What can I use to patch cracked concrete foundations between each cinder block?

We have the motar in the foundation of our house that is slowly falling out. What can we used to fill the small gaps? They are for cinder blocks that are in good condition, however the cement in between is decaying. We've never had to replace or repair something like this. Any recommendation?What can I use to patch cracked concrete foundations between each cinder block?
if you are going to go through the trouble to fix it , do it right...grind out the bad joints ...dampen joints and tuck with fresh mortar...mix it in a bucket 2 1/2 sand to one mortar by volume...keep it as stiff as you can and still work with it...tuck it in with a tucking tool from the hardware store...when almost set joint it with a striking iron...What can I use to patch cracked concrete foundations between each cinder block?
Lowe's sells this motor you can use it then use concreate seal on top of that befor you paint it. i would also get a couple of extra blocks just in case you may need them
If the walls are in good shape, are still vertical, and don't bulge or sag, you could just use some more cement to replace the stuff that has fallen out. Stand at one end of the wall with your head against the block, and sight down along it to see if it bulges.





But if there are large cracks, or if the wall has tilted in, or if it looks like there is a bulge somewhere, you need to have a qualified builder look at it. If the foundation wall is moving, you have a serious problem.
If there is no sign of the wall bulging or cracking then simply scrape out the loose %26amp; crumbling mortar and get something called 'mortar caulk' and squeeze it in there. Smooth it over with your wet fingers and thats about it.