Bio-aggregates Based Building Materials: State-of-the-Art Report of the RILEM Technical Committee 236-BBM (RILEM State-of-the-Art Reports, 23)

The work of the RILEM Technical Committee (TC -236 BBM) was dedicated to the study of construction materials made from plant particles. It considered the question whether building materials containing as main raw material recyclable and easily available plant particles are renewable. This book includes a state-of-the-art report and an appendix. The state-of-the-art report relates to the description of vegetal aggregates. Then, hygrothermal properties, fire resistance, durability and finally the impact of the variability of the method of production of bio-based concrete are assessed. The appendix is a TC report which presents the experience of a working group. The goal was to define testing methods for the measurement of water absorption, bulk density, particle size distribution, and thermal conductivity of bio aggregates. The work is based on a first round robin test of the TC-BBM where the protocols in use by the different laboratories (labs) are compared. p> Preface 6 Contents 9 TC 236-BBM Members 10 RILEM Publications 12 Contributors 21 List of Figures 22 List of Tables 29 1 Chemical Composition of Bio-aggregates and Their Interactions with Mineral Binders 30 Abstract 30 1.1 Introduction 30 1.2 Composition of Hemp Stem 31 1.3 Processing of Hemp Stem and Microstructure of Hemp Shiv 32 1.4 Cell Wall Components 33 1.4.1 Cellulose 34 1.4.2 Hemicellulose 34 1.4.3 Lignin 35 1.4.4 Pectin 36 1.4.5 Extractives 36 1.4.6 Ash 36 1.4.7 Water 37 1.5 Chemical Composition of Bio-aggregates 37 1.5.1 Chemical Composition of Bio-aggregates Measured by Indirect Methods 37 1.5.2 Other Methods to Characterize Biomass Chemical Composition 44 1.6 Surface Characterization of Bio-aggregates—Adhesion Between Lignocellulosic Aggregates and a Mineral Binder 48 1.7 Chemical Interactions Between Bio-aggregates and Mineral Binders 50 1.7.1 Short-Term Interactions Between Lignocellulosic Particles and Mineral Binders 50 1.7.2 Medium and Long-Term Chemical Interactions Between Plant Particles and Mineral Binder 56 1.7.3 Corrective Treatments to Enhance the Compatibility Between Lignocellulosic Materials and Mineral Binders 57 1.8 Conclusion 60 References 61 2 Porosity, Pore Size Distribution, Micro-structure 67 Abstract 67 2.1 Introduction 68 2.2 Techniques Used to Measure Porosity 69 2.2.1 Imaging Methods 69 2.2.1.1 Optical Microscopy 70 2.2.1.2 Scanning Electron Microscopy 73 2.2.1.3 X-Ray Computed Tomography 77 2.2.1.4 Nuclear Magnetic Resonance 80 2.2.2 Other Methods 82 2.2.2.1 Mercury Intrusion Porosimetry 82 2.2.2.2 Thermoporometry 83 2.2.2.3 Physisorption 84 2.2.2.4 Nitrogen Adsorption and BET Analysis 87 2.2.2.5 Dynamic Vapour Sorption 90 2.2.2.6 Pycnometry and Envelope Density Analysis 92 2.3 Conclusion 95 References 96 3 Water Absorption of Plant Aggregate 100 Abstract 100 3.1 Introduction 100 3.2 Wetting of Porous, Heterogeneous Surfaces 101 3.2.1 Surface Tension and Interface Tension 101 3.2.1.1 Contact Angle and Wettability 102 3.3 Transfer Phenomena in a Porous Medium 103 3.3.1 Liquid Transfer in the Laminar Regime 103 3.3.1.1 Capillary Transfer 103 3.3.1.2 Filtration Transfer in a Saturated Porous Medium 104 3.3.2 Transfer of Water Vapour, Particles or Ions by Diffusion 105 3.3.2.1 Fick’s Law 105 3.3.2.2 Einsteinian Laws 106 3.4 Analogy with Adhesion of Mortars to a