Concrete crack repair

[Lion06]

The only thing I can find on acceptable crack widths for concrete is in ACI 224 and is dependent on the exposure of the concrete. Is there anything other than this document that deals with acceptable crack widths? Is there anything specifically for PT?

 

[InDepth]

Try the ICRI concrete repair manuals. You can select the acceptable crack with for exposure based on ACI. I would use this criteria since in PT you usually also have mild steel reinforcing. Now remember that these acceptable crack widths, I believe, are mainly for corrosion prevention. There is a critical limit though in the ACI document which discusses loss of structural integrity fir the concrete to maintain it's shear strength through aggregate interlock. I used to have a concrete repair table where below a certain with I used an epoxy injection system for aesthetics; and above critical crack width (1/8?) I specified a structural epoxy injection system to regain the slab shear strength. Above 1/4" I believe youneed to really figure out what the distress is being caused by and developing a solution beyond epoxy repairs.

Also, is your PT system a lightweight concrete system or a NWC system? I've seen a lot of trouble with 1970s era lwc PT slabs.