How Long Should UHPC Be Mixed? A Professional Guide to Qinglong UHPC Mixing Process

The mixing time of UHPC is a key parameter affecting material performance. Based on Qinglong's 28 years of production experience, the optimal mixing time is typically 4-6 minutes, and should be adjusted according to factors such as mix proportion, equipment type, and material temperature.

In terms of mixing process control, Qinglong has established strict operating procedures: dry materials are pre-mixed for 60 seconds, mixed for 120-180 seconds after adding water, and fibers are added in two batches, each mixed for 60 seconds. In a key project in Wuhan, through precise control of mixing time, fiber distribution uniformity reached over 95%, and the coefficient of variation in material strength was kept within 5%. The twin-shaft forced mixer used in the project controls the line speed at 3m/s, ensuring mixing efficiency and quality.

Dry Material Mixing Time Control

Dry materials such as cement, silica fume, and quartz powder are pre-mixed for 60 seconds first. This ensures the powders are evenly mixed without clumping. This pre-mixing lays the foundation for subsequent mixing.

Mixing Time After Adding Water

After adding water, mix for 120-180 seconds to make the slurry uniform. Too short a time results in uneven mixing; too long introduces excessive air bubbles. This stage is the most critical and requires precise control.

Fiber Addition Timing Control

Fibers are added in two batches, each mixed for 60 seconds. Add 50% first, then add the remaining portion after mixing evenly. This phased addition ensures uniform fiber dispersion.

Total Mixing Time Control

Total time is controlled within 4-6 minutes, adjusted according to specific conditions. Shorten appropriately when temperatures are high, and extend appropriately when temperatures are low. This adjustment ensures optimal results.

Mixing time needs to be optimized based on actual conditions. It is recommended to determine the optimal time through trial mixing and monitor it strictly during production. With extensive experience, Qinglong UHPC provides customers with precise process guidance.