Glass bead is the main reflective material in road marking. Road marking needs to be complete, clear, bright and beautiful, especially for highway, which not only requires obvious marking during the day, but also needs to provide effective visibility at night to ensure traffic safety. There are many factors affecting the visibility of road marking at night. It includes the roundness of glass beads, particle size range, the specific gravity of glass beads, the amount of distribution, refractive index, etc., the details are as follows.
- Only the glass beads close to the ideal sphere can reflectthe light to the driver’s eyes, if glass beads roundness is not ideal, light will make multiple reflectioninside of the glass beads, finally through the glass bead back, light will deviate from the driver’s field of vision, as a result, in the process of road marking construction, need optimizing glass bead, It is usually required that the roundness is bigger than or equal to 90% to ensure that there is enough reflecting light back to the driver’s eyes.
- The thickness of the road markingisusually thinner, so the glass bead size needs to be controlled in a certain range, if the glass bead is bigger, then it will be embeded smaller, easy to fall off under the external force, if the glass bead is smaller, then it is easy to be whole mergence line internal, if the glass bead size is not uniform, the degree of its mergence is uneven, small glass beads are easy to be shaded by big glass bead, will not receive the light from the headlights, or can’t produce an effective regression reflection, all these will affect the visibility of the line at night, usually the glass bead size range is 20-60 mesh.
- The larger the refractive index of glass beads is,the betterregression reflectioneffect it will get. However, considering the cost, usually use the glass beads with refractive index greater than or equal to 1.7 for road marking.
- The specific gravityof glass beads is 2.4-2.6g/cm3, which is more suitable. The position of glass beads embedded in the coating film with40%-50% exposed is the best reflective effect.
- The amount of glass beads has an effect on reflection, too much or too little is not good, the best effect is between 0.37-0.45kg/m3.
