This reference book presents the theory and methodology to conduct a finite element assessment of concrete structures subjected to chemically induced volumetric expansion in general and alkali aggregate reaction in particular. Subjects treated are: Constitutive model: Theoretical model, equations, constitutive driver. Micro-Model: Example of a micro model which simulates the expansion of an aggregate, and transition to a macro-model. Macro Model: How to prepare the relevant data prior to analysis, and how to conduct the numerical simulation. How to perform a Matlab based system identification to determine key AAR parameters. Sensitivity Analysis: Through parametric studies assess the importance of key parameters (such as what should be the smalles time step, how important is it to model temperature spatial and temporal variations). Validation: Assessment of the model through simulation of simple laboratory tests. Case Studies: Two detailed case studies will be provided; a dam and a heavily reinforced massive concrete structure. Field Assessment.