With the rapid development of highway construction in China, the market for safety guardrails has been expanding. However, due to the fact that this product has been produced and used in my country for less than ten years, product standards have only been issued for five or six years, and national standards for highway guardrails for just two years, manufacturers have varying levels of understanding of the product's performance, technical parameters, and production processes, resulting in inconsistent product quality. In some sections, guardrails with improper anti-corrosion treatments become heavily rusted within one or two years, affecting the visual appeal of the highway, significantly shortening the effective lifespan of the guardrails, and increasing maintenance costs.
In the early days, my country typically used painting for protection, later gradually adopting hot-dip galvanizing, which remains widely used. Guardrails are large, long-term outdoor facilities, and the choice of protection system must be tailored to different atmospheric environments. The newly issued national standard GB/T18226-2000, "Technical Conditions for Corrosion Protection of Steel Components in Highway Traffic Engineering," classifies guardrail protection into four categories: galvanizing, aluminizing, galvanizing (aluminum) followed by plastic coating, and plastic coating. In rural areas and less polluted regions, single-layer hot-dip galvanized or single-layer powder-coated guardrails can be used.
However, in heavy industrial areas or coastal cities, especially in areas with acid rain, ordinary hot-dip galvanized or powder-coated single-layer guardrails may become ineffective before their service life is up, significantly increasing maintenance costs. Hot-dip aluminum guardrails offer better corrosion resistance than ordinary hot-dip galvanized guardrails, but their application is not widespread due to factors such as manufacturing processes, technology, cost, and environmental impact. Using a hot-dip aluminum + powder-coated protection system is less economical than using a hot-dip galvanized + powder-coated system. A dual-protection system of galvanized sheet + powder coating achieves better corrosion resistance in heavily polluted areas, especially in acid rain regions, significantly extending service life and making it the most durable protection method.
