Rehab of Spalling Precast Concrete

[azcats]

I'm working on a project which involves the rehabilitation of precast concrete double tees. The tees are structural members supporting the roof and the web cantilevers about 2 feet beyond the edge of roof for architectural reasons. Most of the spalling occurs in this architectural cantilever. It appears that the degradation is caused by corrosion of the rebar because the rebar is visible and rusting. It also appears that the cover distance is much less than required by code. The structure is approximately 30 years old, in the Phoenix area, and the impacted areas are exposed to weather.

I am looking for tips on how to stop the spalling and patch the existing problems. However, what should be done with the existing corroded bars? Should the existing concrete be removed around the bars until no further corrosion is encountered and then clean the bars and patch the tees?

Another option is to sawcut and remove the architecural cantilevers. However, the corrosion could extend into the tee beyond the cut. Then, I have also exposed the bars or strands in the tee to weather. Is there a product that could be applied to that sawcut to act as concrete cover?

Thanks for your input and if there are any questions please ask. I also have pictures if anyone is interested.

John