Kỷ yếu hội nghị Khoa học Môi trường và Công nghệ sinh học năm 2011
130

STUDY ON UTILIZING OF INDUSTRIAL – AGRICULTURAL WASTE IN
THE BUILDING CONSTRUCTION INDUSTRY

Vu Hai Yen
Department of Environment and Biotechnology, Ho Chi Minh City University of Technology

TÓM TẮT
Việt Nam có những lợi thế về sản xuất nông nghiệp. Hằng năm lƣợng phế thải dƣ
thừa trong quá trình chế biến các sản phẩm nông sản, thực phẩm rất lớn. Với việc sản
xuất đƣợc hơn 38,5 triệu tấn lúa trong năm 2009, chỉ riêng rơm, rạ, vỏ trấu thải ra trong
quá trình thu hoạch, xay xát thành hạt gạo đã có khối lƣợng cả chục triệu tấn. Tuy
nhiên, so với tiềm năng dồi dào của nguồn phụ, phế thải trong nông nghiệp hiện nay thì
những công trình nghiên cứu, ứng dụng còn rất khiêm tốn. Lƣợng vỏ trấu, rơm rạ, xơ
dừa, mùn cƣa thải đƣợc tận dụng không nhiều, phần xả thải ra các kênh rạch, sông ngòi
chiếm tỷ lệ khá cao. Bên cạnh đó, một ngành công nghiệp cũng rất đáng lƣu ý về chất
thải đó là ngành công nghiệp giấy. Công nghệ sản xuất giấy là một công nghệ tiêu thụ
nhiều nƣớc. Tùy thuộc vào công nghệ và sản phẩm, lƣợng nƣớc cần thiết để sản xuất
một tấn giấy dao động khoảng 200-500 m
3
. Nƣớc sử dụng trong quá trình rửa nguyên
liệu, nấu ăn, làm sạch, xeo giấy và sản xuất hơi nƣớc. Trong bùn thải rất khó xử lý bởi
thành phần đa dạng và phức tạp, hầu hết chứa cellulose và lignin, thành phần rất bền
vững và khó bị phân hủy. Vì vậy, để tận dụng bùn làm vật liệu xây dựng cũng là một sự
quan tâm nghiên cứu đáng kể.
Nghiên cứu này sử dụng từ các vật liệu là phế phẩm công – nông nghiệp nhƣ vỏ
trấu, xơ dừa và bùn từ hệ thống xử lý nƣớc thải nhà máy giấy để trộn với xi măng, cát
và nƣớc (tỷ lệ pha trộn 1 phần xi măng: 3 cát phần: ½ phần nƣớc) để sản xuất vữa. Mẫu
đƣợc pha trộn vào hỗn hợp tỷ lệ các thành phần khác nhau để thay thế chức năng của

Currently, there are many directions for recycling of industrial wastes - is agriculture, such
as combustion boiler, as fertilizer In particular, this waste for recycling as construction materials
is also a considerable flow direction mind. This experiment was conducted with three subjects: rice
hulls, coconut fiber and sludge from wastewater treatment systems for the paper industry of
building materials. The aim of the project not only aims to make use of waste products - agriculture,
but also save natural resources, sustainable development

RESEARCH OBJECTIVE AND CONTENT
Research objective
This study aims to be making sample from mixing mortar to build models of agricultural
waste products including rice husk, coconut fiber and sludge from wastewater treatment system of
the paper mill with cement, sand and water.
Research
The experiment included the following:
- Handling pre - determine the composition, physical and chemical properties of waste
samples.
- Determine the composition and properties of mixed materials: cement, sand and water
- Mixing cement, sand, water and paper sludge under different treatments with mortar model
for certification includes cement, sand and water.
- Determining the physical properties of cement mortar mixed paper sludge: density, water
permeability, compressive strength, bending strength with the traditional cement mortar.

RESEARCH METHODS
Determining the composition and preliminary treatment of waste product
Before performing experiments, have been identified: The origin arise, the primary features of
the sample or faulty products (size, color, smell, humidity, )
Rice husk taken from Duc Hoa District of Long An Province. After removing the husks in the
dry state, foam, lightweight, and many impurities such as straw, hotel, land, gravel Coconut from
Hoc Mon District, Ho Chi Minh City. Sludge from the sedimentation tanks of the Binh An paper
factory.

Experiment type
Criteria
Sieves experiment
TCXDVN311-2004
Determine the physical and chemical properties
Calcium absorption
TCXDVN311-2004
TCVN 3735-1982
Water properties determination
Mixed water is domestic water. Mixed water is determined some parameters: pH, TDS, TSS,
Cl
-
, SO
3
2-
, CO
3
2-
.

