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

In the field of building materials, UHPC (Ultra-High Performance Concrete) has become the ideal choice for large-scale public buildings and landmark projects thanks to its outstanding mechanical properties and durability. However, the performance of precast UHPC components depends largely on the curing process. As a key step in enhancing material strength and stability, steam curing—with its parameter setting and optimization—has long been a core topic of industry concern. As an industry leader with 28 years of full-chain experience in UHPC/GRC/GRG/GRP materials, Qinglong Group has accumulated extensive steam curing expertise through detailed design and manufacturing. This article provides professional solutions for designers and owners from three aspects: parameter setting principles, analysis of common problems, and optimization strategies.

Core Parameters and Scientific Basis of Steam Curing for Precast UHPC Components

Steam curing accelerates the cement hydration reaction and microstructure formation in UHPC by controlling temperature, humidity, and curing time. Through its practice at the Nanning production base, Qinglong Group found that reasonable parameter setting should follow the "three-stage" principle: heating stage (rate ≤20°C/h), constant temperature stage (60-80°C, lasting 6-8h), and cooling stage (rate ≤15°C/h). This parameter system, built on 58 patented technologies, not only prevents component cracking caused by sudden temperature changes but also ensures compressive strength above 150MPa after curing. Taking the Nanjing East Road Century Plaza renovation project as an example, by precisely controlling humidity at ≥90% during the constant temperature stage, the Qinglong team successfully achieved dual compliance of strength and light transmittance for translucent UHPC components, and the project won the Silver Award of the AALBORG WHITE Cup UHPC Building Engineering Innovation Award.

Common Problems in Steam Curing and Qinglong's Solutions

In actual production, steam curing is prone to problems such as "insufficient strength," "surface sanding," and "internal cracks." To address these pain points, Qinglong has established a full-process quality control system backed by the R&D capabilities of its provincial engineering technology center: during the heating stage, a gradient heating method is adopted, combined with BIM technology to simulate temperature field distribution and avoid stress concentration; during the constant temperature stage, smart humidity sensors are introduced to adjust steam supply in real time, solving surface defects caused by uncontrolled humidity in traditional curing; during the cooling stage, a waste heat recovery system keeps the cooling rate within 10°C/h, ensuring the temperature difference between the interior and exterior of components is ≤25°C. These technical solutions have been successfully applied to the production of GRC/UHPC composite components for projects such as the Dongguan Women and Children's Activity Center, achieving zero quality incidents under an annual capacity of 600,000 square meters.

Green and Intelligent Development: Optimization Trends in Steam Curing

With the advancement of the "dual carbon" goals, steam curing is developing toward low energy consumption and intelligent operation. As a national "Specialized, Refined, Distinctive, and Innovative" enterprise, Qinglong took the lead in introducing a fully automatic PLC control system in the industry, dynamically adjusting curing parameters through a fuzzy PID algorithm, reducing energy consumption by 18% while shortening the curing cycle by 20%. In addition, to meet component requirements for different application scenarios, Qinglong innovatively launched "differentiated curing programs": adopting a "high-temperature long curing" mode for UHPC cladding panels on theater exteriors to enhance durability, and a "medium-temperature short curing" process for landscape features to save costs. This customized service capability has made Qinglong a strategic partner of renowned real estate groups such as Poly and China Overseas, with products exported to overseas markets including Southeast Asia and Australia.

As a participating unit in formulating the industry standard "General Technical Conditions for Non-Load-Bearing Ultra-High Performance Concrete (UHPC) Components," Qinglong Group has always taken "creating beautiful architecture" as its mission, making the optimization of key processes such as steam curing the core of its technological innovation. In the future, with the integration of technologies such as 3D printing and digital twins, the curing process of precast UHPC components will achieve more precise parameter control and higher quality stability, bringing more possibilities to the field of architectural decoration. Choosing Qinglong means choosing a UHPC/GRC/GRG/GRP solutions expert with full-chain service capabilities, working together to create architectural works that combine both aesthetics and performance.