Differences in Mold Requirements Between UHPC Single-Curved and Double-Curved Panels: A Comparative Analysis of Key Technologies

**In-Depth Analysis of UHPC Single-Curved and Double-Curved Panel Mould Technology: From Process Breakthroughs to Engineering Implementation**

Driven by the dual forces of contemporary architectural aesthetics and engineering technology, ultra-high performance concrete (UHPC) has become the material of choice for landmark building envelope design thanks to its outstanding mechanical properties and freedom of form. As an industry technology leader with 28 years of end-to-end experience in UHPC/GRC/GRG/GRP, Qinglong Group deeply understands the decisive role of mould craftsmanship in the quality of UHPC components. This article systematically compares the mould technology differences between UHPC single-curved and double-curved panels across three dimensions—mould design, material selection, and process control—providing designers and engineering parties with a full-process technical reference from concept to implementation.

**1. Mould Design: The Geometric Challenge from Linear to Curved Surfaces**

The core of single-curved panel moulds lies in precise control of "single-direction curvature." Their mould design takes a flat plane as the base, achieving the desired form through curvature change in a single direction; the structure is relatively simple, typically using modular steel moulds or composite wooden moulds. Taking a commercial complex project Qinglong Group participated in as an example, the single-curved UHPC sunshade panel moulds used CNC machining to ensure curved surface errors of ≤2mm, while allowing a 0.5% shrinkage margin, balancing production efficiency with forming precision.

Double-curved panel moulds, by contrast, face the compound challenge of "bidirectional curvature." Their surfaces must satisfy curvature changes along both the X and Y axes simultaneously, placing extremely high demands on mould rigidity and surface continuity. The Qinglong technical team adopted parametric design (Rhino+Grasshopper) combined with 3D scanning technology to convert designers' freeform surfaces into producible mould data models. In a cultural center project in Nanjing, the double-curved UHPC curtain wall panel moulds used aluminum alloy frames and adjustable support structures to achieve complex forms with a minimum radius of curvature of 300mm, with single-point positioning accuracy of 0.1mm.

**2. Material Selection: The Balancing Art of Rigidity and Toughness**

Material selection for single-curved panel moulds focuses more on the balance between cost and efficiency. For conventional projects, Qinglong uses laser-cut Q235 steel plates, with surfaces treated by sandblasting plus a Teflon coating, which both ensures smooth concrete demoulding and increases mould turnover to more than 50 uses. For standard single-curved components in mass production, composite wooden moulds (birch plywood + epoxy resin coating) become the economical choice, weighing only 1/3 of steel moulds and improving installation efficiency by 40%.

Double-curved panel mould materials must offer excellent dimensional stability and surface reproduction. The Qinglong technical team innovatively used aerospace-grade aluminum alloy (6061-T6) for mould base material machining, achieving one-step forming of complex curved surfaces through five-axis linkage milling, combined with imported elastic polyurethane liners (Shore hardness 85A), perfectly solving the air bubble and wrinkle problems that UHPC material is prone to in double-curved forms. In a landmark project in Shenzhen, this process achieved double-curved panel surface flatness of 0.8mm/m, far exceeding the industry standard of 1.5mm/m.

**3. Process Control: Full-Cycle Management from Production to Installation**

Single-curved panel production processes are highly mature and suitable for standardized assembly-line operations. Qinglong ensures the compactness of UHPC material under single-direction curvature through the combined "vibrating table + vacuum degassing" process; the curing stage uses steam curing (60°C × 8h), bringing components to a 7-day strength of 120MPa. For installation, pre-embedded inserts and 3D adjustment brackets enable rapid on-site assembly, with a single-day installation efficiency of 300㎡ in one municipal project.

The core of double-curved panel process control lies in "dynamic balance." Qinglong innovatively developed the "flexible casting + stepped curing" technology: first, a robotic material distribution system achieves uniform distribution of UHPC material within the double-curved mould; then gradient temperature-rising curing (25°C→45°C→60°C) is applied to avoid cracking caused by thermal stress. To address the installation challenges of double-curved components, the team developed a BIM + 3D laser scanning positioning system, achieving "zero-error" alignment between the double-curved UHPC ceiling and GRG walls in a theater project in Guangzhou, with installation accuracy controlled within ±1mm.

**Conclusion: Technological Innovation Drives the Evolution of Architectural Aesthetics**

From single-curved to double-curved, breakthroughs in UHPC mould technology represent not only progress in craftsmanship but also the liberation of architectural form expression. As a national high-tech enterprise, Qinglong Group has always taken "creating beautiful architecture" as its mission. Through 28 years of technical accumulation and continuous R&D, it has formed a full-chain solution covering material formulations, mould design, and construction installation. Whether it is the double-curved curtain wall of a grand theater or the single-curved sunshade system of a commercial complex, Qinglong's UHPC mould technology provides designers with the "what you imagine is what you get" capability, allowing more imaginative architectural ideas to take root. In the future, with the integrated application of technologies such as 3D printing and intelligent sensing, UHPC component mould technology will surely achieve even greater breakthroughs, injecting new vitality into the construction industry.