What Are the UHPC Casting Methods? Forming Processes and Adaptive Application Solutions from Qinglong Group

There is no single casting method for UHPC; the optimal process is selected from among several mature techniques based on factors such as “component shape, dimensions, reinforcement ratio, production conditions, and performance requirements.” Through years of engineering practice, Qinglong Group has mastered and applied a variety of processes, including “self-compacting casting, compression molding, spray molding, extrusion molding, centrifugal casting, and 3D printing.” For example, in the hyperbolic panel project for the Wuhan Han Show Theatre, we adopted self-compacting casting combined with precision molds; for certain thin-walled landscape components, spray molding may be used. Choosing the right casting method is a key step in ensuring that UHPC's outstanding performance is translated from the laboratory into actual structures.

1. Self-Compacting Casting Method (Most Common)

This process exploits UHPC's exceptional flowability and segregation resistance, filling the mold under gravity without vibration or with only slight auxiliary vibration. It is suitable for most precast panels, beams, columns, and components with complex shapes. Key points: pouring points and flow paths must be well designed to prevent cold joints or entrapped air. For deeper components, layer-by-layer casting can be adopted. Qinglong Group has achieved great success using this method in the production of large precast bridge deck panels.

2. Compression/Vibration Press Molding Method

A measured amount of UHPC mix is placed into the mold and compacted by pressure (or by pressure combined with vibration). It is suitable for products with high requirements for surface flatness and patterning, such as thin panels, floor tiles, and exterior wall cladding panels. This method achieves extremely high density and strength, with a smooth surface finish. The high-strength UHPC floor tiles produced by Qinglong Group use this process and offer excellent wear resistance.

3. Spray Molding Method

UHPC slurry and chopped fibers are conveyed separately through pipelines, mixed at the nozzle outlet, and sprayed at high speed onto the mold or substrate. It is particularly suitable for producing special-shaped curved surfaces, reinforcement layers, and thin-shell structures built on site. Its advantages are good fiber orientation and high bond strength with the substrate, but it places high demands on equipment and technicians.

4. Centrifugal Casting Method

The UHPC mix is placed into a high-speed rotating tubular mold and compacted under centrifugal force. It is mainly used to produce ring-shaped cross-section components such as high-strength pipes and utility poles. It forms a layered, dense structure with a very smooth inner wall.

5. 3D Printing (Additive Manufacturing)

This is a cutting-edge technology in which UHPC material is deposited layer by layer through a print head to form three-dimensional solids. It is suitable for producing highly complex, customized architectural components or artworks that are difficult to achieve with traditional molds. Qinglong Group has already begun R&D in this field, exploring new possibilities for the architecture of the future.

Qinglong Group's recommendation: when selecting a casting method, close consultation with the material supplier and the mold manufacturer is essential. In most construction projects, the self-compacting casting method is the most widely used, mature, and reliable choice. Regardless of the method chosen, mold precision, rigidity, and sealing, as well as air venting measures during casting, are universal success factors that must be given the utmost attention.