A thin asphalt overlay on concrete is stripped with PCD tooling or very coarse metal-bond discs run at low speed. PCD shaves and scrapes the soft asphalt without loading up, then a coarse metal-bond pass cleans the residue down to sound concrete.
Asphalt is soft, sticky and heat-sensitive. Standard grinding discs clog quickly because the asphalt melts and loads the bond. PCD tooling works because the hard polycrystalline diamond tips scrape and shear the asphalt instead of grinding it — the same action that makes PCD effective on epoxy and glue. For thicker overlays, first shave off most of the asphalt with a scraper or PCD pass, then grind the thin residue.
Use a floor grinder with PCD tooling such as Werkmaster PCD tooling, run at low speed with moderate pressure. The PCD tips shave the asphalt layer off in strips. Keep the pass direction consistent and overlap each pass. On very thick asphalt, cut it into manageable sections or use a cold planer before grinding.
After the bulk layer is gone, switch to coarse metal-bond discs (16# or 30/40) to remove the thin asphalt film and expose clean concrete. This pass also removes any PCD ridge marks. A PCD cup wheel on an angle grinder handles edges and small patches where the big machine cannot reach.
A>Only for the thin residue layer. Grinding thick asphalt with metal bond loads and glazes the disc quickly. Start with PCD for the bulk, then metal bond for cleanup.
A>PCD handles thin overlays (a few mm) well. For thick asphalt (25 mm+), shave most of it off with a cold planer or scraper first, then finish with PCD and grinding.
A>Asphalt can leave oil-based staining. After grinding to clean concrete, check for dark bands; a degreaser wash or a shallow extra pass removes most staining.
A>Only if you run machines that rotate in different directions. Confirm your grinder's rotation and order the matching PCD direction.
Removing an asphalt overlay from concrete is a two-stage job: shave the bulk with PCD at low speed, then grind the residue with coarse metal bond to clean concrete, and clean up thoroughly before recoating. With JOY PCD coating-removal tooling matched to your machine, the overlay comes off fast and the slab is ready for its next use.
