Concrete Fracture A Multiscale Approach

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.

Introduction—Why a New Book on Fracture of Concrete?Contents per ChapterClassical Fracture Mechanics ApproachesStress ConcentrationsLinear Elastic Fracture Mechanics (LEFM)Plastic Crack-Tip ModelFictitious Crack Model (FCM)Determination of FCM ParametersMechanics Aspects of Lattice ModelsShort Introduction to Framework AnalysisEquivalence between a Shell Element and a Simple Truss (Hrennikoff)Effective Elastic Properties of Beam LatticesSimilarity between Beam Lattice Model and Particle ModelFracture CriteriaLattice Geometry and the Structure of Cement and ConcreteSize/Scale Levels for Cement and ConcreteDisorder from Statistical Distributions of Local Properties Computer-Generated Material StructuresMaterial Structure from Direct Observation Lattice Geometry and Material Structure OverlayLocal Material PropertiesElastic Properties of Lattice with Particle OverlayUpper and Lower Bounds for the Young’s Modulus of CompositesEffective Young’s Modulus of a Two-Phase Aggregate-Matrix CompositeEffective Elastic Properties in Three DimensionsFracture of Concrete in TensionAnalysis of Uniaxial Tension ExperimentsFracture Process in TensionEffect of Particle Density on Tensile FractureSmall-Particle EffectBoundary Rotation Effects and NotchesIndirect 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 BehaviorStage (A): (Stable) Microcracking Stage (B): (Unstable) Macrocracking Stage (C): Crack-Face Bridging Four Fracture Stages, yet a Continuous ProcessSimilarity between Tensile and Compressive Fracture Ramification to Other Materials Multiscale Modeling and Testing Structure of Cement at the µm-Scale and Its PropertiesThe Role of Water at the µm ScaleF-r Potentials: From Atomistic Scale to Larger Scales Structural Lattice ApproachConclusions and OutlookFracture Mechanisms Theoretical ModelsReferences Appendix 1: Some Notes on Computational EfficiencyAppendix 2: Simple Results from Linear Elastic Fracture MechanicsAppendix 3: Stability of Fracture ExperimentsAppendix 4: Crack-Detection TechniquesAppendix 5: Active and Passive ConfinementIndex

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).