How to Set Steam Curing Parameters for Precast UHPC Components? Curing Process and Qinglong Group's Intelligent Temperature Control System

Steam curing is the key process for UHPC to achieve early high strength and low shrinkage. Its parameter settings must follow three major principles: "slow heating, sufficient constant temperature, gradual cooling," specifically including four-dimensional control of temperature (60-90°C), time (12-48h), humidity (≥95%), and heating/cooling rate (≤15°C/h). Based on 28 years of UHPC production data and laboratory research, Qinglong Group has developed optimized curing curves for different components: standard panels use 80°C×24h curing, reaching strength above 50MPa in 1 day; thick and large components use stepped heating (60°C×6h→80°C×18h) to avoid thermal cracking; ultra-thin components (thickness<15mm) use low-temperature, long-duration curing (70°C×36h) to reduce deformation. In the production of 120,000 square meters of roof panels for the Hainan International Convention and Exhibition Center, our intelligent curing system (temperature control ±2°C) kept the strength variation coefficient within 5%, with component flatness error ≤2mm/2m. Scientific curing is the "catalyst" for unleashing UHPC's performance potential.

Temperature and Time Settings Must Be Tailored to Each Component

Curing temperature affects the hydration rate; 24 hours of hydration at 80°C is equivalent to the strength of 7 days of standard curing at 20°C. Through testing, Qinglong Group determined the optimal temperatures: 80°C for C50-grade UHPC and 90°C for C80 and above; when component thickness exceeds 100mm, the constant-temperature period is extended to 36h to ensure full hydration of the core. In curing the red double-curved panels for the Wuhan Han Show Theatre, we adopted an 82°C×26h curve, ensuring uniform strength development and no color variation.

Humidity Control and Heating/Cooling Rates Are the Guarantee of Quality

Humidity below 90% causes surface water loss and cracking; Qinglong curing chambers are equipped with built-in steam nozzles to maintain humidity ≥98%. Excessive heating/cooling rates generate thermal stress; we control the rate at ≤10°C/h, reduced to 5°C/h for thick components. In the thin panel curing for the Shenzhen Yirui project, program-controlled heating at a rate of 8°C/h resulted in zero cracks in the finished products.

Intelligent Monitoring System Enables Precise Execution

Qinglong Group introduced an intelligent curing system from Germany, with 12 temperature sensors arranged in each chamber and data uploaded in real time to the MES system. The system automatically adjusts valve openings to ensure a uniform temperature field (temperature difference ≤3°C). Production data is fully traceable, generating a "curing ID card" for each batch of components.

Steam curing is not simple heating—it is precise control of chemical reactions. Through 28 years of data accumulation, Qinglong Group customizes the optimal curing plan for each UHPC component to ensure maximum performance.