Cdng nghiep rdng
BE TONG DON ROM - PHU'ONG PHAP QUAN LY CHAT THAI NONG NGHIEP BEN VITNG
Dang Van Thanh, Le Tan Qu5'nh, Nguygn Thi Van Hoa Trudng Dgi hoc Ldm nghiep
TOM TAT
0 cac viing nong nghiep - nong thon Viet Nam hien nay, giai quydt v5n dS xii ly rom ra sau m6i raua v\i sao cho anh huong nho nhat den moi trircmg dang la nhiem vu dac biet quan trpng; boi giam thilu tac dpng moi truang la yen cau ngay cang co y nghia trong cac hotit dong s6ng ciia con nguoi. Bai bao d§ xudt va chi ra phuang phap sii dung rom lam chdt don cho be tong. Dya tren cac tieu chi ciia be tong nh?, qua viec kifim tra cac tinh nang co ban cho thay, loai be tong sit dung chSt don rom, khi dupe thi§t kS thanh phin hgp ly se dap img dupe cac chi tieu vg khoi luang the tich va cuang dp chiu nen quy dinh d6i v6i be tong nhe. K6t qua nghien ctru cho thay, voi loai be tong don rom duac tao ra tu be tong nSn B i 5, ham lupng rom trong khoang 10 - 18% theo khoi lirong xi mang dam bao phii hop voi quy dinh ciia tieu chuan Viet Nam ve be tflng nhe. Sir dung loai be tong nay khong chi giam duac chi phi ve nguyen vai Heu, ma con g6p phan dang ke vao viec giam thieu tac dpng moi trudng gay ra tu cac phe thai nong nghiep.
Tir kboa: B^ tdng nhe, be tong ram, cinnig do nen, khdi lirtmg the tich, phi thai nong nghiep.
1. DAT VAN DE
Trong thiic te xay dung cac cong trinh hien nay, vat lieu xay dyng chiem mgt ti le rat Ion trong gia thanh xay dung; vice san xuat va cung cap cac loai vat lieu xay dung phu hgp, dap ung dugc day du cae ygu can xay dung c6 mot vi tri rat quan trgng, quyet dinh dgn thanh gia va chat lugng cong trinh. Bg tong la mgt loai vat lieu hien dang dugc su dung rat rgng rai trong cac ITnh vuc xay dung. Tiiy thugc vao yeu can sir dung trong cae ket cau cong trinh ma be tong dugc che tao vai nhigu chung Ioai va nhieu dac tinh khac nhau. Ciing voi muc tigu tao ra dugc nhung loai bg tong eo cuong do cao - chat lugng cao, thi van de tan dung cac phg thai tir san xuat va doi song vao viec chg tao be tong, gop phan giam thigu tac dgng moi truang cung la van dg dang dugc quan tam.
Trong nong nghiep, tinh trimg binh m6i ha mgng liia se co thg cho ra khoang 6 tan rom ra.
Vai ty le hau hgt lugng rom ra dugc dot hay bo lai tren dong rugng nhu hien nay, khong chi gay lang phi, ma con anh huong xau den moi trudng. Chinh vi vay, viec nghien ciru tan dung rom ra - nguon vat lieu tai cho san co a nong thon dg lam chat dgn chg tao be tong, lam phong phu thgm nguon vat lieu phuc vu xay dung nong thon moi, dong thcri gop phan lam giam tac dgng tieu cue cua cac phg thai nong nghiep toi moi trudng la thuc su can thiet.
Trong khi do, trgn thg giai van con rat it ket qua nghign cuu duge cong bo vg sir dung rom lam vat lieu xay dung noi chung va lam chat dgn bg tong noi rigng.
