The use of renewable agricultural by-Products as building materials

Abstract

The basic unit for straw bale constructions is the straw bale, so bales preparation in the field is very important for this purpose. Therefore, it must be produced with a good properties and tested for building purposes. Straw bale buildings are capable of successfully surviving humid climates, but less is known about the interaction of humid air and bales than probably any other aspect of bale building. Hopefully future research will help provide greater clarity in understanding how humidity affects bales in different climates and conditions (Steen et al., 1994). Agricultural waste utilization depends on the presence of information about the physical, mechanical and thermal properties of these materials. This knowledge helps the designer
and decision makers to asses the best ways to get benefits from those wastes also to avoid the hazards resulting from burning it or leaving it to deteriorate in the field.
In the last few years, Egypt has had a difficult problem with air pollution because most of the farmers burn rice straw illegally after harvesting. This, is because of the huge production of this straw (about 3 million tons / year) which is considered a big problem for the farmer when he stores it near to his house or in his field. The straw is a suitable medium for the growth of insects and pests. Moreover, during the summer this straw could
burn by itself. Each ton of rice straw produces 56 kg CO when burned (Steen et al., 1994). The farmers need to get rid of it and consequently, they start to burn it, causing also the black cloud and severe pollution in the atmosphere, especially in delta regions. Health problems are caused by the smoke. As a partial contribution to solve all of these problems, this study aimed to investigate the role of using straw bales in building construction in Egypt to insure comfort, safety, low costs and low energy consumption and more important to reduce air pollution. Due to the lack of information about the straw bale properties (physical, mechanical and thermal), it was necessary to study these properties and the thermal behavior of such buildings.
Objectives
The specific objectives of this work are as follows:-
(1) Studying physical properties of the straw and bales, which include, bale dimensions, density, straw particles lengths, moisture content and equilibrium moisture content.
(2) Studying the mechanical properties of straw bales that include stress, vertical strain, horizontal strain, stress-strain relation, modulus of elasticity and Poisson’s ratio.
(3) Studying the thermal properties of straw bales, which include thermal conductivity, thermal capacity, thermal effusivity, thermal diffusivity and time lag.
(4) Studying the thermal performance and stability of using straw bales as building’s walls.

Full text

The use of renewable
agricultural by-Products as
building materials
Ph. D Thesis
By
Taha Hassan Mokhtar Abd El-Fattah Ashour
Faculty of agriculture, Moshtohor
Zagazig University
Benha Branch
2003
All rights reserved
Contact:
Taha Ashour
Agricultural Engineering Department
Faculty of Agriculture, Benha University
Moshtohor, Toukh, Kaliobia, Egypt.
Email: thashour@yahoo.com
Telephone Nr.
Work: 002-013-2467034
Mobile: 002-012-7406101
This thesis was made available as a PDF-file by the german straw bale
association FASBA in June 2006. It should match exactly with the
original edition, but there is no guarantee for it, though we tried to put
all elements, such as tables and figures in the same way together as
Taha Ashour did it 2003 for the original edition.
Fachverband Strohballenbau Deutschland e.V. (http://www.fasba.de)
Contact: Dirk Scharmer, Tel. 0049 4131 727804, Email: ds@fasba.de

TABLE OF CONTENTS
LIST OF TABLES ...........................................................................vii
LIST OF FIGURES ..........................................................................xi
1. INTRODUCTION..........................................................................1
1.1 Back ground.........................................................................................................1
1.2 Problems analysis................................................................................................ 3
1.3 Objectives............................................................................................................. 5
2. REVIEW OF LITERATURE....................................................... 7
2.1 History of Straw-Bale Constructions................................................................... 7
2.2 Benefits of Straw-Bale Construction.................................................................... 8
2.2.1 Beauty and Comfort.......................................................................................... 9
2.2.2 Ease of Construction....................................................................................... 10
2.2.3 Energy Efficiency............................................................................................ 10
2.2.4 Environmental Benefits................................................................................... 12
2.2.5 Sustainability................................................................................................... 13
2.2.6 Fire Safety....................................................................................................... 14
2.2.7 Termites and Pests, Allergies and Odors........................................................ 18
2.3 Straw Properties ................................................................................................ 20
2.3.1 Physical Properties......................................................................................... 20
2.3.1.1 Bale Dimensions ..........................................................................................21
2.3.1.2 Bale Density................................................................................................. 21
2.3.1.3 Moisture Content.......................................................................................... 22
2.3.1.4 Equilibrium Moisture Content ..................................................................... 31
2.3.2 Mechanical Properties.................................................................................... 41

