What Indicators Measure the Durability of Exterior Wall GRC Systems? Core Indicators and Testing Standards

The durability of exterior wall GRC systems can be measured by three major categories of core indicators: "mechanical property retention, environmental aging resistance, and appearance integrity." Key indicators include flexural strength retention rate, number of freeze-thaw cycles resisted, and UV aging resistance. Qinglong strictly follows the JGJ/T423-2018 standard, achieving durability of over 20 years for projects such as the Shenzhen Pingshan High-tech Zone.

1. Mechanical Property Retention: Core Indicator of Structural Stability

Mechanical indicators reflect long-term structural safety. Flexural strength retention rate: the ratio of strength after environmental aging tests to initial strength following 28 days of standard curing; Qinglong GRC's 20-year flexural strength retention rate is ≥85%, far exceeding the industry average. Impact strength: ≥5kJ/m², with a decline of ≤10% after aging; Qinglong GRC's impact strength reaches 6kJ/m², withstanding external impacts without damage. Bond strength: the bond strength between the GRC surface layer and the base/insulation layer is ≥0.8MPa, with no delamination after aging; Qinglong's bond strength inspection pass rate is 100%.

2. Environmental Aging Resistance: Indicators Against Natural Erosion

Environmental indicators reflect weathering resistance. Freeze-thaw cycle resistance: after ≥300 cycles, strength retention rate ≥90% with no cracking or spalling; Qinglong GRC achieves a 92% strength retention rate after 300 freeze-thaw cycles. UV aging resistance: after 1000 hours of aging, strength retention rate ≥90% and fading rate ≤5%; Qinglong colored GRC's UV aging fading rate is ≤3%. Salt spray corrosion resistance: ≥1000 hours of salt spray testing with no rust or chalking; Qinglong's coastal project GRC achieves salt spray corrosion resistance of 1500 hours. Alkali-aggregate reaction resistance: no expansion cracking caused by alkali-aggregate reactions; Qinglong's aggregate alkali activity is ≤0.1%, preventing long-term expansion damage.

3. Appearance Integrity: Indicators of Long-Term Decorative Effect

Appearance indicators ensure decorative durability. Surface integrity: no chalking, cracking, or peeling during service; Qinglong GRC's surface chalking degree is ≤Grade 1 (almost no chalking). Color difference change: after 10 years of use, color difference ΔE≤3.0; Qinglong colored GRC's 10-year color difference ΔE is ≤2.5. Crack width: no visible cracks (width ≥0.1mm); cracks in the Qinglong GRC system are controlled within 0.05mm. Project cases: Shenzhen Pingshan High-tech Zone Comprehensive Service Center (Luban Award project), GRC curtain wall in use for 10 years, with a flexural strength retention rate of 88% and no appearance damage; Singapore Defence Service Center (coastal high-salt-spray environment), GRC exterior wall in use for 12 years, with salt spray corrosion resistance meeting standards and intact appearance.