Nam 2013, Larisa Brojan, Alja Petric va Peggi L.Clouston qua nghien curu so sanh vg eac he thong tuong gach va tuang ram da chi ra rang: viec sir dung cac cau kien rom la mgt lua chgn tot thay thg cho gach. Nam 2014, Larisa Brojan, Peggi L. Clouston qua viec phan tich T^P CHI KHOA HOC VA CONG NGHE LAM NGHIEP SO 2 - 2019 135
Cdng nghiep rdng
mgt so uu nhugc digm cua viec dung cac cau kien chg tao tir ram trong xay dung da khang dinh: cung voi thach eao hr nhign, buc tuong rom se tao ra moi trudng bgn trong cua ngoi nha ygn tmh, an toan va lanh manh han. Nam 2016, Muhammad Usman Farooqi va Majid Ali qua nghien cuu ve viec su dung sgi ram cho be tong mat dudng da kgt luan: bg tong gia cudng sgi rom su dung cho ao dudng la rat co tiem nang.
Nam 2012, Jun Liu, Honghong Zhou va Bing Zhang da nghign cthi anh hudng cua ti le ram dgn cae tinh chM vat ly cua bg tong rong chi ra ring: khi ty le ram tang tir 0 ~ 15% thi cudng do chiu nen, cudng do chiu keo uon va tinh on dinh nude cua be tong giam dan, tuy nhign van dap img cac yeu cau quy dinh vdi bg tong rong thong thudng. Nam 2010, Andrew Alcorn va Michael Donn qua nghien ciiu ve tiem nang cua cau kien diing ram va gd doi vdi viec hap thu cacbon trong xay dung nha da khang dinh: co the giam lugng khi thai COi theo hudng can
bang nang lugng bang each sir dung eac vat lieu sinh hgc nhu ram va go. Nam 2011, Behzad Sodagar, Deepak Rai, Barbara Jones, Jakub Wihan va Dr Rosi Fieldson qua nghiem cuu vg tigm nang giam cacbon ciia nha ram da minh hoa vai trd ciia ram nhu mgt loai vat lieu va ky thuat xay dung dg giam cac anh hudng tdi nha 6 bang phuang phap xay dung mo hinh hoa hieu suat phat thai CO2.
C) Viet Nam, chua cd ket qua nghien ciiu chinh thiic nao vg sir dung rom lam vat lieu noi chung va lam chat dgn bg tong noi rieng dugc cong bo.
2. PHUONG PHAP NGHIEN ClTU 2.1. Nguyen vait lieu
Chat kgt dinh: sir dung xi mang pooe lang PCB-40 dugc san xuat tai Cong ty co phan xi mang Nam Son - Viet Nam. Cac thong so ky thuat CO ban cua loai xi mang nay deu thoa man quy dinh ciia Tieu chuan Viet Nam TCVN 2682: 2009 va dugc thg hien d bang 1.
Bang 1. Chi tieu ky thuat cua xi mang PCB-40 TT Chi tieu liy tliuat
Giai lian ben nen:
1 - Sau 3 ngay ± 45 phut - Sau 28 ngay ± 8 gia Thai gian dong Icet 2 - Bat dau
- Ket thuc
Do nghien min, xac dinh theo:
3 - Phan con lai tren sang Idch thuac 16 0,09mm - Be mat lieng, phuang phap Blaine
Tris6
>21N/mm^
> 40 N/mm^
> 45 phiit
< 375 phiit
< 1 0 %
> 2800 cmVg Cot lieu nhd: sic dung la loai cat vang song
Hong, khai thac tai khu vuc Son Tay - Ha Ngi;
cot lieu Idn: la loai da dam dugc chg bign tu md da Hoa Thach - Quoc Dai - Ha Ngi. Cac thong so ky thuat cua cot lieu dgu thda man quy dinh ciia Tieu chuan Viet Nam TCVN 7570: 2006.
136
Ch4t dgn rom: su dung loai rom mdi (ram ngay sau vu thu hoach); ram dugc phai kho, sau do bam cat thanh doan nho cd chigu dai khoang 3 - 5 cm. Ngay trudc khi dua vao nhao trgn, ram dugc ngam 20 - 30 phut trong nude sach, roi vdt ra de rao. Hinh anh vg loai sgi rom va qua hinh xii ly dugc thg hien d hinh 1.
