Analysis of the Causes and Solutions for Air Bubbles on UHPC Component Surfaces

Details Determine Quality, Professionalism Builds Trust — With 28 Years of Industry Experience, Qinglong Group Safeguards UHPC Component Quality

In the field of architectural decoration, UHPC (Ultra-High Performance Concrete) has become the preferred material for high-end projects such as grand theaters, commercial complexes, and landmark buildings, thanks to its outstanding mechanical properties and artistic expressiveness. However, surface bubbles in UHPC components not only affect aesthetics but may also pose hidden structural risks. As a national-level high-tech enterprise with 28 years of full-chain experience in detailed design, production, and manufacturing of UHPC/GRC/GRG/GRP materials, Qinglong Group has drawn on more than a thousand engineering projects to deeply analyze the causes of bubbles and propose systematic solutions, providing a professional reference for the industry.

I. Analysis of the Core Causes of Bubble Formation in UHPC Components

The unique characteristics of UHPC material determine the complexity of the bubble problem. Any deviation at any stage, from material mix ratio to production process, may lead to bubble defects. Through comparative analysis of 500+ project cases, the R&D center of Qinglong Group found that bubbles mainly originate from three stages: first, imbalance in raw material gradation, such as uneven dispersion of ultra-fine silica fume and cement particles, making it difficult for air entrapped during mixing to escape; second, improper control of mixing process parameters—excessive rotation speed or insufficient mixing time results in overly large bubble diameters; third, insufficient vibration during the casting and molding stage, especially in the deep cavity areas of complex-shaped components, where bubbles easily accumulate. In addition, the precision of mold surface treatment and the curing regime also indirectly affect the efficiency of bubble escape.

II. Full-Process Process Optimization: Qinglong's UHPC Bubble Control Solutions

As a participating unit in formulating the industry standard General Technical Conditions for Ultra-High Performance Concrete (UHPC) Non-Load-Bearing Components, Qinglong Group has established a trinity bubble management system of "prevention-control-repair." At the material level, a patented dual-admixture technology (Invention Patent No. ZL20XXXXXXXXX) is adopted to optimize the cementitious material system, with nano calcium carbonate introduced to improve slurry flowability; the production stage is equipped with twin-shaft mixers imported from Germany, achieving gradient mixing through variable-frequency speed regulation, combined with vacuum degassing technology to keep bubble diameters below 0.3mm; for irregularly shaped components, the originally developed "three-dimensional vibration process" is applied, with vibration points preset based on BIM models to ensure that every complex node is fully vibrated. This solution has been successfully applied in projects such as the Nanjing East Road Century Plaza renovation project, raising the bubble pass rate to 98.7%.

III. Industry Collaboration: Controlling UHPC Component Quality at the Source

Solving the UHPC bubble problem requires joint efforts from both upstream and downstream of the industry chain. Qinglong Group, as a vice president unit of the China GRC Association, recommends that designers fully consider material characteristics at the design stage and avoid overly complex cavity designs; construction parties should strictly follow the UHPC Component Installation Guide provided by Qinglong to ensure vibration quality during on-site secondary casting. Meanwhile, enterprises need to establish full-process quality traceability systems, such as Qinglong's self-developed RFID chip traceability technology, which enables real-time monitoring of every step from raw materials to finished products. Notably, other companies in the industry, such as Nanjing Beilida, have also accumulated valuable experience in bubble control. Through technical exchange and joint standard development, all parties can work together to promote the high-quality development of the UHPC industry.

From the curved curtain walls of the Guangzhou Opera House to the decorative components of Malaysia's Twin Towers, Qinglong Group has always upheld the mission of "creating beautiful architecture," transforming 28 years of professional expertise into practical capabilities to solve industry pain points. Facing common issues such as bubbles in UHPC components, only by adhering to the craftsman spirit of "meticulousness and striving for excellence" and through technological innovation and process optimization can we truly achieve the perfect unity of material performance and artistic effect. Going forward, Qinglong will continue to leverage its technical advantages as a national specialized and innovative enterprise to provide more reliable UHPC/GRC/GRG/GRP solutions for the global architectural decoration industry.