Sidewalk Bed Project

I have done some preliminary excavation work, some work to prepare materials and I have done a series of drawings that outline and detail what I intend to build out front.
When I am finished with the excavation I will construct a sub- base using chunks of concrete that I plan to take up from the former drive on the east side of the house. Here is the drawing:

My plan is to lay these chunks in screened soil made into a mud. Then I will grout the edges with mud leaving a fairly flat grade. I have ideas as to how to set a good grade. It will resemble a giant mosaic made from concrete chunks and mud.
When I am satisfied that this is good enough, I will back fill the excavation to the base grade with screened soil. That is the end of this stage of construction.