TAP CHI KHOA HOC VA CONG NGHE LAM NGHIEP SO 2 - 2019
Cong nghiep rdng
Hinh 1. Quy each va qua trinh xir ly rom
2.2. Phuomg an thiSt kS va phuong phap thi nghigm
2.2.1. Phirffng dn thiet ke
Sir dung phuang phap tinh toan ly thuyet kgt hgp thuc nghiem de thigt kg thanh phan ca ban (thanh phan ban dau) cua be tong rom;
bang each tinh toan xac dinh thanh phan cua bg tong nen cd cudng do chiu nen trung binh yeu can la 20 MPa (tuang duong bg tong B15); sau dd, diing phuang phap thuc nghiem thir dan (trgn hdn hgp, true quan va thir do sut) dg thay thg mgt phan cot lieu Idn bang rom. Trgn ca sd thanh phan vat lieu ca ban, thay ddi ham lugng ram, qua cac chi tieu khoi lugng thg tich va cudng do chju nen cua cac miu d tudi 28 ngay vdi hai trang thai: kho tu nhign va ngam bao hda, xac dinh ham lugng ram hgp Iy tir thuc nghiem.
2.2.2. Phirffng phdp thi nghiem
Thi nghiem cac tinh nang ca ban cua cdt lieu, eua hdn hgp bg tdng va bg tdng dugc thuc hien theo tieu chuan Viet Nam hien hanh:
TCVN 7572 - 1-18: 2006 - cac thi nghiem cdt heu; TCVN 3106: 1993 - thi nghiem do sut;
TCVN 3118: 1993 - thi nghiem cudng do chiu nen; TCVN 3115: 1993 - thi nghiem kh6i lugng thg tich.
3. KET QUA VA THAO LUAN 3.1. Tinh toan va lua chon thanh ph^n ban dau 3.1.1. Xdc dinh lirang nude nhdo trgn
Lay bg tdng B15 la loai bg tdng nen thiet kg (cudng do chiu nen trung binh Rb = 20 MPa);
dung da dam cd dudng kinh danh dinh Idn nhat Dmax = 20 mm va cat hat thd cd do am 7%;
chgn muc tieu do sut eua hon hgp S = 2 ~ 6 cm (tucmg img vdi bg tdng it hoac khdng sit dung cdt thep), tra bang (Tieu chuan Viet Nam TCVN 2682: 2009) cd dugc lugng nude nhao trgn N = 190 - 205 lit, chgn N = 200 lit.
3.1.2. Xdc dinh ti le xi mdng/nirdc Sir dung cong thiic Bolomey - Skramtaev (Pham Duy Him va cdng sir, 2011) dg xac dinh ti le XI mang/nudc nhao trdn (X/N):
Vdi be tdng thudng (X/N - 1,4 - 2,5):
N
AR,
Trong dd:
Rx - cudng do (mac) cua xi mang, xi mang P C B 4 0 c d R x = 40MPa;
Rye - cudng do chiu nen yeu can cua be tdng d hidi 28 ngay, ldy Rye = 20 MPa;
A - he so chat lugng cdt lieu, chgn A = 0,6 (vdi cdt lieu cd chat lugng tuang ddi tdt).
Thay eac thong sd vao cdng thuc tinh toan, xac dinh duge ti le xi mang/nudc (X/N) la 1,42.
3.1.3. Xdc dinh lirgng xi mdng
Tir lugng nude N - 200 lit va ty le X/N la 1,42 xac dinh dugc lugng xi mang su dung cho Im^ be tdng la 292 kg; gia tri nay dam bao TAP CHi KHOA HOC VA C 6 N G NGHE LAM NGHIEP SO 2 - 2019 137
Cong nghiep rdng
nam trong khoang quy dinh ve lugng xi mang tdi thigu va tdi da theo tigu chuan Viet Nam.
