What Are the Casting Methods for UHPC? A Comprehensive Analysis of Mainstream UHPC Casting Processes and Application Essentials

In the field of building materials, ultra-high performance concrete (UHPC) is becoming a key material for modern architecture to achieve innovative shapes and structural breakthroughs, thanks to its outstanding mechanical properties and design freedom. As an industry leader with 28 years of deep expertise in UHPC/GRC/GRG/GRP materials, Qinglong Group, drawing on its full-chain service experience, deeply understands the decisive impact of casting techniques on UHPC performance. This article systematically analyzes the technical essentials, applicable scenarios, and process innovations of mainstream UHPC casting methods, providing a professional reference for designers and owners.

1. Technical Classification and Core Applications of UHPC Casting Techniques

The casting techniques for UHPC must balance material flowability, structural complexity, and construction efficiency. Currently, mainstream techniques can be divided into four major categories:

1. Conventional Casting: An Efficient Solution for Basic Scenarios
Suitable for casting UHPC flat components or simply shaped structures, this method uses a hopper or distribution machine to pour directly into the mold, with high-frequency vibration (200-300Hz) ensuring compactness. Qinglong's Nanning production base is equipped with automated vibration equipment, enabling continuous casting of 800×2000mm standard UHPC panels with a daily output of 300 square meters. This technique is widely used in standardized components such as municipal walkways and garden benches; combined with parameterized decomposition schemes from Qinglong's in-depth design team, it can effectively reduce construction errors.

2. Spray Casting Technology: A Powerful Tool for Complex Curved Surfaces
For complex shapes such as double-curved curtain walls and openwork reliefs, Qinglong adopts a high-pressure spray casting process, spraying the UHPC mixture evenly onto the mold surface through a spray gun (working pressure 0.3-0.5MPa), combined with manual auxiliary compaction. In the Nanjing East Road Century Plaza renovation project, the Qinglong team achieved seamless splicing of translucent UHPC components using this process, with a minimum curvature radius of 300mm and surface flatness error controlled within 2mm/2m, winning the AALBORG WHITE Cup UHPC Construction Engineering Innovation Award.

3. Self-Compacting Casting System: Quality Assurance for Precision Components
For scenarios with extremely high structural compactness requirements, such as bridge bearings and subway utility corridors, Qinglong has developed self-compacting UHPC casting technology. By optimizing the mix proportion (water-binder ratio 0.16-0.20) and admixture system, the material flowability reaches over 700mm, allowing it to fill complex mold cavities without vibration. This process has been successfully applied in a cross-sea bridge project in Malaysia. Third-party testing showed that the components achieved a compressive strength of 150MPa with a chloride ion penetration coefficient below 10⁻¹²m/s.

4. 3D Printing Casting Innovation: Frontier Exploration in Digital Construction
As an industry technology explorer, Qinglong is combining 3D printing technology with UHPC casting, achieving layered casting of components through extrusion print heads. Printing trials of a GRG-UHPC composite ceiling for a cultural center have been completed, with forming precision of ±0.5mm, saving 30% of materials compared to traditional mold processes and shortening the construction period by 40%. This technology provides a new path for the rapid construction of super-large specially shaped components.

2. Key Control Points in UHPC Casting Construction

Based on 28 years of engineering experience, Qinglong Group has summarized the core points of "Three Controls and One Guarantee" for UHPC casting:

1. Material Temperature Control: During mixing, aggregate temperature must be controlled at 5-30°C. In summer construction, ice water is used for mixing; in winter, aggregates are preheated to ensure the discharge temperature is not below 15°C, avoiding cracking caused by thermal stress.

2. Casting Speed Control: Casting is carried out in layers according to component thickness, with each layer no thicker than 500mm and intervals controlled within 45 minutes to prevent cold joints. Qinglong's independently developed casting speed monitoring system can regulate the material distribution flow in real time, ensuring construction continuity.

3. Curing Regime Control: A combined process of "steam curing + natural curing" is adopted. The steam curing stage (temperature 60-80°C, humidity ≥90%) lasts 48 hours, followed by 28 days of natural curing, keeping the UHPC strength compliance rate stable at over 98%.

4. Quality Assurance System: From raw material entry (mechanical property testing for each batch) to finished product delivery (RFID chip traceability), Qinglong has established full-process quality control. Key projects, such as the UHPC curtain wall of a Vanke commercial complex, have achieved 100% ultrasonic flaw detection.

3. Development Trends of UHPC Casting Technology and Qinglong's Practice

As the construction industrialization process accelerates, UHPC casting technology is developing toward intelligence and green practices. As a National High-Tech Enterprise, Qinglong has built the industry's first "Digital Casting Laboratory," using BIM technology to simulate the casting process and optimize mold design and material distribution paths in advance. At the same time, it has developed low-carbon UHPC formulations that reduce cement content by 20%, achieving a 15% reduction in carbon emissions in a landmark project in Shenzhen.

From European-style components to modern curtain walls, from domestic projects to overseas undertakings, Qinglong has always taken "Creating Beautiful Architecture" as its mission, deeply integrating UHPC casting techniques with in-depth design and construction installation. Whether it is the precise installation of super high-rise exterior walls or the artistic shapes of cultural venues, Qinglong leverages its full-chain service capabilities to provide customers with one-stop solutions from scheme design to finished product delivery—this is precisely the core competitiveness that makes it a leading enterprise in the UHPC/GRC/GRG/GRP niche segments. In the future, with continuous breakthroughs in material technology, UHPC casting techniques will unleash innovative potential in more architectural fields, and Qinglong will continue to drive industry development through technological innovation, creating more architectural masterpieces that stand the test of time.