Porous Support 106 3.4.1 Capillary Absorbency of a Porous Support 106 3.4.2 Transport of Particles During Filtration 108 3.5 Overview of the Processes of Binder/Wood Adhesion 108 3.5.1 Hygroscopic Behaviour When Immersed 109 3.5.2 Water Absorption/Adsorption by Immersion 109 3.5.3 Behaviour in Terms of Water Adsorption/Absorption 111 3.6 Conclusion 116 References 116 4 Particle Size Distribution 118 Abstract 118 4.1 Introduction 118 4.2 General Characteristics of Shiv Particles 119 4.2.1 Fibre Contents 120 4.2.2 Dust Content 121 4.2.3 Methods to Measure PSD 121 4.3 Sieving Methods 122 4.4 Image-Processing Methods 123 4.5 Image-Analysis 125 4.5.1 Size Estimation 126 4.5.2 Distributions 128 4.5.2.1 Frequency Distribution 128 4.5.2.2 Area Fraction Distribution (Projected Area) 128 4.5.2.3 Mass Fraction Distribution 129 4.5.2.4 Average Flatness Estimation 131 4.5.3 Comparison with the Results Obtained by Sieving 131 4.6 Characterization of the PSD 132 4.6.1 Means and Standard Deviations 132 4.6.2 Distribution Models 133 4.6.2.1 Log-Normal Distribution 133 4.6.2.2 Rosin-Rammler Distribution 133 4.6.3 Fitting of the Distribution Laws 134 4.7 Conclusions 135 References 136 5 Bulk Density and Compressibility 138 Abstract 138 5.1 Introduction 138 5.2 Density and Porosity, Case of Hemp Shiv 139 5.3 Bulk Compressibility 140 5.3.1 Low Stress Compression in a Die 140 5.3.2 High Stress Compression in a Die 141 5.3.2.1 Measurements, Boundary Conditions and Stress 142 5.3.2.2 Compressibility 145 5.3.2.3 Effect of the Moisture Content 146 5.3.3 Unconfined Compression 147 5.4 Conclusions and Perspectives 149 References 149 6 Hygric and Thermal Properties of Bio-aggregate Based Building Materials 152 Abstract 152 6.1 Introduction 152 6.2 Hygric Properties 153 6.2.1 Moisture Storage: Sorption Isotherm 153 6.2.2 Moisture Transfer: Water Vapor Permeability, Capillarity, Moisture Diffusivity 155 6.2.3 Moisture Buffering: Moisture Buffer Value 159 6.3 Thermal Properties 161 6.3.1 Thermal Conductivity 161 6.3.1.1 Thermal Conductivity of Bio-aggregate Based Building Materials 161 6.3.1.2 Effect of Formulation and Manufacturing Method on Thermal Conductivity of Bio-Aggregate Based Building Materials 163 6.3.1.3 Effect of Water Content on Thermal Properties of Bio-aggregate Based Building Materials 166 6.3.2 Heat Capacity and Thermal Diffusivity 167 6.3.2.1 Heat Capacity and Thermal Diffusivity of Bio-aggregate Based Building Materials 168 6.3.2.2 Effect of Formulation and Manufacturing Method on Heat Capacity and Thermal Diffusivity of Bio-Aggregate Based Building Materials 168 6.3.2.3 Effect of Water Content on Heat Capacity and Thermal Diffusivity of Bio-Aggregate Based Building Materials 169 6.4 Concluding Remarks on Hygrothermal Behavior of Bio-aggregate Based Building Materials 170 References 171 7 Bio-aggregate Based Building Materials Exposed to Fire 175 Abstract 175 7.1 Introduction 175 7.2 Fire Reaction 177 7.2.1 European Class of Fire Reaction 177 7.2.2 Tests Methods 178 7.2.2.1 Non Combustibility Furnace [Test According to (ISO 1182 2010)] and Calorimeter [Test According to (ISO 1716 2010)] 178 7.2.2.2 Single Burning Item, Fire Technical Testing of Building Products [Test Method (EN 13823 2013)] 178 7.2.2.3 Cone Calorimeter [Test According to (ISO 5660 2015)] 179 7.2.2.4 Reaction to Fire Tests for Floorings (ISO 9239 2010) 179 7.2.2.5 Reaction to Fire Tests (ISO 11925-2 2010) 180 7.2.3 Euroclass of Bio-agreggate