A bit extreme, but try using a cement made by DAP or USG. Using it would be a trifle expensive and you will have to anchor your track in the bed. I've used it and it works. I had to transverse 30" of sidewalk. Of course, the better half had me tear the sidewalk up the following year. So, my labors should have waited a year.
The product comes in a tube and is used in securing landscape blocks. You can find it at Lowe's, Home Depot, etc. Usually in the paint department with the adhesives.
Another alternative would be a mortar or sand mix concrete bed. You will have to make sure the old concrete is cleaned and etched, at least have a surface for the new stuff to adhere. Personally, I haven't tried that remedy. But, as they say, it looks good in theory. And now there is no need to worry on my garden layout. No sidewalks.
Bob
The product comes in a tube and is used in securing landscape blocks. You can find it at Lowe's, Home Depot, etc. Usually in the paint department with the adhesives.
Another alternative would be a mortar or sand mix concrete bed. You will have to make sure the old concrete is cleaned and etched, at least have a surface for the new stuff to adhere. Personally, I haven't tried that remedy. But, as they say, it looks good in theory. And now there is no need to worry on my garden layout. No sidewalks.
Bob