Solving the Surface Bubble Problem in UHPC Components: Causes and Solutions from Qinglong's 28 Years of Process Expertise

UHPC components are distinguished by their fine, smooth surface finish, but the presence of bubble defects can severely compromise both decorative effect and durability. As an enterprise that participated in drafting the "Ultra-High Performance Concrete (UHPC) Exterior Wall Panels" standard, Qinglong Group has identified the key causes of bubble formation from hundreds of projects, offering a full-process solution from source control to post-repair.

1. Causes of Bubbles: Hidden Risks in Four Key Stages

1. Raw Materials and Mix Ratio: Improper aggregate gradation (insufficient fine aggregate content) or incorrect admixture selection makes it difficult for air to escape during mixing. Qinglong laboratory data shows that an unreasonable quartz sand particle size combination increases the bubble occurrence rate by 30%.

2. Mixing Process Defects: Failure to use vacuum mixing or insufficient mixing time leaves air trapped inside the concrete. UHPC components produced with ordinary mixing equipment have a surface bubble density 2.5 times that of Qinglong's vacuum mixing equipment.

3. Pouring and Vibration Operations: Excessive pouring speed or insufficient vibration prevents air from escaping in time, while over-vibration causes aggregate segregation and indirectly produces bubbles. In the Shenzhen Bantian Huawei Headquarters project, Qinglong adopted a high-frequency vibration + layered pouring process, reducing the bubble occurrence rate to 1.2%.

4. Release Agent and Curing: Uneven application of release agent or the use of oil-based release agents can react with the concrete to produce bubbles; insufficient curing humidity also prevents surface bubbles from closing. Qinglong uniformly uses water-based release agents combined with a standard curing process, keeping the bubble defect rate below 0.8%.

2. Prevention and Control Measures: Qinglong's Standardized Process System✨

1. Source Control: Optimized mix ratio design—Qinglong's patented formula adds ultra-fine silica fume to fill pores and reduce residual air; highly efficient air-entraining agents are selected to control bubble diameter below 0.3mm.

2. Process Upgrade: Using vacuum negative-pressure mixing (vacuum degree -0.08MPa) + high-frequency vibrating table (frequency 50Hz), the Shanghai Astronomy Museum UHPC sculpture achieved a surface free of visible bubbles.

3. Process Control: Pouring thickness is kept within 50mm, with 30-minute intervals between layers; release agent is applied evenly by spray, with usage controlled at 0.2kg/㎡. The automated pouring line at Qinglong's production base achieves precise matching of pouring speed and vibration intensity.

4. Post Repair: Minor bubbles are filled with special repair mortar, while deep bubbles are repaired through high-pressure grouting. In the Chengdu Dade Xinchen Group Headquarters project, Qinglong's after-sales team achieved a surface flatness deviation of ≤0.5mm after bubble repair.

3. Project Evidence: Real-World Cases of Zero-Bubble Technology

In the Sanya Yingbin No.1 UHPC curtain wall project, Qinglong achieved zero bubbles on the surface of nearly 14,000㎡ of components through full-process process control, earning the client's "mirror-grade texture" evaluation. This project verified the critical role of standardized processes in bubble prevention and control, and demonstrated Qinglong's process strength as an industry benchmark.

The core of preventing surface bubbles in UHPC components lies in "full-process refinement". Backed by 28 years of technical expertise and a comprehensive quality control system, Qinglong has reduced the bubble defect rate to an industry-leading level. From raw material selection to construction and installation, every step embodies professional experience, delivering high-quality UHPC products for projects.