【Drum Method】Test for Surface Damage and Retroreflectivity Decay of Glass Beads

It’s very difficult to evaluate the durability of road markings on site owing to being too many factors that could cause impact on it. Many researchers have been trying to find a suitable attenuation model that can predict its retroreflectivity

A known alternative to on-site assessment is the use of turntables where, under controlled conditions, road markings are subjected to tire action that successfully simulates road wear; this method is used to collect some data for road markings (4 to 6 million wheel pressure tests). The main drawback of the turntable test is the use of idealized conditions; No literature report was found to directly correlate the results of turntable evaluation with on-site performance. Nevertheless, the turntable test is the officially recognized durability test method for road markings in Germany, Spain, Korea and other countries; therefore, the validity of the results obtained from such an ideal evaluation scheme should not be questioned.

Another type of durability evaluation for glass beads is using the internal proprietary wear study setting, a program developed as a rapid screening test for the adhesion of glass beads to a variety of coatings. The grinding test machine consists of a slowly rotating drum in which the template with the test road markings is exposed to the grinding medium so does the glass beads are uniformly and unidirectionally to it, as shown in Figure 1. This device has not been described in any standards, and its accuracy has not been thoroughly evaluated in the cycle assessment. Nevertheless, it is more suitable for the purpose of this experiment and to determine the degree of wear of glass beads. Due to the special nature of this scheme and the maximum exposure to the grinding medium, the measured retroreflectivity should not be directly compared with the on-site retroreflectivity.

Corundum is used as a grinding medium in this scheme. Corundum is a very hard material (Mohs hardness of 9) which can easily scratch glass (Mohs hardness of 5-6).

Figure 1: The Diagram of Drum abrasives and Road Markings Template

Different types of glass beads used for road marking have been shown to have different wear resistance, and the results of their measurement in the drum grinding test confirm that the initial retroreflectivity index is not a sufficient indicator of the service life of road markings. Consideration should be given to the same paint coating, while using high-quality glass beads that can provide high retroreflectivity + wear resistance is considered the most sustainable option. The ultimate purpose of installing and maintaining road markings is to improve road safety; for this, high-quality raw traffic safety materials are essential.

As a leading manufacturer of traffic safety materials with more than 30 years’ experience, Tory is committed to ongoing product development and excellent customer services that makes us the perfect partner for your road marking paint supply needs. We can provide you with raw materials (such as reflective glass beads, MMA resin, AW element etc.) with very competitive prices which can be customized to meet the specific requirements of customers and projects. For more information, or to get started on your traffic safety solution: https://www.cntory.com/

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