Third RILEM International Conference on Concrete and Digital Fabrication: Digital Concrete 2022 (RILEM Bookseries, 37)

This book gathers peer-reviewed contributions presented at the 3rd RILEM International Conference on Concrete and Digital Fabrication (Digital Concrete), held in Loughborough, UK, on June 27-29, 2022. Focusing on additive and automated manufacturing technologies for the fabrication of cementitious construction materials, such as 3D concrete printing, powder bed printing, and shotcrete 3D printing, the papers highlight the latest findings in this fast-growing field, addressing topics like mixture design, admixtures, rheology and fresh-state behavior, alternative materials, microstructure, cold joints & interfaces, mechanical performance, reinforcement, structural engineering, durability and sustainability, automation and industrialization. Preface Organisation Conference Chair International Scientific Committee Chair of the Committee Co-chairs of the Committee Members of the Committee Organising Committee Keywords Contents RILEM Publications RILEM Proceedings (PRO) RILEM Reports (REP) Alternative Processes Zero-Waste Production of Lightweight Concrete Structures with Water-Soluble Sand Formwork 1 Introduction 2 Materials and Methods 2.1 Formwork Material 2.2 Powder-Bed-Based Formwork Manufacturing Unit 3 Design and Production of Lightweight Concrete Beam 3.1 Design of the Lattice Beam 3.2 Preparation and Printing of Formwork 3.3 Casting, Demolding and Reuse of Formwork Material 4 Conclusion References An Early Trial on Milling 3D Printed Concrete Geometries: Observations and Insights of the Process 1 Introduction 2 Milling a Printed Panel Part 3 Results and Discussion 4 Conclusions References Mobile Additive Manufacturing: A Case Study of Clay Formwork for Bespoke in Situ Concrete Construction 1 Introduction 2 State of the Art 3 Method 3.1 Design Principles and Mobile Manufacturing Process 3.2 Casting Process 3.3 Navigation, Localization, and Positioning 4 Case Study and Initial Results 5 Conclusion and Further Research References Adaptive Foam Concrete in Digital Fabrication 1 Introduction 2 Experimental Setup 3 Material Design 3.1 Raw Material 3.2 Mix Design 4 Applications 5 Conclusions and Outlook References Structural Design and Optimisation Mesh Mould Prefabrication 1 Introduction 2 Methods, Materials and Techniques 2.1 Computational Structural Design 2.2 Robotic Prefabrication of Mesh Moulds 2.3 Concrete Infill and Finishing Materials 2.4 Material Characterisation of the Infill Material 3 Implementation 4 Conclusion and Outlook References The Production of a Topology-Optimized 3D-Printed Concrete Bridge 1 Introduction 2 Design 3 Manufacturing 3.1 3D Concrete Printing 3.2 Transportation 3.3 Assembly 4 Conclusion References Injection 3D Concrete Printing (I3DCP) Combined with Vector-Based 3D Graphic Statics 1 Introduction 2 State of the Art 3 Experimental Setup and Design Method 3.1 Robotic Setup 3.2 Materials 3.3 Design Method 4 Investigation of Joints and Fabrication Procedure 4.1 Investigation of Modularization 4.2 Design and Fabrication Procedure 5 Conclusions and Outlook References 3DCP Structures: The Roadmap to Standardization 1 Problem Statement 2 From Trial to Standards 2.1 Material Design 2.2 Structural Design 2.3 Execution Design 2.4 Durability Design 2.5 Use Phase 3 Implementation Further Ahead 4 Conclusions References Binders and Aggregates 1: Aggregates Mix Design for a 3D-Printable Concrete with Coarse Aggregates and Consideration of Standardisation 1 Introduction 2 Standardisation 3 Mix Design 4 Experimentation 5 Conclusion References Fresh and Hardened Properties of 3D Printable Foam Concrete Containing Porous Aggregates 1 Introduction 2 Methodology 2.1 Materials and Sample Preparation 2.2 Testing Procedure 3 Results and Discussion 3.1 Flow Measurement 3.2 Density and Compressive Strength Measurements 3.3 Porosity Measurements 4 Conclusion References Sustainable 3D Concrete Printing with Large Aggregates 1 Introduction 2 N3XTCON Mix Design Strategy 3 3DCP