I have a large exposed aggregate concrete walkway that goes to my backyard patio and it has partitions in between (maybe granite?). I live in an older 60's bungalow and I assume the walkway is original and it is well past it's life span. It is very difficult to walk on and chipping-away. I am wondering if it is possible to go over it with concrete and if the concrete will bond. I am looking for a more modern look. Any options or feedback would be greatly appreciated.
My suggestion would be to blast away the surface dirt with a pressure washer, then clean it off with something strong like muriatic acid. (Or hire a neighborhood teen to do it. ;-> ) Then apply concrete bonding agent and leveling compound. Leveling compound is pricey, but it can be applied in thin sheets and it sets up fast (very, very fast).
You'll have to put some sort of forms up, but you can use cut up cardboard boxes, because you're only adding 1/8" (3 mm) or less to the thickness.
If you DIY this, please, please do an experiment with about 1 square foot of compound on some cardboard or something, first. It's really a mix-pour-spread-set product, so you want to be ready.
Best option would be to clean it good, removing as much loose debris as possible, then getting a concrete bonding agent and applying according to the directions with the proper timing of your concrete pour. To get a lasting sidewalk, you will want the new slab to be the proper thickness and expansion gaps installed, otherwise it will just crack and break apart. Plus this will also make your sidewalk higher on both ends, you may need to slope the ends or use a step.
Other option is to completely remove the old sidewalk and pour a new one. Depends on how much work you want to do. First option less work, but might be a little higher in cost to ensure the new slab "sticks" to the old area.