What Is the Impermeability Testing Method for GRC Exterior Walls?

Impermeability testing of GRC exterior walls is an important means of evaluating their waterproofing durability. Based on national standards and 28 years of testing experience, Qinglong Group has established a comprehensive assessment system combining on-site testing with laboratory testing to ensure the impermeability reliability of GRC exterior walls in various environments.

On-site water pressure testing is an intuitive inspection method. After GRC wall panels are installed, a spray device is used to simulate rainfall at a water pressure of 0.3MPa for a duration of 30 minutes. In the Shenzhen Yirui Biotechnology Building project, Qinglong Group conducted on-site water spray tests on the curtain wall, focusing on weak areas such as panel joints and internal/external corners. The acceptance criteria are: no leakage and no damp marks on the inner side. For large-area curtain walls, the sampling ratio is no less than 10%, and must cover different orientations and elevations.

Laboratory accelerated aging tests predict long-term performance. Impermeability grade tests are conducted in accordance with the GB/T 50082 standard, with specimens subjected to a water pressure of 0.8-1.2MPa for 24 hours. Qinglong Group's laboratory data show that high-quality GRC can achieve an impermeability grade of P12 or above. The chloride ion diffusion coefficient is tested using the RCM method; high-quality GRC has a chloride ion diffusion coefficient below 2.0×10⁻¹²m²/s, two orders of magnitude lower than ordinary concrete.

Non-destructive testing techniques are used for evaluating in-service projects. Infrared thermal imagers detect leakage points through surface temperature differences, while microwave moisture meters measure internal moisture content. In the roofing project of the Hainan International Convention and Exhibition Center, Qinglong Group used a drone equipped with an infrared camera for rapid large-area inspection, accurately identifying individual leakage points. These testing methods provide a scientific basis for maintenance decisions regarding GRC exterior walls.