Saddled with a foundation problem

Homeowner seeks best fix for 1872 farmhouse

Q: My question regards the best way to stabilize the perimeter foundation on my 1872 farmhouse. The "concrete" surface is turning to dust in places where the harder finish coat has been chipped or broken away. I know the core of the continuous perimeter foundation is good and hard, because I’ve drilled into it when I bolted the house down and shear-paneled the cripples.

Small gaps are appearing between the mudsill and the concrete and my thought is to stuff in some oakum strands before applying the concrete finish.