What Indicators Can Measure the Durability of Exterior Wall GRC Systems? A Full Life-Cycle Performance Evaluation System

The durability of exterior wall GRC systems is a comprehensive concept that must be predicted and evaluated through a scientific system of quantitative indicators, rather than summarized by a single data point. Based on 28 years of long-term performance tracking data and research, Qinglong Group has established an evaluation system covering three dimensions: "material durability", "structural durability", and "appearance retention". This system not only focuses on laboratory accelerated aging data, but also places great emphasis on tracking feedback from actual projects spanning more than ten years, aiming to precisely predict the performance evolution of the system throughout its entire life cycle.

The core quantitative indicators of material durability include: carbonation resistance (average annual carbonation depth ≤0.1mm), chloride ion penetration resistance (electric flux method ≤1000 coulombs), freeze-thaw resistance (strength loss rate ≤15% after 300 freeze-thaw cycles, mass loss rate ≤5%), and the strength retention rate of alkali-resistant glass fiber (≥80% after 28 days of immersion in saturated Ca(OH)₂ solution at 80°C). For example, the GRC we supplied for a project in Hainan showed a chloride ion migration coefficient as low as 1.2×10⁻¹² m²/s after its 28-day specimens were immersed in 3.5% NaCl solution for 180 days, indicating an extremely long service life in marine environments.

Structural durability is verified through systematic testing. This includes dynamic water tightness testing (no leakage after 15 minutes of continuous spraying under fluctuating wind pressure), wind pressure deformation resistance testing (residual deformation not exceeding L/300 under 1.5 times the design wind pressure, where L is the support spacing), and seismic pseudo-static testing (the connection system remains effective under the simulated fortification intensity). All curtain wall systems of Qinglong Group must pass the full set of laboratory tests above and obtain the corresponding certifications. In addition, the salt spray test duration of metal connectors (e.g., hot-dip galvanized parts must reach 1000 hours) is also a key indicator.

Appearance retention is the most intuitive perception for owners, and its measurement indicators include: color difference change (ΔE ≤3.0 after 5000 hours of xenon lamp aging), gloss retention rate (≥70%), and surface contamination grade (grade 0-5, with grade 0 being the best). Through regular follow-up visits and image analysis technology, we have established an appearance performance database of numerous engineering cases. For example, a building in Shenzhen that has been in use for more than 10 years has a GRC curtain wall with an average color difference ΔE of only 1.8, and its surface shows no visible cracks or efflorescence, demonstrating the system's excellent long-term durability. This multi-dimensional indicator system provides a solid basis for scientifically evaluating and improving the durability of GRC exterior wall systems.