with Mortar and Concrete 4 Conclusions References Design and Fabrication of Spatially Graded Concrete Elements with Ice Aggregate Method 1 Introduction 2 I - Spatial Patterns of Ice Aggregate and Their Properties 2.1 Uniaxial Compressive Strength Test 3 II - Design Application of Ice Aggregate 3.1 Form Finding and Discretization 3.2 Fabrication of a Prototypical Voussoir 4 Conclusions References Binders and Aggregates 2: Alternative Binders Accelerating Early Age Properties of Ultra-Low Clinker Cements for Extrusion-Based 3D Printing 1 Introduction 2 Materials and Methods 2.1 Materials 2.2 Methods 3 Results and Discussion References Developing Printable Fly Ash–Slag Geopolymer Binders with Rheology Modification 1 Introduction 2 Materials and Methods 3 Results and Discussion 3.1 Summary and Findings References Formulation and Characterization of a Low Carbon Impact Cementitious Ink for 3D Printing 1 Introduction 2 Materials and Methodology 2.1 Materials 2.2 Mix Design 2.3 Experimental Procedures 3 Results and Discussion 3.1 Fresh State Properties 3.2 Hardened State Properties 3.3 3D Printing Tests 4 Conclusion References Strategies for Reducing the Environmental Footprint of Additive Manufacturing via Sprayed Concrete 1 Introduction 2 Concrete Design and Performances 2.1 Concrete Recipes 2.2 Mechanical Performances 2.3 Durability 3 Environmental Assessment 4 Conclusions References Mechanical Performance of 3-D Printed Concrete Containing Fly Ash, Metakaolin and Nanoclay 1 Introduction 2 Materials and Methods 2.1 Materials and Mix Proportions 2.2 Testing Procedure 3 Results and Discussions 3.1 Compressive Strength of Standard and Layered Cubes 3.2 Flexural Strength of Standard Prisms 4 Conclusion References Binders and Aggregates 3: Strain Hardening Materials Incorporation and Characterization of Multi-walled Carbon Nanotube Concrete Composites for 3D Printing Applications 1 Introduction 2 Experimental Procedure 2.1 Materials and Specimens 2.2 Uniaxial Unconfined Compression Test 2.3 Hardened State Mechanical Tests 3 Experimental Results 3.1 Uniaxial Unconfined Compression Test 3.2 Hardened State Mechanical Test on Printed Samples 4 Conclusions References Properties of 3D-Printable Ductile Fiber-Reinforced Geopolymer Composite 1 Introduction 2 Materials and Experimental Program 2.1 Materials and Mixture Design 2.2 Mixing and 3D Printing 2.3 Characterization Methods 3 Results and Discussions 3.1 Rheological Proportions 3.2 Mechanical Properties 4 Conclusion References Feasibility of Using Ultra-High Ductile Concrete to Print Self-reinforced Hollow Structures 1 Introduction 2 Experimental Program 3 Result and Discussion 4 Conclusion References Development of Cementitious Metamaterial with Compressive Strain Hardening Characteristics 1 Introduction 1.1 Metamaterial 2 Materials and Methods 2.1 Metamaterial Design 2.2 Specimen Preparation 2.3 Compression Test 3 Results and Discussions 3.1 Cast Specimens 3.2 Printed Specimen 4 Conclusions References Consistency of Mechanical Properties of 3D Printed Strain Hardening Cementitious Composites Within One Printing System 1 Introduction 2 Methodology 2.1 Materials 2.2 Printing Sessions 2.3 Compression Test and Apparent Density 2.4 4-point Bending Test 2.5 Uni-axial Tensile Test 2.6 Statistical Methods 3 Results and Discussion 3.1 Compressive Strength and Apparent Density 3.2 4-point Bending Test 3.3 Uniaxial Tensile Test 3.4 Statistical Analysis 4 Conclusions References Design and Digital Workflow Uncertainty Quantification of Concrete Properties at Fresh State and Stability Analysis of the 3D Printing Process by Stochastic Approach 1 Introduction 2 Chosen Methodology 2.1 Adopted Failure Criteria of the Printed Concrete Structure 2.2 Uncertainty Quantification of Random Variables by Bayesian Inference 2.3 Kriging-Based Reliability Analysis 3 Numerical Applications 4 Conclusions References Simulation of 3D Concrete Printing Using Discrete Element Method 1 Introduction 2 Modelling Approach 3 Material Model Calibration 4 Simulating 3D Concrete Printing 5 