What Are the Surface Decoration Treatment Methods for UHPC Exterior Wall Panels?

The surface decoration treatment of UHPC facade panels is the key to their elevation from a structural material to a vehicle of architectural art; these treatment processes directly determine the building's final visual effect, tactile texture, and long-term durability. As the Qinglong Group with 28 years of R&D and engineering practice in ultra-high performance concrete, we have categorized the UHPC surface decoration technology system into five major dimensions: “mold forming, surface grinding, color integration, texture shaping, and functional coatings.” In the renovation project of Century Plaza on Nanjing East Road, Shanghai New World, we used high-precision silicone mold transfer technology to perfectly replicate the delicate grain and growth rings of natural wood on the UHPC surface, and combined it with light-transmitting design to achieve artistic effects that differ between day and night, fully demonstrating the infinite possibilities of UHPC in surface decoration.

Mold forming is the foundational process for shaping surface texture. UHPC's excellent rheology enables it to accurately reproduce every detail of the mold. Using high-strength molds precision-machined by CNC (such as steel molds, GRP molds, and silicone molds), Qinglong can form in a single step complex three-dimensional textures ranging from mirror-smooth high-gloss surfaces and natural, rustic matte finishes to various faux stone (such as granite and limestone), faux wood, weaves, and geometric reliefs. The precision of the mold directly determines the realism and consistency of the decorative effect.

Surface grinding and polishing are the core steps for achieving a leap in texture. According to design requirements, UHPC can undergo wet grinding with abrasive pads of different grits after demolding and curing. From coarse grinding (removing laitance and repairing air bubbles) to fine grinding (achieving a smooth touch), and then to high-grit precision grinding and mechanical polishing, a gloss range from matte texture all the way to mirror finish can be formed. For the UHPC curtain wall panels Qinglong supplied to the Shenzhen Yirui Biotechnology Building, after multiple stages of wet grinding and polishing, the surface flatness error is less than 1mm/2m, presenting the ultimate purity and refinement pursued by minimalist architecture.

Color integration technology gives UHPC rich expressiveness. Qinglong employs two mainstream coloring processes: the first is “body coloring,” in which highly weather-resistant inorganic oxide pigments are uniformly mixed into the matrix at the mixing stage, providing lasting, stable color that is consistent throughout and suitable for areas requiring long-term color retention or subject to heavier wear; the second is “surface coloring,” in which colorants are applied to the formed panel surface by spraying or impregnation, offering more flexible color choices and enabling special artistic effects such as gradients and antique finishes. We strictly control pigment quality and formulation to ensure color stability across different batches.

Functional surface coatings are the key to enhancing durability and special performance. To strengthen UHPC's stain resistance, self-cleaning ability, and UV resistance, Qinglong applies dedicated protective agents to its surface. Common ones include: 1) penetrating hydrophobic agents (such as organosilicon types), which create a “lotus effect” for waterproofing and stain resistance; 2) anti-graffiti coatings, which make surface stains easy to clean; 3) transparent fluorocarbon topcoats, which provide the strongest protection against weathering and chemical corrosion while enhancing the base color. For light-transmitting UHPC panels, high-transmittance resin is used for surface impregnation and filling. Through systematic surface decoration treatment, UHPC can meet the aesthetic needs of a wide range of architectural styles, from modern minimalism to classical revival.