This is an old concrete patio, in a residential backyard, that has been darkened over time by organic debris falling from the overhead tree canopy. The light-colored area in the middle is where a large rectangular glass table sat for an extended period of time.
Pressure washing alone would not be sufficient to get down to clean concrete. So the concrete was first, shot-blasted (photo left), and then ground smooth (photo right), to prepare the patio to be resurfaced with a thin cement overlay.
Next, the numerous settlement cracks throughout the slab (photos above left and above right) were filled and repaired with a semi-rigid epoxy, and then ground flush with the existing surface.
At this point, with the surface prep done, a thin base coat of gray cement was trowelled down (above), and then saw-cutting was done (below) to add a border and divide the large rectangular slab segments into equally sized square tiles.
Two texture coats of integrally-colored cement were then sprayed down (below left and right) to provide uniform color, give the final finish a somewhat "gritty" look and ensure adequate slip resistance.
Lastly, the patio was sealed (below left and right) with three coats of a high durability, long-lasting polyurea sealer, darkening it to the charcoal color chosen by the homeowners.