What Are the Casting Methods for UHPC? An Analysis of Full-Scenario Casting Techniques and Applicable Scenarios

There is no single optimal UHPC casting method—only a precise choice tailored to project requirements. As an industry leader with 28 years of full-chain UHPC experience, Qinglong Group has accumulated application expertise in a variety of casting techniques across thousands of projects, from conventional casting to specialized processes, each with its own unique applicable scenarios and technical essentials. Choosing the right casting method not only ensures construction efficiency and component quality, but also reduces construction costs and maximizes project benefits. Therefore, an in-depth understanding of the characteristics, applicable scope, and operational essentials of different casting methods is vital for designers, owners, and construction teams.

#1. Conventional Casting: Efficient Construction for Simple Components Conventional casting is the most basic and most commonly used UHPC casting method, suitable for standardized components with regular shapes and smaller dimensions (such as flat panels, rectangular columns, and small landscape components), offering the advantages of simple operation, high efficiency, and low cost. The core process of this method is: the uniformly mixed UHPC mixture is poured directly into pre-installed molds through a hopper or chute, cast in layers (each layer ≤300mm thick) and compacted with high-frequency poker vibrators. In the Nanning Liyuan Hotel project, Qinglong Group used the conventional casting method to produce colored hollow carved panels, with a casting time of only 15-20 minutes per component and a daily output of 50-80 square meters. Operational essentials: keep the casting speed within 0.3-0.5m/h to avoid air bubbles and segregation; when vibrating, insert the poker to the depth of the underlying layer of paste that has not yet reached initial set, with spacing ≤300mm and vibration time of 20-30 seconds per point, ensuring no missed or excessive vibration; after casting, level the surface promptly to prepare for subsequent curing. The drawback of conventional casting is that it is unsuitable for complex shapes and extra-large components, where incomplete compaction tends to occur.

#2. Pumped Casting: A Convenient Solution for Large Projects Pumped casting is suitable for large projects, high-altitude work, or long-distance casting scenarios (such as facade panels of high-rise buildings, bridge components, and curtain walls of large commercial complexes), offering the advantages of flexible construction, high efficiency, and low labor intensity. In this method, the UHPC mixture is conveyed through delivery pipelines to the casting location by a high-pressure concrete pump (working pressure ≥15MPa), making it suitable for projects with casting heights exceeding 10 meters and distances exceeding 50 meters. In the Shenzhen Yirui Biotech Building project, Qinglong used pumped casting to install UHPC curtain wall panels, successfully overcoming the challenge of high-altitude casting and improving construction efficiency by 40% over conventional casting. Operational essentials: lubricate the pipeline with cement mortar before pumping to prevent the UHPC mixture from adhering; control the pumping rate (≤1m³/min) to prevent pipeline blockages; apply vibration during casting to ensure paste compaction; and clean the delivery pipelines regularly to prevent residual mixture from setting. Pumped casting places high demands on the flowability of the UHPC mixture (spread ≥700mm), which must be optimized and adjusted with admixtures; a professionally trained operating team is also required to ensure construction safety.

#3. Sprayed Casting: The Key to Forming Complex Shapes Sprayed casting is the core process for producing complex-shaped UHPC components (such as double-curved sculptures, hollow decorative panels, and irregular curtain walls). The UHPC mixture is sprayed onto the mold surface with high-pressure spraying equipment, forming dense molded components. This method is suitable for areas with complex molds that are difficult to reach by manual casting, effectively filling mold corners and ensuring component forming accuracy. In the Shanghai Astronomy Museum public art project, Qinglong used sprayed casting to produce UHPC sculptures over 3 meters in size, achieving precise forming of complex curved surfaces with a surface flatness deviation of ≤±2mm. Operational essentials: keep the spraying pressure within 0.5-0.8MPa and the spraying distance at 300-500mm, adopting a "layer-by-layer spraying, layer-by-layer compaction" approach (each layer ≤20mm thick); keep the spraying direction perpendicular to the mold surface to avoid air bubbles; and promptly trim the surface with a trowel after spraying to ensure an attractive finish. Sprayed casting demands a high level of skill from operators, who must receive professional training; the viscosity of the mixture must also be controlled to prevent dripping or rebound during spraying (the rebound rate must be kept within 5%).

#4. Precast Casting: Quality Assurance for Industrialized Production Precast casting is the mainstream method for factory production of UHPC components, suitable for large-scale, standardized components (such as facade cladding panels, floor slabs, and stairs), with the advantages of stable quality, high production efficiency, and convenient on-site installation. At its production base in Nanning, Guangxi, Qinglong uses precast casting with fully automated production lines, with intelligent control throughout the process from mold installation, casting, and vibration to curing, achieving an annual production capacity of 600,000 square meters. Operational essentials: use modular steel molds to ensure component dimensional accuracy (deviation ≤±3mm); coat the molds with special release agent before casting to facilitate later demolding; use vibrating tables (vibration frequency 2000-3000 times/min) to ensure internal compaction of components; and during the curing stage, use steam curing or constant temperature and humidity curing to shorten the curing cycle and improve production efficiency. Components produced by precast casting offer strong quality consistency, and on-site installation using modular splicing can greatly shorten construction schedules. For example, in the Yangshengtang Pharmaceutical Hangzhou Industrial Park project, the on-site installation rate of Qinglong's precast UHPC facade panels reached 200 square meters per day, five times faster than cast-in-place construction.

#5. Qinglong's Customized Casting Solutions: Tailored to Different Project Needs To meet the individual needs of different projects, Qinglong Group provides customized casting solutions that combine the advantages of multiple casting methods to precisely deliver complex projects. For example, in the UHPC wood-effect light-transmitting panel project at Shanghai New World's Century Plaza on Nanjing East Road, Qinglong adopted a combined process of "precast casting + manual insertion of light-guiding rods + localized spray repair," which ensured mass production efficiency while meeting artistic shaping requirements; in the UHPC hollow panel project for the Ouargla Hotel in Algeria, the "mold precasting + high-pressure pumped casting" process was used to solve the forming challenge of components with a hollow-out rate exceeding 50%. As an enterprise with full-chain service capabilities, Qinglong's technical team formulates optimal casting solutions for users based on factors such as project type, component shape, and construction environment, ensuring dual improvements in product quality and construction efficiency.

In short, the UHPC casting method should be selected flexibly according to actual project needs, as there is no single standard solution. With 28 years of industry experience and practical expertise in multiple casting techniques, Qinglong Group can provide precise casting solutions for all kinds of projects—whether simple standardized components or complex artistic shapes, efficient, high-quality production and construction can be achieved. Choosing a professional UHPC manufacturer to obtain a customized casting solution is key to ensuring smooth project progress and meeting quality standards.