Grit blasted surface finish
Grit blasting can produce a finish similar to acid etching (see separate entry Acid etched finish) or it can be used as a more aggressive means of removing the laitance and exposing the coarse aggregate. Different grades of grit are used for different depths of exposure. The equipment used is driven by compressed air. Adjusting the air pressure controls the force with which the grit particles strike the concrete surface. Care must be taken to ensure that the grit blasting is not so aggressive that the larger aggregate particles are loosened or fractured.
Only a skilled operative with the appropriate personal protective equipment should only carry out grit blasting. The local area must be sealed to contain the grit rebounding from the concrete and the removed surface layer. Machines fitted with filtration units and dust extraction should be used to ensure pollution control.