Core Indicators of Marking Reflective Glass Beads and Their Road Safety Applications
Reflective glass beads are essential components in road markings, enhancing nighttime visibility by retroreflecting vehicle headlights. Their performance hinges on three core indicators: refractive index (RI), sphericity, and particle size distribution.
Refractive Index (RI): Determines light reflection efficiency. Standard beads (RI 1.5) provide 150–450 mcd retroreflective brightness, while high-RI beads (RI 1.6–1.7+) deliver ≥600 mcd, with specialized rain-night variants (RI 1.7+) exceeding 1000 mcd for wet conditions .
Sphericity: Beads with ≥80% sphericity ensure optimal light focus and reduce mechanical wear. Low sphericity causes uneven reflection and accelerates pavement marking degradation .
Particle Size: Graded sizes (e.g., 50–850μm) serve distinct functions: finer beads (50–150μm) are pre-mixed for sustained reflectivity, while coarser ones (150–600μm) are surface-sprinkled for immediate brightness. Uniform distribution prevents bead overlap or insufficient coverage .
Applications in Road Safety:
Glass beads are embedded in thermoplastic, two-component, or water-based markings. Applied via pre-mixing (20% volume) or surface sprinkling (0.5 kg/m²), they maintain reflectivity for 3–8 years. High-RI beads (≥1.7) are critical for rain-prone areas and intelligent transport systems (ITS), enabling ADAS and autonomous vehicles to detect lanes under adverse conditions .
Standards & Compliance:
Quality conforms to GB/T24722-2020 (China) and EN1423 (EU), mandating tests for abrasion resistance, UV stability, and environmental durability. Certified products (e.g., ISO9001, CCPC) ensure longevity and reduce relining frequency by 40% .
In essence, glass beads transform passive markings into active safety guides, balancing initial brilliance with long-term performance through precise optical and mechanical engineering.
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