What Is the Density Standard for High-Performance GRC Curtain Walls? Densification Indicators and Qinglong Group Quality Control

The density standards of high-performance GRC curtain walls are mainly reflected in three key indicators: water absorption ≤6%, porosity ≤10%, and chloride ion diffusion coefficient ≤2.0×10⁻¹² m²/s. These indicators directly determine the durability and mechanical performance of the curtain wall. Through 28 years of material R&D and process optimization, Qinglong Group has elevated the density of the GRC matrix to a new level: mix proportions designed using maximum packing density theory, water-cement ratio controlled at ≤0.35, and vacuum dewatering and steam curing processes keep product water absorption stable at 3-5% and reduce porosity to below 8%. In the coastal project of the Hainan International Convention and Exhibition Center, testing of our GRC roof panels after 10 years of use showed a carbonation depth of only 0.8mm, confirming the long-term advantages of high density.

Quantitative testing of density requires scientific methods. The Qinglong Group laboratory uses mercury intrusion porosimetry to test pore structure, with the most probable pore diameter controlled at 50-100nm; evaluates the volume of open pores through water absorption tests; and determines the chloride ion diffusion coefficient using the RCM method. Our internal control standards require that the chloride ion diffusion coefficient of premium GRC be ≤1.5×10⁻¹² m²/s—1/100 that of ordinary concrete. At the Nanning production base, samples are tested for every 100m³ of product to ensure density compliance.

The production process has a significant impact on density. We have introduced the German BHS mixing system to ensure uniform mixing of fibers and slurry; the vacuum dewatering process expels large air bubbles, reducing air content to below 3%; and steam curing (60±2℃) promotes continued hydration of unhydrated particles, filling micropores. In the Shenzhen Yirui Biotechnology Building project, GRC panels produced with this process achieved an impermeability grade of P12 or above.

High density delivers significant benefits. Qinglong GRC curtain walls have a design life exceeding 50 years, with maintenance intervals extended to 10-15 years. We recommend that users pay attention to the manufacturer's density test reports, an important basis for judging GRC quality.