Conclusions and Outlook References Influence of Infill Pattern on Reactive MgO Printed Structures 1 Introduction 2 Materials and Methods 2.1 Materials 2.2 Experimental Methodology 2.3 Finite Element Modeling 3 Results and Discussions 4 Conclusion References Durability Evaluation of Durability of 3D-Printed Cementitious Materials for Potential Applications in Structures Exposed to Marine Environments 1 Introduction 2 Materials and Methods 3 Experimental Results 4 Discussion 5 Conclusions References Two Year Exposure of 3D Printed Cementitious Columns in a High Alpine Environment 1 Introduction 2 Concrete Choreography 3 Exposure and Damage Observation 3.1 Exposure 3.2 Description of Damage 4 Discussion 5 Conclusion References Salt Scaling Resistance of 3D Printed Concrete 1 Introduction 2 Methodology 2.1 Materials and Mixtures 2.2 3D Print Experiments and Sample Preparation for Salt Scaling Tests 2.3 Mercury Intrusion Porosimetry 3 Results and Discussions 3.1 Salt Scaling 3.2 Total Porosity from MIP 4 Conclusions References Influence of the Print Process on the Durability of Printed Cementitious Materials 1 Introduction 2 Materials and Methods 2.1 Materials and Mix Composition 2.2 Print Process and Sample Preparation 2.3 Carbonation Resistance 3 Results and Discussion 4 Conclusions References Freeze-Thaw Performance of 3D Printed Concrete: Influence of Interfaces 1 Introduction 2 Materials and Methods 3 Results and Discussion 4 Conclusions References Heterogeneities and Defects Mechanical Properties and Failure Pattern of 3D Printed Hollow Cylinders and Wall Segments Under Uniaxial Loading 1 Introduction 2 Experimental Methodology 2.1 Materials and Mix Design 2.2 Test Procedures for Mechanical Properties of Printable Mix 2.3 Test Procedures for Mechanical Properties of Printed Structures 3 Results and Discussions 4 Conclusions References Impact of Drying of 3D Printed Cementitious Pastes on Their Degree of Hydration 1 Introduction 2 Experimental Procedure 2.1 Preparation and Geometry of Cement Paste Samples 2.2 Degree of Hydration Measurements Using Neutron Radiography 2.3 Degree of Hydration Measurements Using Thermogravimetric Analysis 3 Results and Discussion 4 Conclusion References The Environment’s Effect on the Interlayer Bond Strength of 3D Printed Concrete 1 Introduction 2 Experimental Program 3 Results and Discussion 4 Conclusion References Evaluation of the Bond Strength Between 3D Printed and Self-compacting Concrete 1 Introduction 2 Materials and Methods 2.1 Materials 2.2 Methods 3 Results 3.1 Failure Mode 3.2 Bond Strength 4 Conclusions References Interlocking 3D Printed Concrete Filaments Through Surface Topology Modifications for Improved Tensile Bond Strength 1 Introduction 2 Experimental Setup 2.1 Materials 2.2 Nozzles 2.3 Printing Variables and Process 2.4 Sample Preparations and Tensile Test 3 Results 3.1 Tensile Results 3.2 Practical Implications 4 Recommendations 5 Conclusions References Digitally Fabricated Keyed Concrete Connections 1 Introduction 2 Digitally Fabricated Connections: Materials and Methods 2.1 Test Setup 2.2 Specimen Design 2.3 Material Properties 2.4 Specimen Production with EggshellTechnology 2.5 Instrumentation 3 Digitally Fabricated Connections: Results 4 Conclusion and Outlook References Material Jetting A 3D Printing Platform for Reinforced Printed-Sprayed Concrete Composites 1 Introduction 2 Printing System Description 3 Manufacturing Concept 4 Demonstration and Outlook 4.1 Demonstration of System 4.2 Discussion and Outlook References Influence of Material and Process Parameters on Hardened State Properties of Shotcrete 3D-Printed Elements 1 Introduction 2 Material and Methods 2.1 Mixture Composition and Experimental Design 2.2 Methods 3 Results and Discussion 3.1 Strand Geometry 3.2 Interface Tortuosity and Flexural Strength 4 Conclusion and Outlook References Shotcrete 3DCP Projection Angle and Speed Optimization: Experimental Approaches and Theoretical Modelling 1 Introduction 2 Theoretical Model 2.1 Concrete Composition Modelling 2.2 Concrete Acceleration