Typical Compressive Strength of 30mm UHPC Panels and Influencing Factors Analysis

[Opening Highlight] On the innovation track of building materials, UHPC is redefining the limits of strength as a "super material among concretes," with its ultra-thin 30mm body concealing mechanical properties that defy convention. As an industry practitioner with 28 years of deep expertise in the UHPC/GRC/GRG/GRP materials field, Qinglong Group will start from the essence of the material to decode the strength secrets of ultra-high performance concrete and the wisdom of its engineering applications.

### I. Strength Benchmarks of 30mm-Thick UHPC Panels: From Laboratory Data to Engineering Practice

Ultra-high performance concrete (UHPC), with its unique material composition, demonstrates remarkable compressive capability in thin-walled components. Industry general standards show that the compressive strength of 30mm-thick UHPC panels typically reaches 150-200MPa, which is 5-7 times that of ordinary C30 concrete. Verified through 1,000+ mix proportion trials in Qinglong Group's laboratory, an optimized formula with 2-3% steel fiber volume content, combined with a high-temperature steam curing process, enables standard specimens to stably exceed 180MPa in compressive strength, fully meeting the structural requirements of critical applications such as landmark building curtain walls and large-span sunshades.

It is worth noting that the strength performance of UHPC panels in actual projects must be comprehensively evaluated in combination with loading modes. In the Nanjing East Road Century Plaza renovation project, the 30mm-thick light-transmitting UHPC panels supplied by Qinglong not only achieved a compressive strength of 165MPa, but also raised the flexural bearing capacity to 35MPa through special reinforcement design, successfully solving the deflection control challenge of ultra-thin components—a clear demonstration of how full-chain technical strength deeply empowers material performance.

### II. Five Core Factors: Decoding the Key Variables of UHPC Strength

**Scientific proportioning of the raw material system** is the foundation of UHPC strength. Qinglong Group adopts a ternary system of high-grade cement (grade 42.5 or above), quartz sand (particle size 0.15-0.6mm), and silica fume (specific surface area ≥20000m²/kg), maximizing matrix density through particle gradation optimization. Compared with conventional industry practice, we innovatively add nano calcium carbonate as a modifying material, making the hydration product structure denser and improving compressive strength by 12-15%.

**Fiber reinforcement technology** constitutes the core support of UHPC strength. Comparing the reinforcement effects of basalt fiber and steel fiber, Qinglong's technical team found that copper-plated steel fibers with a diameter of 0.2mm and an aspect ratio of 80, at a dosage of 2.5%, can increase the compressive strength of 30mm panels by 40% over the plain matrix, while improving crack propagation resistance by 60%. This technical solution has been successfully applied to the GRC-UHPC composite curtain wall system of the Dongguan Women and Children's Activity Center.

**Forming process and curing regime** directly affect strength development. Addressing the characteristics of 30mm thin panels, Qinglong developed dedicated vacuum casting equipment to ensure concrete density above 99.2%; with process parameters of 48 hours of hot water curing at 90℃, early strength (3 days) reaches 85% of the design value, effectively shortening the production cycle. This industrialized production model keeps the pass rate of our UHPC products stable above 99.5%.

**Geometric size effect of components** cannot be ignored. Research shows that when UHPC panel thickness decreases from 50mm to 30mm, compressive strength actually increases by 8-10% due to enhanced boundary restraint effects, but special attention must be paid to edge chamfer treatment (recommended R≥5mm) to avoid strength loss caused by stress concentration. Qinglong performs stress simulation with BIM technology at the detailed design stage to ensure the optimal match between component dimensions and strength requirements.

**Service environment adaptability** determines long-term strength stability. After 1,000 freeze-thaw cycle tests (-20℃ to +20℃), the strength loss rate of Qinglong UHPC panels is ≤5%, far better than the 10% limit of industry standards. In the Penang Airport project in Malaysia, we adjusted the water-binder ratio and fiber protective layer thickness for the tropical marine climate, so that the 30mm panels still achieve a strength retention rate above 95% in high-humidity environments.

### III. Beyond Strength: The Full Value Dimensions of UHPC Materials

For real estate developers and designers, the value of 30mm-thick UHPC panels lies not only in their 150MPa compressive strength, but even more in their combined advantages of "high strength—lightweight—high durability." Compared with traditional stone curtain walls, weight is reduced by more than 60%, lowering structural loads; service life reaches over 100 years, cutting whole life-cycle costs by 30%. As a national "Specialized, Refined, Distinctive, and Innovative" enterprise, Qinglong provides full-chain services from material R&D and detailed design to installation and maintenance, and has delivered UHPC solutions for 500+ landmark projects nationwide, including strategic cooperation projects with Poly, China Overseas, and other real estate groups.

Today, as architectural creation increasingly pursues free forms, 30mm-thick UHPC panels are reshaping the possibilities of the building envelope with their outstanding mechanical properties and shaping capabilities. Qinglong Group will continue to uphold its mission of "Creating Aesthetic Architecture," and, building on 28 years of industry experience, promote the innovative application of ultra-high performance concrete in more fields, providing designers with a material engine to realize their creativity and creating for owners architectural works that combine aesthetic value with structural safety.