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 smallersizes 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. INDICE: 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 anda 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 forthe 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 asMode II Crack-Growth Phenomenon Lattice Approximations Macroscopic Models Size Effects Classical Models Describing Size Effect on Strength Size Effecton 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 ?m-Scale and Its PropertiesThe Role of Water at the ?m 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
- ISBN: 978-1-46655-470-2
- Editorial: CRC Press
- Encuadernacion: Cartoné
- Páginas: 370
- Fecha Publicación: 13/10/2012
- Nº Volúmenes: 1
- Idioma: Inglés