3.1.4. Xdc dinh lirang cdt lieu Idn vd cdt ligu nhd
* Xac dinh lugng cdt lieu Idn (da dam - D) Lugng da dam cho lm"* be tdng dugc xac djnh theo cdng thirc (Pham Duy Hiiu va cdng sir, 2011):
1000
D = k.-rn-;kg
ToD YaD T r o n g d o :
YoD, YaD v a r o - k h d i l u g n g t h g t i c h , k h d i l u g n g rigng v a d o r d n g c u a d a d a m ;
kd - h e sd d u viia.
Tir k e t q u a thi n g h i e m c d : YOD ^ l , 4 8 g / c m ^ , YaD = 2 , 8 g / c m ^ v a r o = 0 , 4 7 ;
V d i l u g n g x i m a n g l a 2 9 2 k g , t r a b a n g c d h e sd du v u a k d ^ 1,36.
Thay cac thdng sd vao cdng thiic tinh toan, xac dinh dugc lugng da dam: D = 1197 kg.
* Xac dinh lugng cot lieu nhd (eat - C) Sau khi xac dinh dugc lugng nude nhao trdn
1000-
-N •Yacikg (N), lugng xi mang (X) va lugng da dam (D), viec cac dinh lugng cat (C) dugc thuc hien theo cdng thiic sau (Pham Duy Hihi va cdng su, 2011):^ YaX 1'aD
Trong dd: yax, 7aD va yac - khdi lugng rieng eua xi mang, da dam va cat; theo sd lieu tir nha san xuat va ket qua thi nghiem cd dugc: yax = 3,05 g/em\ Yao ^ 2,8 g/cm^ Yac ^ 2,75 g/cm^
Thay cac thdng sd vao cdng thuc tinh toan, xac dinh dugc lugng eat: C = 747 kg.
3.1.5. Xdc dinh lirffng rffm thay the mgt phdn cdt lieu Idn
Tir kit qua tinh toan thanh phan bg tdng ngn, thir dan bang each trdn hdn hgp, quan sat bang mat va do do sut; cudi cimg xac dinh dugc lugng cdt lieu Idn nit bdt la 40% (so vdi khoi lugng cdt lieu Idn ban dau) va thay vao dd bang 10% ham lugng ram (ti le phan tram giiia khdi lugng khd cua rom va xi mang). Cu thg vg kgt qua tinh toan va lira chgn thanh phan vat lieu ban dau che tao bg tdng ram dugc thg hien d bang 2.
Bang 2. Thanh phan vat li|u ban dau D ( k g )
718
C ( k g ) 761
X ( k g )
292
N ( U t )
200
R ( k g ) 29,2
3.2. Xac dinh ham lugng r a m hffp ly bang thuc nghiem
Dung ket qua cac thanh phan vat lieu d bang 2 va thay ddi ham lugng ram trong cac khoang hrang irng 10%; 12%; 14%; 16% va 18% dg che tao cac mau thi nghiem. Khao sat anh
Bang 3. Thanh phan vat lieu che tao cac nhom mau
hudng cua ham lugng rom den khdi lugng the tich va cudng do chiu nen, tir do xac dinh ham lugng rom hgp ly tir thuc nghiem. Cu the vg thanh phan vat lieu ehe tao eac nhdm mau duge ghi d bang 3.
Nbom mau Mio%
M,2./.
M , « M,s-/.
M,,,,.
Rfltg) 29,20 32,58 36,50 40,15 43,80
D(kg) 718 718 718 718 718
C(lcg) 747 747 747 747 747
X(ltg) 292 292 292 292 292
N (lit) 200 200 200 200 200
138 TAP C H i KHOA H O C VA C 6 N G NGHE L A M N G H I E P SO 2 - 2019
Cong nghiep rimg T6ng hap ket qua cirong do chiu nen tu6i 28 ngay o trang thai kho tit nhien va ngam bao ngay a trang thai kho ty nhien va ngam bao hoa (yo va yobh) ciia cac m l u be tong thu diroc hoa (RbVa Rbbh) va kh6i luong thg tich tu6i 28 tu thi nghiem dugc the hien a bang 4.
Bang 4. Tinh nang ctf biin cija cac nhom mau
R(kg) RJMPa) Ri„,(MPa) Yo(g/cm') robb(g/cm') M,„./.
