Retroreflective Road Markings

Transcription

1 Retroreflective Road Markings

2 Road markings: safer mobility by day and night

3 The secret of night time visibility of road markings: glass beads

4 What happens at night Without beads, there is no retroreflection! The poor visibility of the road marking is only based on the contrast between the illuminated striping and the dark pavement.

5 What happens at night Glass beads create retroreflection! The visibility of the road marking rises significantly, because the color of the striping is reflected to the car driver.

6 Retroreflection how it works The headlight beam penetrates the glass bead, hits the pigmented road marking, and is reflected. The color of the road marking is retroreflected. The striping seems to light up. reflected light marking material

7 Quality features of glass beads refractive index low index: 1.5 high index: >1.9 roundness (min. 80%) transparency sieving gradations coatings flat glass cullet is recycled into a road safety product

8 Quality of retroreflection depends on Bead quantity applied Bead distribution in/on the marking Ratio of bead size and layer thickness of the marking Degree of bead embedment (ideally % of bead circumference) Viscosity of marking material Ambient conditions (rain, quality of road surface, etc.)

9 Drop-on beads Glass bead types For high initial retroreflection, applied onto the road marking material before it sets at a consumption rate of g/m2 Intermix beads Mixed into the road marking material for improved long term reflectivity and durability of the line (thermoplastics) Injection beads Beads that are injected into the road marking material during the application process (high build paint)

10 STANDARD Drop-on bead types Size range from microns Primarily in paints, thermoplastics, and cold plastics Typical application rates of g/m2 LARGE (MEGALUX-BEADS ) Size ranges from microns Higher roundness (>90%) and smoother surface High performance road marking systems (wet night profiled), cold plastics and thermoplastics Typical application rates of g/m2 BLENDS Blend size ranges from microns Applied in any road marking material for improved performance Typical application rates of g/m2

11 Glass bead specification applied in Saudi Arabia AASHTO M247: Glass Beads used in Traffic Paints The beads shall be transparent, clean, colorless glass, smooth and spherically shaped, free from milkiness, pits, or excessive air bubbles and conform to: Roundness minimum 70% Refractive index minimum 1.5 Crushing resistance: retained mm (no. 40) sieve 133 N (30 lb) minimum Moisture Resistance-Flow Characteristics: beads shall not absorb moisture in storage; shall remain free of clusters and lumps and shall flow freely from dispensing equipment Flotation: minimum 90% beads shall float in xylene

12 Thermoplastic specification applied in Saudi Arabia AASHTO M249: White and yellow reflective thermoplastic striping material (solid form) colors: white or yellow resins: alkyd or hydrocarbon specific gravity of thermoplastic material shall not exceed 2.15 material supplied either in granular or block form application by spraying, screed extrusion, or ribbon extrusion, as specified by the purchaser

13 Thermoplastic specification applied in Saudi Arabia The thermoplastic material shall be homogeneously composed of pigment, filler, resins and glass reflectorizing spheres. Composition acc. to AASHTO M249 [%]: COMPONENT WHITE YELLOW Binder 18.0 min 18.0 min Glass beads Titanium dioxide 10.0 min - Calcium carbonate & inert fillers 42.0 max at the option of the manufacturer Yellow pigments -

14 Reflectivity standards (European Standard EN 1436) EN 1436 defines the performance requirements of road markings: daytime visibility nighttime visibility color skid resistance Minimum nighttime visibility value for white road markings in Germany: > 150 mcd

15 5x brighter with high performance glass beads

16 M. SWAROVSKI GmbH / Amstetten / Lower Austria SWARCO s Competence Center for Glass Technology linked to Reflective Road Safety

17 Thanks for your attention!