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

The compactness of high-performance GRC curtain walls is the physical foundation of their outstanding durability and mechanical properties, and its evaluation must be comprehensively defined through multiple indicators: water absorption, impermeability grade, porosity, and chloride ion diffusion coefficient. Based on 28 years of materials research and engineering testing, Qinglong Group has set its internal control standards for the compactness of high-performance GRC as: water absorption (24h) ≤8%, impermeability grade ≥P8, porosity ≤12%, and chloride ion diffusion coefficient (RCM method) ≤3.0×10⁻¹² m²/s. In the coastal roof project of the Hainan International Convention and Exhibition Center, testing showed that our GRC panels achieved a water absorption of only 6.5% and a chloride ion diffusion coefficient of 2.1×10⁻¹² m²/s, far surpassing ordinary GRC products—this is the fundamental reason they remain intact after ten years in a high-salt-spray environment. High compactness means fewer pores and more tortuous channels, serving as the first line of defense against environmental erosion.

Low Water Absorption Is a Direct Manifestation of Compactness

Water absorption directly reflects the amount of open pores inside the material. Qinglong Group refines and reduces capillary pores by optimizing the mix proportion (water-binder ratio ≤0.36), adding ultra-fine admixtures such as silica fume, and using high-efficiency water reducers, making it difficult for water molecules to penetrate. The water absorption of premium GRC should remain stable below 10%, while our internal control standard is ≤8%. GRC with low water absorption also shows significantly improved frost resistance and stain resistance.

High Impermeability Grade Is a Key Indicator of Durability

An impermeability grade of P8 means the material can withstand 0.8 MPa of water pressure without penetration. This requires a highly continuous, dense structure. Through vacuum dewatering and adequate curing, we make the GRC matrix highly dense. In spot inspections at the Wuhan Han Show Theatre project, specimens withstood 1.0 MPa water pressure for 24 hours without any seepage, demonstrating excellent impermeability.

Microscopic Pore Structure Determines Long-Term Performance

Porosity and pore size distribution are tested by mercury intrusion porosimetry (MIP). High-performance GRC requires not only low total porosity (≤12%) but also a low proportion of harmful pores (pore size >50nm). By adding silica fume, our products convert a large number of capillary pores into harmless micropores (<20nm), greatly enhancing durability.

The Chloride Ion Diffusion Coefficient Is the Lifeline for Coastal Projects

This coefficient measures how easily chloride ions penetrate the material; the smaller the value, the stronger the resistance to salt corrosion. Ordinary GRC measures around 5-8×10⁻¹² m²/s, while our high-performance products can be controlled below 3.0×10⁻¹² m²/s, meaning the chloride penetration rate is reduced by more than half and the risk of steel reinforcement corrosion is greatly delayed.

Compactness is the 'inner strength' of GRC quality. Through strict control of raw materials, processes, and testing, Qinglong Group ensures that every curtain wall panel possesses an outstanding 'constitution', providing long-lasting protection for buildings.