M,2./.
M„./.
M|6./, M , j . / .
29,20 32,58 36,50 40,15 43,80
6,32 5,65 4,78 4,07 3,44
,85 ,83 ,80 ,76 ,72
2,14 2,11 2,05 1,97 1,85
Tir bang 4 cho thay: Cac tinh nang cua bg tdng deu bien ddi khi ham lugng ram thay ddi.
Quan he giGa ham lugng rom vdi khdi lugng
the tich va cudng do chiu nen ciia be tdng duge the hien qua do thi d eac hinh 2 va hinh 3.
~ -—
r
—
- - . • -
—
y = -0.03S3i+2.5207
~—.^^___^ ^ R' = 0.9385
<
v = -0.0172i+2.0324 • , R' = 0.9826
• 28 Dgay-fcho tu nhien
• 2SDgay-baah6a
— — Linear (28 ngay - kh6 ty nhien) Linear (28 ngay - bSo hoa)
1
Ham lirong rom, %
Hinh 2. Quan he ham tuvng rom va khoi luong the tich
Uiim lirtfng rcnn, "/o
Hinh 3. Quan he ham lirong rom va cutrng do chiu nen
TAP CHI KHOA H O C VA CONG N G H E L A M N G H I E P SO 2 - 2019 139
i i i
Cdng nghiep rimg
Tir kgt qua thi nghiem va dd thj hinh 2 va hinh 3 cho thiy: Khdi lugng thg tich va cudng do chiu nen eua eac man bg tdng deu giam dan khi ham lugng ram tang vdi tdc do giam tuong ddi dgu. Trong khoang nghign cuu, cudng dg va khdi lugng thg tich Idn nhat tuang iing vdi ham lugng ram la 10% va nhd nhit tuang iing vdi ham lugng ram la 18%; cac gia tri nay dgu dam bao phii hgp vdi quy dinh eua tieu chuan Viet Nam ve be tdng nhe. Qua day, bude dau cd thg nhan dinh: Cung nhu cac loai bg tdng nhe thdng thudng khac, be tdng ram cd thg ling dung vao viec xay dung mgt sd kgt cau cdng trinh cSn giam trgng lugng ban than ma khdng yen cau chiu lire Idn.
Vdi kgt qua thi nghiem cua cae nhom mau cung chi ra rang, ham lugng ram anh hudng ro ret dgn cae tinh nang co ban ciia loai bg tdng tao ra. Trong khoang thi nghiem khao sat, cac chi tieu vg khoi lugng thg tich va cudng do chju nen quy dinh vdi bg tdng nhe deu dugc thda man. Nhu vay, khi thiet ke che tao be tdng dgn ram, can can cii vao ygu cau vg miic do hgp ly vg khdi lugng thg tich va cudng do chiu nen dg chgn ham lugng rom.
4. KET LUAN
Qua cac ket qua nghign ciiu cho thay, cd the su dung ram lam chat ddn che tao be tong; loai bg tong nay cd the diing trong viec xay dung cac hang muc cong trinh can giam trgng lugng ban than ma khdng ygu cau chiu luc Idn.
Viec thigt ke thanh phan bg tong ram cd thg thuc hien bang each: tinh toan thanh phan bg tdng ngn, sau dd dung phuang phap thuc nghiem thu dan dg giam lugng dimg cdt lieu Idn va thay vao do bang ham lugng rom tuong img.
Ham lugng rom anh hudng ro ret den cac tinh nang co ban cua loai bg tdng tao ra. Vdi loai bg tdng ddn ram dugc tao ra tir be tdng ngn B15, eo thg chgn ham lugng rom trong
khoang 10 ^ 18% theo khoi lugng xi mang.
Viec nghien ciiu sii dung rom lam vat lieu xay dung ndi chung va lam ehat ddn cho be tdng ndi rigng la rit cM thigt, khdng chi vi muc dich tigt kiem va tan dung nguyen vat lieu, ma cdn mang y nghia sau sac ve mat moi trudng.