Based Building Materials and Products 180 7.3 Fire Resistance 182 7.3.1 Fire Resistance Classes 182 7.3.2 Examples of Fire Tests Performed on Bio-aggregate Based Products 183 7.3.2.1 Straw Wall with Renders: Ecological Building Network (USA) (Intertek 2007a) 183 7.3.2.2 Straw Wall with Timber Frame Structure: “Maison de Montholier”(France) (CEBTP 2004) 185 7.3.2.3 Straw Ball Wall: Performed by Pavus (Czech) (Pavus 2011) 186 7.3.2.4 Facade Element Made with Wood and Straw (France) (CSTB 2009) 187 7.3.2.5 Wall Made with Hemp Concrete Blocks: BCB (France) (CSTB 2005) 188 7.3.3 Fire Resistance of Bio-aggregate Based Products 189 7.4 Real Scale Fire Tests 190 7.5 Other Quaint Matter Fire Test 190 References 190 8 Durability of Bio-based Concretes 192 Abstract 192 8.1 Introduction 192 8.2 Accelerated Aging Protocols for Bio-based Construction Materials 195 8.2.1 Environmental Aging 195 8.2.2 Biological Aging 195 8.2.2.1 Description of the Microorganisms 195 8.2.2.2 Mechanisms of Biodegradation 196 8.2.2.3 Methods for Determination of Fungal Resistance of Construction Products 196 8.2.2.4 Proposal of a Fungal Resistance Test Development Tailored to Bio-based Insulation Materials 197 8.3 Aging of Bio-based Concretes 197 8.3.1 Natural Aging of Bio-based Concretes 197 8.3.2 Influence of Environmental Aging on the Mechanical Properties 199 8.3.2.1 Static Conditions 199 8.3.2.2 Dynamic Conditions 200 Wetting and Drying Cycles 201 Full Immersion in Water and Drying Cycles 201 Climatic Simulations 203 Accelerated Carbonation Test 204 Other Aging Tests 206 8.3.3 Microbial Aging 206 8.3.4 Conclusion 207 8.4 Aging of Natural Fibres-Cement Composites 208 8.4.1 Mineralisation of the Vegetal Fibres 209 8.4.2 Degradation Mechanisms of Vegetal Fibres 209 8.5 Concluding Remarks 210 References 210 9 Effect of Testing Variables (Method of Production) 213 Abstract 213 9.1 Introduction 214 9.2 Materials and Methods 216 9.2.1 Manufacture (Mixing, Curing and Compaction) 216 9.2.2 Compressive Strength 217 9.2.3 Microstructure 218 9.3 Results 218 9.3.1 Compressive Strength and Microstructure 218 9.3.2 Effect of Oven Drying on Compressive Strength 220 9.3.3 Effect of Curing at High RH on Strength 221 9.3.4 Effect of Retention in Moulds During Curing 222 9.3.5 Effect of Specimen Geometry on Strength 222 9.4 Conclusion 223 Acknowledgements 224 References 224 Appendix: Technical Committee Report—Rilem TC 236 BBM—Bio based Building Materials—Round Robin test for hemp shiv CHARACTERISATION 226 ROUND ROBIN TEST FOR HEMP SHIV CHARACTERISATION: PART 1: EVALUATION OF INITIAL WATER CONTENT AND WATER ABSORPTION 229 ROUND ROBIN TEST FOR HEMP SHIV CHARACTERISATION: PART II: BULK DENSITY AND PARTICLE SIZE DISTRIBUTION 246 ROUND ROBIN TEST FOR HEMP SHIV CHARACTERISATION: PART 3: THERMAL CONDUCTIVITY 269 Front Matter....Pages i-xxxiii Chemical Composition of Bio-aggregates and Their Interactions with Mineral Binders....Pages 1-37 Porosity, Pore Size Distribution, Micro-structure....Pages 39-71 Water Absorption of Plant Aggregate....Pages 73-90 Particle Size Distribution....Pages 91-110 Bulk Density and Compressibility....Pages 111-124 Hygric and Thermal Properties of Bio-aggregate Based Building Materials....Pages 125-147 Bio-aggregate Based Building Materials Exposed to Fire....Pages 149-165 Durability of Bio-based Concretes....Pages 167-187 Effect of Testing Variables (Method of Production)....Pages 189-201 Back Matter....Pages 203-263