Re: concrete walkway pad repair
I had a similar problem with a concrete driveway, suffering from salt damage, from previous owner(s). The top 1/2" or so flaked away in large areas.
Not having the $1500 to replace the drive, I tried some 6000# sand mix, applied somewhat wet. Just screed and troweled smooth. It looked a little ratty, but 9 years later, only a few tiny areas of the patch had flaked off. The repairs cost me $35.
I believe that the repair held much better, because I had applied Quickcrete concrete bonding agent to all damaged areas, beforehand. it looked like Elmer's school glue (probably was), but seemed to get the job done, even through many freeze-thaw cycles and daily auto traffic.
Good luck.