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

Steam Curing of Precast UHPC Components: A Practical Guide to Parameter Optimization and Process Innovation

Across the entire production chain of Ultra-High Performance Concrete (UHPC) components, the steam curing process is the pivotal link that turns stone into gold, directly determining the densification of the material's microstructure and the stability of its mechanical properties. As an industry player with 28 years of deep expertise in UHPC/GRC/GRG/GRP materials, Qinglong Group has developed a steam curing parameter optimization system balancing both efficiency and quality, drawing on technical experience from over a thousand projects and the annual capacity of 600,000 ㎡ at its Nanning production base. This article systematically analyzes the core parameter setting logic for steam curing of precast UHPC components, providing the industry with practical process optimization solutions.

### The Parameter Code of UHPC Steam Curing: From Theory to Practice

In essence, steam curing accelerates the cement hydration reaction and microstructure formation through precise control of temperature and humidity. In Qinglong's standardized production process, the curing cycle is divided into four stages: the rest period (2-4 hours, 20-25℃), the heating period (2-3 hours, rate ≤20℃/h), the constant temperature period (6-8 hours, 80-90℃), and the cooling period (3-4 hours, rate ≤15℃/h). This parameter setting not only avoids internal stress cracking caused by overly rapid heating, but also promotes the full formation of C-S-H gel through a constant temperature environment above 80℃. Testing shows that UHPC components produced with this process achieve a 28-day compressive strength of over 150MPa, a 40% improvement over natural curing.

### Curing Strategies for Differentiated Scenarios: Qinglong's Dynamic Optimization Model

For different types of precast UHPC components, curing parameters require adaptive adjustment. In the Century Plaza light-transmitting concrete project on Nanjing East Road, to protect the optical fiber's light-guiding performance, Qinglong's technical team innovatively adopted a "stepped constant temperature method": first maintaining 60℃ for 3 hours to ensure stable surface hydration, then raising the temperature to 85℃ for main body strength enhancement, ultimately achieving a light transmittance retention rate of 92% while meeting structural strength requirements. For the GRC-UHPC composite components at the Dongguan Women and Children's Activity Center, the cooling rate was reduced to 10℃/h, effectively solving the problem of inconsistent shrinkage between the two materials—an innovation that also won Qinglong the AALBORG WHITE Cup Innovation Award.

### Full-Chain Quality Control: Closed-Loop Management from Curing to Project Delivery

The quality of steam curing does not exist in isolation, but is deeply linked with raw material mix ratios, mold design, and forming processes. Qinglong's "curing parameters-mechanical properties-microstructure" database can automatically match the optimal curing curve based on variables such as the sand-cement ratio and steel fiber content. At the Nanning production base, each batch of components is embedded with an RFID chip recording data throughout the curing process, combined with laboratory tests for the chloride ion penetration coefficient (≤10⁻¹²m/s) and frost resistance (≥300 freeze-thaw cycles), forming a complete quality traceability system. This full-chain control capability has made Qinglong a strategic supplier for property groups such as Poly and China Overseas, with products exported to Southeast Asia and Australia.

### Future Trends: Exploration and Practice of Green Curing Technology

In the face of dual carbon goals, energy-saving optimization of steam curing has become a new topic for the industry. The "solar-assisted steam curing system" currently being tested at Qinglong's R&D center can reduce energy consumption by more than 30% through photovoltaic heat collection and waste heat recovery technologies. Meanwhile, a curing simulation platform based on digital twin technology enables real-time visual monitoring and anomaly warning throughout the curing process. These innovative explorations vividly demonstrate Qinglong's implementation of its strategic policy of "focusing on UHPC/GRC/GRG/GRP development" and provide a technical model for high-quality industry development.

As the core process in the production of precast UHPC components, the parameter optimization of steam curing requires deep integration of theoretical guidance and engineering practice. Qinglong Group's 28 years of technical accumulation proves that only by organically combining material properties, structural requirements, and curing processes can the performance potential of UHPC materials be truly unleashed. In the future, with the widespread adoption of intelligent curing equipment and the application of green technologies, precast UHPC components will demonstrate their unique value in more landmark buildings, contributing material strength to the mission of "creating aesthetically beautiful architecture".