When striping on fresh Portland cement concrete (PCC) surfaces, what surface preparation step is critical to ensure paint adhesion?

1. Removing curing compounds and laitance by wire brushing or shot blasting.
2. Applying a heavy coat of diesel fuel over the concrete surface.
3. Washing the concrete with high-pressure steam mixed with motor oil residue.
4. Sealing all concrete joints with silicone caulk prior to striping.