AS3600 - Flexural Crack Width Limit

[structuree]

In the 2018 code, AS3600 poses limits on bar stresses based on limiting your crack width to either 0.2, 0.3 or 0.4mm. Forgive my naivety, but... How much of a difference does 0.1mm difference in crack width really make? Does it make enough of a difference to limit the bar stress by (for example) half to save a few 0.1mm crack width?

I can only really understand if there was concern over waterproofing. Crack widths would ideally be non-existent. But I guess that brings me back to the question - 0.1mm is such a small increment.

 

[Settingsun]

It's also +50% and +100%. But you have to take account of the consequences as you say. Indoors, air conditioned, invisible between carpet and ceiling tiles = WGAF. Environment that promotes corrosion is another matter.

Architectural concrete is another circumstance where easily visible cracks are a design failure.

 

[Tomfh]

0.2, 0.3 and 0.4mm cracks all look different. A 0.4mm crack is a lot more noticeable than a 0.2mm crack. A 0.2mm crack also provides better protection from wet/corrosive environments than 0.4mm crack.