Why Fracture Mechanics?, Historical Perspective, Reasons for Fracture Mechanics Approach, Sources of Size Effect on Structural Strength, Quantification of Fracture Mechanics Size Effect, Experimental Evidence for Size Effect, Essentials of LEFM, Energy Release Rate and Fracture Energy, LEFM and Stress Intensity Factor, Size Effect in Plasticity and in LEFM, Determination of LEFM Parameters, Setting Up Solutions from Closed-Form Expressions, Approximate Energy-Based Methods, Numerical and Experimental Procedures to Obtain KI and G, Experimental Determination of KIc and Gf, Calculation of Displacements from KI-Expressions, Advanced Aspects of LEFM, Complex Variable Formulation of Plane Elasticity Problems, Plane Crack Problems and Westergaard's Stress Function, The General Near Tip Fields, Path-Independent Contour Integrals, Mixed Mode Fracture Criteria, Equivalent Elastic Cracks and R-Curves, Variability of Apparent Fracture Toughness for Concrete, Types of Fracture Behavior and Nonlinear Zone, The Equivalent Elastic Crack Concept, Fracture Toughness Determination Based on Equivalent Crack Concepts, Two Parameter Model of Jenq and Shah, R-Curves, Stability Analysis in the R-Curve Approach, Determination of Fracture Properties from Size Effect, Size Effect in Equivalent Elastic Crack Approximations, Size Effect Law in Relation to Fracture Characteristics, Size Effect Method: Detailed Experimental Procedures, Determination of R-Curve from Size Effect, Cohesive Crack Models, Basic Concepts in Cohesive Crack Model, Cohesive Crack Models Applied to Concrete, Experimental Determination of Cohesive Crack Properties, Pseudo-Boundary-Integral Methods for Mode I Crack Growth, Boundary-Integral Methods for Mode I Crack Growth, Crack Band Models and Smeared Cracking, Strain Localization in the Series Coupling Model, Localization of Strain in a Softening Bar, Basic Concepts in Crack Band Model