Testing and Characterisation of Earth-based Building Materials and Elements: State-of-the-Art Report of the RILEM TC 274-TCE (RILEM State-of-the-Art Reports, 35)

RILEM STATE-OF-THE-ART REPORTS Volume 35 RILEM, The International Union of Laboratories and Experts in Construction Materials, Systems and Structures, founded in 1947, is a non-governmental scientific association whose goal is to contribute to progress in the construction sciences, techniques and industries, essentially by means of the communication it fosters between research and practice. RILEM's focus is on construction materials and their use in building and civil engineering structures, covering all phases of the building process from manufacture to use and recycling of materials. More information on RILEM and its previous publications can be found on www.RILEM.net.The RILEM State-of-the-Art Reports (STAR) are produced by the Technical Committees. They represent one of the most important outputs that RILEM generates -high level scientific and engineering reports that provide cutting edge knowledge in a given field. The work of the TCs is one of RILEM's key functions.Members of a TC are experts in their field and give their time freely to share their expertise. As a result, the broader scientific community benefits greatly from RILEM's activities.RILEM's stated objective is to disseminate this information as widely as possible to the scientific community. RILEM therefore considers the STAR reports of its TCs as of highest importance, and encourages their publication whenever possible.The information in this and similar reports is mostly pre-normative in the sense that it provides the underlying scientific fundamentals on which standards and codes of practice are based. Without such a solid scientific basis, construction practice will be less than efficient or economical.It is RILEM's hope that this information will be of wide use to the scientific community. RILEM Technical Committee 274-TCE 6 RILEM Publications 8 Contents 21 Contributors 23 1 General Introduction 26 1.1 The Origin of Earth 26 1.2 Historical Overview 27 1.3 Classification and Definition of Earth Building Processes 30 1.4 Why Building with Earth? 33 1.4.1 Saving Natural Resources 33 1.4.2 Energy 33 1.4.3 Indoor Comfort 34 1.4.4 Social Impact 35 1.5 The Challenge for Modern Earth Building 35 1.6 Conclusion 37 References 37 2 Characterization of Earth Used in Earth Construction Materials 41 2.1 Introduction 42 2.2 Global Analysis of References Used for This Review—Methodology 44 2.3 Particle Size Distribution 48 2.3.1 Procedures and Standards 49 2.4 Physical and Geotechnical Characterization 56 2.4.1 Procedures and Standards 56 2.4.2 Study of Data from Literature 59 2.5 Chemical Characterisation 63 2.5.1 Procedures and Standards 63 2.5.2 Study of Data from Literature 68 2.6 Mineralogical Characterisation 73 2.6.1 Procedures and Standards 73 2.6.2 Study of Data from Literature 75 2.7 Field Tests 79 2.7.1 Procedures and Standards 79 2.7.2 Study of Data from Literature 83 2.8 Conclusion 86 Appendix 1: Particle Size Distribution of Earth Construction Materials 87 Appendix 2: Atterberg Limits of Earth Construction Materials 87 Appendix 3: Optimum Proctor Characteristics of Earth Construction Materials 87 References 98 3 Hygrothermal and Acoustic Assessment of Earthen Materials 106 3.1 Introduction 107 3.2 Key Material Parameters Involved in Hygrothermal Couplings 109 3.2.1 General Diagram of Heat and Mass Transfers 109 3.2.2 Mass Conservation of Water 110 3.2.3 Mass Conservation of Air 112 3.2.4 Heat Balance 112 3.2.5 Boundary Conditions and Interfaces 113 3.2.6 Summary on the Key Parameters used for Hygrothermal Simulations 115 3.3 Laboratory Measurement of Hygrothermal Parameters 116 3.3.1 Measurement of Thermal Properties 116 3.3.2 Transport Properties 121 3.3.3 Water Vapour Sorption Curves 125 3.3.4 Assessment of the Hygroscopic Buffering and Hygrothermal Potential 127 3.4 Assessment of In-Situ Thermal and Hygrothermal Performance 130 3.4.1 Description of the Instrumented Houses 130 3.4.2 Instrumentation Protocol 131 3.4.3 Results Obtained on Earthen Buildings 133 3.5 Acoustic Properties 135 3.5.1 Measurement of Material Acoustical Properties 136 3.5.2 Measurement of Building Elements Acoustic Properties 136 3.6 Conclusion 139 3.6.1 Concluding Remarks 139 3.7 Appendix 3.1: Characteristics of Houses and Experimental Cells Built with Other Materials Than Earth 140 References 145 4 Mechanical Behaviour of Earth Building Materials 150 4.1 Rammed Earth 151 4.1.1 Introduction 151 4.1.2 Mechanical Properties 151 4.1.3 Full Scale Behaviour and Shear Properties 159 4.1.4 Experimental