2.3.2.1 Stress............................................................................................................ 42
2.3.2.2 Strain............................................................................................................ 42
2.3.2.3 Stress-Strain Relation................................................................................... 43
2.3.2.4 Modulus of Elasticity.................................................................................... 44
2.3.2.5 Poisson’s Ratio ............................................................................................47
2.3.3 Thermal Properties......................................................................................... 50
2.3.3.1 Thermal Conductivity................................................................................... 50
2.3.3.2 Heat Capacity .............................................................................................. 55
2.3.3.3 Thermal Diffusivity ...................................................................................... 55
2.3.3.4 Thermal Effusivity........................................................................................ 56
2.3.3.5 Time Lag...................................................................................................... 57
2.3.4 Chemical and Other Properties...................................................................... 57
2.4 Systems of Straw Bale Construction................................................................... 59
2.4.1 Load-Bearing Bale Walls................................................................................ 59
2.4.1.1 Definitions.................................................................................................... 59
2.4.1.2 Straw Bale Specifications............................................................................. 60
2.4.1.3 Construction and General Requirements..................................................... 61
2.4.1.4 Privacy/Landscape Walls............................................................................. 72
2.4.2 In-Fill Wall System.......................................................................................... 75
2.4.2.1 Definitions.................................................................................................... 75
2.4.2.2 Straw Bale Specifications............................................................................. 76
2.4.2.3 Wall Construction........................................................................................ 76
2.5 Factors Affect the Thermal Performance of the Buildings................................. 81
2.5.1 Climatic Factors ............................................................................................. 82
2.5.1.1 Air Temperature........................................................................................... 82
2.5.1.2 Humidity....................................................................................................... 83
2.5.1.3 Wind Speed................................................................................................... 83
2.5.2 Construction Factors...................................................................................... 86
2.5.2.1 Building Materials .......................................................................................87
2.5.2.2 Building Orientation.................................................................................... 94
2.5.2.3 Glazing and Shading Devices ...................................................................... 95
Table of contents ii

2.5.2.4. Ventilation................................................................................................... 96
2.5.3 User Factors ................................................................................................... 97
3. Materials and Methods................................................................ 99
3.1 Materials............................................................................................................ 99
3.1.1 Materials......................................................................................................... 99
3.1.1.1 Wheat and Barley Straws............................................................................. 99
3.1.1.2 Chemical Substances for Equilibrium Moisture Content Test................. 100
3.1.1.3 Climate Chamber Materials....................................................................... 100
3.1.2 Equipment..................................................................................................... 101
3.1.2.1 Balers......................................................................................................... 101
3.1.2.2 Tractor....................................................................................................... 101
3.1.2.3 Oven Dryer................................................................................................. 101
3.1.3 Measuring Devices....................................................................................... 104
3.1.3 Measuring Devices........................................................................................ 105
3.1.3.1 Automatic Particle Image Instrument........................................................ 105
3.1.3.2 Straw Thermal Conductivity Measuring Device ........................................105
3.1.3.3 Stress and Strain Instrument...................................................................... 109
3.1.3.4 Sensors....................................................................................................... 109
3.2 Methods............................................................................................................ 113
3.2.1 Field Work and Laboratory Measurements.................................................. 113
3.2.1.1 Straw Length of Particles........................................................................... 113
3.2.1.2 Bale Dimensions and Weight..................................................................... 114
3.2.1.3 Density ....................................................................................................... 117
3.2.1.4 Thermal Conductivity................................................................................. 117
3.2.1.5 Moisture Content........................................................................................ 122
3.2.1.6 Equilibrium Moisture Content ................................................................... 123
3.2.1.7 Thermal Stability of Bales.......................................................................... 124
3.2.1.8 Heat Capacity ............................................................................................ 124
3.2.1.9 Thermal Diffusivity .................................................................................... 125
3.2.1.10 Thermal Effusivity.................................................................................... 125
Table of contents iii