Cement properties determination
Cement use is multi-standard cement of Holcim Vietnam company. This cement meets the
demand of TCXDVN311-2004 standard.
Sand properties determination
ISO Sand must comply with the provisions of gradation and moisture content. The
materialsand mix available for each plastic bag with 1350g  5g weight used for packaging not
affect the strength test results. The experiment uses standard sand was distributed by Ha Tien 1
Cement Company.
450
1350
225
0
G-5
427,5
1350
225
22,5
G-10
405
1350
225
45
G-15
382,5
1350
225
67,5
G-20
360
1350
225
90
DC is the form for certification: samples only cement, sand and water, no waste.
Form 4 G-5, G-10, G-15, G-20 left: using waste instead turn 5, 10, 15, 20% cement.
For sample 0 (traditional ratio): The rate of water / cement = 0.5

Figure 4. Mortar mixers and molds of size 40 x 40 x 160 mm.
Mixing

In that:

a
(g/cm
3
, T/m
3
) is the mass of a unit volume material assumption
materials in special status fully. The volume of the material is 40 x 40 x 160 mm =
256 000 mm
3
= 256 cm
3
.
G: material weight (g)
m
1
: the volume of material and in the same volume of water (g)
m
2
: water volume in the same volume (g)
Water absorption determination (TCVN 3113, 1997, BS 1881, Part 112: 1983, BSI, 1983a)
Samples were dried in drying 24 hours, should determine the amount of C (kg). Then,
samples were soaked in water during 24 hour. Sampling from the water, weight loss E (kg).
Water absorption (%) =
100
EC

135

Try half the strength of the prisms on the face side of mold exposure
Place side of half prism into the middle of the plates with mismatch than ± 0.5 mm, and placed
horizontally so that the end face of the prism protruding outside the plates, or cheek pressed about
10mm.
Slowly with increasing load speed 2400 ± 200 N / s during the sample until destroyed. Using
this formula:
Fn : is the maximum load at sample destroyed, calculated as (N)
A: section under compression, calculated by (mm
2
: 40 x 40 = a 600mm
2
)

RESEARCH RESULT AND DISCUSSION
Material reviews
Cement material particles are mixed wastes less material finer than grains of pure cement.
Paper mill sludge samples are less smooth.
(a) (b)


382
377
375
Paper mill
sludge
390
370
350
321
309
Rice husk samples have very high calcium absorption and can be completely used as additives
for mortar, helps increase the durability and waterproof.

Parameter
Unit
Sample
Rice husk
Coconut coir
Paper mill sludge
Moisture
*
%
7,8
15,1
8,8
Calcium absorption
Mg
156,24
99,17
82,83

sludge
5,12
8,31
11,56
14,34
18,78
Water uptake by the higher ash husk coir husk ash is very fine particles and light so the
surface area of water absorbed by a large husk ash. Coconut ingredients and nuts and it also weighs
more than rice husk ash, small surface area of water absorption so that the decrease.
Physical properties of mixed material (TCVN 6290-1997)

Figure 6. Sample G-10 and G-20 of rice husk after 28 days.

Figure 7. Sample G-10 and G-20 of coconut coir after 28 days.
Compressive strength
After 28 days, increased compression ratio decreases when mixed waste increased. It is because
water in the material increases, leading to reduced gravity.
Splitting tensile strength
Similar to compression, bending of the material decreases when increasing the percentage of mixed
waste. It was found that when mixing a high percentage of waste increases the absorption of water
reduces the adhesive properties, decreased strength.
Sample
Symbol
Splitting tensile strength
(kG/cm
2
)
Compressive strength
(kG/cm
2

G-5
6,21
31,24
24,36
G-10
5,87
25,27
37,77
G-15
5,11
22,15
46,37
G-20
4,22
16,91
59,05
Kỷ yếu hội nghị Khoa học Môi trường và Công nghệ sinh học năm 2011
137

-
The
ratio
of
waste
ceme
nt clinker phases to increase the proportion and magnitude decreases. Mixing mortar samples from
the husks down 4.36 to 40.41%, coconut fiber mortar samples decreased from 24.36 to 59.05%,
paper sludge mortar samples decreased from 14.21 to 41.43%. Because of the mixed waste into
cement, it will react with hydrated lime from the lime and the water free of the mineral calcium
silicate minerals are calculated to create sticky, slightly soluble or insoluble. Content of rice husk /


REFERENCES
B. Ahmadi, W. Al-Khaja Utilization of paper waste sludge in the building construction industry,
Department of Civil and Architectural Engineering, University of Bahrain, P.O. Box 32038,
Bahrain, 2000.
Hoang Thi Hanh, Experiment of Building material, Ho Chi Minh City University, 2008.
Nguyen Xuan Hoang, Nguyen Bao Van, Tran Thanh Tuan, Pham Cam Nam, Study to use
diatomite making additives in building material, Da Nang University, 2008.
Vu Hai Yen, Study using agricultural waste to produce building material, Ho Chi Minh City
University of Technology, 2010.
Paper
mill
sludge
DC
6,85
41,30
0
G-5
6,71
35,43
14,21
G-10
6,12
31,22
23,68
G-15
5,94
29,35
28,93
G-20