Scarification removes all of the existing surface material and exposes the underlying coarse aggregate. Exposing the coarse aggregate creates a surface that will bond exceptionally well with a new concrete overlay or repair material. Optimum exposure of the underlying aggregate is achieved by specifying a minimum removal of one-half the diameter of the coarse aggregate. Typical scarification ranges in depth from ¼ – 1.0 inch (6-25 mm). Proper scarification will insure the optimum surface area for bonding repair or overlay materials. Coarse aggregate embedded in the newly exposed surface will provide excellent shear resistance at the bond line.Note the surface profile in each of the photos. 100% of the surface has been removed. The exposed coarse aggregate is undamaged and is clean and crisp ready to provide a strong anchor into the overlay or repair material. The depth of the bonding zone between existing and new materials will equal approximately the size of the coarse aggregate. Rotomilling and other mechanical methods of surface preparation shear off the coarse aggregate and fracture the substrate creating a weak discrete bond line between the existing and new material. During scarification it is essential that the water jet contact all of the original surface area. This will insure that the entire existing surface material has been removed along with any aggregate damaged during previous operations (such as rotomilling). Rampart uses a high-speed rotating nozzle (1,800 rpm) that will remove the entire existing surface. Slow rotation speeds or oscillating nozzles may not be capable of moving fast enough to cover the entire surface. Failure to remove the entire surface, or contact all surfaces with the water jet, may result in reduced bond strength at locations not properly prepared.
Scarification removes all of the existing surface material and exposes the underlying coarse aggregate. Exposing the coarse aggregate creates a surface that will bond exceptionally well with a new concrete overlay or repair material. Optimum exposure of the underlying aggregate is achieved by specifying a minimum removal of one-half the diameter of the coarse aggregate. Typical scarification ranges in depth from ¼ – 1.0 inch (6-25 mm). Proper scarification will insure the optimum surface area for bonding repair or overlay materials. Coarse aggregate embedded in the newly exposed surface will provide excellent shear resistance at the bond line.
During scarification it is essential that the water jet contact all of the original surface area. This will insure that the entire existing surface material has been removed along with any aggregate damaged during previous operations (such as rotomilling). Rampart uses a high-speed rotating nozzle (1,800 rpm) that will remove the entire existing surface. Slow rotation speeds or oscillating nozzles may not be capable of moving fast enough to cover the entire surface. Failure to remove the entire surface, or contact all surfaces with the water jet, may result in reduced bond strength at locations not properly prepared. 
