In the marking construction, the amount of reflective glass beads should be appropriate,If too little, then there are few reflective points, and the reflective brightness of the marking is poor; too much, it is not easy to form a return reflection.
In the construction of road marking, too much reflective glass beads on the surface are easy to form "virtual beads". In this case, the reflective glass beads for road marking can not attach well on the marking, and they are easy to fall off from the marking surface. Before this layer of "virtual beads" falls off, the marking has poor brightness at night, and the marking will appear overall or partial darkening phenomenon.
The results of foreign studies show that when the embedded part of the reflective glass beads is 55% ~ 67% of the spherical diameter of the glass bead, the light can almost completely reflect back. For a single glass bead, when the embedding degree of the glass bead is less than 50%, the regression reflection effect that can be formed is very poor, and the light almost completely penetrates the glass bead and refracts; when the embedding degree of the glass bead is about 60%, the regression reflection effect is the best; when the embedding degree increases, the regression reflection effect gradually decreases, because the number of light entering the glass bead. The amount of glass beads decreases with the increase of the embedding degree. In the actual construction, the distribution of glass beads is rarely single, but from the statistical point of view, the optical behavior of many glass beads is very similar to that of a single glass bead under the above conditions.
The geometric size of glass beads, bulk crushed glass are easier to fall off from the marking surface than glass beads with small particle size in the use of marking, . This is because the torque of glass beads with large particle size are usually larger when they are stressed, but the use of large particle glass beads can significantly improve the visibility of marking line at night. In fact, the improvement of the return reflection effect of large particle glass beads is mainly reflected in the rainy night environment or wet road. Generally speaking, large particle glass beads and small particle glass beads are more effective in the wet and rainy night environment.
The interface condition of glass bead coating and the properties of the interface also affect the retroreflective effect.
In this case, the glass bead film interface is relatively smooth and close to the ideal concave mirror, which has a focusing effect on the light, and the light enters the glass bead almost returns to the driver's vision along the original direction.
The coating itself is relatively rough, and the coating is not too dense after film formation. There are many bubbles or other fillers with larger particles in the coating. The glass bead film interface is relatively unsmooth, in which some glass beads air interface are mixed, and the glass bead film interface becomes smaller. In this case, the light will not only scatter greatly, but also make some light pass through the glass bead air interface. No matter scattering or light passing through the glass bead air interface, it will cause some light loss and reduce the retro reflection effect. The conventional hot-melt road marking coating has less reflective brightness than MMA double-component road marking coating, which is the reason.