5. TAI LIEU THAM KHAO
! Larisa Brojan, Alja Petric and Peggi L Clouston (2013). A comparative study of bnck and straw bale wall systems from environmental, economical and energy perspectives. ARPN Journal of Engineering and Applied Sciences, 1:920-926.
2. Larisa Brojan, Peggi L. Clouston (2014).
Advantages and disadvantages of straw-bale buiding.
Architecture Research, 1-21-26.
3. MuViammad Usman Farooqi and Majid Ali (2016).
Compressive Behavior of Wheat Straw Reinforced Concrete for Pavement Applications. Fourth Intemational Conference on Sustainable Construction Materials and Technologies, Las Vegas, USA, August 7-11.
4. Jim Liu, Honghong Zhou va Bing Zhang (2012).
Effect of Rice Straw Amount Portion on Physical Properties of Adding Admixtures Hollow Block.
Advanced Materials Research: Ill-Til.
5. Andrew Alcorn va Michael Doim (2010). Life Cycle Potential of Strawbale and Timber for Carbon Sequestration in House Construction. Coventry University and the University of Wisconsin Milwaukee Centre for By-products Utihzation, Second Intemational Conference on Sustamable Construction Materials and Technologies, June 28 — June 30.
6 Behzad Sodagar, Deepak Rai, Barbara Jones, Jakub Wihan va Dr Rosi Fieldson (2011). The carbon reduction potential of strawbale housing. Building Research & Information 39 (1): 111-1Z2.
7. Tieu chujn Vi?t Nam TCVN 2682: 2009 - Xi mang Pooc lang - Yeu cau ky thuat. Ha Noi, 2009.
8. Tieu chudn Vi?t Nam TCVN 7570: 2006 - C6t lieu cho be tong va vira - Yeu cau ky thuat. Ha Noi, 2006.
9. TCVN 7572 1 -18 2006 - Cac thi nghiem c6t heu, Ha Noi, 2006.
10. TCVN 3106: 1993 - Hon hgp be tong nang - Phuong phap xac dinh do sut. Ha Noi, 1993.
11. TCVN 3118: 1993 - Be tong nang - Phuong phap xac dinh cucmg dp nen. Ha Npi, 1993.
12. TCVN 3115 1993 Be tong niing - Phuong phap xac dinh khdi litcmg the tich. Ha Noi, 1993.
13. Pham Duy Huu cung cac tac gia (2011). Vat lieu xay dyng. Nha xuat ban Giao thong Van tai. Ha Noi.
140 TAP CHI KHOA HOC VA CONG NGHE LAM NGHIEP SO 2 - 2019
Cdng nghiep rung
STRAW FILLER CONCRETE - SUSTAINABLE METHOD FOR AGRICULTURAL WASTE MANAGEMENT
Dang Van Thanh, Le Tan Quynh, Nguyen Thi Van Hoa
Vietnam National University of Forestry
S U M M A R Y
In the areas of agriculture - rural in Vietnam, solving the problem of straw treatment after each season so that the smallest impact on the environment is an especially important task; reducing environmental impact is becoming an important requirement in human activities. This paper proposes and shows the designing method of the concrete component using straw fillers. Based on the criteria of lightweight concrete, through the testing of basic features, the result shows that the concrete using straw fillers in reasonably proportion will satisfy the basic properties of lightweight concrete. With straw filler concrete made from concrete B15 and the straw content of about 10 ^ 18% by weight of cement, the mixUire ensures compliance with the provisions of Viemam standards of lightweight concrete. The use of this concrete will not only reduce matenal cost but also contribute to reducing environmental impacts from the agricultural by-product.
Keywords: Agricultural by-product, compresive strength, light weight concrete, straw filler concrete, volumetric mass.
Ngay nhan b^i Ngay phan bien Ngay quyet djnh dang
04/3/2019 29/3/2019 05/4/2019
TAP CHI KHOA HOC VA C 6 N G NGHE LAM NGHIEP SO 2 - 2019 HI
