Color Durability of Colored UHPC Curtain Wall Panels: A Study of Influencing Factors, Testing Methods, and Improvement Strategies

In contemporary architectural design, colored UHPC curtain wall panels have become the preferred material for landmark buildings and high-end commercial complexes thanks to their outstanding mechanical properties and rich decorative expressiveness. However, color durability, as a core indicator affecting the long-term aesthetics of building facades, has always been a focal concern for designers and owners. As an industry-leading enterprise with 28 years of full-chain experience in UHPC/GRC/GRG/GRP materials, Qinglong Group draws on its practical experience of participating in the formulation of the industry standard “Ultra-High Performance Concrete (UHPC) Exterior Wall Panels” to provide an in-depth analysis of the color durability assurance system for colored UHPC curtain wall panels from three dimensions: material characteristics, environmental factors, and technological innovation.

**I. Key Factors Behind Color Fading of Colored UHPC Curtain Wall Panels** The color stability of colored UHPC curtain wall panels depends on the combined effect of material components and the external environment. At the material level, pigment type is the core variable: inorganic mineral pigments (such as the iron oxide series), owing to their chemical inertness, can withstand high temperatures above 1000°C and ultraviolet exposure, while organic pigments, though offering high color saturation, are prone to fading after long-term exposure. Qinglong strictly uses German-imported inorganic pigments in production to ensure compatibility between the color paste and the UHPC matrix, avoiding color difference problems caused by pigment agglomeration. Among environmental factors, ultraviolet radiation, temperature and humidity cycling, and atmospheric pollutants (such as sulfur dioxide and industrial dust) are the main threats—in tropical maritime climate regions, high humidity and salt spray corrosion accelerate pigment decomposition, which is also a key technical difficulty that Qinglong has focused on optimizing in overseas projects in Malaysia, Singapore, and elsewhere.

**II. Scientific and Rigorous Color Durability Testing Methods** Commonly used testing standards in the industry include GB/T 1865-2009 “Paints and Varnishes — Artificial Weathering and Exposure to Artificial Radiation” and ASTM G154 “Standard Practice for Operating Fluorescent Ultraviolet (UV) Lamp Apparatus for Exposure of Nonmetallic Materials”. Building on these, the Qinglong laboratory has established a “dual-cycle accelerated aging testing system”: first, 2,000 hours of UV aging (simulating 50 years of natural sunlight), then 100 freeze-thaw cycles (-20°C to 60°C), and finally color difference (ΔE) measured with a spectrophotometer. Test results show that the ΔE value of Qinglong’s colored UHPC curtain wall panels can be controlled within 3, well below the industry pass threshold of 5—a figure verified on site in the translucent concrete project of the Century Plaza renovation on Nanjing East Road. In addition, for special projects, Qinglong also provides on-site weathering exposure testing services, such as the 12-month outdoor exposure test conducted for a project in Saudi Arabia, giving owners performance data under real environmental conditions. For more industry information: +WeChat qlfsbl123

**III. Qinglong’s Full-Chain Solutions for Enhancing Color Durability** Qinglong embeds durability-oriented design concepts throughout the entire process from material R&D to engineering application. In the formulation stage, the synergistic effect of nano-scale silica fume and ultrafine mineral powder lowers the porosity of UHPC (porosity ≤1.5%), reducing the penetration of moisture and pollutants; for surface treatment, an imported fluorocarbon coating is applied to form a dense protective film 50-80μm thick, whose weather resistance rating reaches the highest FW grade. In production, Qinglong has introduced a fully automatic color matching system from Germany’s Sika to ensure a batch color difference of ΔE≤1, together with RFID chip traceability technology to achieve full life-cycle quality management. During construction, a “dry hanging + sealant dual waterproofing” process is adopted to prevent rainwater from seeping into the panels through joints. Notably, Qinglong’s original “color restoration technology” can locally retouch curtain wall panels that have been in service for more than 10 years, restoring their original color through a chemical reaction between a dedicated color paste and the UHPC substrate; this technology has been successfully applied in a number of old building renovation projects in China.

As a national “Specialized, Refined, Distinctive, and Innovative” enterprise and a member of the International GRC Association, Qinglong has always made material durability its core competitiveness. From the special-shaped GRC curtain wall of the Dongguan Women and Children’s Activity Center to the UHPC decorative lines of the Nanning International Convention and Exhibition Center, Qinglong’s 28 years of engineering practice have proven that the color durability of colored UHPC curtain wall panels depends not only on high-quality materials, but also on systematic technical solutions and strict quality control. In the future, with the implementation of the industry standard “General Technical Conditions for Ultra-High Performance Concrete (UHPC) Non-Load-Bearing Components”, Qinglong will continue to drive technological innovation and provide designers and owners with architectural decoration solutions that combine aesthetic value with long-term performance. For more industry information: +WeChat qlfsbl123