Decomposed granite or "Deco" as it is known locally was spread out over work areas for a solid surface to work on (also used for driveways)
Years ago the workbench and caravan annexe areas were cemented over when some free leftovet concrete from a contractor was available. These made a big difference to workability.
Last week some gaps in the workshop floor were concreted over. Prep was to clean loose gravel off the floor and set up straight wooden edges. I hand mixed concrete with a shovel in a wheel barrow, and plastered it onto the ground about 20 mm thick, it may not seem much but the 'deco' base is fairly hard, already compacted and was about 50 mm thick. The test slab under the workbench has stood up to a couple of years of bashing on the workbench no worries.
The new floor makes it easier to get around and reduces the ammount of dirt tramped into the shed.