Procedure 162 4.2 Earth Blocks 171 4.2.1 Introduction 171 4.2.2 Mechanical Properties 173 4.2.3 Experimental Procedures 174 4.3 Cob 190 4.3.1 Introduction 190 4.3.2 Mechanical Behaviour 192 4.3.3 Experimental Procedures 195 References 198 5 Seismic Assessment of Earthen Structures 204 5.1 Introduction 205 5.2 Earth Materials—A Synthesis of Mechanical Characteristics 206 5.2.1 Compressive Strength 206 5.2.2 Tensile Strength 207 5.2.3 Shear Strength 207 5.2.4 Young’s Modulus 208 5.2.5 Shear Modulus 208 5.2.6 Poisson’s Ratio 208 5.2.7 Density 209 5.2.8 Friction Angle 209 5.2.9 Influences of Moisture Content 209 5.3 Dynamic Characteristics of Earthen Structures 210 5.3.1 Typical Geometries of Earthen Buildings 210 5.3.2 Natural Frequencies and Mode Shapes 210 5.3.3 Damping 211 5.4 Analytical and Numerical Modelling 211 5.4.1 Simplified Modelling 211 5.4.2 Finite Element Modelling 212 5.4.3 Discrete Element Modelling 213 5.5 Seismic Assessment 214 5.5.1 Linear Static Analysis 214 5.5.2 Non-linear Static Analysis 214 5.5.3 Response-Spectrum Modal Analysis 216 5.5.4 Non-linear Dynamic Analysis 216 5.5.5 Experimental Tests with Shaking Table 217 5.6 Seismic Strengthening 217 5.6.1 Adobes Structures 217 5.6.2 Rammed Earth Structures 220 5.6.3 Timber Frame Structure with Infill and Timber Laced Masonry 222 5.7 Conclusions 223 References 225 6 Durability of Earth Materials: Weathering Agents, Testing Procedures and Stabilisation Methods 234 6.1 Introduction 235 6.2 Weathering Actions 236 6.2.1 Water 236 6.2.2 Ice 238 6.2.3 Wind 241 6.2.4 Fire 242 6.2.5 Solar Radiation 244 6.2.6 Chemical Agents 245 6.3 Field Measurement of Durability 246 6.4 Laboratory Measurement of Durability 247 6.4.1 Water 248 6.4.2 Ice 248 6.4.3 Wind 249 6.4.4 Solar Radiation 249 6.4.5 Fire and Chemical Agents 250 6.4.6 Standardization of Durability Tests 251 6.5 Stabilisation Methods for Enhancing Earth Durability 251 6.5.1 Organic Stabilisation 252 6.5.2 Inorganic Stabilisation 254 6.6 Conclusions 256 References 258 7 Codes and Standards on Earth Construction 265 7.1 Introduction 266 7.2 Earthen Structures and Construction Techniques 266 7.3 Developments in Earth Construction Standardisation 269 7.4 Types of Earth Building Standards/Codes and Documents 269 7.4.1 Soil or Earth Composition 270 7.4.2 Moulds/machinery and Manufacturing Earthen Building Products 275 7.4.3 Testing/evaluation and Quality Control 275 7.4.4 Design Guidance 275 7.4.5 Construction Methodology and Construction Procedure 276 7.4.6 Earthquake Resistant Guidelines 276 7.4.7 Durability, Limitations and Maintenance 276 7.5 Conclusion and Guidelines for Comprehensive Code 277 References 277 8 Environmental Potential of Earth-Based Building Materials: Key Facts and Issues from a Life Cycle Assessment Perspective 282 8.1 Introduction 283 8.2 Method 285 8.3 Extraction and Production 287 8.3.1 Influence of Clay Content in Raw Earth 287 8.3.2 Influence of Binder in Mix Design 287 8.3.3 Influence of the Scale of Data Collection 289 8.3.4 Influence of Transports 290 8.3.5 Influence of the building’s Design 292 8.4 Use Phase 292 8.4.1 Maintenance of Earthen Walls 292 8.4.2 Heating and Cooling Energy: Thermal Aspects 292 8.5 End of Life 296 8.6 Comparisons of Earthen Walls to Other Construction Techniques 296 8.6.1 Comparisons at Wall Scale 297 8.6.2 Comparisons at Building Scale 297 8.7 General Discussion 298 8.8 Conclusion 301 Appendix 1 303 Calculations of CED and GWP 303 Appendix 2 309 Available Results Concerning Transport 309 Appendix 3 309 Available Results Concerning the Maintenance Phase 309 References 314 This book presents the work done by the RILEM Technical Committee 274-TCE. It focuses on the estimation of the parameters which are necessary to properly design earthen constructions. It provides a compilation of the value classically obtained for the key parameters of earthen materials, a pedagogical presentation of the main testing procedures for earthen materials, their advantage and their drawback and an overview of most standards on earthen materials, whatever their origin and their language. The book is divided into eight chapters. After a general introduction on earthen materials and constructions, the state of the art on the material characterisation technics, the assessment of hygrothermal performance, the mechanical behaviour, seismic resistance and the durability will be presented, each in a dedicated chapter. On the basis of these last chapters, a critical review of the standards which are used for earthen material will be presented in the last chapter. The last chapter is dedicated to the analysis of the environmental potential of earth-based building materials.