Nghiên cứu ảnh hưởng hàm lượng sợi thép và polypropylene cao đến cường độ của bê tông geopolymer

DIEN OAN KHOA HOC CONG NGHE

NGHIEN cufu ANH Hl/CiNG HAM LUONG SOl THEP VA POLY￾PROPYLENE CAO DEN Cl/dNG DO CUA BE TONG GEOPOLYMER STUDY ON THE STRENGTH OF GEOPOLYMER CONCRETE BY USING HIGH CONTENT OF STEEL AND POLY-PROPYLENE FIBERS

PHA N DLCC.HUN G - KhoaXD va CO hoc ifng dung, DH Si/pham Ky thuat TRHCM,

LE AN H TUA N - Khoa XD, OH Bach Khoa TR H6 Chi Minh.

TdM TAT

Be tong geopolymer di/dc xem nhu mpt loai vat lieu xanh vi khong c^n sd dung xi mSng nhi/ng cac tinti chilt cd hoc cua

no lai iL/dng ti; nhi/ be tong xi mang. 06ng thcii, tinh gidn cua be tong geopolymer cung ti/Ong i36i cao, nen can sir dung ck

loai sdi nhi/ sdi thep va sdi poly-propylene 6e gia ci/c)ng tinh chit cd hoc cho be tong nhi/ khk nang chiu uon, chiu keo, cfiiu

vacham, Trong bai bao nay, sdi poly-propylene (ham li/ong la 0,5% theo the tich) va sdi thep (ham li/dng ia 0,5,1.0 va 1,5%

theo the tich} di/Oc bo sung fle danh gia ci/cJng 6b chiu nen va u6n cua be tong geopolymer gia cu'dng c6t sdi so vfli miu tloi

chiJng. K61 qua nghien ci/u cho My, be tdng geopolymer bo sung sdi poly-propylene cd cifdng So chiu nen giam 2 8% va

cL/dng dp chiu udn tang khdng dang ke (0.9%). Trong khi 66, ci/flng do chiu nen va chiu u6n cua be tong geopolymer tang

cao theo ham li/dng sfli thep bo sung, len d^n 41.1 % cho ct/dng do chiu nen va 60.2% ci/dng do chju uon i/ng vdi hSm li/dng

sdi thep su'dung la 1,5%.

Ti/ khoa: SOi thep, soi poly-propylene, be tong geopolymer. dung dich hoat hda

ABSTRACT

Geopolymer concrete is considered as a green matenal because of without cement usage but its mechanical properties are

similar to conventional concrete. Additionally, the brittleness of geopolymer concrete is relatively high; therefore it is necessary

to use fibers such as poly-propylene and steel fibers for reinforcing mechanical properties as flexural strength, tensile strength

and impact resistance, in this paper, poly-propyiene fiber (content of 0.5% by volume) and stee! fiber (content of 0.5,1.0 and

1.5% by volume) vjere used to evaluate the compressive strength and flexural strength of fiber reinforced geopolymer concrete

and then they were compared with control proportion without fiber usage. Research results show that in case of using poly￾propylene fiber, the compressive strength declines about 2.8% and the flexural strength increses slight about 0.9%. Whereas,

both compressive and flexural strength of geopolymer concrete increase with additional steet fiber content, up to 41.1% and

60.2% for 1.5% reinforcement, respectively

Keywords- Steel fiber, poly-propylene fiber, geopolymer concrete, alkaline liquid

1. Gidl THIEU

Ngay nay, vat lieu Geopolymer di/oc quan tam va

nghidn cuu nhl^u hon vcri nhi§u b^ng sdng chg,

nghifen cijru v& umg dung vio cdc ngdnh cong nghe vat

li$u hi^n dai (vat lieu each nhiet, vat li^u chdng chdy

chdt kit dmh v6 co, c6ng ngh^ xi!!f ly chdt thai...) tren

todn thi gi6i. Vdo nhuTig nam 1970, Joseph Davidovits

da gidi thi^u mpt quy trinh t6ng hgp polymer tir cdc

khodng chdt bdng cdch tron cac loai vdt lieu co chua

hdm luong ldn hop chdt silic va nhom vao dung djch

alkaline silicate co ndng d6 kidm cao nhdm tao ra mfit

hop chdt 6 dang gel vd dupc goi Id Geopolymer. Trong

dd, ngudn nguydn vat Ngu co chiia nhidu thdnh phdn

oxit nhdm va oxit silic vd djnh cd thl dupc tim thdy

trong phu pham cdng nghidp nhiet didn (tro bay) ndn

tro bay da dupc chpn nhu mpt trong nhijng loai vat lieu

ndn de chd tao chdt kdt dfnh Geopolymer, [1,2]

Geopolymer dupc xem Id vat lidu xanh va thdn

thidn vdi mdi trutffig, thay thd cho xi mang Portland

thdng thuPng, nhij dp bdn, tinh chdt cd hpc va khd

nang chju nhiet. Tuy nhien, tinh chdt gidn cua bd tdng

geopolymer kdt hpp vdi cac tdc dpng ciJa cdc hien

tupng tir bidn, co ngdt, mdi,... cung nha chju tac ddng

cua tdi trpng vd sir xam thut cua mdl truPng lam kha

nang chju luc cdc kdt cdu cdng trinh bd tdng cdtth6p

bj suy gidm. Ngodi ra, sir xudt hidn cac vdt niit ldn hcfn

gidi han cho phep lam bd tdng mdt khd nang bdo v6

Idp cdt thdp ddn ddn cdu kidn bj an mdn vd phd hoai.

Vide Cmg dung sol cd the dupc coi Id mdt giai phdp 6i

cai thien dp ben udn vd bdn va dap. Cdc logi spi ngan

phan tdn duoc nghidn ciiu nhu mdt phdn ciing c6 cho

mdt cdu tnic ciJa geopolymer. Hodn toan cd th^ bi§n

mdt vat lieu vdn khd gidn tiidnh mdt v^t lifu ddo dai,

dd udn hdn. Spi cd kha nang dnh ht/dng ddn tfnh ch9t

CO hpc vd 6n djnh the tich trong bd tdng geopolymer.

Kdt qua phan tich bd mat cdu tnic v&i sir xudt hidn ciSa

vdt niit cho thdy rang spi cd thl t^o ndn mdt hi^u Ong

chuyen tidp qua cdc Id rdng. [3, 4] Cdc loai spi di/pc

sir dung cho bd tdng geopolymer dupc nghidn aiu

nhu spi thuy tinh, spi thdp va spi ting hpp cho thdy

kha nang dinh bdm cOa spi trong bd tdng geopolymer

tuwng tLT nhu bd tdng xi mdng vd Idm tang tinh chat ctJ

ly cung nhu khd ndng chdng dn mdn tdt hon so vdi t^

tdng xi mang cua ciia bd tdng geopolymer. [4,5]

Do dd, vide nghidn ciiu cdc tdc nhdn dnh hi/iSng

ddn dac tinh ciia bdtdng geopolymer cd siJf dyng s<^

gia cu&ng Id cdn thidt, tCr do dua ra nhOmg loa soi,

ham Iuwig spi phu hpp vdi cdp phdi, Idm tdng nhOng

NGUdl XAY DI/NG s 6 THANG 9 & 10 - 2015 I