94
4K 8,77 8,40 8,77 8,65
5%
9,50 9,13 9,86 9,50
6%
8,40 8,04 8,77 8,40
7%
6,58 6,21 6,94 6,58 Bang 7: Ket qua thinghigm cuvng dg6pchetheodgimh6nhgpv28 ngdy tuoi
Cuvng do chju nen Rec28 (kG/cm') 3% 4% 57.
1 '8,04 9,86 10,96 2 7,67 ,9 50 10,59 V "767^9 50 10,59 TB^" 7,79 "9,62 10,71
6% 7%
10,23! 8,04 9,86 9,86 9,98
7,67 8,40 8,04
f KOO :
% BOOO I 6500:
I MOO -
Hinh 2: BiSu d6 quan h$ quan h$ cuvng do chju n6n theo d0 im a cac ngay tuoi iihac nhau
%\fi.m
&ekhinh9pw(%)
Hinh 3 Bieu do quan h^ cu-img do ep c/id vdf dp im hdn hgp a cdc ngdy tuoi i<hac nhau
Theo ket qua tren bilu do hinh 3 ta thay theo sy tdng dan cua dO l m thi cudng dO dp che mau thi nghiOm d eac ngdy tuoi khae nhau eung theo xu t h i trude tang sau gidm nhu d hinh vd dgt gia trl eye trj d lan cgn dO l m 5%, gia trj cudng dp gap 1,37 lan so vdi cudng dp tgi dO am nhd nhat.
Nhu vdy: Qua cac ket qua thi nghiOm cho thiy nlu ham lup'ng nude tot nhit cho dung trpng khd eao nhat {ung vdi cfing dam nen cua cii Proctor cai tien) la 5,9%
thi dp am cua hfin hp'p cho cudng dO mlu Idn nhat (R7, R14, R28) deu dgt eye tn tgi lan egn dp am 5%, nghTa la thip hon xap xi 1%, cfin khi dO am hon hp'p thap hon 5% ho§c Idn han dO am tot nhat 5,9% thi eudng dp cua hon hp'p tgi 3 mle ngdy tuli giam xuong rat nhieu. Theo thdi gian bao dudng
thi eudng dO mau vdi cdc dO l m khdc nhau cudng dO cua mau deu tdng din vd dgt cyc trj 5%.
4. KHAO SAT ANH HlAJlNG CUA
CQNG DAM NEN O^N CUdNG DO HON HOP CAP PHOI DA DAM GIA CO XI MANG
Cfing dam nen cfi tdc dung trye tilp den viOe tang giam dO chgt cua Idp kit clu cua mat dudng dd dam gia co xi mang, cin phai dge bigt chu trpng trong cdng tdc thi cdng.
Cdn cu kit qua thi nghigm dam ndn che bj mau thu, ung vdi ham lup'ng xi mang 5%, tien hanh due mdu theo eac trudng hp'p: moi Idp dam 56 ehay; moi Idp dam 45 chay; mil Idp dam 30 chay. Moi trudng hp'p c h l bj 18 mau, ngam nudc 07 ngdy va bao dudng am cac ngay edn Igi.
I s 6 l 1 nam 2014 Biiy®nij(§
# # # # # KHOA HOC - C O N G NGHE
Hinh 4: Che bi mau theo cdng dim nen khac nhau
30.00 ' 95% 9 7 % 9 9 % 1 0 1 % 103%
DO chat sau kh< lu I6n(%)
Hinh 5: Biiu d6 quan h^ cuang d0 chju ndn theo do ch$t sau dam n6n 6 di? tu6i f<hdc nhau
Mii chi tieu dup'c thi nghiOm 9 mau d cdc ngdy tuoi 7,14, 28.
