Road marking machine

Road marking machine working in Kenya, March 2012.[1]
Road marking machine working in Bahrain, December 2012.[2]
Thermoplastic convex marking machine, March 2013

Road marking machine (or road marking equipment, pavement marking equipment) is a kind of mechanical device that makes road markings on the surface of highway, runway, parking lots to keep the traffic order and safety. Road marking machines usually can be divided into three categories: thermoplastic paint, cold paint and two-component paint type, depending on the coatings.

Classification

Depending on the coating, road marking machines can be divided into thermoplastic paint, cold paint and two-component paint type. Depending on the driving methods, road marking machines can be divided into driving type, self-propelled type and hand-push type.[3] According to the construction efficiency, the driving type can be further divided into large type, medium type and small type.

Coatings

Road markings are applied using thermoplastic material, cold plastic paint, heated paint and field reactive two component materials. Thermoplastic material is applied hot and sets on laying. It has good durability and is suitable for use on all roads. Cold plastics are supplied in single or multi-component forms. The product is laid on the carriageway and a cohesive film is formed by chemical activity. Regular paints, whether applied hot or cold, are formulated specifically to bond to the road surface, and hold glass beads that are applied immediately into the wet paint (for night time reflectivity). Regular paints are still used world wide and provide the fastest method for applying lines. These paints do not have the life expectancy of thermoplastics or field reactive materials.[4]

Thermoplastic markings

Thermoplastic marking(also called hot melt road markings) often means thermoplastic road marking lines, include reflective pavement lines, virberating traffic lines to divide the road into lanes and guide traffic, to ensure safety. The paint applied to paint thermoplastic road marking is called thermoplastic paint, or hot melt road marking paint, mainly composed of synthetic resin, glass beads, colored pigments, timber fillers, and other additives. The Thermoplastic marking coating is with fast drying character for the thermoplastic characteristics of synthetic resin. The melt adhesion of a synthetic resin makes hot-melt paint a strong adhesive with the road surface. Additives in the coating paint increases the coating plasticity, improving the anti-settling, anti-pollution, anti-tarnish. Marking paint colors mainly are yellow and white. The white marking paint mainly contains titanium white, zinc oxide, lithopone, while the yellow paint is mainly heat-yellowing lead. And the filling materials of road paint can affect the mechanical strength, abrasion resistance and hue of the coating film. Particle size of the paint powder will have influence of the flow, sedimentation and also affected the surface processing. Coating glass beads were added in order to improve the identification at night, and improve brightness and durability of the marking. Glass bead is a colorless, transparent pellet, with refraction of light, and light focus, and directional reflection function. The glass beads were mixed with or spreading on the surface of the coatings, can reflect the light back to the car driver's eyes, thus greatly improving the visibility of the markings.

Construction methods

Hot melt road marking paint is solid powder at room temperature. In construction, the thermoplastic paint was put into a melting kettle called thermoplastic pre-heater, to mix and melt into the molten flow state. Then the melt paint was transferred into the paint tank of hand-push marking car, and then the molten coating will be introduced into the marking bucket and the material insulated remains molten. When the marking work starts, the marking bucket should be on the road surface. Because there is a certain gap between marking shoe and the ground, when the marking car was pulled forward, by automatically flowing, a neat marking lines was scraped out, glass beads sow can automatically evenly spreading a layer of reflective glass beads on the coating lines. The gap of marking shoe controlled the thickness of the coating, and was not dependent on walking speed of the road marking machine.

Machine marking types

Air spray is a way of road marking construction, spraying the atomized paint by compressed air. After atomized by compressed air, the paint form a reticule coating when sprayed to the road surface. The paint is fine and smooth after atomization, but there is air rebound, so paint flyoff is serious, to the line is drew not neat, with burrs. Besides, the applicable paint is of low viscosity, so more solvent was added during the construction, and it was a great waste. The coating is often thicker for low flow of the spraying gun, marking is of weak dynamic sense. Coating is affected by atomized water, oil molecules from the atomized air. The marking quality is not very perfect.

High-pressure airless spraying is to spray and jet the highly atomized paint by high-pressure airless pump with stable pressure and high flow. The paint when pressurized above 10~80kg/cm2, atomized by nozzles of different specifications, was sprayed onto the road surface to form a line coating. The atomized paint is not so fine and smooth as air spray, but no rebound by air. The marked lines is neat, full, lucid, and it will have long service life for painted forcefully and evenly, with strong adhesivity. It can spray paints of high viscosity, and paint a thick coating film at a time. The construction efficiency is 2-4 times of the air spray painting.

Auxiliary equipment

At the construction site, in order to improve construction efficiency and the quality of road markings, except for road marking machine, the construction workers also need some auxiliary equipment. The main auxiliary equipment includes thermoplastic paint pre-heater, hand-push pre-marker and road marking remover. Thermoplastic paint pre-heater is used to melt the solid powder coating into a viscous liquid, guaranteed the road marking machine has a steady stream of paint supply in the construction process. Pre-marker is used to draw a field sketch in advance to avoid faulty marking. Road marking remover is used to clean out old or incorrect markings. Large self-propelled machines usually do not need any support equipment.

See also

References

  1. ↑ "Kenya Customer Feedback the Information of DY-STM". Retrieved Mar 2012.
  2. ↑ "Operators Training of Road Marking Machine in Bahrain". Retrieved Dec 13, 2012.
  3. ↑ "Driving-type, Self-propelled, Hand-push, What do These Words Mean?". Retrieved Dec 13, 2013.
  4. ↑ Opie, David. "President". consultant to pavement marking industry. David H. Opie. Retrieved 7 January 2014.