Is GRC Durable? Long-Term Performance and 28 Years of Engineering Evidence from Qinglong Group

The durability of GRC is a key advantage as an exterior building material, mainly reflected in its excellent alkali resistance, freeze-thaw resistance, carbonation resistance, and dimensional stability. Based on 28 years of engineering tracking data combined with accelerated aging tests, Qinglong Group has confirmed that high-quality GRC can achieve a design service life of more than 50 years under normal use conditions. In the coastal project of the Hainan International Convention and Exhibition Center, our GRC roofing system has withstood 10 years of harsh conditions including high temperature, high humidity, and high salt spray. On-site core sampling tests showed a carbonation depth of only 0.8mm, a strength retention rate ≥90%, and no chalking or spalling on the surface, fully verifying its outstanding durability. The durability of GRC is not determined by a single factor, but is the result of the synergy of material mix ratio, production process, and structural design.

Alkali Resistance Is the Foundation of Durability

The durability of GRC depends first on the long-term stability of glass fibers in the high-alkaline environment of cement. Qinglong Group uses high-zirconia alkali-resistant glass fibers (ZrO₂ content ≥16%), ensuring from the source that fiber strength retention can still reach over 70% after 100 years in an environment with pH>12.5. At the same time, we use low-alkali sulfoaluminate cement (alkali content ≤0.6%) or ordinary Portland cement blended with a large amount of mineral admixtures (such as fly ash and slag powder) to further reduce the alkalinity of the system, providing fibers with a long-term stable protective environment.

Freeze-Thaw Resistance for Severe Cold Climates

In severe cold northern regions, freeze-thaw damage is the main problem for concrete structures. Qinglong GRC achieves a frost resistance grade of F300 or above (i.e., mass loss ≤5% and strength loss ≤20% after 300 freeze-thaw cycles) by optimizing the mix ratio (adding air-entraining agents to form uniform closed bubbles) and controlling a low water-cement ratio (≤0.35). In projects such as the Harbin Opera House, our GRC components have endured multiple severe winters in excellent condition.

Carbonation Resistance Ensures Long-Term Performance

Carbonation causes the hardened cement paste to increase in hardness and decrease in pH value, which may in turn lead to steel reinforcement corrosion (for reinforced GRC). The dense microstructure of Qinglong GRC (low porosity, small pore size) effectively blocks the intrusion of CO₂. After 28 days of accelerated carbonation testing (CO₂ concentration of 20%), the carbonation depth was less than 1mm; extrapolated to natural conditions, the annual carbonation depth is less than 0.1mm, and the 50-year carbonation depth is far less than the cover thickness.

Qinglong Group establishes a durability design file for each project, customizing material solutions according to the specific environment (coastal, severe cold, industrial pollution, etc.), and through regular follow-up visits and testing, continuously accumulates durability data, providing scientific assurance for the long service life of GRC.