Bang 8: Mau thi nghigm theo cong dam nen khdc nhau
Bang 8: Kit qua thi nghiem cuvtng dg chju nen theo do ch$t sau dam nen & 7 ngay tuoi
TT
1 2 3 4 5 6 7 8 9
Ten miiu
MI.55-MI60 MI.61-MI66 MI.67-MI72 MIII.1-MIII6 MIII.7-MIII12 MIII.13-MII118 MIII.19-MIII.24 MIII.25-MIII 30 MIII.31-MIII.36
Ham lu'fng xi mdng
W
5
5
5 am hon h f P
6 Ghi chu
1l6p 66 chay Hop 45 chay Hop 30 chay
sn
1 2 3 Tmng binh
Cuvng d f chju nen Rn7 (l(G/cm') 101%
73.01 74.07 73,01 73,36
98%
47,09 46,03 47,61 46,91
97%
38,09 37,56 39,15 38,27
Bang 9: Kit qua thi nghidm cuwig do chju nen theo theo dg chat sau dim nen & 14 ngdy tuoi
4.1 Ouan h§ giQa cUdng chju nen (RJ vdi dp chat sau khi dam nen:
Ket qua thi nghiOm cho thay cudng dp chju ndn RJ, R^14, R^28 cua cdc miu thay dli theo edng dim nen dugre the hiOn Bang 8-10, trdn ca sd s l liOu do cdc tdc gid da tiln hanh ve bleu do mii quan hg cudng dO chju ndn cua hon hp'p vdi dO am dup'c thi hipn trdn bilu do hinh 5.
sn
1 2 3 Trung binh
Cuvng d f chju nen Rn14 (l(G/cm') 101%
105,81 97,34 105,81 102,99
98%
68,25 67,72 66,66 67,54
97%
55,55 54,49 56,08 55,37
Bang 10: Kit qua thi nghigm cuvng do chju nen theo theo dg chat sau dim nen & 28 ngay tuoi
STT
1 2 3 Trung binh
Crrimg d f chju nen Rn28 (l(G/cm') 101%
121,68 121,68 130,15 124,50
98%
79,36 80,94 80,42 80,24
97%
65,60 62,96 62,96 63,84
Tren hinh 5 ta thay cudng 6() chju nen d cae ngdy tuoi khac nhau tang ten khi dO chat cua cap phoi da dam gia co xi mdng tdng len theo mOt ham dong bien. Khi dp chgt giam tu 100% xuong 98%
dO chgt Idn nhat theo tidu ehuin Proctor thi cudng dp chju nen giam khoang 40%, nlu dp ch§t giam nho hon thi cudng dp giam Idn nhit 95%. Dieu ndy cho thiy neu trong efing tdc thi cdng ngoai hiOn trudng dp ehgt khfing du'Q'c dam bao thi cudng dO ndn cua Idp mdng se c6 the khfing dgt yeu eau theo thilt k l .
4.2 Quan he gi0a ciTdng dp ep c h l (Rec) vdi do chat sau khi dam nen:
Kit qua thi nghigm thi hi§n tren bang 11-13 vd hinh ve 5.
Bdng 11: Kit qua thi nghi^
cuong dg ep che theo dg ch^t sau dam ndn & 7 ngdy tuoi
STT 1 2 3 Tmng binh
Cirong Si chju n6n Rec7 (kG/cm') 101%
5,48 5,48 5,84 5,60
98%
4,02 4,02 3,65 3,90
97%
3,65 3,29 3,29 3,41
^ mm S4l1 nam 2014 I
KHOA H O C - C O N G NGHE SJS^
Bdng 12: Kit qua thi nghidm cwong dg d p che theo dg ch$t sau dim nen at 14 ngdy tuoi
STT 1 2 3 Trung
binh
CiTiing do chju n6n Rec14 (l(G/cm') 101%
8,40 8,04 8,77 8,40
98%
5,11 5,11 4,75 4,99
97%
4,38 4,02 4,02 4,14
Bing 13: Ket qui thi nghidm cuvng dg ep che theo dg ch$t sau d^m nen & 28 ngiy tu6i
sn
1 2 3 Trung
binh
Cudng dO chiu nfen Rec28 (kG/cm^) 101%
10,23 9,86 8,77 9,62
98%
5,48 5,11 5,11 5,23
97%
4,02 4,02 3,65 3,90
Hinh 6: Biiu <^ quan hg cuong dg dp chd theo dO<^ sau dim ndn dr
dQ tudi khdc nhau Tren hinh 6 cho thiy cudng dO 6p che d cdc ngdy tuli khdc nhau tang Idn khi dp eh$t cua d p phli dd dam gia c6 xi mdng tdng ldn. Khi dO ch$t giam tu 100%
xuIng 98% thi cudng dO chju dp chd cung giam theo ty 10 tuong ty cudng dp chju ndn.
