Concrete Fracture
A Multiscale Approach
Preview
Book Description
The study of fracture mechanics of concrete has developed in recent years to the point where it can be used for assessing the durability of concrete structures and for the development of new concrete materials. The last decade has seen a gradual shift of interest toward fracture studies at increasingly smaller sizes and scales. Concrete Fracture: A Multiscale Approach explores fracture properties of cement and concrete based on their actual material structure.
Concrete is a complex hierarchical material, containing material structural elements spanning scales from the nano- to micro- and meso-level. Therefore, multi-scale approaches are essential for a better understanding of mechanical properties and fracture in particular. This volume includes various examples of fracture analyses at the micro- and meso-level. The book presents models accompanied by reliable experiments and explains how these experiments are performed. It also provides numerous examples of test methods and requirements for evaluating quasi-brittle materials. More importantly, it proposes a new modeling approach based on multiscale interaction potential and examines the related experimental challenges facing research engineers and building professionals.
The book’s comprehensive coverage is poised to encourage new initiatives for overcoming the difficulties encountered when performing fracture experiments on cement at the micro-size/scale and smaller. The author demonstrates how the obtained results can fit into the larger picture of the material science of concrete—particularly the design of new high-performance concrete materials which can be put to good use in the development of efficient and durable structures.
Table of Contents
Introduction—Why a New Book on Fracture of Concrete?
Contents per Chapter
Classical Fracture Mechanics Approaches
Stress Concentrations
Linear Elastic Fracture Mechanics (LEFM)
Plastic Crack-Tip Model
Fictitious Crack Model (FCM)
Determination of FCM Parameters
Mechanics Aspects of Lattice Models
Short Introduction to Framework Analysis
Equivalence between a Shell Element and a Simple Truss (Hrennikoff)
Effective Elastic Properties of Beam Lattices
Similarity between Beam Lattice Model and Particle Model
Fracture Criteria
Lattice Geometry and the Structure of Cement and Concrete
Size/Scale Levels for Cement and Concrete
Disorder from Statistical Distributions of Local Properties
Computer-Generated Material Structures
Material Structure from Direct Observation
Lattice Geometry and Material Structure Overlay
Local Material Properties
Elastic Properties of Lattice with Particle Overlay
Upper and Lower Bounds for the Young’s Modulus of Composites
Effective Young’s Modulus of a Two-Phase Aggregate-Matrix Composite
Effective Elastic Properties in Three Dimensions
Fracture of Concrete in Tension
Analysis of Uniaxial Tension Experiments
Fracture Process in Tension
Effect of Particle Density on Tensile Fracture
Small-Particle Effect
Boundary Rotation Effects and Notches
Indirect Tensile Tests
Brazilian Splitting Test
Bending
Combined Tensile and Shear Fracture of Concrete
Tension and In-Plane Shear
Biaxial Tension Shear Experiments
4-Point-Shear Beam Test
Anchor Pull-Out
Torsion (Mode III Fracture)
Compressive Fracture
Mesomechanisms in Compressive Fracture
Softening in Compression
Softening as Mode II Crack-Growth Phenomenon
Lattice Approximations
Macroscopic Models
Size Effects
Classical Models Describing Size Effect on Strength
Size Effect on Strength and Deformation: Experiments
Lattice Analysis of Size Effect: Uniaxial Tension
Lattice Analysis of Size Effect: Bending
Damage Distribution in Structures of Varying Size
Concluding Remarks
Four-Stage Fracture Model
Fracture Process in Uniaxial Tension
Stage (0): Elastic Behavior
Stage (A): (Stable) Microcracking
Stage (B): (Unstable) Macrocracking
Stage (C): Crack-Face Bridging
Four Fracture Stages, yet a Continuous Process
Similarity between Tensile and Compressive Fracture
Ramification to Other Materials
Multiscale Modeling and Testing
Structure of Cement at the μm-Scale and Its Properties
The Role of Water at the μm Scale
F-r Potentials: From Atomistic Scale to Larger Scales
Structural Lattice Approach
Conclusions and Outlook
Fracture Mechanisms
Theoretical Models
References
Appendix 1: Some Notes on Computational Efficiency
Appendix 2: Simple Results from Linear Elastic Fracture Mechanics
Appendix 3: Stability of Fracture Experiments
Appendix 4: Crack-Detection Techniques
Appendix 5: Active and Passive Confinement
Index
Author(s)
Biography
Jan G. M. van Mier received his engineering and Ph.D. degrees from Eindhoven University of Technology. After a postdoctorate year at the University of Colorado in Boulder, he moved to Delft University of Technology. As an associate professor at the Stevin Laboratory, in close cooperation with several Ph.D. students, he developed the Delft lattice model and conducted numerous experiments elucidating the fracture of concrete under a variety of conditions. In 1999, he was appointed "Antonie van Leeuwenhoek" professor at TU Delft, based on excellence in research, and developed and built the new microlab to immerse in fracture studies at smaller size/scales than before. In 2002, he moved to ETH Zurich as full professor and director of the Institute for Building Materials. In 2010, he became president of the International Association for Fracture Mechanics of Concrete and Concrete Structures (IA-FraMCoS).