Modelling 3 Experimental Approach 3.1 Experimental Parameters Influence 3.2 Angle and Speed Optimization 4 Model Assessment 5 Conclusion References ARCS: Automated Robotic Concrete Spraying for the Fabrication of Variable Thickness Doubly Curved Shells 1 Introduction 2 Spray Path Generation 2.1 Methodology 2.2 Sequencing 3 Concrete Shell Fabrication 3.1 Setup 3.2 Prototype 4 Conclusion References Particle Bed Binding Particle Bed Technique for Hempcrete 1 Introduction 2 Materials and Methods 2.1 Materials 2.2 Methods 3 Results 3.1 Influence of Micronized Particles of Hemp on Porous Surface 3.2 Influence of Micronized Particles of Hemp on Imbibition Front 4 Analysis and Discussion 4.1 Washburn Imbibition in a Porous Medium 4.2 Diffusion Coefficient 4.3 Modification of Micronized Particles of Hemp Structure by Water 5 Conclusion References Effect of Curing in Selective Cement Activation 1 Introduction 2 Material and Methods 3 Results and Discussion 3.1 Density and Compressive Strength Measurements 3.2 Geometric Precision 3.3 Calorimetry Measurement 3.4 Electrical Resistance Measurement 4 Conclusion References Evaluating the Effect of Methyl Cellulose on Hardened State Properties in Selective Cement Activation 1 Introduction 2 Materials and Methods 2.1 Material 2.2 Methods 3 Results and Discussion 4 Conclusion References Selective Paste Intrusion: Stability of Cement Paste Mixtures Towards Changing Ambient Temperature 1 Introduction 2 Materials and Methods 3 Results and Discussion 4 Conclusion and Outlook References Printability and Set Control Set-On Demand Concrete by Activating Encapsulated Accelerator for 3D Printing 1 Introduction 2 Materials 3 Mix Preparation 4 Testing Methods 5 Results and Discussion 6 Conclusion References Using Limestone Powder as a Carrier for the Accelerator in Extrusion-Based 3D Concrete Printing 1 Introduction 2 Experimental Program 2.1 Materials 2.2 Testing Procedures 3 Results and Discussion 3.1 Fluidity 3.2 Viscosity 3.3 Structural Build-Up 4 Conclusions References Printability Assessment of Cement-Based Materials Using Uniaxial Compression Test 1 Introduction 2 Materials and Methods 2.1 Materials 2.2 Mixing Sequence and Test Procedures 3 Results and Discussions 4 Conclusions References Monitoring Strain Using Digital Image Correlation During Compressive and Tensile Loading: Assessment of Critical Strain of Cement-Based Materials Containing VMA 1 Introduction 2 Materials and Methods 2.1 Materials 2.2 Methods 3 Results and Discussion 3.1 Measurements of Displacement and Computation of Results 3.2 Influence of Rheological Properties and Load Cases on Material Deformation 4 Conclusion and Outlook References Temperature Impact on the Structural Build-Up of Cementitious Materials – Experimental and Modelling Study 1 Introduction 2 Materials and Methods 3 Results and Discussion 4 Conclusions References Early Age Shear and Tensile Fracture Properties of 3D Printable Cementitious Mortar to Assess Printability Window 1 Introduction 2 Experimental Program 2.1 Mix Design 2.2 Testing Procedure 2.3 Friction 3 Results of the Experimentation 4 Conclusions References A Strain-Based Constitutive Model Ensuring Aesthetic 3D Printed Concrete Structures: Limiting Differential Settlement of Filaments 1 Introduction 2 Model Derivation 3 Experimental Procedure 3.1 Modified UUCT 3.2 DIC Measurement 4 Results and Discussions 5 Conclusion References Process Control, Toolpath and Inspection Process Control for Additive Manufacturing of Concrete Components 1 Introduction 2 Related Work 3 Experimental Setup 4 Algorithm 5 Evaluation and Outlook References Generative Structural Design: A Cross-Platform Design and Optimization Workflow for Additive Manufacturing 1 Introduction 2 Generative Design Process for Mass-Customizable FB 3 Structural Simulation and Optimization Process on MiS 4 Conclusions References A Closed-Loop Workflow for Quality Inspection and Integrated Post-processing of 3D-Printed Concrete Elements 1 Introduction 2 Methods 3 Results 4 Discussion References Force Flow