What Is the Dosage Ratio of High-Efficiency Superplasticizer in GRC? Rheology Control and Qinglong Group's Precise Proportioning Technology

The dosage of high-range water reducers in GRC must be precisely determined based on cement type, ambient temperature, and workability requirements. Qinglong Group typically controls the dosage of polycarboxylate-based high-range water reducers between 0.8% and 1.5% of the total cementitious material mass—a range that both lowers the water-cement ratio to 0.30-0.35 and ensures that the slump loss of the mix does not exceed 20% within 2 hours. Our test data show that each 0.1% increase in dosage raises the water reduction rate by approximately 4%, but dosages above 1.5% easily lead to bleeding and segregation. In the Nanning Wuxiang China Resources MixC One project, we used a precise dosage of 1.2% to keep the GRC mix at a 180mm spread even under 35°C high temperatures.

Determining the water reducer dosage requires a scientific and rigorous approach. The Qinglong Group laboratory conducts cement paste fluidity tests on each batch of cement, plotting a "dosage-fluidity" curve to identify the saturation point dosage, with actual production set at 80% of the saturation point value. We strictly select polycarboxylate-based products with a water reduction rate of ≥30%, whose compatibility with cement is verified over 28 days. For winter construction, the dosage is lowered to 0.9%-1.2%, and retarding components are added to the blend to prevent excessively rapid fluidity loss at low temperatures.

Precise dosing relies on automated equipment. Qinglong Group has introduced a German precision liquid admixture metering system with a metering accuracy of ±0.5%, using PLC control to achieve synchronized feeding with the cementitious materials. We have established a database of dosage adjustments under different temperatures and humidity levels, from which the system automatically retrieves parameters during production. In the Shenzhen Yirui Biotechnology Building project, this system ensured a high degree of consistency in GRC workability during large-volume production.

Qinglong Group advises that water reducer dosage should not be treated as an area for cost cutting. Inferior or excessive water reducers can cause surface powdering and uneven strength after hardening. We specify the water reducer brand, model, and dosage range in our supply contracts and provide third-party test reports to ensure that material performance is transparent and reliable.