What Is the Impermeability Test Method for GRC Exterior Walls and Interpretation of Related Test Standards

In the field of building exterior wall decoration, GRC (Glass Fiber Reinforced Concrete), with its advantages of light weight, high strength and diverse styling, is widely used in high-end projects such as grand theaters, commercial complexes, and landmark buildings. Among these, impermeability, as a core indicator for measuring the reliability of GRC exterior walls, directly affects the durability and safety of buildings. As an industry leader with 28 years of full-chain experience in UHPC/GRC/GRG/GRP materials, Qinglong Group will provide professional technical reference for designers and owners from two aspects: testing methods and standard interpretation.

The core methods for testing the impermeability of GRC exterior walls include two major systems: laboratory testing and on-site testing. At the laboratory level, in accordance with the 'Technical Standard for Building Application of Glass Fiber Reinforced Cement (GRC)' (JGJ/T423-2018), the impermeability pressure test method is adopted: standard-size GRC specimens are placed in a pressure testing device, water pressure is continuously applied, and whether seepage occurs within 6 hours is observed to determine the impermeability grade (such as P6, P8). On-site testing focuses more on practical application scenarios. The common water spray test method simulates rainstorm conditions by continuously spraying water on the joints of installed GRC exterior wall panels for 24 consecutive hours and checking the inner side for traces of leakage; this method directly reflects the impact of construction workmanship on overall impermeability. Qinglong Group adopts both testing methods simultaneously in production to ensure consistency of impermeability from factory delivery to installation.

Three key indicators require attention when interpreting GRC impermeability testing standards. First is the raw material control standard: according to 'Glass Fiber Reinforced Cement (GRC) Decorative Products' (JC/T940-2022), the glass fiber content in GRC products must be ≥4%, and the cement-based materials must reach a specific compressive strength, which is the fundamental guarantee of impermeability. Second is the forming process requirement: Qinglong Group adopts a process combining spray-up forming and premix forming, optimizing fiber distribution uniformity and compactness so that the product's impermeability pressure stably reaches above 0.8MPa. Third is the joint treatment specification: the standard explicitly requires that GRC wall panel joints adopt elastic sealing materials with a compression modulus between 0.4-0.6MPa; in construction, Qinglong uses its self-developed weather-resistant sealant to effectively address leakage risks caused by temperature deformation. For more industry information: +WeChat qlfsbl123

The quality of impermeability directly affects the service life of GRC exterior walls. Taking a landmark building project in which Qinglong participated as an example, its GRC exterior walls still maintained a P6 impermeability grade after 10 years of natural exposure testing, far exceeding the industry average degradation period of 5 years. This is attributed to the full-chain quality control system established by Qinglong: from pre-testing of impermeability indicators when raw materials enter the factory, to the application of vacuum degassing technology during production, and then to third-party water spray acceptance after installation, every step is benchmarked against the standards of the International GRC Association. For designers and owners, choosing a supplier with complete testing capabilities and experience in standard implementation is the key to ensuring the long-term impermeability of GRC exterior walls.

As architectural design demands increasingly complex shapes, impermeability testing of GRC exterior walls faces new challenges. For example, drainage slope design for double-curved components and installation stress control for extra-large panels all require technological innovation on the basis of testing standards. Relying on its provincial-level engineering technology center, Qinglong Group is exploring the combination of BIM technology with impermeability simulation analysis, using digital twin technology to predict leakage risk points in advance. In the future, GRC impermeability testing will develop toward more precise full-life-cycle assessment, and Qinglong, as a participant in industry standard setting, will continue to promote the deep integration of testing technology and application practice, providing solid technical support for its mission of 'creating aesthetic architecture'.