Nhu vOy: Dp ch^t anh hudng rit Idn d i n cudng dO cua hin h(7p d p phli dd ddm gia d xi mdng. Khi dO ch^t gidm tu K=1,0 xuIng K=0,98 thi cudng dp chju ndn vd cudng dO chju dp c h l cua h i n h<7p dd ddm gia d xi mdng
theo eae mic ngdy tuoi (R7, R14, R28) giam xuIng trong khoang 33% - 40%.
T.K^TLUANVAKIENNGHj VOt liOu d p phoi da dam gia d xi mdng Id mpt vat lieu cao d p trong ITnh vyc xay dyng kit d u m^t dudng fi tfi efi dae diem cfi cudng dO chju nen cao, cfi kha nang chju keo khi uln, on djnh nude va nhiOt: cudng dp hau nhu khfing giam khi dp am vd nhiOt dO mgt dudng thay doi. Tuy nhien van chua dup^c sd dung phu hp'p vdi quy mfi trong dudng fi tfi tgi ViOt Nam.
Cdng hghO thi edng Idp mdng d p phoi da dam gia eo xi mang da dup'c thi cong dgi tra tgi mOt so quic gia tren the gidi nhung d nudc ta cfing nghe thi efing Idp mfing ndy mdi chi d pham vi nho, cfing nghp eon lae hgu. Theo cdc quy djnh mdi ve quy trinh thi efing mgt dudng cua ViOt Nam vd cdc chi dan mdi ve thiet ke eho cdc dudng cfi xe tai trpng nang da CO xu hudng su dgng logi vat liOu d p phoi da dam gia d xi mdng lam Idp mdng eho kit d u do dudng tgo dieu kiOn eho viOc phdt tnen eong nghg ndy trong tuong lal.
Thfing qua kit qua thi nghiOm trong vdi to hp'p cac nhdm mdu khao sdt sy anh hudng cua dp I m va cong tac lu len tdi eudng dO {ehju ndn vd chju ep che) cua d p phli dd gia d xi mdng thu duyc mOt so kit qua quan trpng nhu sau:
Cudng dp mau thi nghipm cua hin hp'p d p phoi da dam gia d xi mdng chju dnh hudng Idn bdi dO I m hon hp'p kit qua cho thay dO I m cho cudng dp mau Idn nhit dgt lan c$n tgi 5%, day co t h i la
ket qua tham khao phuc vy cfing tac thi edng ngoai cfing trudng.
Cdng lu len cua hin hp'p d p phoi dd dam gia d xi mang (the hiOn thfing qua dp ehdt K= 0,97 - 1,01) anh hudng rat Idn den eudng dp cua no. Khi dp ehgt cua hon hp'p d p phoi da ddm gia d xi mang thay d l i tu K=0,97 len K=1,0 thi cudng dO chju ndn va eudng dp ehju dp ehe giam tang len lan luvt Id 71,0% va 100%.
Chat luong cua cua d p phoi da dam gia d xi mang anh hudng rat Idn bdi cfing lu len, hon nua mOt dac dilm het sue quan trpng cua cfing tdc thi edng la khing c h l thdi gian lu trong thdi gian ninh kit cua xi mang dieu ndy cfi the lam cho cong tac lu ldn bj anh hudng. Do vay d n tang cudng dam bao dO chgt trong thi cfing de nang eao chit lup'ng vd dam bao tuoi thp cdng trinh.
TAI UEU THAM KHAO 1. Mgt dudng dd gia d chit lidn
kit vfi CO. Nguyln Quang Chtdu - Nguyln Xuan Dao, NXB Xdy dyng 2003 2. Bdo cdo ting kit nghien cuu
hiOu qud dp dgng vd hodn thiOn he thing tidu chuin dung xi mang Idm dudng bd tfing - Vi#n KHCN XSy dyng.
3. TCVN 8858:2011 Mfing d p phoi da ddm vd d p phli thidn nhien gia d xi mdng trong k i t d u do dudng 6 tfi - Thi cfing vd nghiOm thu, Bp khoa hpc vd cfing nghO, 2011.
4. TCVN 8862:2011 Quy trinh thi nghiOm xdc <^nh cudng d l keo khi dp c h l eua vgt
^-•ti liOu hgt lien k i t bdng cdc ( * l t kit dinh, Bp khoa hpc vd cdng nghO, 2011.
I s 6 11 nam 2014
