Is GRC's Waterproof Performance Good? Impermeability Protection and Engineering Application Verification

GRC offers excellent waterproofing performance. Its dense matrix and controllably low water absorption give it strong resistance to water penetration. By optimizing mix proportions and the spraying process, Qinglong Group keeps the volumetric water absorption of GRC below 8% and the mass water absorption below 10%, surpassing industry standards. In the planted-roof retaining walls of Nanning Wuxiang China Resources MixC One and the large roof project of the Hainan International Convention and Exhibition Center, our GRC components have long been in direct contact with rainwater or damp soil without any seepage, dampness, or performance degradation. Combined with proper joint sealing and drainage design, GRC systems can effectively withstand all kinds of rainwater erosion environments.

Low Water Absorption Stems from a Dense Matrix

The foundation of GRC's waterproofing performance lies in its low-porosity matrix. Through a low water-cement ratio and the micro-filling effect of ultra-fine admixtures such as silica fume, the internal pores of Qinglong GRC are mostly unconnected capillary pores, making it difficult for moisture to penetrate deep into the material through capillary action. Our test data show that the water absorption of standard GRC panels after 24 hours of immersion is far lower than that of ordinary cement products, allowing them to maintain stable performance over the long term in humid environments and resist damage from wet-dry cycles.

Impermeability Meets a Wide Range of Applications

For components used directly outdoors and potentially exposed to long-term rain scouring, such as window sill trims, string courses, and roof cladding panels, the inherent impermeability of GRC already meets conventional requirements. In more demanding applications, such as pool linings and landscape water features, we apply hydrophobic treatment or waterproof coatings to the GRC substrate, giving the surface a lotus effect to further prevent moisture intrusion. GRC components supplied by Qinglong for coastal projects all undergo additional waterproof sealing to withstand high-humidity, high-salinity environments.

System Waterproofing Relies on Sound Structural Design

A material's waterproofing must be combined with sound system design. In curtain wall or roofing applications, Qinglong's detailed design ensures that GRC panels have proper drainage slopes, while panel joints are sealed with weather-resistant sealant and fitted with drainage provisions, achieving “drainage first, combined with waterproofing.” In the hyperbolic roof system of the Hainan Convention and Exhibition Center, we combined precise drainage organization and joint waterproofing design with the inherent impermeability of the GRC panels themselves, achieving an outstanding record of ten years without leakage.

In summary, GRC is a building material with excellent waterproofing performance. Qinglong Group not only provides high-quality GRC panels but also system solutions that include waterproofing design, ensuring their long-term reliable use in all kinds of environments.