PAVEMENT MARKING REMOVAL
There are three primary methods to remove pavement markings. Care must be exercised in selecting the correct method. The wrong piece of equipment used on a given road surface can result in a permanent scar to the pavement. No matter which removal method is used the removal equipment should be able to vacuum its own debris while in operation.
Water Blasting uses high pressure water to remove existing markings or curing compound from concrete. The truck mounted waterblaster should be capable of vacuuming the spent water and debris as it goes, leaving the pavement clean and only slightly damp. With a skilled operator, waterblasting causes the least amount of scarring on concrete surfaces and should be the only removal method allowed to remove longitudinal pavement markings off concrete pavement that is to remain in place.
Grinding is the fastest, lowest cost method for removing pavement markings. There are two types of Pavement Marking Removal; longline removal and special markings removal. Longline removal is the removal of longitudinal markings such as roadway centerline and edge line. Longline removal is accomplished by using a truck equipped with multiple grinding heads that can remove an existing line with one pass of the truck. Special markings removal refers to the removal of legends, symbols, crosswalks and stop bars that exist on the road surface. Special marking removal is accomplished by using equipment that is much smaller in size (usually about the size of a lawn tractor). Removal equipment used for both longline and special marking removal should be capable of vacuuming the debris they generate simultaneous to the grinding operation. Because some degree of scarring occurs with grinding it is critical to minimizing scarring by using the correct head/tooth configuration. Grinding is best to use on pavements that will be removed or repaved during construction or when removing a marking that will be replaced with a new marking in the exact same location. Grinding pavement markings is still the best method to use on asphalt surfaces even if the pavement is to remain. In this case it is critical to use the proper piece of equipment with the proper teeth on the grinding heads and to have an experienced operator who can operate the equipment to minimize the resulting scar.
Shot Blasting is a removal method that uses steel shot to “blast” off existing markings. The shot is continually vacuumed and recycled by the machine for continual use. It is a slow method of removal and is best when used in conjunction with a grinder. The grinder removes 90% of the marking while the shot blaster is responsible for removing the last 10%, thus reducing scarring. This method is referred to the Grind / Shot Blast Method.