Can pavers set with polymeric jointing sand be powerwashed?
Yes, they can be powerwashed but only if you take the time to do it right and follow the directions to a tee. The joints should be 1/4" wide and as deep as the pavers. Which means you have to remove all the old sand. After applying the jointing sand, compacting is advised and then adding more sand. Extensive cleaning of the surface of the pavers is critical to remove all jointing sand before wetting down the sand. drying and curing time is important too. I just touched on a few of the procedures to use this stuff. It's a lot of work so if you take on the project, take the time to do it right.

You don't want to use a powerwasher set higher than 1600 PSI on the pavers after using the jointing sand.