3.2.1.11 Time lag (
Φ
)............................................................................................. 126
3.2.2 Compression Test.......................................................................................... 127
3.2.2.1 Stress.......................................................................................................... 129
3.2.2.2 Horizontal Strain........................................................................................ 129
3.2.2.3 Vertical Strain............................................................................................ 130
3.2.2.4 Modulus of Elasticity.................................................................................. 130
3.2.2.5 Poisson’s Ratio .......................................................................................... 131
3.2.3 Wall Testing.................................................................................................. 131
3.2.3.1 Temperature and Relative Humidity Distribution Inside the Wall............. 132
4. RESULTS AND DISCUSSION................................................. 139
4.1 Physical Properties.......................................................................................... 139
4.1.1 Bales Dimensions.......................................................................................... 139
4.1.2 Bale Weight................................................................................................... 140
4.1.3 Length of Straw Particles.............................................................................. 143
4.1.4 Bales Density................................................................................................. 143
4.1.5 Moisture Content........................................................................................... 147
4.1.6 Equilibrium Moisture Content...................................................................... 149
4.1.6.1 Wheat Straw............................................................................................... 149
4.1.6.2 Barley Straw............................................................................................... 156
4.1.6.3 Comparison Between Wheat and Barley Straw..........................................160
4.2 Mechanical Properties of Bales....................................................................... 166
4.2.1 Stress............................................................................................................. 166
4.2.1.1 Wheat Straw Bales..................................................................................... 166
4.2.1.2 Barley Straw Bales..................................................................................... 170
4.2.2 Vertical Strain............................................................................................... 178
4.2.2.1 Vertical Strain of Wheat Straw Bales......................................................... 178
4.2.2.2 Vertical Strain for Barley Straw Bales....................................................... 182
4.2.3 Horizontal Strain........................................................................................... 191
4.2.3.1 Horizontal Strain for Wheat Straw Bales................................................... 191
4.2.3.2 Horizontal Strain for Barley Straw Bales.................................................. 195
Table of contents iv

4.2.4 Stress-Strain Relationship............................................................................. 203
4.2.4.1 Stress-Vertical Strain Curve of Wheat Straw Bales................................... 203
4.2.4.2 Stress-Vertical Strain Curve of Barley Straw Bales................................... 203
4.2.5 Modulus of Elasticity .................................................................................... 208
4.2.5.1 Modulus of Elasticity for Wheat Straw Bales............................................. 208
4.2.5.2 Modulus of Elasticity for Barley Straw Bales............................................ 212
4.2.6 Poisson’s Ratio ............................................................................................. 220
4.2.6.1 Poisson’s Ratio for Wheat Straw Bales...................................................... 220
4.2.6.2 Poisson’s Ratio for Barley Straw Bales..................................................... 224
4.3 Thermal Properties.......................................................................................... 232
4.3.1 Thermal Conductivity.................................................................................... 232
4.3.1.1 Thermal Conductivity for Wheat Straw Bales............................................ 232
4.3.1.2 Thermal Conductivity for Barley Straw Bales ........................................... 236
4.4 Thermal Performance Parameters................................................................... 238
4.4.1 Thermal Performance Parameters of Wheat Straw Bales............................. 238
4.4.2 Thermal Performance Parameters of Barley Straw Bales............................ 243
4.5 Thermal Stability of Bales................................................................................ 246
4.5.1 Temperature.................................................................................................. 246
4.5.1.1 Wheat Straw Bales..................................................................................... 246
4.5.1.2 Barley Straw Bales..................................................................................... 247
4.5.2 Relative Humidity.......................................................................................... 253
4.5.2.1Wheat Straw Bales...................................................................................... 253
4.5.2.2 Barley Straw Bales..................................................................................... 256
4.6 Temperature and relative humidity distribution inside the straw wall.............260
4.6.1 Temperatures ................................................................................................260
4.6.1.1 Wheat straw wall........................................................................................ 260
4.6.1.2 Barley Straw Wall...................................................................................... 276
4.6.2 Relative Humidity.......................................................................................... 286
4.6.2.1 Wheat straw wall........................................................................................ 286
4.6.2.2 Barley Straw Wall...................................................................................... 300
Table of contents v

5. SUMMARY AND CONCLUSIONS......................................... 309
Recommendations .................................................................................................. 318
6.References.................................................................................... 321
Table of contents vi

