Reasonable crack widths for reinforced concrete under service loads are listed in Table 4.1 of ACI 224R-01. However, a footnote warns that, with time, “a significant portion” of the cracks in a structure can exceed these values.

the concrete core, shrinkage will create internal tensile stresses near the surface and compression in the core. Differential shrinkage can result in warping and surface cracks. The surface cracks can, with time, penetrate deeper into the concrete member as the interior portion is subject to additional shrinkage.

Table 1 provide allowable crack widths versus exposure conditions in fiber-reinforced concrete, and the use of fibers as a means to control cracking in overlays. More research is needed on concrete permeability to evaluate current limits and determine the maximum allowable width of exposed cracks in structures.

crack widths are reduced, and the ultimate tensile cracking strain capacity of the concrete is increased. The mechanical bond between the embedded fiber and binder matrix redistributes the stresses.

The control of cracking due to drying shrinkage and crack control in flexural members, overlays, and mass concrete construction are covered in detail. Long-term effects on cracking are considered and crack-control procedures used in construction are presented.

design documents have been used to calculate design crack widths, and the results are also illustrated in Fig 1. The commonest permissible crack width limits at present are 0.3 mm in mild environments, 0.2 mm in moderate environments, and 0.1 mm in severe environments. It will be seen that the slab in question would

A new calculation model for crack control in semi-massive rein-forced concrete tanks used for liquid storage is proposed. The model includes three basic stages for the development of the crack width. The first stage covers the formation of early-age cracks occurring as a result of imposed loads acting during concrete hardening.

Mar 1, 2012 · The main feature of the proposed crack control procedures is that they are explicitly set up as a function of a limiting crack width value.

From a durability point of view, crack-free repairs are desirable; 27 however, in practice, cracking in repairs does occur. Therefore, the goal should be to minimize the extent 28 and width of the cracks. 29 Guidance on tolerable crack widths in concrete structures is presented in ACI 224R and ACI 224.1R.

Mar 1, 1992 · It is suggested that a more conservative limit on the maximum allowable crack-width to protect the prestressed tendons from the effects of corrosion (0.2 mm for exterior exposure and 0.3 mm for interior exposure) be adopted for effective crack …