Discussion on the Minimum Achievable Curvature Radius of UHPC Single-Curved Panels and Analysis of Influencing Factors

Pushing the Boundaries of Spatial Aesthetics: Exploring the Limits of UHPC Single-Curved Panel Curvature Radius and Engineering Practice

As modern architectural design evolves toward personalization and artistry, Ultra-High Performance Concrete (UHPC) has become the core material for shaping smooth curved buildings thanks to its outstanding mechanical properties and design freedom. As an industry leader with 28 years of full-chain experience in UHPC/GRC/GRG/GRP materials, Qinglong Group has been deeply involved in the development of curved components for hundreds of landmark projects in China. This article systematically analyzes the technical limits of UHPC single-curved panel curvature radius and its key influencing factors from three dimensions: material properties, process innovation, and engineering practice.

### Technical Boundaries of UHPC Single-Curved Panel Curvature Radius: From Material Fundamentals to Process Breakthroughs

The minimum curvature radius of UHPC single-curved panels is not a simple numerical concept but a comprehensive reflection of material performance, forming processes, and structural safety. Verified through 28 years of engineering practice, Qinglong Group has proven that under conditions using a fiber reinforcement system (steel fiber volume content of 2-3%) and an ultra-high-pressure forming process (pressure ≥40MPa), standard-thickness (30-50mm) UHPC single-curved panels can achieve a minimum curvature radius of 300mm, a benchmark at the industry-leading level. Compared with traditional GRC materials (minimum curvature radius typically 500mm), UHPC, with a compressive strength of up to 150MPa and a flexural strength of 8MPa, offers more aggressive design possibilities for curved forms.

### Four Key Factors Affecting Curvature Radius and Optimization Paths

**Precise control of the material formulation** is the foundation for achieving extremely small curvatures. Through orthogonal experiments, Qinglong's R&D center found that a combined dosage of silica fume and ultra-fine mineral powder (35-45% in total) significantly improves matrix density, and together with the three-dimensional random distribution of copper-plated steel fibers, effectively suppresses microcrack propagation during bend forming. In the translucent concrete project at Century Plaza on Nanjing East Road, optimizing the steel fiber aspect ratio (15-20) and interface treatment process successfully controlled the single-curved panel curvature radius at 350mm, achieving a perfect fusion of light, shadow, and structure.

**Innovation in mold technology** directly determines forming precision. Qinglong uses CNC-machined ABS composite molds combined with a vacuum infusion process, ensuring curvature errors of ≤1mm/m. In the Dongguan Women and Children's Activity Center project, for double-curved UHPC cladding panels with a 400mm radius, BIM parametric modeling and segmented mold design solved the problem of traditional wooden molds being prone to deformation, raising the first-pass qualification rate of components to 98%.

**Scientific design of the curing regime** is crucial to curvature stability. Extreme environment testing from -30℃ to 80℃ has shown that Qinglong's original "step steam curing process" (60℃×2h→80℃×4h→50℃×2h) can raise the degree of UHPC hydration to over 90%, keeping curvature radius variation within 0.5% during the service life, far below the industry average of 1.2%.

**Collaborative optimization of structural calculation** is key to safety assurance. The finite element analysis model for UHPC curved components jointly developed with South China University of Technology can accurately simulate stress distribution under different curvatures. Taking a 300mm-radius UHPC sunshade panel in a landmark project as an example, a gradient thickness design (30mm at the edges→50mm at the center) combined with a built-in stainless steel skeleton kept the maximum deflection within L/400, meeting the stringent requirements of the General Technical Conditions for Non-Load-Bearing Ultra-High Performance Concrete (UHPC) Components (Plan No. 2024-0232T-JC).

### The Art of Balance in Engineering Practice: Harmonizing Aesthetics, Cost, and Feasibility

As one of the first enterprises in China to participate in formulating UHPC industry standards, Qinglong deeply understands the engineering economics behind extremely small curvature radii. In actual projects, design requirements and cost-effectiveness must be weighed together: when the curvature radius is less than 300mm, custom mold costs increase by 30-50% and the production cycle lengthens by 20%. Designers are therefore advised to collaborate with manufacturers on joint optimization at the design stage. For example, in a commercial complex project, adjusting the local curvature radius from 250mm to 300mm reduced the overall cost by 18% while preserving the visual effect.

From the streamlined UHPC curtain wall at Terminal 3 of Guangzhou Baiyun International Airport to the special-shaped landscape benches beside the Twin Towers in Malaysia, Qinglong's 28 years of technical expertise prove that the curvature limits of UHPC single-curved panels represent not only a breakthrough in materials science but also a perfect fusion of design vision and engineering practice. In the future, with the introduction of technologies such as 3D printing and AI parametric design, UHPC curved components will bring more possibilities to building skins, and Qinglong will continue its mission of "creating aesthetically beautiful architecture," pushing forward the technical boundaries and application innovation of new architectural decoration materials.