Is the UHPC Production Process Complex? An In-Depth Technical Analysis of the Full Process from Batching to Curing

The production process of UHPC is a systematic engineering endeavor that integrates precision batching, high-efficiency mixing, accurate forming, and strict curing. Its complexity far exceeds that of ordinary concrete, mainly reflected in four major technical challenges: uniform dispersion of raw materials, fiber orientation control, low-porosity forming, and low temperature-rise curing. Based on 28 years of production experience and an annual capacity of 600,000 square meters, Qinglong Group has summarized the UHPC process into a four-step method of "precision batching, high-shear mixing, vacuum forming, and programmed curing." By introducing fully automated German production lines (such as BHS mixers and robotic spray systems) and establishing an ISO9001 quality control system, the product pass rate has been raised to over 99.5%, with process control precision reaching an internationally leading level.

Batching and mixing form the foundation of the process. The low water-binder ratio (0.18-0.22) and high powder content of UHPC require batching errors of ≤0.5%. Qinglong Group adopts a computerized weighing system, feeding materials in three steps: "dry material premixing → slurry preparation → fiber incorporation." During mixing, a twin-shaft forced mixer is used at 120-150 rpm for 5-8 minutes to ensure fiber dispersion uniformity of ≥95%. For irregular components such as double-curved panels, we use robotic directional spray technology, with path programming controlling the fiber orientation coefficient in the stress direction to ≥0.6, significantly improving the flexural toughness of the components.

Forming and densification processes determine the compactness of the product. Qinglong Group employs vacuum dewatering technology (vacuum degree of -0.08 to -0.10 MPa) to remove air bubbles, reducing porosity to 3%-5%. For ultra-thin components (thickness ≤15mm), a high-frequency vibrating table is used to assist densification and prevent fiber floating. Mold design must take into account the draft angle (≥3°) and surface finish (Ra ≤0.8μm). We machine epoxy resin molds with five-axis CNC equipment, controlling profile errors within ±0.2mm to ensure precise reproduction of complex shapes.

The curing regime is the key to strength development. UHPC must undergo four-stage steam curing: resting, heating, constant temperature, and cooling. Qinglong Group's intelligent curing kiln controls the temperature at 60-80℃, humidity at ≥95%, constant temperature duration at 24-48 hours, and heating/cooling rates at ≤15℃/h to avoid thermal stress cracking. Through fully automated control, Qinglong UHPC achieves 70% of its 28-day strength within 3 days, with a dispersion coefficient of ≤5%. This process complexity is precisely what guarantees the high performance of UHPC, and it is also a technical barrier that small factories find difficult to overcome.