LINE MARKING REMOVAL
Mechanical grinding is used to remove various types of marking materials from asphalt and concrete surfaces. However, it is not a recommended method to remove line marking from sprayed seals or high texture asphalt. Grinding is achieved by the motorised, high speed rotation of hardened steel or tungsten carbide cutters. Pressure on the cutter head and the depth of grinding can be adjusted during the work to achieve satisfactory results.
Grinding is one of the most cost-effective methods of removing pavement markings. Grinding does not, however, always leave the pavement surface undamaged, ‘Ghost lines’ a term used to describe the appearance of a line that is not actually there often result as a consequence of a rough surface profile created by the grinding process. However, when used in conjunction with the subsequent application of bituminous compounds for “blacking out” the residue shadow of marking left in the pores by shallow grinding, this effect is minimised. Some of these smaller grinding units have the option to include a dust collection system, thus providing a dust free working environment.
At ALM we use a combination of grinders one being a Diamond Head Grinder for applications to concrete and using a Scarifier for asphalt. Both the asphalt & concrete line remover can be pushed and or use a ride on by one person in tight spaces or limited access areas such as city streets, crossings and school safety zones, carparks or warehouses. Grinding is ideal for the removal of thermoplastic lines, removing epoxies and paints
“Blacking Out” is the phrase used to describe the practise of covering up unwanted markings with a topcoat of material similar in colour to the road surface. On bitumen roads, this usually involves the use of black paint to cover the markings no longer required, hence the term “Blacking Out”.
“Blacking Out” is generally prohibited as a permanent method for the removal of line marking. For economic reasons where large or lengthy sections of line marking have been identified or for rectification due to changes in policy or standards “Blacking Out” may be warranted when timing is a critical factor to expedite traffic delineation changes.
Use of “Blacking Out” as a permanent solution to ‘remove’ unwanted lines has resulted in some of the following problems which have the proven potential to confuse motorists.
- The blacked out area can appear to have a different colour and gloss rating than the pavement surface, particularly under different lighting and weather conditions.
- On wet nights, blacked out lines may be reflected by vehicle headlights and cause motorists travelling in the opposing direction to “perceive” the blacked out lines as legitimate markings.
- The blacked out area can change in both colour and gloss as traffic erodes the coating, this has been known to cause problems, especially when sunlight reflects upon the blacked out markings at sunrise and sunset.
- The blacked out area will eventually wear away to reveal the original unwanted
- Worn, blacked out surfaces may exhibit a different skid resistance to the rest of the pavement surface; this may lead to skidding problems especially in wet weather conditions.
- Upon wearing down of the blacked out area, the glass beads on the original line marking will protrude through and reflect light, giving the appearance of true line