Over the last century, over one hundred crack width formulas have been developed to calculate the width and spacing of cracks in reinforced and prestressed concrete elements. It is unclear which formulas are the most accurate. An extensive comparison study is required to determine which formulas accurately describe the crack patterns, consisting of the crack width and spacing. To make such a study possible, this paper proposes categorizing formulas. The categorization of the formulas is based on their applicability, crack pattern representation, and background. The categorization presents an overview of the different assumptions and application areas for describing crack patterns.

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Digital fabrication with cementitious materials is a rapidly growing field of research in which the evolution of strength during the various processes, such as 3D printing, is the key controlling parameter. The strength evolves over multiple orders of magnitude during the process, and thus, it is essential to properly characterize the strength evolution in order to guarantee process success. This chapter summarizes the state of the art in these characterization methods for digital fabrication with fresh cementitious materials, reviewing well-known and more recently developed methods.@en