Compliant Robotic Path Planning Approach for Reinforced Concrete Elements Using SC3DP 1 Introduction 2 Motivation and Concept 3 Computational Design and Path Planning 4 Prototypical Production Process 5 Conclusion and Outlook References Reinforcement Integrating Reinforcement with 3D Concrete Printing: Experiments and Numerical Modelling 1 Introduction 2 Methodology 2.1 Materials and Experiment 2.2 Computational Fluid Dynamics Model 3 Results and Discussions 4 Conclusion References Flow-Based Pultrusion of Anisotropic Concrete: Mechanical Properties at Hardened State 1 Introduction 2 Description of the FBP Process 3 Mechanical Properties of Anisotropic Concrete 3.1 Materials and Methods 3.2 Influence of Reinforcement Ratio 4 Conclusion and Perspectives References Core Winding: Force-Flow Oriented Fibre Reinforcement in Additive Manufacturing with Concrete 1 Motivation and Background 2 Conception of CWR Based on the SC3DP Setup 3 Development of CWR End-Effector and Robot Control 4 Real-Scale Case Study 5 Results and Discussion References Integration of Mineral Impregnated Carbon Fibre (MCF) into Fine 3D-Printed Concrete Filaments 1 Introduction 2 Mineral Coated Fibres (MCF) 3 MCF Integration and Processing 4 Test Setup and Results 4.1 Scope of the Experiment 4.2 Pull-Out Tests 4.3 Uniaxial Tension Tests 4.4 Microstructure Analyses 5 Summary and Outlook References Flexural Behaviour of Steel-Reinforced Topology-Optimised Beams Fabricated by 3D Concrete Printing 1 Introduction 2 Design and Production 2.1 Beam Layout and Printing Production 2.2 Steel Reinforcement 3 Flexural Test and Results 4 Conclusion References Fundamental Study on Automated Interlayer Reinforcing System with Metal Fiber Insertion for 3D Concrete Printer 1 Introduction 2 Materials 3 Outline of the Experiment 3.1 Multiple Metal Fiber Insertion Device 3.2 Preparation of the Specimens 3.3 Experimental Procedures (X-Ray CT Analysis and Bending Test) 4 Results and Discussion 4.1 X-Ray CT Analysis 4.2 Bending Test 5 Conclusion References Robotically Placed Reinforcement Using the Automated Screwing Device – An Application Perspective for 3D Concrete Printing 1 Introduction 2 Automated Screwing Device (ASD) 2.1 Design and Application 3 Conclusion References Proof-of-Concept: Sprayable SHCC Overlay Reinforcement Regime for Unreinforced 3D Printed Concrete Structure 1 Introduction 2 Sprayable SHCC Overlay Reinforcement 3 Validation: Experimental Work 4 Results and Discussion 5 Conclusion References Pre-installed Reinforcement for 3D Concrete Printing 1 Introduction 2 Pre-installed Reinforcement 3 Segmented and Optimised T-beam 3.1 Design 3.2 Fabrication 3.3 Structural Performance 3.4 Discussion 4 Conclusion References Wet Material Property Control Material Design and Rheological Behavior of Sustainable Cement-Based Materials in the Context of 3D Printing 1 Introduction 2 Materials and Methods 2.1 Mixture Design Methodology and Experimental Program 2.2 Raw Materials 2.3 Mixture Design 2.4 Mixing Procedure 2.5 Constant Rotational Velocity Test 2.6 Penetration Test 2.7 3D Printing Test 3 Results and Discussions 4 Conclusions References Measuring Plastic Shrinkage and Related Cracking of 3D Printed Concretes 1 Introduction 2 Experimental Setups 3 Materials and Mixture Proportions 4 Preparation of the Samples and the Experimental Procedure 5 Results and Discussion 6 Conclusion References Automated Visual Inspection of Near Nozzle Droplet Formation for Quality Control of Additive Manufacturing 1 Introduction 2 Automated Test Setup 2.1 Load Cell Measurement 2.2 Visual Measurement 3 Error in Mass Measurement 4 Error Due to Out-of-Plane Object Rotations 5 Comparison Between Mass and Volume Measurements 6 Conclusion References Selected Test Methods for Assessing Fresh and Plastic-State 3D Concrete Printing Materials 1 Introduction 2 Materials and Methods 2.1 Rheometry and Plastic-State Compression Tests 2.2 Gravity-Driven (Slug) and Slow Cone Penetration Tests 3 Results and Discussion 4 Roadmap for Application and Conclusion References Author Index