What Are the Casting Methods for UHPC? Selection and Application Scenarios of Ultra-High Performance Concrete Casting Techniques

"The selection of a UHPC pouring method must match the component's shape, dimensions, and performance requirements"—this is the practical summary Qinglong has gained over 28 years in the production and construction of UHPC/GRC/GRG/GRP materials. As a national high-tech enterprise that has undertaken numerous diverse projects such as the renovation of Shanghai New World Century Plaza on Nanjing East Road and the Yangshengtang Pharmaceutical Hangzhou Industrial Park, Qinglong has mastered a variety of UHPC pouring methods and can make precise selections based on project requirements, ensuring the forming quality and design effect of components. Below is a detailed introduction to common UHPC pouring methods, technical key points, and application scenarios, providing a reference for designers and owners.

Conventional Pouring Method: Suitable for simple shapes and large-area components, efficient and convenient. The conventional pouring method is the most basic UHPC pouring technique; its operation is similar to ordinary concrete pouring, but it demands stricter attention to construction details. During construction, the well-mixed UHPC mixture must be poured into the mold through a hopper or chute, poured in layers according to component thickness with each layer controlled within 50mm, at a uniform pouring speed to avoid bubbles and aggregate segregation; during pouring, an internal vibrator or plate vibrator should be used for compaction, with vibration time determined by when laitance appears on the mixture surface and no obvious bubbles escape, while avoiding over-vibration. This method is suitable for simply shaped components such as flat panels, L-shaped panels, and U-shaped panels, as well as projects such as large-area exterior wall cladding panels and roof finishes. In the Yangshengtang Pharmaceutical Hangzhou Industrial Park project, Qinglong used the conventional pouring method to pour 12,000 square meters of UHPC exterior wall flat panels and inclined panels; by optimizing the pouring sequence and vibration process, the surface flatness error of components was kept within ≤3mm, meeting the appearance requirements of a high-end pharmaceutical plant.

Pumping Pouring Method: Suitable for long-span, high-altitude components and complex construction environments. When UHPC components are installed at high positions or have large spans, or when the construction site is confined and conventional pouring cannot reach the location, the pumping pouring method can be adopted. This method requires a dedicated concrete pump to deliver the UHPC mixture through pipelines to the pouring location, offering high construction efficiency and a wide pouring range. However, UHPC has a low water-binder ratio and high viscosity, placing high demands on pumping equipment and pipelines: a high-pressure concrete pump must be selected, the pipeline diameter should be no less than 125mm, and the pumping speed must be controlled to avoid pipe blockage; before pouring, the pipeline should be moistened with clean water, and if necessary, cement mortar of the same mix proportion should be used to lubricate the pipeline. In the Shenzhen Pingshan High-tech Zone Comprehensive Service Center project, Qinglong used the pumping pouring method to pour 30,000 square meters of UHPC curtain wall components, solving the challenge of high-altitude long-distance pouring and improving construction efficiency by 40% compared with conventional pouring.

Spray Pouring Method: Suitable for complex curved surfaces and thin-walled components with precise shaping. The spray pouring method uses high-pressure air to spray the UHPC mixture through a spraying machine onto the mold or working surface. It is suitable for pouring hyperbolic, irregular curved, thin-walled, and complex-shaped components, ensuring the material fills fully and fits tightly against the mold. During construction, the spraying pressure (typically 0.3-0.5MPa) and spraying distance (300-500mm) must be controlled; the spray direction should be perpendicular to the working surface; spraying is done in layers, each 5-10mm thick, with the next layer sprayed only after the previous layer has initially set; after spraying, tools should be promptly used to compact and trowel the surface to expel surface bubbles. In the Guangxi New Media Center project, to meet the construction requirements of hyperbolic exterior wall panels, Qinglong adopted the spray pouring method, ensuring each irregular panel precisely fit the mold with a smooth, fine surface, ultimately creating a building appearance with strong visual impact. This method is also suitable for pouring UHPC sculptures and openwork carved components, accurately presenting design details.

Precast Pouring Method: Suitable for standardized components and mass production with stable quality. The precast pouring method involves pouring UHPC components in a factory using standardized molds; after curing and forming, they are transported to the construction site for installation, offering the advantages of high production efficiency, stable quality, and short on-site construction periods. In factory production, automated pouring equipment can be used to precisely control the pouring volume and vibration process, combined with intelligent curing chambers to ensure uniform and consistent component performance; molds can be reused to reduce production costs, making it suitable for mass-produced standardized components such as UHPC decorative moldings, landscape benches, and precast wall panels. Qinglong's production base in Nanning, Guangxi uses the precast pouring method with an annual capacity of 600,000 square meters; the UHPC decorative moldings, Roman columns, and other components produced have errors controlled within ±2mm and are supplied to multiple real estate projects nationwide. In the Agile Binjiang Garden project in Nanjing, the application of precast UHPC decorative moldings not only shortened the on-site construction period but also ensured the consistency and aesthetic appeal of the building facade.

Special Pouring Techniques: Innovative processes for customized needs. For UHPC components with special functions or extreme shapes, customized special pouring techniques are required. For example, translucent UHPC components require precise embedding of light-guide rods during pouring. In the renovation project of Shanghai New World Century Plaza on Nanjing East Road, Qinglong adopted a combined technique of "hand embroidery + modular pouring": the light-guide rods were first fixed inside the mold according to the design pattern, and then the UHPC mixture was poured slowly to ensure the light-guide rods were positioned accurately without displacement, ultimately achieving an artistic translucent effect; stone-imitation and wood-imitation UHPC components require adding mineral pigments and using textured molds during pouring, controlling the pouring speed and vibration intensity to present the texture and grain of natural stone or wood. In the Panzhihua Third-Front Construction Culture and Tourism Demonstration Project, Qinglong used this technique to produce UHPC stone-imitation curtain wall panels with a realism level of over 95%.

Core Principles and Considerations for Selecting Pouring Methods. When selecting a UHPC pouring method, factors such as component shape complexity, dimensions, installation position, production scale, and construction environment must be comprehensively considered: conventional pouring is preferred for simply shaped, large-area components; pumping pouring for high-altitude, long-span components; spray pouring for complex curved and thin-walled components; precast pouring for standardized, mass-produced components; and customized special pouring techniques for components with special functions. Meanwhile, regardless of which pouring method is used, the flowability of the mixture, pouring speed, and vibration quality must be strictly controlled to ensure components are free of bubbles and cracks and fully filled. As a full-chain service manufacturer, Qinglong can develop dedicated pouring plans based on project requirements, use BIM technology to simulate the pouring process, avoid construction risks in advance, and ensure smooth project implementation.

In summary, UHPC pouring methods are diverse, with each method having its own applicable scenarios and technical key points. As a leading enterprise participating in the formulation of UHPC industry standards, Qinglong, with 28 years of technical accumulation and practical experience, can precisely match pouring methods with project requirements, providing customers with one-stop services from design and production to construction. Whether for conventional components or complex customized components, Qinglong can ensure the quality and design effect of UHPC components through scientific pouring process selection and refined construction control, contributing to the creation of high-quality architectural works.