LIST OF TABLES
Table Page
3.1 Chemical substances used for adjusting different relative
humidity values ……………….………………………………100
3.2 Specifications for baler type AP61 and baler type
AP730………………………………………………………………102
4.1 Equilibrium moisture content(%, db) of wheat straw at
different temperatures and relative humidity values. 151
4.2 Equilibrium moisture content (%,db) of barley straw at
different temperatures and relative humidity
values……………………………………………….……158
4.3 Effect of different densities on the stress at vertical and
horizontal oriented Wheat straw bales……………168
4.4 Effect of different densities on the stress at vertical and
horizontal oriented barley straw bales……………… 172
4.5 Stress data of vertical and horizontal orientations for wheat
and barley straw bales…………………………………176
4.6 Effect of different densities on the vertical strain at vertical
and horizontal oriented wheat straw bales……………180
4.7 Effect of different densities on the vertical strain at vertical
and horizontal oriented barley straw bales……………………185
4.8 Vertical strain data of vertical and horizontal orientations for
wheat and barley straw bales………………………………………189
4.9 Effect of different densities on the horizontal strain at vertical
and horizontal oriented wheat straw bales…………………………193

4.10 Effect of different densities on the horizontal strain at vertical
and horizontal oriented barley straw bales…………………………197
4.11 Horizontal strain data of vertical and horizontal orientations
for wheat and barley straw bales……………………………………201
4.12 Effect of different densities on the modulus of elasticity at
vertical and horizontal oriented wheat straw bales……………210
4.13 Effect of different densities on the Modulus of Elasticity at
vertical and horizontal oriented barley straw bales……………214
4.14 Modulus of elasticity of vertical and horizontal orientations for
wheat and barley straw bales……………………………………218
4.15 Effect of different densities on the Poisson’s ratio at vertical and
horizontal oriented wheat straw bales…………………………222
4.16 Effect of different densities on the Poisson’s ratio at
vertical and
horizontal oriented barley straw bales…………………226
4.17 Poisson’s ratio of vertical and horizontal orientations for wheat
and barley straw bales……………………………………………230
4.18 Thermal conductivity, k and thermal resistance, R, of wheat straw
bales at different densities and temperatures…………………234
4.19 Thermal conductivity, k and thermal resistance, R (for bale
thickness 38 cm), of barley straw bales at different densities and
temperatures………………………………………………………240
4.20 Thermal parameters for a wall of 48 cm thick made
from wheat straw
bale…………………………………………………………242
List of tables viii

4.21 Thermal parameters for a wall of 48 cm thick made
from barley straw
bale…………………………………………………………245
4.22 Temperature stability of wheat straw bales with different densities
during the time…………………………………………………………248
4.23 Temperature stability of barley straw bales with different
densities during the time……………………………………………249
4.24 Relative humidity stability of wheat straw bales with different
densities during the time……………………………………………255
4.25 Relative humidity stability of barley straw bales with different
densities during the time……………………………………………258
4.26 Average temperature at different locations and times inside the
wheat straw wall on both horizontal and vertical orientation of bale
density of 80 kg/m3 …………………………………………………262
4.27 Average temperature at different locations and times inside the
wheat straw wall on both horizontal and vertical orientation of bale
density of 100 kg/m3………………………………………………267
4.28 Average temperature at different locations and times inside the
wheat straw wall on both horizontal and vertical orientation of bale
density of 111 kg/m3………………………………………………273
4.29 Average temperature at different locations and times inside the
barley straw wall on both horizontal and vertical orientation of bale
density of 85 kg/m3………………………………………………278
4.30 Average temperature at different locations and times inside the
barley straw wall on both horizontal and vertical orientation of bale
density of 115 kg/m3………………………………………………283
List of tables ix

4.31 Average relative humidity at different locations and times inside
the wheat straw wall on both horizontal and vertical orientation of
bale density of 80 kg/m3…………………………………………288
4.32 Average relative humidity at different locations and times inside
the wheat straw wall on both horizontal and vertical orientation of
bale density of 100 kg/m3……………………………………………293
4.33 Average relative humidity at different locations and times inside
the wheat straw wall on both horizontal and vertical orientation of
bale density of 111 kg/m3……………………………………………297
4.34 Average relative humidity at different locations and times inside
the barley straw wall on both horizontal and vertical orientation of
bale density of 85 kg/m3……………………………………………302
4.35 Average relative humidity at different locations and times inside
the barley straw wall on both horizontal and vertical orientation of
bale density of 115 kg/m3…………………………………………306
List of tables x

LIST OF FIGURES
Figure
3.1 Baler Type
AP61………………………………………………103
3.2 Baler Type AP730………………………………103
3.3 Wood frame for climate chamber test..............104
3.4 Oven dryer ….………………………………..…..106
3.5 Schematic diagram showing an automatic particle
image instrument …………………………………….……107
3.6 Photograph showing the