Abstract
The relation between steel rod diameter, reinforcement per cent tensile stress, and maximum crack width is elucidated and a formula showing this relation is discussed. The theory of crack formation in bending-loaded concrete structures is rather complicated, whereas, in purely tensile force leaded slabs, problems are much simpler. An equation is derived, which shows the crack width as a function of the attachment length. The relation between crack distance and attachment length is described and an example of calculation is given. Practical consequences of the theory and experiences obtained from a provincial concrete highway are discussed.