Hi Melissa - I'm actually in the Chicago area. Here are a few companies in your area that use polyurethane for lifting concrete:
POLYTEK 360 INC. 855.360.POLY (7659)
Concrete Resources Inc. (780) 910-8105
I hope this helps - Mike
Hey Guys - I just happened to stumble across this discussion and thought I'd add my opinion...I raise settled concrete with polyurethane foam professionally. ChrisDavies is correct - foam will last longer than traditional mudjacking material. Although, I am not aware of being able to rent this...