What Are UHPC Casting Methods? Comprehensive Analysis and Application Techniques

What Are the Casting Methods for UHPC? Comprehensive Analysis and Application Techniques

As an industry leader with 28 years of experience in detailed design, manufacturing, construction and installation, and after-sales maintenance in the field of UHPC/GRC/GRG/GRP materials, Qinglong Group (hereinafter referred to as Qinglong) deeply understands the critical role of ultra-high performance concrete (UHPC) in modern architecture. With ultra-high strength, excellent durability, and outstanding shaping capability, UHPC has become the preferred material for high-end projects such as grand theaters, commercial complexes, and landmark buildings. This article systematically analyzes the core casting methods of UHPC and their application techniques, providing professional reference for designers and owners.

I. Classification and Technical Points of UHPC Casting Processes

1. Conventional Casting: The Core Process for Basic UHPC Applications

Conventional casting is the most fundamental and commonly used construction method for UHPC, suitable for flat components, simple special-shaped structures, and mass production scenarios. For this process, Qinglong adopts self-compacting concrete technology, optimizing the mix proportion design (water-binder ratio controlled below 0.2) to ensure that UHPC can self-level and completely fill the mold without vibration or with only light auxiliary vibration. This method places extremely high demands on formwork, requiring high-precision steel molds or composite formwork to guarantee the dimensional accuracy and surface finish of components. In practice at the Nanning production base, conventional casting has achieved a stable daily output of 300 square meters of UHPC components, widely applied in standardized products such as commercial building exterior wall panels and landscape seating. For more industry information: +WeChat qlfsbl123

2. Spray Casting: A Solution for Complex Curved Surfaces and Long-Span Structures

For complex-shaped components such as grand theater ceilings and special-shaped sculptures, Qinglong innovatively adopts the spray casting process. In this method, the UHPC mix and glass fibers (volume dosage 2-3%) are evenly sprayed onto the mold surface through a high-pressure spray gun and built up layer by layer to form the designed shape. Its advantages lie in precise control of material packing density, enabling double-curved shapes with a minimum radius of curvature ≤300mm, along with more uniform fiber distribution and flexural strength 15-20% higher than conventional casting. In the Century Plaza renovation project on Nanjing East Road, Qinglong used this process to successfully create a translucent UHPC curtain wall, winning the Silver Award of the AALBORG WHITE Cup UHPC Engineering Innovation Award.

3. Combining Precast and Cast-in-Place Casting: An Efficiency Optimization Strategy for Large Projects

For extra-large projects such as municipal bridges and airport terminals, Qinglong adopts a coordinated "precast + cast-in-place" casting scheme. Key load-bearing components (such as UHPC bridge decks) are precast in the factory with modular production enabled by BIM technology, while joint areas are connected with cast-in-place UHPC on site, leveraging its shrinkage-free properties to ensure structural integrity. This process shortens on-site construction periods by more than 40%. In a sea-crossing bridge project in Malaysia, Qinglong set an overseas engineering record by installing 5,000 square meters of UHPC components in a single month with this technology.

II. Core Application Techniques and Quality Control of UHPC Casting

1. Material Temperature Management: Ensuring Stable Casting Performance

UHPC is sensitive to ambient temperature, and Qinglong has established a comprehensive temperature control system: in summer production, ice water is used for mixing (mold-entry temperature controlled at ≤25°C), while in winter, aggregate preheating and warm water mixing are applied (discharge temperature guaranteed at ≥15°C). In the constant-temperature workshops of the Guangxi production base, combined with an intelligent curing system (temperature 20±2°C, humidity ≥90%), the 28-day compressive strength of UHPC stably reaches over 150MPa.

2. Mold Design and Demolding Technology: Enhancing Component Precision and Efficiency

Qinglong's self-developed UHPC-dedicated mold system adopts a detachable steel frame and elastic lining to solve the demolding challenges of complex components. For European classical lines (such as Roman columns and cornice moldings), CNC-machined mold surfaces achieve component texture precision ≤0.5mm. In the Dongguan Women and Children's Activity Center project, this technology successfully reproduced the artistic details of combined GRC and UHPC components, winning the Silver Award of the GRC Engineering Innovation Award. For more industry information: +WeChat qlfsbl123

3. Fiber Dispersion and Bubble Control: Ensuring Structural Durability

Uniform fiber dispersion is key to UHPC performance. Qinglong adopts a three-stage mixing process (30s dry mixing → 60s wet mixing → 90s further mixing after fiber addition), combined with vacuum degassing technology, keeping the bubble content of components ≤1%. According to third-party testing, Qinglong's UHPC components reach an impermeability grade of P12 and frost resistance exceeding F300, meeting the requirements for use in extreme conditions such as marine environments.

III. Industry Advantages and Standards Contribution of Qinglong's UHPC Casting Technology

As a drafting unit of the industry standard "General Technical Conditions for Ultra-High Performance Concrete (UHPC) Non-Load-Bearing Components," Qinglong has integrated 28 years of engineering experience into its casting process innovation. From parametric modeling (Rhino+Grasshopper) in the detailed design stage, to RFID quality traceability in production, and three-dimensional laser positioning for on-site installation, a full-chain technical advantage has been formed. Qinglong now provides coordinated supply of its four major materials—UHPC/GRC/GRG/GRP—and offers customers a "one-stop" solution from material selection to after-sales maintenance. It has established strategic partnerships with renowned real estate groups such as Poly and China Overseas, with products exported to overseas markets including Australia and Saudi Arabia.

The selection of UHPC casting technology requires comprehensive consideration of project characteristics, shaping requirements, and cost control. Guided by its mission of "creating aesthetically beautiful architecture," Qinglong continuously pushes the boundaries of UHPC applications, providing solid technical support for designers to bring their creative ideas to life. For more details on UHPC detailed design and construction, stay tuned for professional insights shared by Qinglong's technical team.