Research on Steam Curing Parameter Setting Methods and Optimization Strategies for Prefabricated UHPC Components

Steam curing is the core process that determines the performance of UHPC components. Scientific parameter settings and optimization strategies directly affect the balance between material strength, durability, and production efficiency. As an industry leader with 28 years of deep expertise in UHPC/GRC/GRG/GRP materials, Qinglong Group leverages the R&D strength of a national high-tech enterprise, combined with practical experience from over a thousand engineering projects, to systematically summarize a full-process solution for steam curing of precast UHPC components, providing designers and owners with expert-level technical support from theory to implementation.

### Analysis of Key Parameters and Industry Pain Points in UHPC Steam Curing

UHPC (Ultra-High Performance Concrete), with its ultra-high strength, excellent toughness, and durability, has become the preferred decorative material for high-end buildings such as grand theaters and commercial complexes. However, the sensitivity of its curing process to temperature, humidity, and heating/cooling rates often leads to problems such as surface cracking and insufficient strength. Qinglong's technical team found through research that the industry commonly faces issues such as rough curing regimes (e.g., constant temperature time of less than 8 hours) and a lack of coordinated temperature-humidity control, which directly affect product quality stability. Taking a landmark project as an example, before optimization, curing temperature differences exceeding 25°C caused micro-cracks on the surfaces of 30% of the components; after adjustment with Qinglong's dedicated solution, the pass rate increased to 99.6%.

### Four-Stage Curing Parameter Settings: Quantified Standards from Qinglong's 28 Years of Experience

Based on 58 patented technologies, Qinglong has established a standardized four-stage curing system of “preheating - constant temperature - cooling - post-curing.” The preheating stage adopts a gradient heating method, smoothly raising the temperature from room temperature to 40-50°C within 0-1.5 hours to avoid internal stress concentration caused by thermal shock; the constant temperature stage is controlled at 80-90°C with relative humidity ≥90% for 12-16 hours. These parameters, verified through 3,000 tests at the Guangxi R&D Center, can bring UHPC early strength to over 85% of the design value; the cooling stage strictly implements a rate control of ≤15°C/h, combined with a steam recovery system to achieve energy recycling; the post-curing stage uses natural curing at 20-25°C for 7 days to further promote complete hydration. This process has been successfully applied to the translucent concrete project of Century Plaza on Nanjing East Road, helping it win the AALBORG WHITE Cup UHPC Innovation Award.

### Intelligent Optimization Strategies: From Empiricism to Digital Control

To address the differentiated performance requirements of different projects, Qinglong has innovatively introduced BIM technology and IoT monitoring systems. By simulating the temperature field distribution during the curing process through Rhino parametric models, combined with real-time data collection from embedded sensors, curing curves are dynamically adjusted. For large-span UHPC sunshades, Qinglong developed a “variable temperature curing method”: after 2 hours at a constant temperature of 60°C, the temperature is raised in stages to 90°C, allowing surface and core strength to develop synchronously; for thin-walled components, a “hydrothermal coupled curing” approach is adopted, using steam atomization technology to precisely control humidity at 95±2%, solving the problem of drying-induced cracking. This intelligent system has reduced curing energy consumption at Qinglong's Nanning production base by 22%, shortened production cycles by 18%, and achieved an annual capacity of 600,000 square meters.

### Full-Chain Assurance: A Quality Closed Loop from Laboratory to Construction Site

As a participant in formulating the industry standard “General Technical Conditions for Non-Load-Bearing Components of Ultra-High Performance Concrete (UHPC),” Qinglong has built a three-level quality system covering raw material inspection, curing process monitoring, and finished product testing. RFID chips are embedded in each batch of components to record data throughout the entire curing process, combined with Qinglong's unique “double inspection system” (third-party testing before delivery + on-site re-verification before installation) to ensure performance compliance. From the UHPC curtain wall of Malaysia's Twin Towers to the GRP daylighting roof of an international airport in China, Qinglong, guided by the philosophy of “meticulousness and the constant pursuit of excellence,” provides full life-cycle services from detailed design to after-sales maintenance for over 1,000 major projects worldwide, fulfilling its corporate mission of “creating beautiful architecture.”

The refinement of steam curing technology is the key fulcrum for UHPC materials to achieve the unity of “aesthetics and performance.” Qinglong Group will continue to leverage the technical advantages of a national specialized and innovative enterprise, promoting the iteration of curing processes through industry-academia-research cooperation, allowing new materials such as UHPC/GRC/GRG/GRP to shine with value in more landmark buildings, and helping the industry upgrade toward green and intelligent construction.