In this chapter, the authors present the outline of the multi-scale modeling of structural concrete as a systematic knowledge base of both cementitious composites and structural mechanics. An object-oriented computational scheme is proposed for life-span simulation of reinforced concrete and soil foundation. Conservation of moisture (Chapter 2, Chapter 3), carbon dioxide (Chapter 4), calcium (Chapter 5), oxygen, chloride (Chapter 6) and momentum is simultaneously solved with hydration, carbonation, steel corrosion, ion dissolution, damage evolution (Chapters 7-10) and their thermodynamic/mechanical equilibrium. As it is essential for verifi cation of the holistic system to be based upon reality, efforts are also directed to the systematic examination and checking of modeling. The detailed modeling at each scale is presented in the subsequent chapters of this book.